GEOLOGICAL AND METALLOGENIC RECONNAISSANCE OF SOUTH OF MANBIJA

GEOMINES

1. INTRODUCTION

1.1. OBJECT OF THE PROJECT AND USED METHODS

The purpose of the project consists of elaborating a detailed geological map (1: 2000) of a region of 632 hectares or rather 6.32 km² located immediately to the South of the auriferous zone of Nambija, on current development. With this purpose, an equipment composed by two geologists and a topographer, and complementing afterwards with a geophysical, they have stayed during 10 weeks in the area of the project, from May 22 to October 1st, 1987. The maps and the final report have been elaborated in the offices of Geomines Ltee in Montreal, Quebec, Canada.

In first term, it has been proceed to effect a topographic raising to scale 1:2000 of the creeks and paths using compass and cord. Then, the geological map simultaneously has been elaborated. they have been taken superficial rock samples and sediments of the rivers using bats. These samples have been after mashed and analyzed in laboratories by 36 elements. Of the same way, they have been developed geophysical explorations by magnetometric and electromagnetic (VLF) on a mesh NS - EW with exploration lines that have 16 km of length.

Also, it has been effected a geological recognition to scale 1:5000 with takes simultaneous samples of bat rock, in a region of some 18 km2 located to the South and to the East of the maping region to the detail.

1.2 LOCATION AND ACCESS

Nambija is located in Southeast of the Ecuador, at 20 km to the East of Zamora, capital of the province of Zamora Chinchipe, and 420 km to the South of Quito.

The first section of the route to Nambija is from Quito to Loja. In this first section can be traveled by plane from Quito to La Toma (airport of Loja) in a flight that take approximately an hour or in car, in a trip that delay 18 hours, by asserted highway. From Loja part a second category route to Zamora, whose normal tour delay two hours and a half, but the frequent landslides that produce in this route can cause serious arrears. From Zamora the route continues to Namírez, place to where is arrived after a trip of an hour. In Namírez is necessary to cross the river Zamora, either in boat, if the level of the water is not too high, or using a peatonal pendulous bridge. The trip continues then in car or bus by an additional hour until Cumay Alto (locally called San Carlos), place where it can be rented mules to rise to Nambija in a trip of three hours and a half, duration by a horse-shoe road in wrong state.

1.3. TOPOGRAPHIC AND CLIMATE

The region in study is located in the mountain chain of Nanguipa that form part of the buttresses of the Eastern mountain chain of the Andes. The relief is very injured, with altitudes that vary between 1400 and 2400 msnm. The area is characterized by the numerous defects presence and scars let by the landslides.

The drainage system of the region is certified by the tributaries of the Quebrada del Fierro. The waters of this gaps empty successively in the rivers Nambija, Zamora, Santiago, Marañon and Amazon and finally in the Atlantic Ocean. The climatological information is extremely limited.

The climate is tropical wet. The temperature oscillates between 7°C in the evening and 20°C in the day, but exceptionally it can reach 30°C. The region is frequently covered of fog and the rainfall surpasses 3000 mm by year, what has hindered much the advance of the field projects.

In September has been observed a certain truce in the rainfalls that possibly will be extended until December.

The vegetation is of the type florets pluvial equatorial and therefore very dense, to such point that it is necessary to use machetes to open path. The rock outcrops better exposed are found in the creeks, that constitute at the same time the improvements access process.

1.4. LOGÍSTIC

The communications are difficult in Nambija. The only one transmitting radio station - receiving of the place is found in the branch of the Central Bank for internal use. Within little time, the bank will be equipped also with a telephone operated at micro - waves. Concerning the public facilities, the IETEL of Zamora offers international telegraphic and telephonic services but it does not have telex.

The most next Airport is La Toma, near to Loja, that gives services in regulars flights to Guayaquil and to Quito. Exist also a runway and a military heliport in Cumbaratza. In Nambija, there is a heliport located in the facilities of the Central Bank.

Also, it is possible to rent pickup trucks without difficulty, taxi to Loja and to the airport La Toma, the same as to Zamora. Insofar as the provisions, the basic products can be acquired in Nambija, but the variety is limited. The available water in Nambija has a high risk of be contaminated, so that in the present campaign the personnel has been provisioned of spring water, considerated pure, that buds in the South flank of Mapasingue.

In Nambija is difficult to find a housing adapted to stay by long time. Therefore, it should be to consider the need of building a base camp. Because of the climate, the type of construction more common is of wood, up with respect to the natural surface and with zinc roof. The wood in plates can be acquired of the local rafters but the zinc must be bought in other place. Taking into account to the temperature descends

by the nights, it will be very useful to have any type of heater (to kerosene for example).

In the place is found kerosene, oil diesel, gasoline and also gas balls. Electricity can be acquired of some proprietary of stamp mills equipped with electrical generators.

Also, in the area is possible to find hand of work not qualified: guides - cutters, carrying, pawns, etc. The availability of this labor fluctuates of agreement at the rate of the mining production.

1.5 HISTORY AND METHODS OF EXPLORATION

The development of the gold in the region date of the pre-Columbian era. To mid of the XVI Century, the Spanish continued the development using the indigenous labor, but around the end of this century the diseases and the social instability caused to the close of the mining activity in the region.

It is recently the beginning of the present decade that the deposit of Nambija was rediscovered for the gold seekers that were soaring the creeks washing the sediments by batting. At the beginning, the development were made discreetly, but the secret could not be kept by far time and the region was quickly invaded by thousands of persons contaminated by the fever of the gold. According to our estimates, to the moment of elaborating this report, the population of Nambija is between 7 and 10 thousand inhabitants.

Regrettably, the deposit is being exploited of inefficient and chaotic way. Many small mining their dig where better galleries seem, without planning and without taking into account the most elemental safety rules.

To trigger the driller hammers are used compressors activated by diesel motors. Once the drills are punctured, they are put dynamite charges and is flown the rock. After is separated visually the sterile fraction from the mineralized fraction that is transported immediately by the shoulder to one of the numerous windmills of stamping where the rock is mashed in water presence.

The product of the grinding is gone through a wash channel in order to separating the heavy fraction. Immediately, this last fraction is washed in mercury presence to obtain finally a ball from amalgam from mercury - gold that then is burnt to the blowpipe to make to boil the mercury and to obtain relatively pure gold. After, this product is transported to the local branch of the Central Bank that buys the metal after have been molten and heavy.

1.6 GRATEFULNESS

The authors wish to thank to the Central Bank of the Ecuador by the price help that has provided, in particular, to the Chief of the Marketing Department of the Gold in Quito, Lcdo. Oswaldo Hernández, and to the managers of the branch of Nambija, Lcdo. Galo Román, Lcdo. Fausto Andrade and Lcdo. Baltasar Guaruizo.

Our permanency in Nambija has been more agreeable thanks to your hospitality, his experience with respect to the local conditions and your logistics assistance, without speaking of the banking services.

In Zamora, we want to thank to Mr. Magner Turner and his equipment by the borrowed logistical services and by the visit to the mine of Guaysimi.

Two teachers of the University of Quebec in Montreal, Dr. Michel Gauthier and Dr. Michel Jebrak, they have encouraged us much with theis stimulant discussions on the nature of the deposit.

We thank also to Dr. Robert Wares (Ph.D.), they specialized in skarns that it has contributed largely in the elaboration of the chapter "Metallogenic" already to Mrs. Anne Charland (M.SC.) that has participated with their knowledge of volcanic rocks, both of the University McGill in Montreal.

In the University of Laval in Quebec, we want to thank to Dr. Réjean Hébert (Ph.D.) and to Mrs. Sylvie Roy (M.SC.) by their petrographic descriptions, as well as to Dr. Robert Ledoux (Ph.D.) by their appreciated concerning advice to the heavy minerals.

We thank, also, to all the equipment of the INEMIN of the Ecuador, whose countless services would certify a vast list. Furthermore, we thank also to the Ing. Edgar Pillajo, who has elaborated the cartography of the vertex NE of the map B.

We are particularly recognized by the services of the Eng. Ivan Endara, Director of the Laboratory of Chillogallo, and Dr. Ahmed Mahmood, belonging to the regional office of Geomines in Rouyn-Noranda (Quebec), by the execution of the petrographic studies.

We thank to the field brigade certified by Mr. Marc Chénier - geologist project chief, Mrs. Sylvie Prud'homme - geologist, Mr. Albert Bastien - technical - topographer - drawing, Mr. Jan Stembera - geophysical, and Mr. Arturo Cabrera - assistant of field and logistical support in Ecuador.

At the end, thank you very much to all the auxiliary personnel so much in Ecuador as the Central headquarters of Géomines in Montréal, Canada.

2. GENERAL GEOLOGY

Exist two recent geological maps, to scale 1:1.000.000. that they cover the Republic of Ecuador. One of them has been published by the DGGM and the French Institute of Oil, in 1969, and the gold by the DGGM and the Geological Sciences Institute, in 1982. The present chapter is widely based on this last and in the explanatory bulletin that accompanies it.

Ecuador is split into three geological provinces that correspond approximately at three regions phisiographycs. These three regions are, from West to East: The Coast, the Sierra split into two mountain chains separated by the Interandino Valley in the North of the country and the East separated in two regions: the subandina zone and the Eastern Basin (Figure 3)

The basement of the coast is constituted by basaltics toleitics rocks of the Cretacic, that would constitute a portion of the Oceanic bark welded to the continent. These rocks are recovered of detritics sediments of the Cretacic Sup. and of the Terciary.

The Western mountain chain is composed by basaltic volcanic rocks of the Cretacic (equivalent to those of the Coast), recovers of andesitics and of piroclastics lavas of the Terciary and of the Quaternary. The Real mountain chain (or Eastern), on the contrary it is formed by a whole slew of metamorphics rocks (esquists to mica) of the Paleozoic. The rut intra -Andean, that separates the two mountain chains in north half of the country, it is a depression whose exact nature is not known due to the fact that the contacts are covered by the volcanics recent.

A great fault of cabalgamiento separates the Sierra from the East, where is found in first term the subandina zone structurally separate, but stratigraphicmently forming part of the properly such Eastern Basin located more to the East. This basin is composed of sedimentary rocks deposited in three phases on the precambrics rocks of the Shield Guyano-Brasilian. First, the marine sedimentary of the Paleozoic and of the low Mesozoic (Formations Pumbuiza, Macuma, Santiago and Chapiza), phase ended by the volcanism (member Misahuallí of the Formation Chapiza). Then, the marine sediments deposition geosinclinales of the Cretacic Superior (Fm. Hollín, Napo and Tena regrouped also under the training name Lemon). The end of the Cretacic brand the origin of the Andean orogenismo that is characterized by a classic sedimentation originating from the West.

The subandian zone has been distorted in the Terciary Superior. The fault that defines the West limit of the subandian zone and their contact with the Real mountain chain is labeled by the presence of a series of batholith granitic of the Jurassic (?), probably displaced by the tectonic associated with raising of the proto -mountain chain (end of the Cretic). The volcanic rocks and subvolcanics associated with certain batholiths, as the batolite of Abitagua and included in the miembre Misahuallí of the Chapiza Formation, they could represent a late phase of that same plutonic (evidence of comagmátic origin). By extension, this theory would be related perhaps also to home volcanic rocks observed within the limits of the Batholith of Zamora, in the area object of the present study. In addition to rocks plutonics granitics, they have been mapping, very about this region, sedimentary rocks of the Santiago and Chapiza Formations to the North and to the South and possibly to the East

(Feininger, 1987), the same as sediments more youths of the Lemon Formation (to the North).

Feininger (1987) proposes a theory according to the one which Ecuador would be split into five "lands" allotóctonosos, between those which is found the "Santiago Terrane" that understands the South half so much of the Real mountain chain as the of subandian zone (including the Batholith of Zamora), zone characterized by the exclusive presence of the Santiago Formation that would be absent in the other areas.

Santamaría et all. (1983) and Pillajo (1983) have effected projects in the region of Nambija (photogeologyc maps and general recognition visits). Both identify a sedimentary and volcanic rocks zone to the inferior of the batholith, zone that would have been in part skarnificated. The auriferous deposit of Nambija is found within this zone.

3. GENERAL GEOLOGY

3.1 LITOLOGIC DESCRIPTIONS

3.1.1 GENERALITIES

In the framework of the present work have been carried out two geological raisings. The first, to scale 1:2000, it has covered a zone of 6 km2 located immediately to the South of the deposit of Nambija on current development. To the East and to the South of this detailed zone, was effected a mapping of recognition level, to scale 1:5000, that covers a total surface of 18 km2 .

During the development of these raisings were described about 700 outcropss and the litological and structural information obtained were registered on the respective topographic maps. In order to determine the nature of the litological units found, very affected locally by hydrothermal alteration, and to specify the nature of the auriferous mineralization, they have been studied 180 sample thin plates and 56

thin polish plates with the intervention of five specialists in petrography. All the samples originate of the zone of 18 km2, 29 that they were taken within sector of the mine of Guaysimi. The conclusions of these petrographic studies form part of the description of the different litological units and of the chapter "Metallogenic".

The region of Nambija is little known geolgically, the few existing maps are very general and they have been elaborated for the most part by photogeological interpretation. This region located to the South of the Ecuador, in the subandian zone, it is a characterized by the sediments presence and volcanic of age Paleozoic to Mesozoic cut by batholiths of composition between tonalitic and granodiorític of Jurassic age (?). The zone is tectonicly active and constitutes a strongly ridden waist that is displaced currently to the East.

The estratigraphy of this zone is relatively well known in the North and in the central part of the country, largely thanks to the oil exploration projects. On the contrary, in the South of the country, to the East of Zamora, the place is not very documented and, according to certain recent projects (Feininger , 1987), would seem that the estratigraphy and the tectonic evolution in this place would have been different with relation to the North parth.

Consequently, even though the rocks observed in these raisings seem to belong to the training Santiago (Jurassic - Superior), lack geological data to regional and local scale in the region of Nambija, so that the restricted surface of the studied zone does not permit to establish estratigraphic correlations in the present study. Furthermore, the relationships between the different litological units found not always they can be clearly established in reason to the numerous defects that cut all the considerated zone.

During the mapping, we have attempted of regrouping the studied rocks by phases recognizable on the area, that is to say, in lithologics maps. In general way, is found a sequence volcanic - sedimentary that houses to the auriferous mineralizations, forming a band of some kilometers of broad in the bosom of a batholith of granodiorític composition . This band volcanic - sedimentary seems be extended by

several kilometes according to direction N-S and it is limited from East to the West by probably normal defects.

The sequence is constituted by proplastici rocks ( volcanic gap, block tuffs and lapillis, crystal tuffs) between those which are intercalated thin horizons of calcareous (sands and calcareous shales) metasomatcs in skarns and associated with the auriferous mineralizations. All these materials are cut by dikes and by small stocks of diorite, of apilitc and of subvolcanic rocks of composition as same as the strusive rocks also volcanitcs (basalt alkaline) and late dolerites in the defects and shear zones.

3.1.2INTRUSIVE ROCKS

3.1.2.1 Granodioritic (G and G1)

This litological units, probably located in the lower part of the stratigráfic sequence of the studied zone, is found in the edges East and West of the mapping surface, constituting in fact a batholith that is extended throughout several kilómeters within the region. In the considerate place, this unit is cut by numerous defects that they have given cause for a collapse structure within the one which has been deposited thereinafter a sequence volcanic – sedimentary.

The unit that is all right characterized in the outcrops and it can or not to present alterations. The rock is of pink color, gray and white with small black stains caused by the crystals of hornblende. The texture is generally mean and equigranular. In the eastern part of the mapping zone, in the region of the river Guaysimi, is observed a facies of phenocrysts of hornblende with middle size that varies between 5 mm and 1cm.

Locally, the granodioritc can contain intrusive fine material enclaves of obscure gray color and of variable diameter between 2 and 10cm. It is equally certain note composition zones more potassic than confer to the rock a most reddish color.

At petrographic level, the granodiorite is mainly composed by waved extinction quartz, of plagioclase (oligoclasas-andesina) and of pheldespatos potassics kaolinizeds and sericitizeds, of hornblende and of small quantities of biotite with alteration in chlorite and of traces of disseminated opaque minerals (mainly pyrite). It is observed equally trace of apatite and of zircón as incorporation in the plagioclase, as well as esfene. The epidote, under the form of prismatic crystals, is found in the form of incorporation in the plagioclases pheldspars, replacing to the hornblende and in the form of veins. Finally, they are found secondary carbonatics altering the plagioclases and the hornblende.

3.1.2.2 Tonalite-diorite (T)

The second intrusive important unit of the region seems to cut the granodioritic. its composition, though locally tonalite, it is mainly diorite. It is frequently found in the granodiorite in the edges of the e mapping zone in touch of defect with the volcanitcs according to the direction NS. It is note also the presence of some dikes as well as of a small stock in intrusion within the volcancs in the central part of the region (Bankrupt #15). In this place, the diorite is cut by numerous defects and the intrusion contacts with the volcanic that surrounds it seem labeled by defects.

The rock is of fine texture, (1 mm), equigranular, of clear gray color to gray middle, locally cut by pink veins of potassic alteration. In the eastern part of the region, are observed locally outcrops of granitic thoroughly pink inside of this unit.

The rock is composed mainly of pheldespar potassics and of plagioclase kaolinized, sericitized and epidotized, of waved extinction quartz, and of hornblende and altered biotite in chlorite. It is note also intersiticial secondary calcite in the plagioclase and the hornblenda, as well as in the form of veins. They are equally present the opaque minerals. In a sample (#1101), is observed a "stockwork" of veins of pyrite, pirrotine and calcopyrite, with impregnations of magnetite associated with the alterations in epidote-chlorite.

The dikes observed in the region can be microdiorítics, of whitish color, sericitized, with the mafics minerals thoroughly altered.

In the center of the region, in the Bankrupt #11, are noted dikes with epidote, clinozoisite and tremolite-ferro -actinote. A little more to the East, in the Bankrupt #14, to the height of the Wells Eight, can observe an intrusive of whitish color and of fine texture, probably semi - deep and located throughout a defect E-W, the one which are associated some occurrences of skarn. The rock presents an n biotític precocious alteration, a very strong hydrothermal sericítice alteration with piritizatión and finally a potassic alteration.

3.1.2.3 Subvolcanics Intrusives (A1 and A2)

Between the intrusives that they seem late and that they cut the granodiorite and the diorite, it is note a hipoabisal facies of andesitic composition that is presented under the form of small intrusions in the Southwest part as well as in the center of the region, associated with the skarns of the mineralized zones on current development of Nambija. It has been noted their its presence in the sector of Mapasingue, where seems intercalated with the horizons of ashes tuff, as well as in the zone of the Playón.

To fresh surface, the rock is of porphiritic texture with phenocrysts of plagioclase whitish of 1 to 2 mm, in the bosom of a gray color greenish counterfoil, frequently pyritized. When the rock is altered, is presented of whitish color and of rather mean texture.

Microscópicmently, they are observed phenocrysts of plagioclase, strongly sericitized, in a quartz counterfoil – feldspar microgranular. The mafics amphiboles minerals are entirely decomposed in clorite, ferro-actinote, calcite and epidote. It is note equally secondary quartz and calcite in microfisures.

In the contour of the stock dioritic, in the part east-central of the region, the results of the geophysical raising indicate the probable presence of a dike of granitic of direction NW - N. The outcrops in the

surroundings indicate the rocks presence of type lode, hollocristaline and porphyritics. The rock shows a beige counterfoil color to clear brown with phenocrysts of whitish plagioclase from 2 to 4 mm. Microscopicmently, in addition to the plagioclase, is note the green hornblende, a little of quartz in a quartz counterfoil - feldspar with esfeno, tourmaline and opaque accessory. The composition is tonaític.

3.1.2.4 Reddish composition dikes tonalitic-dioritic (D1)

To the Northwest of the mapping zone, in particular in the bosom of the diorite, are observed dikes of some meters of thickness, of direction E-W, NE-SW and of abrupt slope, constituted of a brown material - reddish to reddish, of slightly texture porphyritic, compound of plagioclase (and of Kfeldspar) altered by the calcite and epidote, of quartz, and of a fierro -magnésic (amphibol) clorotized. It is note also the apatite, in incorporation within the plagioclase, and the epidote. Locally, the dikes present edges of about 1 m of broad composed of a fine material, laminated, of beige color. In thin plates, the rock is leucócrata, constituted of felsics minerals thoroughly sercitized. The global composition of the dikes seems be from tonalitic to granodiorític.

Finally, these dikes seem be displaced by the defects N and NE.

3.1.2.5 Dikes of dolerite (D2)

Some dikes of dolerite cut the volcanics in the central part, to the South of the region. These dikes, of direction NW, seem associated with the important defect of the same direction and slightly decalados by the direction defects N-S and NE-SW.

These dikes, with a broad maximum of about 2 meters, present a fresh surface of obscure green color, of fine texture to mean or slightly porphyritic. They are composed of plagioclase moderately basic,

kaolinized, of pyroxene (augite) fractured with a chlorític alteration and a little of disseminated opaque minerals. Locally, they have been able to observe tapes in the bosom of the dikes with an edge aphanític obscure and obscure color levels and of fine texture to mean, altering with levels clearer.

It should be to note that the dikes, subsequent to the volcanic, they are not affected all over the net of fractures that cut to these last.

3.1.2.6 Dikes aplitics and intrusive felsics several (D3)

Flat several of defects N-S and E-W they are associated with the presence of aplitcs or of intrusives felsics, generally of clear gray color and of bulk texture.

These rocks are composed mainly of plagioclase (oligoclasa-andesina) and Kfeldspar, kaolinized, sericitized and with alterations in epidote and carbonates.

3.1.2.7 Dikes of andesite porphyritic (D4)

In the north - center of the region, in the Bankrupts #11 and #14, are noted "dikes" or washes of andesite porphyritic of about 1 m of broad cutting the pyroclastics rocks. In the outcrops, the rock is of gray color - greenish clear with phenocrysts from 2 to 5 mm of diameter and obscure color.

In thin plates, is observed a counterfoil formed by microlits of plagioclase, phenocrysts sub - automorfs of an ancient ferromagnesiane (piroxene or hornblende) entirely replaced for the counterfoil. Finally, it is note the presence of pyrite and of calcopyrite, in irregular bulks of about 5 mm of diameter disseminated in the rock.

3.1.3 VOLCANIC ROCKS

3.1.3.1 Generalities

The lion's share of the mapping territory for this study is composed of volcanic rocks, that certify a sequence volcanic - sedimentary. Such as has been mentioned previously, these rocks form a band of some kilometers of broad, of direction N-S, and it is in touch of defect with the granodiorite.

Seem, to the light of the field observations, that the volcanic rocks would be subsequent to a batholith granodioritic. However, the volcanic rocks are cut by dikes and by small instrusions of composition tonalite-diorite, as well as by dikes of dolerite, intrusives felsics and, less frequently, by rocks hipoabisals, lava washes andesitics and injected basaltics in the shear zones.

The sequence is formed mainly of piroclastics rocks in those which the composition seems quite uniform, of andesitic to dacitic locally. In general way, they are observed tuffs of lapilli, , they are constituted by crystals of plagioclase and by fragments of traquiandesite in the bosom of a volcanic counterfoil. With much frequency, is note the minerals presence metamorphics such as the epidote, zoisite, tremolite-ferro - actinote, chlorite, vesubianite, calcite, probably due to a metamorphism of contact. The final facies constitute the cornea rocks.

Such as has been mentioned in the introduction of this chapter, the different mapping facies represent descriptive facies (litological map units) before that litoestratigráphic units in the strict sense. The distinction between the various parts, even though it is substantially granulometric, it is given also by the color and the texture of the rock, as well as by the percentage and the composition of its constituent. Locally, the rocks present own characteristics in several facies and not always it has been able be established a very clear distinction.

3.1.3.2 Volcanic Breccia (V1)

The facies most characteristic facies consists of a volcanic breccia located in the Northeast part of the mapping area, that is to say, in the Bankrupt of the Diamond and to the East of the mountain chain of Nanguipa.

In the outcrops, this litology unit is presented either masive or intercalated with block tuffs, lapillis and ashes, forming visible tapes to the natural scale. The composition of these tuffs seems the same that of the breccia, with the only difference of the smaller size and the abundance of the fragments in the rock.

The breccia facies presents a whitish alteration surface to beige clear with dusky color fragments. In fresh surface, the counterfoil is generally mean greenish to obscure. The rock is composed mainly of a counterfoil criptocristaline quartz - feldspar, of phenocrystals of plagioclase of about 2 mm and of litics subangulares fragments of middle size, about 1 to 4 cm, being able to reach a ten centimeter. These fragments are of volcanic origin, originate of trachite compounds rocks of microlits of plagioclase with volcanic glass and present a fluidal texture. The global composition of the volcanic breccia is andesitic.

3.1.3.3Tuff of Lapillis (V2)

This facies occupies most share of the mapping surface and it can present various aspects. However, in general terms this unit is composed of phenocrysts and of litics volcanic subangular fragments of variable size between 1 mm and 3 cm (with an average about 1 to 2 mm) in the bosom of a fine counterfoil. The alteration surface is of gray color - greenish middle beige clear, spotty of black points that present an aspects that denotes the differential erosion of the fragments.

In the eastern part of the Bankrupt of the Diamond, this fragment tuff litics and of phenocrysts is the equivalent of the volcanic breccia of

bulk grain described previously. It is note equally in the same sector, and frequently intercalated with these facies, a rock a little different with a clear gray fresh surface showing fragments, of phenocrysts pale and obscure.

In thin plates, the composition is revealed similar to that of the breccia. They are observed phenocrysts of plagioclase (0.2-1 mm), occasionally sericitized and epidotized with rock fragments andesitic of traquític texture. The counterfoil composed of quartz, of feldspars and locally of micas, it is finely crystalline. It can be also to note alterations in chlorite, epidote and serecite, as well as secondary quartz and coals in veins. The global composition of the rock is andesític and dacitic locally.

3.1.3.4.- Crystals tuff (V3)

Even though understand occasionally litics fragments and are related also with the tuffs of lapillis described before, the rocks grouped under the present facies contains a percentage relatively topmost of phenocrysts. To fresh surface, this litologic unit presents whitish phenocrysts of plagioclase of about 1 to 2 mm in the bosom of an obscure gray counterfoil to black. When the rock is altered can present a greenish or clear gray dye.

Microscopicamently, they are observed crystals of plagioclase (oligoclase-andesine) that they can be sericitizeds or epidotizeds with the hornblende chloritizade locally in a counterfoil criptocristaline quartz - felddpar. It is note frequently an alteration in epidote, chlorite, calcite and a secondary silicification in all the rock whose composition can vary of generally andesític to riodacític locally.

In the zone located in the immediacys of the stock of tonalite-diorite, in the center of the region, that is to say, in the intersection of the Bankrupt of the Fierro and of the Bankrupt of the Green Snake and in the road of Guaysimi, the rock shows a potassic pronounced alteration. They are noted Kfeldspar and the presence of epidote and occasionally of garnet.

3.1.3.5 Black Tuff (V4)

This faices groups to the grain rocks highly finer in comparison with the others faices described before and understands the ash tuffs as well as the tuffs lítics of crystals riodacític composition to andesític. In the bosom of this unit are observed frequently originated tapes for the alternation of ash caps, of lapillis and crystals, in particular in the center of the region, being directed northward and the hill of Mapasingue (head-board of the Bankrupts #5 and #11).

The litologic characteristic of this facies is a tuff of obscure gray color to black, of afanitic texture and of andesitic composition. In thin plates, are noted crystals of plagioclase, quartz and biotite, recristalized with a size middle size of about 0.05 to .5 mm. Equally, they can be consisted the volcanic glass presence in process of desvitrification, being transformed into chlorite. This black tuff can be observed, between other, in the Bankrupt of the Fierro, between the South branch of this same bankrupt and the Bankrupt of the Green Snake.

In the Bankrupt #11, it can be stressed the outcrops of a rock of obscure gray color, slightly reddish and of aphanitic texture. Locally, this rock shows phenocrysts of plagioclase and litics traquiandesítics fragments whose size varies from 1 to 4 mm, as well as greenish lodes of epidote. The criptocristaline quartz - feldspar counterfoil is epidotized and the tremolite and the quartz replace locally the lítics fragments.

3.1.3.6 Welded Tuff and Ashes Tuff (V5)

This facies understands the piroclastics rocks located on the hill of Mapasingue, in the part center - north part center of the mapping region , and associated with the auriferous skarns. Include, equally, the identical piroclastics that they have been observed in contact with the

skarns of the development of Nambija that they are designated "box" by the inhabitants of the place.

The outcrops of this rock show an alteration surface beige clear and an afanitic texture. This alteration penetrates profoundly in the rock and alone very rarely it can be perceived a freshest surface of bluish pale gray color. In thin plates, this facies reveals a litic tuff composition with fragments weld of tranquiandesite and of hialine rock with vitreous cement and phenocrysts of plagioclase. The grains counterfoil very fine is sericitizade. It is note, equally, an intensive silicification expressed by numerous beaches, aggregates and quartz lodes, as well as of epidote, of calcite and of vesubianite in the contact zones with the skarns.

These afanitics levels can be intercalated to the centimetric scale with horizons of whitish material of fine texture, the same that they are particularly observed in the summits of Mapasingue toward the South flank. The horizons are constituted of tuffs with phenocrysts of plagióclase thoroughly sericitized and some traquític fragments rock, whose plagioclase are transformed into tremolite esferulitic. It is note also a fort silicification of the rock.

In the extremity East of the Mapasingue hill is observed a similar rock, but in the one which the size of the crystals is superior to those of the others piroclastic rocks. For that reason, this rock has been represented under the facies of crystal tuffs on the geological map. This piroclastics is the equivalent of a traquiandesite or microdiorite with a counterfoil holocristaline and some composition fragments andesitic. The rock has suffered, on the other hand, a tectonic sharp, such as reveals it the parallel fractures presence full of quartz, as well as a metamorphism of contact with epidot and vesubianite.

From the point of view petrographic, the rocks belong to that facies can be approximated with those of the facies " black tuff" with tapes. it would said that its current aspect, as well as its low magnetic susceptibilities, they would be due to a strong hydrothermal alteration and to an intensive silicification, before that an original composition more felsic.

Some occurrences (Bankrupt #5 et #14) of welded tuff more typical ("ash-flow tuff") have been included equally in this facies. This litic tuff of crystals is constituted substantially of plagioclase sericitizade and epidotizade in a vitreous counterfoil altered in zealots or hidrobiotite and presents flowing structures (laminations and stretched glass thorns).

3.1.3.7 Alkaline Basalt (V6)

In certain greater defect zones (Bankrupt #5, Bankrupt of the Fierro South, Well Ramón), is note the late lavas presence.

In the outcrops, the rock is of obscure green color, of afanitic texture to porphyritic, with phenocrysts of plagioclase that reach 1 mm of size, epidote and chlorite.

In thin plates are observed plagioclase sericitizade and epidotizade either with hornblende or with a piroxene (titano-augita). The counterfoil is composed of microlits of plagioclase and of volcanic glass replaced by clorite and serpentine. The epidote, the quartz and the carbonats are present in veins and the chlorite under the form of alteration mafics minerals. The opaque minerals are disseminated in the counterfoil or in the form of incorporation in the amphibolite.

These rocks have been classified as andesitcs or andesitc basaltic when they have been effected the petrographic studies. The chemical analysis of total rock reveal, however, an alkaline affinity for these rocks that they have been regrouped under the denomination of "alkaline Basalt's" in attention to the geochemistry studies more detailed.

3.1.3.8 Volcanic Indeterminate (V)

This category has been used on the geological map in the places in which they have not been possible to specify the type of volcanic rock, either in reason to the lack of data or to the intensive hydrothermal alteration that they do not permit the identification of the rock.

3.1.4 SEDIMENTARY ROCKS

3.1.4.1 Calcareous and Sandstones (k)

The alone important occurrence of calcareous in the region is located in the surroundings Well Ramón, to the Northeast of the mapped region. In this place, is observed with calcareous intercalated with some few sandstone banks as well as with litchis tubas of lapillis. Certain banks of calcareous are metamorphosed in skarns.

The calcareous observed are constituted by calcarenitas, calcisititas and calcilutitas, slightly marmorized in contact with the skarn. A fragment of braquiópodo not identifiable has been stressed locally.

The sandstone banks have between 0.5 and 2 m of broad and they are composed of feldspar angular sericitized and kaolinized, rounded quartz grains as well as rock effusive fragments constituted of submicroscopic crystals. The cement is carbonated.

3.1.5 METAMORPHICS ROCKS

3.1.5.1Generalities

The places where are found the cornea rocks and the skarns represent zones of metamorphism of contact, accompanied of metasomatism in the case of the training of the skarns. These rocks derive from the transformation from a sequence volcanic - sedimentary in rocks the one which piroclastics are intercalated with calcareous and calcareous sandstones.

In the immediate surroundings to the mapped region, the only important zones where they can be observed the skarns constitute the

same sites of mining development of Nambija and of Guaysimi. In these places, the original carbonats rocks are thoroughly altered in skarns, while the piroclastics rocks, substantially of very fine grain, they are transformed into cornea rocks.

3.1.5.2 Cornea Rocks

Most of rocks of this unit are associated with the horizons of skarn presence, though also are found isolated outcrops in the bosom of the piroclastics in contact with any intrusive.

In the sectors of auriferous development of Nambija and Guaysimi the cornea rocks are presented under the form of rocks of clear green color, of fine texture to aphanitic and of aspect silicificated. The rocks can show equally fine laminations (2 mm) parallel and be interstratificade with horizons more bulk of epidote or garnet. Generally, they are not found meaningful auriferous values in the bosom of this facies; however, it is observed a mineralized cornea rock, intimately associated with the zones of auriferous skarns, of obscure green color and of very fine texture. Finally, they are found rocks thoroughly epidotized, of green pistache color and of aphanitic texture.

In the zone of Wells Eight, several outcrops enclose a mineralogy derived from a metamorphism of contact probably due to the presence of the intrusive dioritic. In this way, it is note a rock cornea of clear greenish gray color, of fine texture to aphanitic, with pyrite and chalcopyrite in veins.

To the East of the mountain chain of Nanguipa, to the edge of the batholith granodioritic, are observed prompt outcrops of skarns and of granodioritic, are observed outcrops prompt of skarns and of cornea rock in the bosom of the piroclastics. As a rule, the rock is of fine texture to moderately fine, of obscure green color, with altered zones of pink and clear green color and veins of epidote.

In thin plates, all the described rocks demonstrate a volcanic origin, belong generally to the litics tuffs with crystals, of fine texture (black tuff V4, ash tuff V5) and exhibit a metamorphic mineralogy. They are observed various mineralogical assemblies that understand essentially to the epidote, zoisite, vesubianite, diopside, tremolite - ferroactinolite and calcite. The counterfoil is frequently chloritized, epidotized and sericitized could note locally a secondary silicification of all the rock.

3.1.5.3 Skarns (M2)

Very few outcrops of skarns properly said have been able be observed in the mapped region for this work. They are noted some prompt occurrences within area with geological raising at recognition level to the East of the mountain chain of Nanguipa that seem be derived from the metamorphism of thin intercalated carbonates caps with piroclastics rocks.

In the center of the region. In the surroundings of the Wells Eight, it has been verified the presence of skarns and of cornea rock in touch with the intrusion diorite subvolcanic thoroughly altered hydrothermally.

The West edge of the intrusive presents a skarns of calcics garnets and carbonateds that derive probably from a carbonated rock, while the eastern extremity is found a rock base of vesubianite and zoisite that shows an intensive silification and constitutes, probably, a endoskarn.

In the sector Well Ramón is note the presence of skarns in the bosom of the outcrops of calcareous under the form of small lenses in those which the contacts continue the stratification plans. In Well Ramón, it can be seen one of these caps, of about 5 m of thickness, that it has been thoroughly exploited.

In this place, the skarns, of bulk texture, it is composed mainly of calcics garnets, of calcite, vesubianite, epidote, diopside and quartz, as well as a mineralization of pyrite, pyrrhotite, chalcopyrite and sphalerite. The piroclastics horizons intercalated with the calcareous are above all epidotized in these alterations.

On the mining developments of Nambija and Gauysimi are observed auriferous skarns that contain mainly garnets calcics (grossular), diopside, vesubianite, quartz, calcite and adularia. The calcite, under the form of bulk plates, alters and includes the vesubianite. Of the same form, the secondary quartz invades the rock, including and surrounding the metamorphic minerals.

The skarns are frequently presented with tapes in those which can be observed thin striping of clear green color and of fine grains that represent rock level corneas derived from piroclastics, altering with beds of skarn of garnets, of texture more bulk.

3.2 TOTAL CHEMICAL ANALYSIS OF ROCK

3.2.1 Sampling and Analysis

In order to determine the chemistry nature of the different lithologics units as well as of the hidrothermals alterations that affect them, it has been selected 94 samples for total analysis.

The samples were selected in form such of having a representative sampling of all the observed facies, so much of the rocks that present few or no alteration as of those that appear altered in the area. The origin of these samples is as continues: 22 correspond from the different intrusive rocks, 46 to the sequence of piroclastics and volcanic, 6 to the outcrops of skarn within the studied region, including 9 samples of the mine of Nambija and 2 of the mine of Guaysimi.

The rock samples have been ground until obtaining a grain that passes the mesh 200 in the laboratory of the INEMIN, in Chillogallo (Quito), and transmitted then to the laboratory Bondar - Clegg of

Ottawa, Canada. The chemical analysis has been effected by spectrometrics of the atomic emission of the plasma for the greater elements such as Si02, Al203, Faith (total), Mg0, Ca0, Na20, K20, Ti02, P205, Mn0, as well as for the C02 et S (total).

3.2.2 Results

The general results are presented in Annex II - 1.2 for numerical order. Annex includes the corresponding lithologic each sample as well as a legend of the used abbreviations.

All the places of origin of the analyzed samples are identified on the location map C-1, exception made of 6 samples of skarn originating from the development of Nambija , (#1287 - A, 1287 - B, 1289, 1336 - C, 1340, 207), and of the two samples of skarn belonging to the development of Guaysimi (#G-2, G-5) that are located outside of the limits of the map. The remaining three show of Nambija (# 1290 - A, 1290 - B,et 1290 - C) are included in the location map. It should be to note that most of samples analyzed by the greater elements, they are equally analyzed by 36 smaller elements.

On 46 volcanic rock samples and 22 of intrusive rocks, that is to say, on 68 of 94 analyzed samples have been applied computer procedures. The figures 5 to 9 present the binary variation graphs of oxides: Na20 K20 versus Si02, for the two groups and K20 versus Si02, Na20 versus Si02 and Na20 versus K20 for the volcanic rocks only. The number of each sample is convenient identified above all the graphs and the different lithologics units are represented by different symbols.

3.2.3 Succinct Interpretation

The examination of the variation graphs indicates in the first place the similarity of composition between the intrusive and extrusive rocks; the two groups present the same dispersion standard about the curve that separates the alkaline fields and subalcanics. This characteristic

would suggest equally the character of transition of the originating means in these rocks.

Even though the high alkali contents in certain samples located about the zones of skarns, of smaller defects or of the intrusive in the case of the piroclastics, demonstrate without no doubts the presence of a potash alteration in the bosom of the rocks, seems doubtful that this alone fact will be responsible of the character highly alkaline of certain samples. This situation, to be compared with the two populations obtained of Na as a result from the processing of the geochemical data to see chapter 4.2, alone permits to speculate by the moment on the possibility of the existence of different two episodes of magmatism or of two alteration episodes potash. In the group of volcanic rocks, seems be noted a trend subalcaline trace - alkaline in the piroclástics, while the lava washes relatively little altered found sporadically in the defect zones associated with the late magmatic episodes, would reveal an alkaline trend and would belong, therefore, to the basalts alkaline.

Of the same form, the intrusive rocks that present few or no alteration show also a subalcaline trend, except for the hypoabisal rocks associated equally with the late magmatic events that present compositions located in the alkaline field.

These observations could then to indicate the presence of two sources or volcanic episodes and of a tectonic means in transition. A tectonic basin environment after - arch associated with a continental magmatic arch and with volcanism trace - alkaline, it can be easily considerate. A potash enrichment and an evolution toward smaller magmatic episodes more alkaline, it is not thing unknown in this type of context (Reading, 1978; Best, 1982).

Finally, the examination of the results of the analysis of the samples that are presented altered on the area the area does not reveal, to first sight, differences labeled with the freshest samples, as would have been able to wait. In any case, is present a potash alteration, such as has gone mentioned before and the figure 9 shows the relationship inversely proportional between Na20 and K20. it is note equally a trace alteration – silice in the bosom of the rocks located about zones of skarn.

3.3 STRUCTURAL GEOLOGY

3.3.1 Generalities

In the course of the geological raisings, they have been taken about 2000 structural mediations, the same that they were thereinafter processed by computer methods. The stereonet obtained are presented in the figures 10 to 15. The studied zone presents mainly flat of defect and faulting and would be interesting to make a structural raising directly within mineralized sector of Nambija, in order to understand better the relationships between the same flat and with the zones of mineralización.

3.3.2 Photointerpretation

The results of the photogeological interpretation are presented in the figure 4.

The lineaments most labeled to regional scale are guided in the address NS and seem to delimit a volcanic rocks corridor -sedimentary, in the form of abrupt combs, in the granitoides bosom rocks that present relief more rounded. The deposits of auriferous skarns of Cambana, Campanillas, Nambija and Guaysimi are located in the bosom of this rocks band that seems be extended by several length kilometers. The most attentive examination of the lineaments NS reveals than would be tried to normal defects, possibly with a of the central sections and a collapse to the edges East and West.

They are presented also numerous lineament of direction N-NE and NE and limited by the outcrops NS. In the center of the considerate region is presented an important lineament NW cutting the deposits of Nambija and Guaysimi.

Other general direction elements EW are equally important and cut the structure NS in one way more extensive. As a rule, the hydrographyc system reflects the structural lineaments.

In conclusion, to the South of the studied region is note a structure in a way regulation and of origin done not know. Between other possibilities, the structure would represent traces of an ancient volcanic center. This structure is cut by a lineament NW akin to that that joins the deposits of Nambija and Guaysimi. In certain zones of the mountain chains, are found boiler systems associated with the tectonic graves (grabens) and with the lode deposits (by example., San Juan, Colored, USA). Would be interesting to explore this structure in form more intense in order to verifying its nature and its importance.

3.3.3 General Structures observed on the Area

In general form, all the studied zone is fractured and failed. Such as indicates it the photogeological interpretation, the region is cut by numerous and important, with directions N-NE, NE (as the visible defect in the sector of the mine of Nambija and of the defect throughout the Bankrupt #5) and NW (as the defect that continues the Bankrupt of the Fierro South and is extended of Nambija to the Guaysimi Mine).

It is observed, also, important defects in direction EW (more precisely to 280°-290°). In the Bankrupt of the Fierro, to the center of the studied region, exist flat of shear and important defects, as well as in the Wells Eight, where a defect EW seems to dial the edge of an intrusion and gives rise to an important shear zone in the Bankrupt #14.

In end, in the extremity NE of the hill of Mapasingue in the sector of the mine of Nambija, is note a greater defect plan guided to 280°-290° to what is long of which is observed a tectonic gap. It is possible that this defect, as that of the Wells Eight, is extended toward the East, crossing

the mountain chain of Nanguipa, such as suggests it the photointerpretation and the interpretation of the geochemical values in gold that seem to follow these lineaments.

The movements observed throughout the defect plan NS, N-NE they are always vertical movements, while the horizontal displacements seem have taken place preferably according to the flat EW. This is particularly evident in the sector of the Playón of the mine of Nambija, where it can be observed flat two subvertical defects that seem conjugated with the directions 20° and 110°. The flat NE and NW limited by the defect NS would represent extence bound fractures to a principal system NS and to secondary systems N-NE and EW.

It is difficult to establish precisely the chronology of the defect plans without a structural study more meticulous. However, it can be supposed that the first located system has been the system NS, responsible for the collapses and of the creation of a graben. The subsequent systems would be the defects NW/SE and NE/SW throughout those which are found dikes of dolerite and of basalts alkaline, respectively. Finally, they would be intervened the flat EW and NS, of possibly conjugated way, and the numerous intrusives félsics would have been inserted according to those fracture plans, as for example the intrusive volcanic félsic of the Wells Eight or the granitic dikes of the Bankrupt of the Fierro South. The fact of the that the system NS could have returned to move tardily it is indicated, between other, by the traces now rectilinear of that primary system. The structural observations to the scale of the outcrops goes equally in the same way. The systems of quartz veins - pyrite located in the volcanic are almost exclusively guided according to that plan and cut often the others systems. The dikes of dolerite, late in relationship to the volcanic, they are only cut by join and veins of direction NS.

Unwillingly to speculate too, we mention that the defect systems NNE and EW they have been recognized in the Southwest of the Ecuador, bound to the ENE movement of the Plate of Nazca in the Terciary Superior. The porphyry copper of Chaucha in the Southwest of the country is located in the intersection of those two transverse defects (Frutos, 1986).

Finally, they have been measured some tens of stratification plans within the piroclastics and calcareous units , demonstrating the direction NW of the caps, with a slope toward the NE in the part West of the slope band toward the NE in the part West of the band volcanic - sedimentary (sector of the Mapasingue), and a direction SE, with a dips toward the SW in the part East (sector of the Well Ramón and of the mountain chain of Nanguipa). This, along with the lithologic contacts observed, suggests a structure sinclinale with the piroclatics bulk sediments to the foreign happening to the finest sediments associated with the carbonates sequences and with the auriferous skarns toward the interiorof the structure. The lineament NW/SE that cut the deposits of Nambija and Guaysimi would correspond approximately to the shaft of the structure. Finally, it seems that a defect EW, located in the surroundings of the Bankrupt of the Fierro, it has given place to the displacement of the structure toward the left.

The determination of the important structural shafts is confirmed by the stereonet obtained with the computer processing from the data.

3.3.4 Stratification

The figure 10 presents the stratification pole means. This graph suggests, of general way, a shaft structure NW/IS with irregular micropliegues, probably due to the movements throughout the numerous defects.

3.3.5 Faults

The figures 12 and 13 represent the concentrations of the poles of the defect plans and the strias that are associated respectively.

They can be defined four (4) large plan families. The most important groups to the direction plans N-NE/S-SW (5° to 20°) and of mainly abrupt slope (70°-90°). A second family would have as flat

middle a direction NE/SW (30°) with a slope 55° to 70°. A third family would follow a direction NE/SW (40°) abrupt slope by 80° to 90°. Finally, a last family, less important by the fractures density that characterizes it, with a direction between 90° and 115° and a slope on the SW of about 50° to 80°.

3.3.6 Join

The figure 11 represents the graph of density contours of the fracture poles. The join with direction multidirectional with generally abrupt slopes. In spite of all, the most frequent systems are substantially the same than for the defects, that is to say, the systems N-NE/S-SW, NE/SW, E-W, and a plans family less important NW/SE.

3.3.7 Veins

The veins (fig. 14) are guided continuing the important fractures system, that is to say, in connection with a flat N-NE (5°-10°) with a mean slope of 65°. Other two secondary plans can be equally observed according to the hosiery directions of NE/SW(60°-80°) and NW/SE (300°-330°) with subverticales slopes.

3.3.8 Dikes

The figure 15 presents a graph of directions and slope poles of the dikes, with different symbols according to their composition. As a rule, the plans compiled in this graph show a mean direction NW-SE.

4. GEOCHEMICAL OF THE ROCKS AND OF THE HEAVY MINERALS

4.1 INTRODUCTION AND USED METHODS

During the geological cartography campaign, they have been gathered systematically superficial rock samples as well as samples of the heavy fraction of the sediments in the creeks, these last concentrated using bat that are employed to carry gold. They have been obtained 565 sample rocks and 321 sample sediments, what makes a total of 886 samples. These samples have been withdrawals above all within the region of 682 hectares but also in the recognition zone of 18 km2. the site of the sample points is indicated in the Maps C-1 and D-1, respectively.

The sample rocks have been mashed in the laboratory of the INEMIN, in Chillogallo (in Quito), until the resulting material pass the mesh 200 and then they have been sent to be analyzed in the laboratory Bondar-Clegg, of Ottawa, Canada. The heavy mineral samples have been also ground in this same laboratory.

866 samples have been analyzed by neutronic activation simultaneously to the gold and to 33 elements more and by atomic absorption to the copper and to the lead. The results have been send to Géomines in diskettes and transferred then to our electronic file. An impression of this file, including all the results of the analysis and the coordinates of each sample, figure in Annexes II - 1.1 and III - 1.

The data of this file have been processed numerically with help of the program GDM (Geological Date Management) in a computer IBM PC-AT. The rocks and the heavy minerals have been treated separately to produce the following documents: tables of statistics base, counterfoils correlation, histograms of laws, binary graphs and geochemical maps to scale 1:5000.

For the binary graphs, it has been used the logarithmic scale in reason to the great extension of the values (to see Table 1).

The histograms show the distribution of the concentrations of each investigated element. For the same previous reason, not always results possible to present graphically the whole the laws, so that in some histograms has been necessary to put explanatory notes. The geochemical maps to the scale 1:5000 show, with the aid of symbols, the distribution of the laws within the region of each one of the considerate elements. Additionally, it has been indicated with a black point above all the geochemical maps, the site of 32 sample rocks in those which the concentration of the gold is presented anomalous, i.e. 100ppb (to see chapter 4.2).

4.2 GEOCHEMICAL OF THE ROCKS

The examination of the histograms of laws of gold in the analyzed rocks has permitted to define the anomalous concentrations limit in 100 ppb, above the one which exist 32 samples. Confronting the geometric averages of the laws of each element of this subgroup (Table 1) is observed that the average of the average is topmost for the arsenic, the fierro and the lead and bottommost for the sodium and the bario (has not been taken into account the tungsten on account of the pollution had to the crushing). These five elements have been considered as accompanist elements of the gold and therefore they have been elaborated the histograms (Annex II - 2), the binary graphs of each one of them versus the gold(Annex II - 4) and the geochemical maps to the scale 1:5,000 of the distribution of each one of these elements within the region (Maps C-2 to C-7).

The laws of gold in the rocks of the region vary from less values than the direction index (5 ppb) until a maximum of 37,900 ppb (Table 1). The anomalous laws(>100 ppb) are frequently associated with the defects or with the shear zones and appear some times aligned according to the greater defect plans, as for example throughout the Bankrupt of the Fierro - The Diamond, with a possible prolongation to the East of the comb of the mountain chain of Nanguipa. In the Northwest corner of the zone, the anomalous values , is note a values concentration increased in the extreme part North of the region, about deposit of Nambija. It is of noting that to the East of the comb of the

mountain chain of Nanguipa, the laws of gold are generally very decrease with exception of one of them .

The laws of arsenic in the rocks of the region vary from smaller values than the detection index (1 ppm) until a maximum of 383 ppm. The great majority of laws are located in less than 40 ppm and the geometric average is of 4.99 ppm (to see Table 1). The anomalous concentrations are found grouped within the region of Mapasingue, where the laws of gold are relatively high, and directly to the such region South, in the sector of "The Wells Eight", where the laws of gold are rather decreases. In the Bankrupt of the Wasps, to the East of the comb of the mountain chain of Nanguipa, there is a certain correspondence between the high values of the laws of the gold and of the arsenic. In the others places (for example more to the West and to the Southwest), where the laws of gold are increased, there is no correspondence with the arsenic. These observations demonstrate the limited value of the arsenic as indicative of the gold presence within the region in study.

The presence of the fierro in the rocks varies also from laws more decreases than the detection limit (i.e. 0.5%) until a maximum of 43%. The great majority of the laws is being in less than 10% and the geometric average is of 3.8% (to see Table 1 and Annex II - 3). The high laws are generally associated with the presence of the pyrite. The fierro is a staunch companion of the gold in all the areas of the world (Boyle, 1979) and Nambija is not an exception. The fierro continues very near to the gold in the sense of the fact that where the values of the gold are increased, those of fierro are also and conversely (to see Map C-4).

The content in lead in the rocks varies from smaller laws than the detection index (i.e 2 ppm) until a maximum of 10,600 ppm with a geometric average of 6.47 ppm (Table 1). Though the geometric average will be topmost for the samples with gold to >100 ppb that for the whole the samples, there is no actually correlation between the lead and the gold. This is evident in the binary graph (Annex II - 4) where, for the major share of the anomalous samples in gold, the corresponding value in lead is not very high. Observing the geochemical map of the element (Map C-5), stressed remain that the high lead concentrations are found grouped in two sites in particular: "Well Ramón" and the "Wells Eight". In first case, is found also a little of zinc associated with the anomalous low laws of bario. From the geological point of view is

found within the calcareous stratified where is found galena and sphalerite. The wells have been abandoned after a first attempt of development on account of a decrease law of gold. In the "Wells Eight" the high laws of lead also they are associated with the decrease laws of bario. It is found a little of skarn, but the principal rock is an altered tuff. The wells have been quickly abandoned.

However, the first accompanies to the gold in the Bankrupt to the West, in an important defect zone. Agree to note that the corresponding sodium contents are particularly low.

It is found also a series of anomalous lead concentrations aligned according to a shaft NS, on a parallel located to the East of the comb of the mountain chain of Nanguipa.

The law of bario in the rocks varies from values less than the detection index (100 ppm) until a maximum of 28,200 ppm, with a geometric average of 458 ppm (Table 1). For the group of samples in those which the gold is anomalous, the corresponding geometric average to the bario is of 217 ppm (Table 2), quite bottommost that for the set of the samples. On the binary graph (Annex II - 4) is seen clearly this trend. In the geochemical map of the element (Map C-6), the anomalous low values of bario are generally associated with the high laws of gold, but are found also decrease laws of bario in the region of "Well Ramón" and "Wells Eight". Furthermore, is evidence a alineament of anomalous values of bario on the flank East of the mountain chain of Nanguipa.

The sodium characteristics in the rocks vary from 0.1 to 6.7% with a geometric average of 1.6%. for 32 samples, in those which the gold content is superior to 100 ppb, this average is of 0.2%, highly bottommost. According to the binary graph of the sodium versus the gold (Annex II - 4) seems have two (2) populations: a first with high sodium values for the laws of gold less than 100 ppm and a second population with decrease laws of sodium.

On the geochemical map of the sodium (Map C-7) is seen that the low laws of this element are associated with the high gold contents. But

is found also places, as "Well Ramón", where there is no practically gold, but lead and zinc associated with decrease laws of sodium. The sodium would would have, then, scarce value as indicative of the gold in the region.

In the chapter 3.2, they have been bought the values of k20 versus the values of Na20 for 46 volcanic rock samples in those which have been effected total analysis. Turned out to be it a relationship inversely proportional. Would be interesting to analyze the whole of the taken samples of the region in relationship to their contained of potassium and to put the results on a map in order to seeing if it can be located in this way the potash alteration zones that they would be perhaps bound to the presence of the gold.

4.3 GEOCHEMICAL OF THE HEAVY MINERALS

For 321 samples of the heavy fraction of the collected river sediments and concentrate by batting and then analyzed by 36 elements (Annex III - 1), it has been elaborated also a table of statistics base(Table 3), two correlation counterfoils: arithmetic and logarithmic (Annex III - 3), a histogram of gold concentrations (Annex III - 2) and the geochemical map of the gold (Map D-2).

Furthermore, the same as for the rock samples, it has been elaborated a statistics table for the samples that had high gold concentrations, or rather greater than 1500 ppb (Table 4). Comparing the geometric hosieries of the elements of this table with those of the whole the samples, evidenced remain that the average is topmost in the subgroup for the arsenic, the antimony, the bario and the tungsten, those which would be therefore accompanied elements of the gold in the concentrate by batting.

For this study have been considered solely the values of the gold, seen that it is the own gold indicative the best by the gold. The law varies from values less than the detection index (5 ppb) until a maximum of 41,500 ppb, with a geometric average of 182 ppb.

On the geochemical map of the present gold in the concentrate by batting, is seen that the contents increased in gold are found grouped in four places in particular:

- Firstly, in the lion's share of the creeks that drenan the South flank of Mapasingue, in the sector NW of the region, what does not result surprising if is considered the proximity of the deposit of Nambija.

- In the second place, is found a concentration of high laws in the center section - south of the Bankrupt of the Fierro. This anomaly is interesting on account of the favorable conjuncture: important defect and proximity of volcanic rocks of fine grain (frequently associated with calcareous) (to see chapter 5).

- A third high values concentration of the gold content in the bat is found in the recognition zone, in the corner SW of the region of the Bankrupt 24, where nearly all the samples present values. Considering that is added to this the proximity of an important defect in direction NS, the anomaly results very interesting. Since the laws of gold are very high, it is possible that it will be due to the presence of this metal in the form of pips, what would be possibly associated with a porphyry (seen the predominance of intrusive in that sector). Of all way would be needed to make a geological mapped and a more detailed sampling in this sector.

- A fourth anomaly, also in the recognition zone, is found in the sector SE of the region, waters down of the auriferous deposit of Guaysimi, on current development, on the Bankrupt #22. the taken sample waters up present the risk of be contaminated by the relaves of the mines, but the four anomalous values samples have been taken waters down, in the affluent that come of the West. This zone would deserve be better examined: in addition to the anomalous values found in the bat, it should be take into account the presence of a great calcareous rolled song observed in the Bankrupt #22, between the samples B92 et ++B93. Additionally, the existing geological conditions on the flank East of the comb of the mountain chain Nanguipa would be favorable to the presence of skarn: or rather volcanic sediments mapping not far from there, possibly with

intercalates of calcareous (the rolled song) and the proximity of an important defect in the address NS throughout the comb.

5. METALLOGENIC

5.1 GENERALITIES

This chapter presents the conclusions of a paragenetic study accomplished in order to define a metallogenic model of the deposit of Nambija. The surface covered by our field projects do not include own deposit of Nambija. Having accomplished solely two project sessions and available having only the taken samples, the conclusions that are presented are proposed solely as a first stage within elaboration process of a genetic model of the deposit. It will be recommended to effect subsequent stratified studies, , structural and paragenetics, in the same sites of all the deposits known of the volcanic - sedimentary band (Cambana, Campanilla, Nambija and Guaysimi) in parallel with studies of the regional geological context in order to specifying the model.

The examined samples have been taken in the sectors of Mapasingue, of The Arch and of the Playón in the mineralized zone of Nambija, in the mine Guaysimi during a visit to the earthly, as well as in different places included in the mapped surface to the detail, mainly in the sector of the Well Ramón.

The paragenetic study has encompassed:

1) A megascopic evaluation of the alteration within the skarns and the associated volcanic rocks, including alteration tests potash.

2) An examination in polished thin plates of the skarns auriferous and sterile.

3) A tending bibliographical conference to compare these deposits with the others auriferous skarns (to see Annex I SAW - 2).

5.2 CONTEXT LITHOLOGICAL AND STRUCTURAL OF THE GOLD MINERALIZATIONS

The auriferous mineralizations are located within the skarns in the bosom of a volcanic - sedimentary sequence. This last constitutes a rocks band of some kilometers of broad, of direction NS and of unknown extension, limited to each side by defects that seem to define a tectonic pit (record) to the interior of a batholith granogioritic.

The sequence is constituted of piroclastics (volcanic breccia, block tuffs and lapillis, crystals and ash tuffs) and of volcanic mixed alkaline and trace - alkaline (basalts alkaline, andesite, dacite) within those which are intercalated thin horizons of calcareous (sands and calcareous shales). The set is cut by dikes and by small stocks of diorite, applies and subvolcanics rocks of similar compositions to the extrusive rocks. They have not been observed sedimentary pelitics rocks. The sequence volcanic - sedimentary is affected by foulding more or less irregular than define globally a synclinal structure of shaft NW/SE, strongly cut by defects N-S, N-NE, NW/SE, NE/SW with vertical movements and by defects E-W throughout those which have been produced horizontal displacement.

Of the foreign toward the interior of the sinclinal is gone from bulk piroclastics facies toward the finest facies.

They are observed two types of skarn in the region. The first, it is located in the eastern part of the studied zone (Well Ramón), it is in touch of defect with piroclastics means to bulk. The values in gold are weak and the mineralization observed is constituted by pyrite, chalcopyrite and sphalerite with a little of galena.

The auriferous skarns properly said are located in the center of the studied region, in the heart of the synforme structure and they are associated with the ash tuffs being able to be presented finally laminated, silicated and metamorphosed. The magnetic susceptibilities of these rocks seem be more decreases than of the surrounding rocks, what remain demonstrated by the geophysical raising. The explanation of this fact - intrinsic properties of the rocks or product of the hydrothermal alteration very intensive - is still unknown.

It is note equally the stocks presence and of dioritics dikes as well as of subvolcanics intrusions mineralizated in pyrite in contact of the skarns. In the mine of Nambija, sector of the Playón, it has been observed locally a rock that is resembled to a intrusive breccia (diatreme) associated with the mineralized zones.

Finally, the deposit of Guaysimi, located within same type of rock that of Nambija, is found in the prolongation of the lineament NW/SE that defines the shaft of the sinclinal.

5.3 MORPHOLOGY OF THE DEPOSITS

The mineralization auriferous economic seems bound exclusively to the horizons of skarns and of intercalated cornea rocks, though is note also an enrichment in gold of the greater defect zones inside of the volcanic rocks. The levels of calcareous, skarns and ashes more competent constitute very fractured and permeable trainings than permit the passage of mineralized solutions. The matters precipitants presence (Fe, C02) can equally to play a trap geochemical role in addition to structural trap originated by the great number of fractures.

In Nambija, the auriferous mineralization is presented under the form of gold in native state, so much disseminated in the rock, more frequently between the garnets of the skarns of bulk texture (derivatives from the metamorphism of carbonates rocks quite pure), as of the lenses or of the quartz veins - potash feldspars that cut the skarns and the cornea rocks (derivatives from the metamorphism of the piroclastics rocks).

In Guaysimi, the context is similar. The observed typical sequence, according to certain mining, they would be tuffs altered by elements (calls "quartzite"), followed by laminated metamorphosed tuffs in cornea rocks, of clear green color, followed after gaps (not always present) and by skarn properly said.

The mineralization is disseminated in the skarns but in certain zones, is presented under the form of veins of quartz - potash feldspars that cut all the sequence before described.

5.4 ALTERATION HYDROTHERMAL

An megascopic examination of about 25 samples originating from the mapped sector and of the deposit of Nambija indicates two types of important alteration:

1) A potash Alteration in the igneous rocks and piroclastics. This alteration understands the replacement of the plagioclases, in the form of phenocrysts and within the counterfoil, by a potash feldspars and by the epidote as well as the replacement of the amphiboles for the biotite or the chlorite. The pyrite can be introduced in the fractures.

The dyed of the samples with cobaltinitrito of sodium indicates that all the rocks are altered, unless possibly the aplits, in those which the dye is presented weak. The potash intensive alteration is manifested by a pink color alteration, beige or gray pale in the counterfoil of the rock (#1056 a, 1056c, 1065 a, 1175, 1329c) throughout the veins and fractures (#79 a, 209, 1033 a). The phenocrysts of plagioclase are thoroughly replaced (1329c) or altered throughout the plans of cleavage (#1056 to). The sample #1037b presents an potash alteration cut by a sterile quartz vein.

2) Alteration of calco - silícea of the calcareous (exoskarns)and, in touch with the exoskarns, a similar but limited alteration of the piroclastics (endoskarns). The exoskarns are characterized by a trace assembly -

silíce of grain means of green color, beige or brown pale. The mineralogy and the paragenesis of the exoskarns are described in the following chapter.

5.5 PARAGENETIC OF THE SKARNS COPPER

The primary skarns of Nambija present texture and simple mineralogy, with an assembly of seed clinopiroxene of grain means. The garnet crystals (70%) are mainly allotriomorfos and of 0.5 to 1mm of broad. Furthermore, the crystals have concentric colored bands and they are anisotropics and distorted. The deformation textures include you laminate and "kinks" of sobretensión, waved extinctions and cataclastics textures (fracturación, brechificación). In a originating sample from the surroundings Well Ramón (1329C) is observed a garnet isotropic idiomorfo that replaces to the anisotrópicos garnets (photo 21), what indicates at least two garnet generations, being the most subsequent youths to the deformation than there have sobretensionado the precocious garnets. Chemically, the garnets are members of the series of the solid solution grossular-andradite (C03(A1, Fe)2Si3012). The color beige of the garnets suggests mainly the grossular, while the andradite is customarily of obscure color. The clinopyroxenes (30%) are of the series diopsida-salita, with allotrimorfos crystals of up to 0.5 mm of length that form irregularmixed bulks with the garnet crystals. It is observed, they associated with the diopside, about 1% of grains of pyrite and of chalcopyrite as well as trace of calcite and of epidote. In the sample 1329C, the sphalerite (10%) fill the fractures and provide the breccia characteristic to the garnets (photo 22). This texture represents a removilization of mineralization primary associated with a deformation.

The primary assembly is retrogradado in a sample originating from Well Ramón by an episode of zinc mineralization. The bulks of sphalerite that house small incorporation of chalcopyrite and of galena (<0.1 mm of broad) are associated with an assembly of pyrite - chancopyrite - calcite - quartz – chlorite - tremolite - epidote.

The primary assembly of the skarns is also retrogrado for the episode of auriferous mineralization. To megascopica scale are observed small lenses and discontinue veins (tension fissures) of quartz – k-

feldspar - calcite – hematite – chlorite – zoisite – gold, that alter the skarn. The quartz, the hematite and the zoisite fibrous replace to the garnet, while the calcite and the hematite replace to the diopside. The pyrite is replaced by the hematite. The adularia is identified by the morphology of the potash feldspars. This secondary assembly replace to the primary minerals in the edge of the veins and also in the nets of microfracturas present in the skarns. Small veins of late sericite cut the auriferous assembly.

The gold is found in the form of grains or of allotriomorfas bulks of 0.1 to 5mm of broad in the skarns altered or in the veins (photo 23). No silver-bearing phase or other sulfurized phase has been observed in the veins, indicating that this mineralizador episode is substantially monometalic.

The sample 70ª. Taken in the Bankrupt of the fierro, a located defect zone outside of the zone of skarns auriferous, it is a skarn thoroughly retrogradado in an assembly of chlorite - hematite - quartz -calcite. This sample is anomalous in gold (1860 @@ppb Au) and is presumed that this alteration is the result, perhaps the equivalent distal, of the episode of auriferous mineralization, though in native gold and the adularia are absent.

In short, they are recognized three states of mineralization in the studied samples (figure 16):

1) Primary Mineralization of pyrite - sphalerite - chalcopyrite continuing a deformation of the assembly of skarn;

2) Secondary Mineralizacion of sphalerite - pyrite - chalcopyrite - galena that there has retrogradado the assembly of skarn;

3) Auriferous Mineralization of the type lode that also there has retrogradado the primary assembly. Though it can not be determined the paragenetic relationship between the states 2 and 3, is presumed that the stadium 2 constitutes a secondary mesothermal alteration of the skarn and that it is older than the episode of auriferous mineralization.

5.6 DISCUSSION

The skarns of the region of Nambija present the characteristics of the calcics skarns coppers. These characteristics include:

1) Mineralization of pyrite, pyrrhotite, chalcopyrite and sphalerite in a trace bargain - silicea of garnet (andradite-grossular), diopside, wollastonite, magnetite, etc.

2) Retrogradación of the primary skarns by late mesothermales processes.

3) Association to the trace calco - alkaline intrusions (diorite, granodiorite, Qz monzonite).

4) Tapping of metasomatism of calcareous beds in the volcanic cogenetics sequences (andesites, dacite).

5) Middle tectonic orogenic of continental arch (Einaudi et al., 1981; Einaudi and Burt, 1982).

We think that the skarns studied are derived from a metasomatism of calcareous observed in the volcanic sequence -sedimentary. The presence of piroclastics altered is not unknown in means hydrothermales and the training of skarns in the igneous rocks (endoskarns) is typically a local process (Einaudi et to the., 1981; Meinert, 1986). The skarns of Nambija are poor in sulphurs (pyrite, chalcopyrite, sphalerite late) and they are associated with an activity hydrothermal apparently bound to the intrusions dioritics local. The alteration potash important of the piroclastics, the volcanic and the intrusions subvolcanics is geographically associated with the skrans and it is probably contemporary to the training of they. The alteration potash of the igneous rocks or pelítics associated with the genesis of the skarns coppers that is all right documented (Einaudi et to the., 1981; Carten, 1986; Wares 1986).

The auriferous mineralization is very rich in the skarns. The gold is presented in native state, mainly housed in the discontinue veins that fill the tension fissures, what represents a state of the type secondary lode that was seeming be independent to the training of the skarns. The mineral assembly 2gico of the veins indicates an epithermal episode (<300°C) of type adularia-sericita (Hayba, 1985), while the skarns are normally formed at high temperatures (400°-600°C, mesothermals conditions).

It has not been observed no auriferous mineralization in the volcanic rocks, except for the piroclastics levels intercalated with the skarns. Alone have been found quartz veins slightly pyritized that cut the potash alteration, what seems particular because, customarily, the epithermals deposits of type adularia-sericite are associated with defect zones or they are housed in a variety of lithologics, mainly of volcanic calco - acaline. This type of mineralization is normally deposited a million of years after the training of the hosted rock rocks. These facts indicate that the structural controls on this epigenetic mineralization are more important than the nature of the hosted rock rocks (Buchanan, 1981; Hayba, 1985). Thus the auriferous mineralization of Nambija represents a particular situation where the skarns have served as structural traps or, being rich in fierro, of geochemicals traps where the structures have permitted an infiltration of the bearing gold fluids. The receiving behavior of the lithologic ferríferas on the auriferous bisulfurados fluids is documented for the trainings of fierro of the Precámbric (Phillips et al., 1984), what can be relevant in relationship to the skarns studied. At world level, the skarns of Nambija are compared with difficulty to the skarns known, yet if these last have been formed in similar tectonic means (Einaudi, 1981, 1982), already they will be the means of the oceanic arch or of the orogenics continental edges (principal arch and hind arch). The "auriferous" skarns are typically ferríferos or coppers skarns where the gold is extracted as by-product from the development from the usual metals (Einaudi et al., 1981; Shimazaki, 1980; Mainert, 1986). These skarns are generally poor in gold (<3g/t ++Au) and the metal form part of the primary mineralization or it is enriched in the polimetalics mesothermals veins that alter the skarns. The auriferous mineralization is frequently it associated with the pyrite nickelífera and cobaltífera in the ferríferos skarns and with the small quantities of bornite/calcosina, arsenopyrite, sulphur of bismuto, telururos or sulfosales in the coppers skarns. Table 5 summarizes the characteristics of the exploited skarns by the usual metals and by the gold.

The auriferous deposits of the region of Nambija present a form of uncommon mineralization. In Ecuador, as in the Peru, the mineralizations of usual metals of type skarn and the polimetalics/auriferous mineralizations of the type epithermal lode are found almost exclusively in the volcanic Mesozoics and Cenozoics of the Western mountain chain (Petersen, 1965, 1977, 1979; Goossens, 1972, 1976). Nambija constitutes then a discovery only of hydrothermal mineralization cutting a calcic copper skarn.

The exact geological context of the region of Nambija stays uncertain, taking into account the following facts:

1) The subandian zone is a waist ridden in active comprehension;

2) The volcanic - sedimentary band is limited by defects (where the in-depth nature is unknown); the band defines a lineament NS according to the air photograph;

3) The rocks within the band are not submitted to a metamorphism of contact. We permitted ourselves to speculate that the band is housed in a thin laminates ridden between two intrusives with important horizontal displacement. The absence of metamorphism of contact excludes the possibility of a gigantic enclave (roof pendant) within the batholiths. The alkaline mixed nature/trace - alkaline of the volcanic compatible with the training of a hind arch basin (graben) that in the origin was, probably, the means of sequence accumulation volcanic - sedimentary

The Andean tectonic evolution consists of a successive stages overlapping of compressions with foulding, inverse defects and intrusive magmatism followed by extended periods characterized by the normal defects occurrence, development of grabens and predominance of intrusive magmatism.

The singenetic deformation textures within the skarns (garnets sobretensionados, epithermales veins within the tension fissures) attest

the deposits training in a means in comprehension state. This fact would explain the overlapping of two types of mineralization (epithermal and skarn) in the deposits if is speculated that, continuing the sequence training volcanic - sedimentary has been transported at lithotectonics topmost levels, permitting the epithermal mineralization under the conditions of <300°C and of <0.1 kb.

In resume, the auriferous mineralization of the skarns of Nambija is highly secondary. These skarns are different of the auriferous typical skarns by virtue of the wealth and of the monometalic and epithermal nature of the mineralization. We concluded then in which the mineralization can not be classified as type " auriferous skarn ", since it constitutes a auriferous epithermal mineralization housed in a skarn.

This discovery is economic and geologically important because indicates the existence of an economic potential for the epithermals auriferous deposits not only in the subandian zone, but in the coppers skarns as a rule.

6. CONCLUSIONS AND RECOMMENDATIONS

6.1 CONCLUSIONS

From the geological point of view, is found a rocks volcanic -sedimentary guided in direction NS of some kilometers of broad that houses to the auriferous mineralizations. This band is found in the bosom of a batholith granodioritic composition. The auriferous mineralization is associated with skarns and with piroclastics fine rocks. The set is cut by dikes and small stocks of diorite, aplita and subvolcanics rocks. Locally, they are observed also volcanic and late doleritas in the defect and shear zones.

From the metallogenic point of view, the auriferous mineralization in the skarns of Nambija is highly secondary. These skarns are different of the auriferous typical skarns by virtue of their wealth and of the monometalic and epithermal nature of the mineralization. We concluded that the mineralization can not be classified as of the type "skarn

auriferous", since constitutes an auriferous epithermal mineralization housed in a skarn and represents therefore a new style of mineralization in the Andes.

From the geochemical point of view, the determination of the gold in the concentrate materials to the bats seems us the most useful way prospectus gold in the region. Three characteristic zones have been determined in this way (to see recommendations). The geochemical of the rocks indicates us that the lead is associated with the large defect zones(current phenomenon in the grabens zones) and that the gold seems associated with arsenic in the favorable lithologcs related to a structural control NW-SE.

The magnetometrics and electromagnetic geophysical raisings VLF have been useful to help mapping the lithologics units, but not directly to recognize the auriferous zones.

A summary inspection of the same deposit of Nambija leads us to believe that the auriferous mineralization would be distributed in small rich lenses in gold in the skarns, but also under the form of stockworks and would be associated with the stocks and intrusive lode rocks as well as with the controls of structural order.

6.2 RECOMMENDATIONS

6.2.1 To effect an air photographic raising in order to produce a series of airphotographics more detailed .

6.2.2 Photogeological study of these photos and regional mapped in order to specifying the regional geological context, especially the extension of the band volcanic - sedimentary and the structure (especially the grabens and the boilers).

6.2.3 Samples litogeochemical analysis for the potassium in order to delimiting the alteration potash zones (those with a high relationship k : Na).

6.2.4 Follow-up of the three (3) characteristic zones determined by the anomalous gold presence in the heavy sediment samples: detailed mapped, closed sampling of heavy sediments, litogeochemical sampling for the gold, the sodium and the potassium. The skarns zones associated with the intrusive rocks and of lineament in direction NW, the skarns are frequently about tuffs to fine grain. In the corner SW of the recognition zone, the geological characteristic zone possibly a phorphyry granitic.

6.2.5 Geophysical magnetrometric and electromagnetic raisings VLF on the deposits known of Nambija, Cambana, Campanilla and Guaysimi in order to determining if agreing to use these methods with the purpose of exploration.

ANNEX IV: GEOPHYSICAL REPORT

1. INTRODUCTION

In the area of the South - East project, of Ecuador, they have been effected magnetrometrics raisings to total field, as well as electromagnetic raisings T.B.F. (VLM-EM) from August 27 and October 1st, 1987. These raisings have been effected with the principal purpose from obtaining basic information that serves of support for the best geological knowledge of the earthly and also in order to seek the geophysical evidence in relationship to the prolongation of the deposit of Nambija southward, that is to say, within area where was developed our investigations.

2. PERSONAL

In the raisings has participated the following personal:

- J. Stembera, geophysical responsible of the project.- A. Bastien, technical.- 2 Workers.

3. LOCATION

The geophysical mesh is located between the Bankrupt of the Fierro and the North limit of the area of the project.

The site of the principal lines in direction East - West has been determined by the presumed North - South direction of the general structures, accordant is detached of the analysis of the air photographs, as well as by the distribution of the field workers that they have accomplished before the arrival of the geophysical equipment. It is important to indicate that, in some places, the site of the lines has been influenced by the inaccessibility of the earthly.

4. ACCOMPLISHED PROJECTS

MagnetomEtrics raisings to total field: 15.0 km

Raisings VLF-EM, Station NAU :15.7 km Station NLK :13.9 km

The readings have been taken each 12.5 m for the magnetomEtrics raisings and each 25.0 m for the raisings.

The lines have been signaled with stakes located each 25.0 measured m horizontally. The lines LB 0+00 have served as base to certify the mesh.

In order to have a fixed reference point for the successive workers, it has been installed a concrete plate in the progressive 0+75E of the line LB 0+00.

5. RAISINGS MAGNETOMETRIC

5.1 Instrumentation

The magnetometric raisings has been executed with the aid of a nuclear procession appliance, model G-856A of GEOMETRICS. To permit the due alterations to the daytime variations, it has been installed in the place a base station that it has operated during the execution of all the raising . The precision of the appliance is of 0.5 gamma.

5.2 Results

The results were presented in the form of profile on a map of field total values (Map E-1). Furthermore, is included a map of field total contours. The base level in the profiles map is of 29500 gammas. The position of the magnetic bodies is represented by a shaft that joins the center of the anomalies of each profile. The lines 4+875N and the part North of the line 8+75E were not lifted due to technical problems.

5.3 Interpretation

The magnetometric raising has revealed many zones with different magnetic susceptibilities, indicating thus the existence of litostratified different units.

We indicate, at the same time, that the intensity variations are, as a rule, between 100 and 500 gammas approximately. The magnetic relief in the West part of the zone of the project is more stressed between the lines LB 0+00 and 2+00S of the map E-1. the relief is composed of four (4) magnetic shafts - not. 1,2,3 and 4. the intensity vary between 100 and 400 gammas and suggest the presence of a quite physical means homogeneous (intrusive body) possibly shortened by dikes or lavas washes. Seem also that this unit would be extended toward the East until approximately 10+00W (above all between the lines LB O+OO and L 1+00S), being associated to the conducting shaft T.B.F not. 3(Map E-3).

In the central part of the area of the project, between the lines LR 4+00W, and 8+00W, are observed two (2) magnetic shafts # 5 and 6 (Map E-1) with an intensity of 200-400 gammas approximately. It should be to note that the shaft # 5 probably it does not continue until the line 4+50S since the intensity on this line is less strong, of the order of 100-150 gammas. The magnetic shaft # 7 (Map E-1) is not associated with the mentioned shafts previously, being able to the same to continue until the shaft # 5 on the line 2+00S. This possibility seems be reinforced by the decreases magnetic intensity of its West flank that they can be observed until the line 1+00S, suggesting thus the presence of a defect NW - SE, or the presence of a dike with the same direction, in the prolongation of the outcrops of basalt aclcaline trachytic observed in the Bankrupt # 5. The shafts # 8,9 and 10 (Map E-1) between the lines 3+50S and 4+50S delimit rocks of possibly volcanic origin that present highly stronger susceptibilities than the rocks located to the North, that is to say, between the lines LB 0+00 and 2+00S. This zone is extended perhaps until 2+00E approximately (on the lines 3+50S and 4+50S) and their limit is labeled by the magnetic shaft # 12.

It is observed, on the flank East of the shaft # 12 (Map E-1), a magnetic depression of clean-looking continuity that is extended

northward, to the progressive 362.5E (L4+50S), 337.5E (L3+50S), 237.5E (L2+00S) and perhaps to 2+00E (l1+00S).

This zone would represent phyllitic rock bands limited on the flank East by the magnetic shaft # 13 of the line L2+00S(Map E-1).

The magnetic shaft # 14 (Map E-1), with a nearby intensity to 200-400 gammas, delimited probably the West flank of a intrusive is associated to the weak magnetic intensity; it seems be recovered in its North extremity by the volcanic rocks, what can explain the strongest intensity, of about 100 ranges, on the line 1+50N.

6. ELECTROMAGNETIC RAISINGS T.B.F.

6.1 Instrumentation

This raising has been accomplished simultaneously with the magnetic raising, using an appliance CRONE RADEM of Crone Geophysics that permits to measure the slope angle (dip angle) of the great shaft of the polarization ellipse. The measures were taken each 25 m and immediately filtered and transformed continuing the method FRASER. As source networks have been used two stations T.B.F - Puerto Rico (NAU) to 28.5 kHz and Seattle, Washington (NLK) to 24.8 kHz. Initially had been chosen the station Laulauli of Hawai, but it had to be abandoned on account of its weak sign.

6.2 Results

The results obtained with the station NAU, that it was selected as principal station, are presented in the form of a profiles map (Map E-3). The lines East - West of the discussed raising mesh are in relationship to the direction given by the network station. Additionally, the anomalies of the station PR are represented in the form of contours (Map E-4) in a filter map Fraser on the slope angle (such as is described in Geophysics,

Vol. 34, 1969). For the interpretation of the results it has adopted the convention of Crone. It should be to note that the values on the North - South lines have been incorporated in the computer treatment of the contours, causing thus a light certain anomalies displacement on the map Fraser, without influencing, however, on the quality of the results. The network station SW has been related to the North - South lines of the traced mesh (Map E-5). The lines 1+50N, 12+00W, 14+25W and a part of 1+00S have not been lifted on account of an interruption in the sign of the station. One must to note that the quality of the results of the station SW are not all satisfactory due to the weakness of the sign. However, the obtained results have been incorporated in the report.

6.3 Interpretation

They have been identified seven (7) numbered different conducting zones of the 1 to the 7 on the map Fraser of the station NAU (Map E-4), probably located in the rock.

Conducting Zones 1 and 2

These two (2) conducting zones appear in the West corner of the area of the project, between the lines LB0+00 and L2+00S (zone 1) and LB 0+00 and 4+50S (zone 2). They correspond to the conducting shafts T.B.E 1, 2 and 3. The zone 1 reaches an intensity of 1 degrees Fraser and shows a good association with the shafts of the magnetic bodies 1 and 2 (Map E-1) that represent magnetic intensity of the order of 200 to 300 gammas. The type of the magnetic anomaly indicates that would be tried to susceptibility contrasts either due to the lithologic abrupt changes, those which can be indeed associated with a intrusive shortened by dikes or to a zones of direction defects N-NE.

The conducting zone 2 ( conducting shaft T.B.F. 3) show the strongest intensity, of up to 25 degrees Fraser, that are associated with the weak magnetic anomalies, next to 100 gammas. The conducting zones 1 and 2 should possibly to indices of pyrite present in the intrusive rock and associated with the defect zones.

Conducting Zone 3

This zone is located between the lines LB 0+00 and 3+50S between 6+00 and 10+00W, continuing an direction NE-SO. The zone reaches 20 and 25 degrees of intensity and it is represented by the conducting shafts T.B.F. 4 and 5 (Map E-3). In some places (L12+00S and 3+50S between 6+00W - 9+00W) the zone shows direct magnetic associations of 200 to 400 gammas that they are represented by the shafts of the magnetic bodies 5 and 6 (Map E-1). it should be to note that the anomalies T.B.F and magnetic are not extended until the line 4+50S.

Conducting Zone 4

This mean intensity zone (10 to 15 degrees Fraser) is located between the lines 3+50S and 4+50S in the level 6+00W. The zone seems be associated with magnetic bodies shaft # 7 (Map E-1), with intensity of 200 to 300 gammas but of limited extension. A lava mafic or a failed zone and mineralized in pyrite can be the origin of this zone, whose West flank is adjacent to a magnetic intensity zone very irregular (L 4+50S between 6+00W and 8+00W) that suggests the presence of a failed zone.

Conducting Zone 5

East zone is limited by the lines LB 0+00 and 4+59S as well as by LR+00 in the This and LR 4+00W. In some places, the zone reaches strong intensity that be at the point 25 degrees Fraser and seems be divided in two (2) segments, the first on the line 1+00S (0+50W) and the other between the lines 3+50S and 4+50S (20 degrees Fraser). This zone is represented by the conductor # 9 (Map E-3) of clean-looking continuity. However, its site on the line 2+00S (0+75W) is not all right identified. The North segment of the zone does not correspond to no magnetic anomaly.

On the contrary, the South segment is associated to several magnetic intensity anomalies media to strong, between 200 and 500 gammas, that they are represented by the magnetic shafts 8, 9 and 10 (Map E-1). This characteristic would indicate the presence of various lithologics types (volcanic and intrusive dikes). The anomalies would correspond also this time to pyritized zones inside of these rocks.

Considering what is mentioned previously, the most probable interpretation of the conducting shaft #9 (Map E-3) would be that it is considered a defect, probably mineralized, that there can in effect be the prolongation of the structures that affect to the deposit of Nambija to the other side of the mountain. Within this failed zone is returned to find, on the other hand, the very prompt presence of skarn and of mineralization in pyrite.

Conducting Zone 6

This zone, of limited extension, sample high intensity that be at the point 30 degrees Fraser between the lines 3+50S and 4+50S between2+00 and 3+00E and corresponds to the conducting shaft # 10 on the profiles map NAU (Map E-3). It can be observed a direct association with the shaft of the magnetic body # 12 (Map E-1). This conduct zone seems be located in the South extremity of a slightly zone NO - SE that corresponded to the magnetic shaft # 12 (Map E-1) and quiz160s also to the shaft # 11 (Map E-1). it should be not to forget that this zone is found within shaft of the sinclinal bound structure to the deposit of Nambija.

Conducting Zone 7

This zone is located in the extremity East, between the lines 1+50N and 1+00S, and presents hosiery intensity of 15 degrees Fraser. The zone does not correspond to no meaningful magnetic anomaly, has a

limited extension and it is probably located to the middle of a intrusive structure.

7. CONCLUSIONS AND RECOMMENDATIONS

In how much concerns to the evaluation of this part of the area of the project in relationship to the prolongation of the deposit of Nambija, it should be take into account the following:

1) The geological raisings effected do not reveal the presence of auriferous skarns neither in the adjacent zone to the deposit of Nambija nor in the explored region, to exception of the skarn of the Well Ramón where two (2) samples have gold contents moderately high.

2) The interpretation of the geochemical information does not demonstrate no meaningful association between mineralization in gold and mineralization of metal gold in the skarns investigated, what hinders the election of appropriate geophysical methods.

The projects effected in the area of the project have permitted to detect seven (7) conducting zones. Most of them demonstrates a good association with the magnetic anomalies. The structural conclusions or lithostratigraphyc relevant to each one of the zones are found in the par. 5.3 and 6.3 respectively.

In light of the mentioned reasons previously, two (2) zones of limited importance could be taken in consideration for the contingent confirmation of the projects. These are:

1) The conducting zone # 5 (Map E-4) defined by the conducting shaft T.B.F. # 9(Map E-3), in particular its segment between the lines LB 0+00 and L 2+00S, I would be investigated insofar as the possibility of finding isolated zones of skarn as well as to understand better the structural elements within this zone.

Methods of resistive such as the provoked polarization or the provoked spectral polarization could be used. In the event of requiring in-depth investigation, they could be taken in methods consideration magneto - telluric (AMT, CSAMT).

It is pointed out that the zones is decreased resistive would not have to be the most interesting, since they could correspond to zones of mineralization in pyrite (defects). These zones, yet if present anomalous values in gold, they are not probably interesting from the economic point of view.

The investigation and the adequate interpretation of the rocks of high resistive could also be hindered by the rocks presence with similar geophysical standards (intrusive, piroclastic, etc).

2) The zone of skarn located between the well Ramón and the road Guaysimi would be explored more in detail. They could be discovered thus the rich zone mineralized in isolated gold. The task probably would be facilitated by the meaningful mineralization in zinc that seems be associated with this skarn. The population provoked in configuration dipolo-dipolo seems be the most appropriate method.

OBSERVATIONS RELATED TO THE CONTINUATION OF THE PROJECTS TO THE SOUTH OF THE BANKRUPT OF THE FIERRO

1) Lineament spaced each 100 m as maximum.

2) Magnetic Raising ( total field and gradient), not to identify the possible extension of the deposit but rather to delimit the extension of the litológicas units.

3) Measure of the magnetic susceptibility directly on the rock samples in order to facilitating the interpretation of the raisings magnetometrics.

4) Location of the structural lineaments (defects with pyrite) with the help of the method EM-VLF.