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GORD DAVIES PETROGRAPHIC STUDY
STATEMENT OF COSTS
30 Thin sections
314.50 3 Polished thin sections
33 K-spar stained reject blocks 4.85 x 2 = $9.70 Shipping
Photomicrographs
Basic charge $50.00 20 prints @ $5.00
20 duplicates @ $1.00
50.00
100.00
20 .oo
Pqtrogra'phic study
Transmitted light 30 x $42.50 1 275.00 Reflected light 3 x 50
Report preparation
150.00
K.E.N. Professional fees 4 day @ 250./day 125 .OO
Typing 125 .OO Reproduction 26.00
Draughting 80 .OO
Total cost
4,
$ 324.00
170 .OO
. . 1 425.00
356.00
$2 275.00
PETROGUPHIC REPORT
December 15, 1985
FOR THE GORD DAVIES CLAIMS
TOODOGGONE GOLD CAMP
Omineca Mining Division
Latitude 57'32'N Longitude 127'3'W
NTS 94E/llE
for
Western Horizons Resources Ltd.
Coquitlam B.C.
by K.E. Northcote and Associates Ltd.
Agassiz, B.C.
K.E. Northcote Ph.D.,P.Eng.
TABLE OF CONTENTS
LOCATION CLAIM STATUS PREVIOUS WORK
PRESENT WORK
SUMMARY OF PETROGRAPHY TOODOGGONE VOLCANICS TALKA GROUP MINERALOGRAPHY CERTIFICATE PETROGRAPHIC DESCRIPTIONS PHOTOMICROGRAPHS
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LIST OF FIGURES
FIGURE 1 Location of Toodoggone Gold-Silver District FIGURE 2 Gord Davies Claim Map FIGURE 3 Geology of Breccia Peak Area FIGURE 4 Gord Davies Claim Sample Locations
LIST OF TABLES
TABLE I Gord Davies Claim
PETROGRAPHIC REPORT ON THE GORD DAVIES CLAIM
L 0 CAT I ON
The GORD DAVIES claim is located approximately 36 kilometres north of the Sturdee River airstrip. west of Breccia Peak between Moosehorn and the headwaters of McClair Creeks, Latitude 57'32'N. Longitude 127"3'W, NTS 94E/llE, Omineca Mining Division. accessible by helicopter from the Sturdee River airstrip.
The property lies 31 kilometres south-
The claim ranges from 1500 to 2000 metres elevation and is
CLAIM STATUS
A total of 18 units comprise the GORD DAVIES claim. See Figure 2 .
TABLE I GORD DAVIES CLAIM
CLAIM UNITS RECORD NO. ANNIVERSARY DATE
* GORD DAVIES 18 4881 (11) November 3, 1985
The legal comer post is located at 1520 metres elevation 5 kilo- metres southeast of Moosehorn Lake. The GORD DAVIES claim overstakes 3 two-post claims owned jointly by Kennco Explorations (Western) Ltd. and Conwest. The position of the HAR claims relative to the GORD DAVIES claim is shown on Figures 2 and 3 .
* One year's assessment work, reported herein, has been applied to the
GORD DAVIES claim to extend the expiry date to November 3, 1986.
I
.-.-- < To* FORT NLLBON
I TOOOOGGONE JOINT V E N T U R E
LOCATION OF TO 0 D 0 G G ON E G . 0 L 0- SILV E R
DlSTR I CT
FIGURE: I. SCALE: I : 10,000,000 DRAWN BY: P.STOECKLY DATE: NOV 1985
I Km
127000'
I T O O D O G G O N E J O I N T VENTURE
I GORD DAVIES CLAIM
I DRAWN BY, PSTOECKLY OAT€: N O V . 1985
I
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PREVIOUS WORK
Kennco Explorations (Western) Ltd. and Conwest submitted assessment reports in 1973 and 1975 covering silt-soil and rock geochemistry programs on the HAR claims. were staked and geological reconnaissance and rock geochemical surveys were conducted on these claims by Lacana Mining Corporation in 1981.
These data were not filed for assessment purposes.
Subsequently the GORDON DAVIES claims
In 1982 the GORD DAVIES claim was staked by Elaine M. Thompson and was subsequently transferred by Bill of Sale to Western Horizons Resources Ltd. to assess the potential of the claim. 1983 on the GORD DAVIES Property dated November 30, 1983 by K.E. Northcote, was filed to cover two years assessment.
In 1983 a geological reconnaissance program was conducted A Report for Exploration During
PRESENT WORK
A total of 33 thin sections or polished thin sections were pre- pared from suites of rock and mineralized specimens taken from the GORD DAVIES claim. or reflected light were completed in the period October 10 to 2 4 ,
1985. A total of 20 photomicrographs support the petrographic and mineralographic descriptions. are shown on Figure 4..
Macroscopic and microscopicanalyses with transmitted
The locations of the suites of specimens .
I
- 57O 11.5'
TOODOGGONE JOINT VENTURE
GQWD DAVlES CLAIMS SAMPLE LOCATIONS ,
I SCALE: I : 12 500 .flGURE: 4
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SUMMARY OF PETROGRAPHY OF VOLCANIC SUITES
FROM THE GORD DAVIES CLAIM
_ - , I Preliminary regional geologic map #61 Sheet 1, 1 85 by L.J. Diakow, A. Panteleyev and T.G. Schroeter shows the GORD DAVIES claim is underlain
by Toodoggone volcanics (McClair Creek Formation (5)) on the west in fault contact with Takla volcanics (TR) on the east. A portion of their
map covering the GORD DAVIES claim is reproduced as Figure 3.
The following description of the geology o f the GORD DAVIES claim combines field observations by Northcote from field notes and Report on Exploration During 1983 on the Gord Davies Property, November 30, 1983. with results of the present petrographic-mineralographic study.
TOODOGGONE VOLCANICS (trachyandesite to andesite)
Toodoggone volcanics on the west side of the property, suites 402
and 403 represent interbedded massive to weakly porphyritic flows, flow breccia, few pyroclastic crystal tuffs and crystal tuff lithic breccias. Minor volcaniclastic sediments are also present. report, the cliff faces show a branching system of slightly lighter colored, less intensely fractured, porphyritic dykes of monzodiorite composition. plutonic rocks and their volcanic hosts. rock were noted as inclusions within volcanics suggesting a close comag- matic, coeval relationship between these plutonic and volcanic units.
A s was noted in the 1983
Blocks of talus show sharp intrusive contacts between
Fragments of similar plutonic
The sample suites consist of volcanic flows, flow breccias, and
lesser pyroclastic crystal tuffs, crystal lithic tuff breccias and microgranitic rocks. They show wide variation in grain-size and texture. Some beds, particularly sedimentary tuffaceous rocks at the southwest end of the cirque,have a strong hematitic matrix. in thin section.
These were not examined
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The volcanic rocks are most commonly porphyritic or fragmental but massive fine grained to very weakly porphyritic varieties are also abundant.
(An33 to ranging from (-0.05 t o 3.0 mm) brown aphanitic feldspar-rich matrix. K-spar free rocks,the matrix of many stained slabs indicate weak to moderate interstitial K-spar content.
Porphyritic flows and crystal tuffs contain plagioclase
and lesser chloritic mafic phenocrysts or fragments 35 in a dark green-grey or medium reddish
Although there are examples of
The Toodoggone rocks show generally weak alteration consisting mainly of chlorite and carbonate. alteration affects plagioclase phenocrysts and fragments as well as the feldspar-rich matrix. occur as minute irregular grains or aggregates of grains randomly disseminated throughout the matrix.
A weak sericite and dusting of clay(?)
Opaque minerals, ranging up to 2 to 5%,
TAKLA GROUP (trachyandesite to andesite with some quartz)
The Takla Group rocks on the east side of the claims are also composed of volcanic flows', pyroclastic crystal tuffs, crystal lithic ~
tuff breccias andvolcaniclastic sediments. Rocks in the floor of the east side of the cirque are represented by samples 406 and 407.
409 and suite 410 were taken from the north and northeast wall of the cirque. moderately sericitic, argillic dusted, lesser carbonate and epidote altered plagioclase (An to and chloritized mafic ranging from (0.1 to 2+ mm). Irregular, rounded partly resorbed quartz fragments ( 0 0 0.7 mm) are conspicuous in maw-thin sections.
is composed of very fine granular (-0.01 to 0.05 mm) plagioclase laths and microlites commonly with 30 to 35% interstitial K-spar but
the latter is absent in some beds.
Sample
These rocks contain 20 to 30% phenocrysts/fragments of weak to
33 35
The groundmass
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These Takla volcanic rocks have undergone weak to moderate chlorite- This alteration becomes intense accompanied carbonate-epidote alteration.
by impregnations of quartz, albite ( ? > , K-spar and pyrite, as represented by specimens in suite 411 taken from close proximity to plutonic rocks in the east comer of the cirque. and impregnated rocks are cut by the uppermost part of an intrusive porphyry with offshoots of aplite dykes and irregular bodies.
These strongly altered, brecciated
MINERALOGRAPHY
A mineralographic study was made of three samples (402 , 403 and 451) containing gold and silver-bearing lead, zinc, copper mineralization in talus from the south wall of the cirque. in these s.amples. Metallic minerals identified include in order of abundance, sphalerite, galena, pyrite, chalcopyrite, polybasite and covellite. quartz with polybasite in the more silic.eous gangue associated with covellite.
No native gold was observed
These minerals occur in a gangue of carbonate, barite and
CERTIFICATE
I, K.E. Northcote of 2346 Ashton Road, R.R.#l, Agassiz, B.C. do hereby certify that:
11 I have been practising as a professional geologist for a period of approximately 25 years for petroleum exploration companies, mining exploration and consulting companies, federal and provincial agencies.
21 I obtained a Ph.D. in geology from U.B.C. in 1968 and qualified for registration with the Association of Professional Engineers of B.C. in 1967.
31 The petrographic microscopic examination ini.this: report was dbne by K.E.' Northcote in the period October 12 to 2 4 , 1985 utilizing specimens collected in the field by Northcote/ cj 41 I am a shareholder and director of Western Horizons Resources Ltd., owner of the GORD DAVIES claim.
51 I consent to the use of this report in, or in connection with, a prospectus relating to the raising of funds.
GORD DAVIES PROPERTY
PETROGRAPHIC DESCRIPTIONS
October 2 4 , 1985 K.E. Northcote Ph.D.,P.Eng.
October 2 4 , 1985
GORD DAVIES PROPERTY
PETROGRAPHIC DESCRIPTIONS
' t j
SD 85-401 Oxidized breccia
MAcRoscoPIc Oxidized breccia, fragments less than 1 mm to several crns, weathered, iron-stained. Volcanic fragments very fine grained, altered, weathered, in a limonitic very fine fragmental matrix. No conspicuous quartz.
Stained slab: some fine grained volcanic fragments show high K-spar content,
MICROSCOPIC Transmitted.light Fragments; range from -1 nrm to several crns diameter. Feldspathic, clay and/or albite-sericite alteration. Some fragments retain porphyritic texture with low degree of alteration. very fine granular'texture (-0.01 to 0.20 mm) with mQre intense alteration
Other fragments have a secondary
Matrix; fine fragmental , masked by Fe-stain.
Sp 85-402-1 Volcanic breccia, hematitic, trachyandesite
NACROSCOPIC Volcanic fragments from a few mm to several crns, polymictic, varied colors and compositions; porphyritic fine to coarse and varied phenocryst abundance. Red coloration throughout, particularly in matrix of fragments. Stained slab, fragmental texture is clearly visible; some fragments K-spar- rich. Matrix between fragments contains diffuse K-spar.
MICROSCOPIC Transmitted light Dense close packed porphyritic volcanic breccia, pervasive "dusty1'
d,
2
pppearance resulting from alteration and hematitic dusting, particularly
the matrix of some porphyritic fragments. phenocrysts dense feldspathic with felted mass of small crystals. Ground- mass between breccia fragments also fragmental.
Matrix between plagioclase
Feldspar phenocryst abundance, size range and degree of carbonate alteration are varied from one porphyritic breccia fragment to the next. alteration, lesser sericite.
Patchy carbonate
Minerals Present
Plagioclase; 80%, euhedral/subhedral crystals forming phenocrysts to + 1.0 mm; and as felted matrix (- 0.01 mm) between phenocrysts and fragmental groundmass between breccia fragments. An 37+ . Carbonate and lesser sericite alteration. Sericite; -5%, bladed crystallites (-0.01 to 0.05 mm) alteration of plagioclase.
Carbonate; lo%, irregular patches to (0.2 mm) replacing plagioclase
phenocrysts; matrix of fragments and groundmass between fragments. Apatite; -l%, subhedral (0.4 mm), accessory Opaque; -5% jarosite, Fe-stain. Altered mafic; shredded, associated with magnetite, carbonate, sericite(?) and Fe-stain.
irregular grains (-0.05 to 1.0 mm) associated with limonitel Close association with altered mafics.
Sp 85-402-111 Altered porphyritic trachyandesite flow
MACROSCOPIC Porphyritic texture, plagioclase phenocrysts in an aphanitic reddish brown matrix. Widely scattered fine to medium-grained mafic phenocrysts.
Dense. Stained slab; matrix strong uniformly distributed, very fine-textured K-spar
3
MICROSCOPIC Transmitted light
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Altered ''dusty" overprint on plagioclase phenocrysts,single or clusters, (-1.0 to 2 or 3 mm) in a fine (-0.01 to 0.03 mm) anhedral feldspathic (plagioclase and K-spar) matrift, also with strong "dusty" alteration' overprint. Scattered, shredded chloritic, sericitic altered mafic. Iron-staining in fractures. Carbonate alteration forms small irregular masses and small irregular very discontinuous clusters of grains. plagioclase.
Weak sericitic alteration of
Minerals Present Phenocrysts, approximately 30% of total rock. Plagioclase; 20%, euhedral/subhedral, (-1.0 to 3.0 mm) in single grains or clusters, clounded by dusty alteration. Twinning still visible,
%26 to 36' . Quartz ; -5%, clusters of anhedral grains (0.03 to 0.05 mm)
Apatite;' -l%, euhedral to subhedral crystals (-0.1 to 1.0 bn)
Mafic; -5%, chloritic, sericitic alteration, irregular shredded grains (-0.1 to 0.5 mm>
Opaque; -l%, subhedral grains, isolated and in clusters, disseminated
lacking zoning
throughout matrix- and associated with altered mafic.
Matrix
50%, anhedral grains, (0.01 to 0.03 rmd estimated 40% Plagioclase K-spar K-spar from stained slab, altered. Quartz; 20%, anhedral grains, (0.01 to 0.02 mm), clear, unaltered
Sp 85-402-IIIA Trachyandesite- porphyritic flow (tuff ? ) breccia
MACROSCOPIC Porphyritic volcanic, approximately 15% plagioclase phenocrysts (-1 to
4 mm) in an aphanitic matrix, containing scattered clusters of mafic
4
grains. with more abundant chloritic mafic giving the fragment a greenish color.
the porphyritic volcanic matrix contains a high percentage
Fragment appears fine to very fine-grained, very weak porphyritic
Stained slab; of K7spar;with the fragment, although with K-spar present, less rich.
MICROSCOPIC Transmitted light A . Porphyritic volcanic; 15% plagioclase phenocrysts, euhedral to subhedral
(-1.0 to 2 or 3 mm), weak dusted alteration; in a felted very fine granular (-0.01 to 0.02 mm) matrix with a strong reddish brown dusting of alteration. Note- this texture strongly resembles the very fine fragmental texture of a tuff.
grains associated with carbonate in some cases showing diffuse out- lines of former mafic crystals. Also chlorite as small clusters of crystals '(-0.01 to 0.02 mm) disseminated in matrix. Plagioclase crystals and mafic shows varied intensity of carbonate and lesser
Clusters of diffuse radiating chlorite
sericite alteration. Minerals Present Phenocrysts 20%
Plagioclase; euhedral/suhedral clusters, (An33), weak dusting
(-1.0 to 3.0 mm) as single crystals or of alteration, some crystals strong
carbonates and all showing less intense sericite alteration.
Chlorite and Carbonate; alteration of former euhedral mafics.
Matrix 80%
Feldspathic material Plagioclase ? K-spar; estimated +50% in stained slab
Quartz -lo%, anhedral grains (0.01 to 0.02 mm), as single grains and aggregates
Chlorite; 15%, anhedral diffuse grains and aggregates of grains interstitial to plagioclase
ODaaue; 1-2%, anhedral grains (-0.01 to 0.5 mm), diffuse dissemination of finer grains, scattered coarser grains and aggregates of grains
5
(7: B. Fragment Volcanic flow rock, weakly porphyritic with plagioclase phenocrysts (1 to 0.2 mm), weak to moderate sericitic alteration. Interstitial fibrous/bladed chlorite (-0.05) and chlorite and sericite intermixed with amphibole in remnant mafic crystals. Irregular interstitial carbonate masses (-0.05 to +1.0 mm). Fine interstitial matrix (-0.01 mm) of "dusty" altered feldspathic (K-spar) matrix. Weak disseminated opaques, irregular, very fine (-0.02 mm) associated with Fe-stain.
Minerals Present Plagioclase; 50% euhedral crystals and laths (-0.1 to 2 mm) , A"33.,
weak to moderate sericitic alteration K-spar; 20%, very fine (-0.01 mrn) interstitial, dusted alteration Chlorite; bladed (-0.05 mm), commonly with carbonate in altered amphibole . Carbonate; lo%, irregular interstitial masses, (0.05 to 1.0 mm)
Opaque; -l%, irregular grains (-0.02 mm)
20%, altered amphibole grains and interstitial fibrous/
Sp 85-402 IV Porphyritic trachyandesite flow
MACROSCOPIC Weak porphyritic, -15% phenocrysts, fine-grained phenocrysts (-1 to 2 mm). Aphanitic matrix, medium to dark brown-grey. Weak disseminated fine-grained mafic. Massive, dense.
Stained slab; aphanitic matrix shows moderate to strong, 30%, K-spar content.
MICROSCOPIC Transmitted light Porphyritic flow, euhedral plagioclase crystals, weak sericitic alteration in a matrix of finer plagioclase laths in a felted texture with very
fine interstitial K-spar. and carbonate masses interstitial to the plagioclase phenocrysts. Disseminated opaque throughout the matrix.
Alteration consists of a mixture of chlorite
Phenocrysts, +15% Plagioclase; 15%. euhedral/subhedral, (-0.5 to 2.0 mm) ghost-like ,
twinning, lacks zoning, An slight mottled dusty clouding.
Sericitic and lesser carbonate alteration 35
Alteration, 20% (phenocrysts and matrix) Carbonate; -lo%, irregular crystals and masses (-0.03 to 0.4 mm),
interstitial to plagioclase phenocrysts. Chlorite; -lo%, irregular masses (0.02 to 0.4 mm) diffuse in matrix, interstitial to plagioclase phenocrysts, commonly associated with and filling fractures in carbonate. Quartz; trace, anhedral aggregates of grains, (-0.05 mm), inconspicuous. (Possibly untwinned unaltered albite) Apatite; trace, subhefral, (0.05 mm)
Matrix 65% (plus alteration) Plagioclase; 40%, felted groundmass, fine laths and anhedral grains,
(-0.02 to 0.05 IIIIU)
K-spar; 30%, very fine interstitial, dusted groundmass between plagio- clase laths
Opaque; -5%, very irregular grains (-0.01 to 0.2 mm), disseminated throughout matrix.
Sp 85-402 V Porphyritic trachyandesite flow
MACROSCOPIC Porphyritic flow, fine/medium pinkish brown, phenocrysts (-1 to 5 mm)
in a medium brownish-grey fine/aphanitic matrix. Matrix flecked with fine strong disseminated chlorite (10%). Weakly amygdaloidal with carbonate and chlorite filling scattered small vesicles.
7
Stained slab indicates high percentage K-spar (30%) in matrix inter- stitial to plagioclase phenocrysts.
MICROSCOPIC Plagioclase phenocrysts (-1.0 to 5.0 mm) as single euhedral crystals or aggregates of crystals comprise 35% of the rock. The phenocrysts have a mottled dusting alteration which partly masks twinning. eminated irregular chloritic mafic.
Diss-
Minerals Present Phenocrysts 20%
Plagioclase; 20%, euhedral (0 .5 to 5.0 m m ) , dusted alteration, twinned, Irregular chlorite and carbonate grains produce a
35 ' unzoned An
seive texture Alteration 15%
Chlorite lo%,-irregular masses, brown and brown-green mottled, bladed/ granular, anomalous yellowgrange under X-nicols, common close association with carbonate. Filling vesicles?
. .
Carbonate; -5%, small irregular masses, (-0.05 to 0.5 mm) associated with clorite.
Matrix 65%
Plagioclase; 30%, fine (-0.02 to 0.1 mm) felted groundmass Chlorite; 5 % , fine aggregates interstitial to plagioclase K-spar; 25%, very fine, interstitial to plagioclase
Opaque; -5%, aggregates of very fine grains, (-0.01 to 0.03 mm) in matrix interstitial to plagioclase laths.
Sp 85-402 VI Oxidized, altered porphyritic gndesite flow (?)
MACROSCOPIC Clay altered, rounded to subangular porphyritic remnants surrounded by and containing internal concentric iron-stained zones with fine crushed, brecciated appearance but with preferred orientation of
8
of altered plagioclase crystals. Pinpoint drusyness, some coated with very fine granular black waxy material. Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Porphyritic with plagioclase phenocrysts (0.1 to f 2 mm), moderate "dusty" alteration,sericitic, weak zoning evident by poorly developed internal rings of more intense sericitic alteration. feldspathic, felted to fine granular, strong sericitic with scattered irregular sericite patches. granular quartz (albite?) and black opaque waxy material. Iron- stained areas contain limonitic, jarositic and hematitic lined cavities
Matrix fine
Pinpoint drusy zones lined with fine
and fracture fillings.
Minerals Present . . .
Phenocrysts; 50% . . An34 Plagioclase; 50%, euhedral/subhedral crystals, weak zoning,
sericitic alteration
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Matrix; 50% Feldspathic grains; 40%, felted/fine granular, (-0.01 to 0.05 m),
strong sericitic but with twinning still distinct, An34. "dusty" alteration throughout matrix.
Mottled
Sericite; 5%, alteration of plagioclase, acicular (0.01 to 0.02 mm)
and in fibrous masses filling former cavities in matrix. Quartz; -5%, as aggregates of fine grains (-0.01 to 0.04 mm) clear,
unaltered with (+) relief with respect to plagioclase, appears to be lining and filling cavities in matrix.
Opaque; +1% anhedral (-0.01 to 0.5 mm)
(a) metallic (b) opaque, greasy black granular substance partially filling drusy cavities (non mineral?)
9
c,
0
Hematite, jarosite, limonite, diffusions in layers and concentric shells in matrix. Jarosite and hematite also lines drusy open spaces and fills fractures.
Sp 85-406 Porphyritic andesite/dacite ( ? )
MACROSCOPIC Porphyritic volcanic, fine phenocrysts (to 1.0 mm) in a very fine light grey matrix. aggregates of grains.
Flecked with black chlorite and opaque grains and
Stained slab,,no evidence of K-spar
MICROSCOPIC Transmitted light Porphyritic texture, phenocrysts plagioclase (0.1 to 1.0 mm), sericitic and lesser carbonate alteration in a fine feldspathic altered matrix.
Altered/impregnated matrix contains twinned ani untwinned albite and quartz with diffuse irrggular networks and masses of sericite, carbonate and chlorite.' Scattered coarser (to 0.4 mm>
irregular grains of sericite.
Phenocrysts, 35%
Plagioclase; 30%, subhedral, (0.1 to 1.0 mm) moderate strong sericite, lesser carbonate alteration masking twinning, An Albitic alteration. 34 Sericite; -5%, subhedral (to 0.2 mm) widely scattered throughout matrix Quartz; trace, anhedral, (0.5 mm) associated with albite, carbonate and sericite. Uniaxial (+)
Matrix, 65%
Feldspathic material, fine granular (-0.01 to 0.05 mm) most grains strong sericitic, lesser carbonate alteration. Scattered fine aggregates of grains, clear unaltered but showing multiple twinning.
10
63
' L i
Albite; clear, unaltered, multiple twinned. Impregnation ( ? )
Quartz; suspected, not positively identified, poor uniaxial (+)
figures, irregular grains similar to albite. Impregnation ( ? )
Opaque; -l%, anhedral/subhedral grains (-0.01 to 0.6 mm) disseminated
and aggregates of grains.
Alteration Sericite; 20% diffuse masses of very fine grains (-0.01 to 0.02 mm)
Carbonate; 5%, diffuse masses of very fine grains, associated with sericite and chlorite Chlorite; -5%, diffuse masses of very fine grains associated with sericite and carbonate
Sp 85-407 Andesite crystal tuff (breccia)
MACROSCOPIC Light grey, mottled cream, fine fragmental. with scattered fragments to a few cms.. Weakly disseminated pyrite. Iron staining along crackle fractures Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Fine crystal tuff (breccia), lithic fragments are crystal tuff similar to the matrix they are in. Scattered fragments of flow rock. Abundant crystal fragments of disseminated plagioclase and altered mica (biotite) in a fine tuffaceous matrix composed of similar material. Breccia groundmass is mottled by patches of aggregates of less altered feldspar (albite) and quartz. intense ''dusting" of alteration and lack the mottling of less altered
albite and/or quartz aggregates. along fractures.
Lithic fragments are evident because of more
Irregular diffuse iron-staining
11
c3
Minerals Present Crystal and lithic fragments Plagioclase; 30%, crystal fragments, subhedral to sharp angular
(-0.2 to +3 mm) twinning masked by mottled "dusty" alteration, An 34- + '
Biotite; 15% anhedral/subhedral, shredded, altered to sericite, some remnants show brown birefringence, sieve texture as a result of alteration, pitted.
Opaque; 2%, anhedral (-0.01 to 0.5 mm) irregular grains and aggregates of grains
Sphene; trace anhedral (0.2 mm)
Matrix Feldspathic, very fine (-0.01 to 0.02 mm) with dusty alteration and sericite, mottled by fine granular, less altered aggregates of albite and/or quartz, poor uniaxial interference figure. altered mafic.
Clusters of shredded Diffuse iron staining along fractures.
Sp 85-409 Porphyritic trachyandesite flow
MACROSCOPIC Randomly disseminated pinkish plagioclase phenocrysts to 3.0 mm in a medium to dark grey fine grained to aphanitic matrix. Stained slab; shows strong K-spar content in matrix
MICROSCOPIC
Transmitted light Porphyritic flow, altered plagioclase and mafic phenocrysts in a fine feldspathic granular matrix with abundantly scattered small plagioclase laths. Phenocrysts clouded by varied intensity of alteration, dusting, sericite and carbonate. Mafics altered to mixture of chlorite and carbonate with some green mica and sericite/muscovite remnants. Noted few lithic
The fine granular component of the matrix may be largely K-spar.
12
fragments, feldspzthic flow rock, felted mass of plagioclase laths (0.05 to 0.5 mm)
Minerals Present Phenocrysts; 25%
Plagioclase; 15%, euhedral/anhedral, (-0.1 to 3.0 mm) twinning clouded with sericite in crystallographic 34 ’ by a dusting of alteration, An
orientation and lesser carbonate a1though:some crystals are almost entirely replaced by carbonate.
Mafic; -lo%, pseudomorphus outlines (-0.1 to 1.0 mm) altered to mixtures of carbonate and chlorite. Remnants of sericite/muscovite and green pleochroic high birefringent mica
Zircon (?) trace, anhedral (to 0.15 mm)
Opaque; -1% fine irregular grains and aggregates of grains Apatite; traces, euhedral (to 0.05 mrh)
Matrix; 75% feldspathic, fine granular texture (-0.01 to 0.02 mm) and Stained slab indicates high K-spar content small laths (0.05 mm).
which is probably represented by finegranular material inter- stitial to fine plagioclase laths.
Alteration; sericite and lesser carbonate alteration of plagioclase laths. Mixtures of chlorite and carbonate pseudomorphous after mafic. Carbonate and chlorite clasts scattered throughout matrix some of which are associated with former mafics.
Sp 85-410 Porphyritic trachyandesite flow breccia
MACROSCOPIC Coarse plagioclase phenocrysts to (4.0 mm) in a very fine/aphanitic medium reddish brown feldspathic, K-spar-rich matrix. with fine mafic crystals and very fine opaques. Mafic minerals are flecked by alteration.
Speckled
13
Contains lithic fragments of finer weakly porphyritic flow rock, richer in mafic than country rock. Stained slab; strong K-spar content in a fine/aphanitic matrix; lithic fragments also K-spar rich but less intense.
MICROSCOPIC Transmitted light Porphyritic flow with plagioclase phenocrysts to (4 .0 mm), clouded by "dusty" alteration and more conspicuous sericite and lesser carbonate in crystallographic orientation. to mixtures of chlorite, carbonate and sericite. Remnants of clear and green moderately birefringent micaceous material. felted mass of feldspar as small plagioclase laths and interstitial granular material, probably K-spar, showing brownish dusting of alteration and scattered patches of.chlorite, carbonate and sericite.
Smaller mafic crystal remnants altered
Matrix is a
. .
The lithic fragment (-0.1 to 0.5 mm) with altered mafic (-0.05 to 0 .3 mm). Widely
is a felted mass of fine plagioclase crystals
scattered phenocrysts to (2.0 mm). Groundmass and phenocrysts show similar sericite, chlorite, and carbonate alteration to the porphyritic country rock.
Minerals Present A. Country rock
Phenocrysts 35%
Plagioclase; 25% euhedral/subhedral, (0.2 to 4.0 mm), moderate to strong sericitic alteration, madks twinning, weak oscillatory zoning, An 35 *
&fic;,-lO%, remnant grains ( 0.2 to 0.5 mm ), complete alteration to chlorite and lesser carbonate, sericite. Some clear, brown and green, moderate birefringent mafic remnants.
14
Opaque; -l%, anhedral (-0.01 to 0.5 mm) aggregates of grains Apatite; trace, euhedral (-0.05 mm)
cj
Matrix 65%
Plagioclase, felted laths, strong alteration dusting( 0.05 to 0.2 mm)
K-spar; interstitial granular, strong alteration dusting, obscures textures
Quartz; -5%, fine anhedral grains, (0.01 to 0.03 mm) unaltered. Suspected, not confirmed by interference figure
Chlorite Carbonate Ser ic i te
B. Inclusion
. Phenocrysts 15% Plagioclase; -lo%, laths ( to 2.0 mm) sericitic Mafic; 20%, anhedral interstitial (-.01 to 1.5 mm) chloritic, green
mica remnants, moderate birefringence. Phenocrysts and groundmass.
Groundmass 85% Plagioclase; 40%, laths, (0.1 to 0.5 mm), felted, sericitic, K-spar; 30%, interstitial granular mass, clouded by alteration. Ouartz; -lo%, anhedral, (-0.01 to 0.03 mm) interstitial, unaltered
aggregates of grains (not confirmed by interference figures). Mafic; included with phenocrysts Opaque; -5%, anhedral grains (0.01 to 0.3 mm) single grains and
aggregates.
15
Sp 85-410-1 Porphyritic trachyandesite flow ( ? I
MACROSCOPIC Porphyritic flow; pink, cream-green plagioclase phenocrysts ( to 2 or 3 mm) with altered mafic (to 1.5 mm) in a very fine-grained to aphanitic medium-brown matrix. others sharp. Quartz not conspicuous. Mafics with distinct outline.
Outlines of somefeldspathic phenocrysts diffuse,
Stained slab; shows matrix is composed of a large percentage of fine granular K-spar which is almost entirely restricted to the matrix. Few stained flecks were noted within some of the plagioclase phenocrysts.
MICROSCOPIC Transmitted light Porphyritic flow, plagioclase and lesser mafic remnant phenocrysts in a very fine granular K-spar-rich matrix. moderate to strongly altered' by sericite and lesser. carb&ate. is evident by differing intensity of alteration. phenocrysts showing irregular but smooth rounded borders some of which are diffuse suggesting resorption. Pseudomorphous replacement of mafics by chlorite and lesser of alteration accompanied by chlorite, carbonate and sericite.
Plagioclase phenocrysts Zoning
Less than 5% quartz
carbonate. Matrix shows stro g "dusting" P
Minerals present Phenocrysts; 35% Plagioclase; 25%, euhedral/subhedral, (-01 to 2.0 mm) as single
crystals or aggregates, stong sericite and carbonate alteration, Varied intensity of alteration as a result masks twinning, An
of zoning. 34
Quartz; -5%, anhedral irregular (-0.05 to 0.5 mm) smooth rounded but irregular outlines, some with diffuse margins, Resorbed?
16
Mafic; -lo%, irregular grains and euhedral pseudomorphs, (0.01 to 1.0 mm), after mafics now composed of chlorite and carbonate.
Remnant grains of sericite/muscovite. ADatite; trace, euhedral (0.05 to 0.2 mm)
ODaaue; 1%, subhedral/anhedral (-0.01 to 1.0 mm)
Zircon; trace,stlbhedral (0.03 mm) high (+) relief, high birefringence
Matrix 65%
Feldspathic; K-spar and plagioclase with irregular blebs of chlorite. K-spar confirmed by stained slab.
Alteration Carbonate; irregular masses (0.01 to 1.0 mm) scattered through matrix
and replacing plagioclase and mafic grains in matrix and pheno- crysts. Close association with chlorite.
Sericite; irregular fibrous grains (0.01 to 0.05 mm) replacing plagioclase phenocrysts and feldspathic material in groundmass. 9 Chlorite; anhedral .irregular outlines and pseudomorphous after mafics, (0.01 to 1.0 mm), close association with carbonate. Fibrous aggregates. Disseminated fine interstitial grains throughout
matrix.
Sp 85-410 I1 A Porphyritic trachyandesite flow
MACROSCOPIC Pink color, diffuse porphyritic in a very fine grained/aphanitk groundmass. Leucocratic, weak, dark flecks mafic and opaque (sulphides) Stained slab; strong K-spar in matrix, interstitial to minute felted plagioclase laths.
MICROSCOPIC Transmitted light Porphyritic flow volcanic, plagioclase phenocrysts (0.5 to 1.0 mm)
17
cj containing patches of strong sericitic alteration.
clase laths, felted, interstitial K-spar. Matrix strong "dusting" of clay (?) alteration, lesser sericite. Scattered small masses of sericite, partly iron-stained,
Matrix of plagio-
pseudomorphous after mafic.
Minerals Present Phenocrysts ; 20%
Plagioclase; 15%, euhedral, (to 3.0 mm) strong patches sericitic alteration in felted-bladed masses, iron stained. Twinning masked by alteration, An 34
,Quartz; -5%, anhedral (to 0.2 mm), mottled extinction, aggregates of L grains.
Matrix, 80%
Plagioclase; small laths (-0.01 to 1.0 mm) sericitic alteration, dusting of clay alteration
K-soar; anhedral interstitial, (-0.01 to 0.15 mm) dusted clay (? )
Quartz; - lo%, anhedral, (-0.01 to 0.2 mm),rounded clear grains .
Opaque; -5%, anhedral (-0.01 to 0.3 mm) aggregates, iron stained.
alteration
Associated with sericitic masses. Zircon; trace, anhedral, 0.02 to 0.10 mm) high (+) relief and
birefringence Sericite, lo%, granular masses (to 0.lOmm) associated with opaque,
replacing mafic ?
Sp 85-410-11 B Crystal tuff polymictic lithic breccia
MACROS COP I C
Polpictic lithic flow and tuff fragments in a dense dark green fine fragmental matrix. Some fragments bleached and show strong epidote alteration.
Strong chloritic and lesser epidote alteration.
18
Stained slab; shows breccia flow fragments,contain abundant K-spar. Scattered smaller fragments are K-spar rich. Tuffaceous groundmass low K-spar content.
MICROSCOPIC Transmitted light Flow fragments; felted plagioclase laths in a fine feldspathic matrix Strong chloritic and lesser epidote and carbonate alteration associated particularly with plagioclase laths. Lithic tuff fragments, feldspathic, chloritic alteration in matrix,
Crystal tuffaceous matrix; broken plagioclase crystals (-0.05 to 2.0 mm), low anhedral quartz content commonly aggregates of grains in a finer feldspathic matrix. Strong chloritic alteration. Irregular masses of epidote and carbonate alteration,
Irregulai, discontinuous carbonate veinlets (-0.01 to 0.05 mm) thick. Lesser elongate siliceous and sericitic segregations
0
Lithic fragments; 35%
(a) Flow fragments Plagioclase; laths (0.05 to 1.5 mm) weak to moderate sericitic
alteration, spotted by epidote-carbonate alteration. K-spar; anhedral (-0.01 to 0.031, interstitial Apatite; trace, subhedral, (0.05 to 0.10 mm)
Alteration; FeldsDathic matrix, strong dark clay (? ) dusting Chlorite ED ido te Carbonate
irregular interstitial masses
cj (b) Tuff
Feldspathic, very fine fragmental (-0.01 to 0.03 mm)
Chloritic alteration forms matrix between feldspathic fragments
19
Crystal tuff groundmass; 65% Plaaioclase; 15%, euhedral fragments, (-0.05 to 2.0 mm) epidote-
carbonate and sericite alteration Feldspathic matrix, very fine fragmental
Chloritic alteration; between feldspathic fragments Sericite; irregular patches Epidote ] irregular patches associated with alteration of plagio- Carbonate clase crystal fragments or aggregates of plagioclase in
lithic fragments
Opaaues; +5%, anhedral, (-.01 to 0.3 mm), irregular blebs aggregates of very fine grains
Veins Carbonate, irregular discontinuous, (0.01 to 0.05 mm) thick
Segregations Quartz Sericite
Sp 85-410-111 Porphyritic trachyandesite
MACROSCOPIC Porphyritic flow; plagioclase, mafic and very minor quartz fragments in a medium brown-grey aphanitic matrix. Stained slab; plagioclase phenocrysts, trace of quartz in a very fine/ aphanitic groundmass of minute plagioclase laths with strong inter- stitial K-spar content.
MICROSCOPIC Transmitted light. Porphyritic, phenocrysts plagioclase, strong sericite-carbonate
20
alteration, twinning obscured. Partly resorbed quartz crystals. Mafic chlorite pseudomorphs with carbonate and opaques (some cubic pyrite outlines)
Minerals present Phenocrysts; 30%
Plagioclase; 15%, subhedral/euhedral (0.05 to 3.0 mm) strong sericite- carbonate alteration masking twinning
Mafic; lo%, subhedral/euhedral (-0.05 to 1.5 mm) chloritic aggregates pseudomorphous after mafic. Sericite-muscovite; trace, bladed crystals (to 0 . 3 mm)
Quartz; -5%, anhedral, rounded, (0.05 to 0.7 mm) sharp with locally
diffuse margins, partly resorbed. Apatite; trace, subhedral (to 0.1 mm)
Opaque; -5%, anhedral/euhedral (0.01 to 1.0 mm) commonly associated with mafic grains.
Matrix; 70%
Plagioclase 35% laths (-0.01 to 0.03 mm), felted K-SDar; 25%, anhedral (-0.01 to 0.03 mm) interstitial to plagioclase Quartz; -lo%, small anhedral quartz grains Opaque; -1% anhedral Moderate dusting of clay (? ) alteration, irregular blebs of chlorite,
weak sericitic.
85-410-V A Porphyritic trachyandesite flow
MACROSCOPIC Plagioclase phenocrysts to 2.0 mm in a medium grey very fine/aphanitic matrix. Flecked with black mafic. Stained slab; shows very strong K-spar interstitial to plagioclase microlites and small crystals in matrix.
2 1
c)
MICROSCOPIC Transmitted light Porphyritic, scattered euhedral/subhedral phenocrysts (to 2.0 mm),plagioclase showing strong carbonate, lesser sericite alteration. Matrix of felted plagioclase microlites and fine crystal laths with interstitial K-spar with strong dusting of clay (?) alteration. Green biotite/chlorite, 15%, as irregular interstitial radiating bladed masses (0.01 to 0.2 mm)
throughout matrix. chiefly. Disseminated opaque, -3%, anhedral grains and aggregates (-0.01 to 0.3 mm) with scattered coarser grains showing euhedral outlines. Iron stained in fractures.
Strong carbonate alteration affecting plagioclase
Phenocrysts; 20%
Plagioclase; -lo%, euhedral/subhedral (-0.3 to 2.0 mm) single and clusters of grains. Strong carbonate, weaker sericitic alteration.
Carbonate -lo%, euhedral pseudomorphs (to 1.0 mm) after plagioclase ( ? )
Snd as irregular masses
Matrix ; 80% Plagioclase; 30% microlite and fine laths (-0.01 to 0.3 mm), felted
mass K-spar; 20% anhedral (-0.01 to 0.03 mm) interstitial to plagioclase,
"dusted" alteration K-spar confirmed in stained slab. Quartz; -5%, anhedral grains and aggregates of grains (-0.01 to 0.3 mm)
unaltered, scattered through matrix., Biotite/(Chlorite); 15%, green, bladed, (-0.01 to 0.2 mm) radiating,
interstitial shows moderate birefringence strong pleochroism, parallel extinction. Chlorite, low birefringence, weaker pleochroism
Carbonate; 5 % - , anhedral (-0.01 to 0.2 mm) as described with phenocrysts but irregular masses scattered throughout matrix
Opaque; -3%, anhedral with scattered coarser grains euhedral, (-0.01 to 0.3 mm), aggregates of grains.
22
Sp 85-410 V B Crystal tuff lithic breccia cj
MACROSCOPIC Pseudoporphyritic crystal tuff, feldspar crystal fragments to 3.0 mm in a medium grey tuffaceous matrix. Widely scattered porphyritic flow fragments with plagioclase phenocrysts in a medium purplish grey matrix. Disseminated hematite grains. Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Crystal tuff groundmass, abundant subhedral plagioclase with lesser rounded quartz crystal fragments. and lesser sericite alteration. Tuffaceous groundmass, feldspathic altered by carbonate, sericite and chlorite.
Plagioclase shows strong carbonate
Scattered hematite grains.
. Widely scattered lithic porphyritic flow fragments to several cms. Plagioclase phenocrysts (to 2 mm) in a feldspathic matrix altered by carbonate, sericite, chlorite, Abundant fine grains disseminated hematite which gives the fragments their purplish color.
Minerals present Crystal tuff Fragments 40%
Plagioclase; 30%,fragments (-0.05 to 2.0 mm) subhedral, many broken, twinning masked by alteration, An33. lesser sericite along cleavage and in crystallographic directions.
guartz; -5%, rounded fragments (to 0.5mm)
Opaque; hematite, -2%, anhedral, (-0.01 to 0.8 mm) Unknown; -l%, anhedral (-0.3 mm), clear, moderate relief, isotropic Unknown; -l%, subhedral, perfect cleavage, light brown mottled pleochroism,
Alteration; strong carbonate,
low (grey) birefringence, parallel extinction, biaxial ( ? ) ,
associated with hematite.
23
Groundmass 60% Feldspathic fragments, 50%, (-0.01 to 0.1 m) anhedral Ouartz; -5%, anhedral (-0.01 to 0.05 mm) aggregates Alteration Ch 1 or i t e Carbonate
Lithic porphritic flow fragments Phenocrysts 40% Plagioclase; 40%, subhedral (to 2.0 mm)
-Matrix, 60% Feldspar, plagioclase; 45% Alteration Carbonate
Ser ici t e Chlorite u Opaclues; , 15%, hematite, anhedral (-0.01 to 0.20. mm) as aggregates of grains
Sp 85-410-VI Altered crystal tuff lithic breccia
MACROSCOPIC The breccia structure indistinctly visible on fresh cut surfaces. High fragment to matrix ratio. Fragments porphyritic showing variations in phenocryst content. Stained slab; no evidence of K-spar.
MICROSCOPIC Transmitted light Breccia fragments have a porphyritic/pseudoporphyritic texture, show similar mineralogy with varied relative amounts of minerals and varied size of groundmass grains among fragments. Plagioclase phenocrysts/
24
fragments show varied intensity of sericite and carbonate alteration. Matrix generally very fine granular, suggesting tuffaceous origin.
gome fragments in matrix are clouded by strong chlorite alteration but generally the matrix shows weak to moderate sericite with lesser carb- onate and chlorite alteration. Carbonate occurs as irregular masses replacing plagioclase phenocrysts and is matrix. the matrix. Iron-stained fracture surfaces.
scattered throughout the There are diffuse impregnations of quartz grains within
Minerals present Phenocrysts Plagioclase; 20%, euhedral (-0.1 to 1.0 mm) twinning masked by sericite
33 and lesser carbonate alteration An Unkndwn; -l%, subhedral rounded (to 0.5 mm) perfect cleavage, parallel
extinction, low birefringence, associated with hematite.
Phenocrysts/matrix Quartz; -20%, anhedral (-0.05 to 0.10 mm) aggregates of grains, probably
a result of siliceous impregnation.
Matrix FeldsDar; 40%, anhedral (-0.01 to 0.05 mm) granular
Alteration Quartz; see above, scattered aggregates of grains throughout matrix
and diffuse irregular veinlets. Sericite; alteration of plagioclase phenocrysts and matrix Carbonate; Chlorite ; associated with sericite
alteration of plagioclase phenocrysts and matrix
Opaque; -5%, fine anhedral, (-0.01 to 0.05 mm) aggregates of irregular grains.
25
Sp 85-410 VI1 Crystal tuff, lithic breccia
'. . c,
MACROSCOPIC Pseudoporphyritic crystal tuff, lithic breccia; plagioclase crystal fragments to 2.0 mm in a medium grey fine fragmental matrix. lithic fragments, porphyritic, some with hematitic groundmass,
Scattered
Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Plagioclase crystal fragments and traces of rounded quartz grains in a very fine fragmental feldspathic matrix. of former mafic crystal remnants with associated hematite fracture fillings in the grains. 'similar to crystal tuff groundmass. tuffaceous groundmass are affected by varied intensity of sericitic, chloritic and carbonate alteration. Strong chloritic alteration localized in some lithic fragments. Dusting of fine opaques with scattered coarser aggregates, some lithic fragments have strong hematitic clouding.
Sericite/muscovite remnants
Lithic fragments of flow rock and crystal tuff Crystal and lithic fragments and
Minerals present Phenocrysts 50%
Plagioclase; 45%, subhedral fragmental, (-0.5 to 2.0 mm). An 35 ' sericitic and carbonate alteration.
Quartz; -5%, rounded (to 0.5 mm) some with diffuse resorbed margins Muscovite/sericite; -l%, shredded
Unknown; traces, euhedral (to 0.4 mm) prismatic, parallel exti.nction, very low birefringence, blood red hematitic fracture fillings, reddish brown mottling, weakly pleochroic.
26
Groundmass 50% Plagioclase; fine fragmental (-0.01 to 0.05 mm) tuffaceous, altered
Alteration Sericite Carbonate Chlorite
Opaque; -5%, very irregular (-0.01 to 0.6 mm) disseminated throughout groundmass, hematitic, abundant in groundmass of some lithic fragments.
Veining;. diffuse, wispy sericitic and chlorite-rich partings.
Sp 85-411 Propylitic altered, quartz, K-spar impregnated crystal tuff.
MACROSCOPIC Volcanic crystal tuff with strong medium green coloration resulting from chlorite add epidote alteration. epidote pseudomorphs after feldspar and/or maf ics and as diffuse dis- continuous veins or screens. Disseminated euhedral pyrite crystals.
- _
LJ Chlorite pervasive in groundmass,
Impregnated by quartz and K-spar.
Stained slab; shows distinct K-spar grains, clusters of grains and diffuse "screens".
MICROSCOPIC Transmitted light Crystal tuff, altered plagioclase crystal fragments in a fine feldspathic matrix, brecciated, impregnated and altered by chlorite, quartz, epidote and K-spar. Disseminated pyrite crystals.
27
Minerals present Phenocrysts/crystal fragments Plagioclase; 20%, subhedral fragmental, (0.1 to 1.5 mm), zoned.
An 3 5 , with albitic rims. cores.
Some crystals with epidote altered
Opaquesi 2%, euhedral pyrite, (0.1 to 0.3 mm) as single and aggregates of crystals.
Matrix Feldspathic grains; +20%, fine granules (-0.01 to 0.1 m)
Chlorite; lo%, dust-like interstitial masses K-spar; -lo%, not positively identified in section but evident in
stained slab. Veins/impregnations/alteration
Quartz; +20%, very fhe/medium granular, (-0.01 to 0.2 mm), 'as discontinuous veins and diffuse impregnations of matrix
I Epidote; 15%, replacing cores of plagioclase crystal fragments and as very fine granular diffuse scre.ens and discontinuous veinlets.
Sp 85-411-1 Altered crysGal tuff
MACROSCOPIC Brecciated crystal tuff, dark green-grey, altered by epidote, chlorite, carbonate and K-spar. Weak veining, scattered siliceous lithic fragments.
Stained slab; indicates K-spar alteration
MICROSCOPIC Crystal tuff, feldspar crystal fragments A a very fine feldspathic matrix altered and impregnated by chlorite, epidote, carbonate, silica and K-spar. Veining by carbonate and coarse epidote.
Weak disseminated aggregates of very fine opaque-grains.
28
Minerals present Fragment s Plagioclase; 25%, euhedral/subhedral, (0.01 to 1.0 mm), altered by
epidote and carbonate Quartz; -lo%, anhedral, (.05 to 0.1 mm)
Matrix Feldspathic material, (-0.01 to 0.05 mm)
Alteration and impregnation Silica Epidote Chlorite Carbonate
Veining Carbonate Epidote
I Sp 85-411-111 Altered andesitic ( ? ) volcanic flow . -
. . MACROSCOPIC
ci Volcanic flow, dark grey-green, fine-grained, massive, with strong chlorite-epidote alteration. veinlets. Stained slab; shows patches of disseminated distrinct K-spar grains
Weak discontinuous network of epidote
MICROSCOPIC Felted texture of fine/medium-grained plagioclase crystals in a fine feldspathic groundmass altered by chlorite-epidote and lesser carbonate
Minerals present Phenocrysts Plagioclase; 30%, euhedral, (0.1 to 1.0 mm) An35 felted mass
Matrix Feldspathic grains; 25%, fine interstitial grains (-0.01 to 0.05 mm)
29
cj
Matrix (continued) K-spar; -5%, not positively identified in thin section, confirmed in
stained slab Chlorite; 15%, interstitial alteration Epidote; 20%, interstitial alteration, lesser alteration of plagio-
clase phenocrysts Carbonate; -10% interstitial alteration Opaque; -10% aggregates of minute dust-like grains forming irregular
clots (to 0.24 mm>
Veining
~ Epidote Carbonate
Sp 85-411-IV A Altered crystal tuff, lithic breccia
MACROSCOPIC 9
Altered crystal tuff lithic byeccia; dark grey-green groundmass, strong chlorite, epidote alteration.’ Disseminated, altered, fine/medium-grained plagioclase crystal fragments. Wide spaced altered lithic fragments. Weak hematitic blebs. Stained slab; K-spar evident as distinct grains concentrated in clots and as discontinuous networks of very diffuse veinlets
MICROSCOPIC Altered plagioclase crystal fragments in a very fine feldspathic matrix altered by chlorite, epidote, carbonate occurring as irregular clots. Cut by irregular veinlets and discontinuous diffuse stringers of epidote and lesser carbonate
Minerals present Crystal fragments plagioclase; 25%, euhedral/subhedral fragments (-0.05 to 1.0 mm)
epidote and carbonate alteration
30
Matrix Feldspathic grains; 30%, plagioclase; K-spar not positively identified
in matrix except in veinlets Opaque; 1%, clusters of minute dust-like grains
Alteration Epidote; 20%, aggregates of minute grains forming interstitial clots
(to +1.0 mm). Lesser clusters of grains in altered plagioclase crystal fragments
Chlorite; lo%, aggregates of fine grains forming interstitialxlots. K-spar; -5%, diffuse impregnations, aggregates of fine grains,
"dusty" a1 terat ion Carbonate; -lo%, aggregates of fine grains forming interstitial clots
Clusters of grains in altered 'plagioclase crystal fragments Veins Epidote; coarse bladed crystals (to 1.5 mm)
Carbonate; diffuse veinlets . K-spar; associ,ated with epidote
Sp 85-411-IV B Altered crystal tuff
MACROSCOPIC Disseminated fine plageoclase and mafic crystal fragments in an aphanitic
pinkish brown matrix. Strong chlorite, epidote alteration. Veined by chlorite and lesser carbonate. Stained slab; shows fine granular K-spar comprising a high percentage of interstitial material between plagioclase and mafic crystal fragments.
MICROSCOPIC Porphyritic texture, plagioclase crystal fragments altered by sericite, carbonate, epidote, chlorite. Chlorite aggregates with carbonate pseudomorphous after mafic crystal fragments. matrix altered by epidote, chlorite, carbonate with an over all reddish
Feldspathic K-spar-rich
31
brown alteration dusting. granules and scattered grains (to 0.15 mm).
carbonate, very weak quartz.
Opaque occurs as aggregates of very fine Veined by epidote, lesser
Minerals present Crystal fragments Plagioclase; 25%, subhedral/euhedral fragments (-0.05 to 1.5 mm),
sericitic with lesser carbonate and epidote alteration.
masked by alteration. Twinning
Mafic; lo%, mixtures of chlorite and carbonate pseudomorphous after mafic grains
Matrix Feldspathic wains; 30%, K-spar, fine granular (-0.01 to 0.05 mm),
red-brown alteration dusting Opaque; 5%, aggregates of very fine opaque granules (-0.01 to aggregates
of- 0.10 m)
Alteration Epidote Chlo r i t e Carbonate Sericite
Veins Epidote Carbonate Quartz
Sp 85-411-V T.S. (2) Altered volcanic flow/crystal tuff
MACROSCOPIC Fine porphyritic flow/crystal tuff, fine plagioclase and mafic pheno- crysts with clots of epidote-chlorite alteration in a pinkish brown aphanitic matrix. Stained slab; shows high percentage of K-spar comprises interstitial aphanitic matrix.
Composite vein of epidote-quartz
32
cj
MICROSCOPIC Altered fine plagioclase and mafic phenocrysts/crystal fragments in a very fine granular K-spar-rich matrix. epidote and shows diffuse margins. granules. feldspar crystal fragments. crystals. specks which occur as crystallographically controlled hair-like structures and associated with epidote-rich Znterlayers.
Plagioclase altered by
Matrix altered by clots of epidote Pervasive reddish brown alteration dusting of matrix and
Disseminated hematitic euhedral pyrite Veined by quartz darkened by an abundance of minute opaque
Minerals present Phenocrysts Plapioclase; 25%, euhedral, (-0.05 to 1.5 mm) most twinning masked
An33 by alteration, Chlorite; 15%, clots, some with pseudomorphic outline possibly re-
placing mafic. Unknown 111 , trace , blue grey to brownish pleochroic mineral , bladed
low birefringence. Unknown #2 euhedral, high (+> relief, isotropic grain.
Matrix Feldspathic material; 40%, K-spar as idicated by stained slab. Fine
granular (-0.01 to 0.05 mm), clouded by light brown alteration dusting .
Alteration Chlorite; 15%, pseudomorphs after mafic and irregular masses Epidote; 25%, alteration of plagioclase and. as clots of aggregates of
fine grains forming irregular masses in matrix. Carbonate; weak Sericite; weak Quartz; scattered aggregates of fine anhedral grains
Veins Composite quartz, epidote, very fine opaque
33
Silicified brecciated crystal tuff
MACROSCOPIC Plagioclase crystal tuff lithic fragments are chloritic and epidotized Fragments of composite opaque-rich quartz veins. forms the groundmass between lithic and vein fragments. Stained slab; some crystal tuff fragments show strong K-spar content interstitial to fine plagioclase crystal fragments.
Fine siliceous material
MICROSCOPIC Brecciated, altered plagioclase crystal tuff with very fine feldspathic plagioclase and K-spar matrix containing clots of epidote and pervasive chloritic alteration. anhedral siliceous grains. Disseminated hematitic pyrite crystals and .
Groundmass between breccia fragments fine
grains.
Minexals present Lithic fragments Crystal fragments Plagioclase; epidote alteration Opaque; hemetitic pyrite
Matrix Feldspathic grains, K-spar and plagioclase Opaque
Alteration
Epidote and chlorite as clots and pervasive chlorite alteration Groundmass Quartz
cj
34
,
.cj
SD 85-411-VI1 Trachyandesite flow
MACROSCOPIC Porphyritic flow, scattered plagioclase and lesser mafic phenocrysts in pinkish brown aphanitic matrix. suggested by plagioclase phenocrystxich clots. Stained slab; matrix between plagioclase phenocrysts rich in K-spar.
Possible flow breccia nature
MICROSCOPIC Plagioclase phenocrysts showing little alteration, clots of chlorite and aggregates of quartz grains in a very fine feldspathic (plagioclase and K-spar) matrix. "dusty" a1 t era t ion.
I
Matrix shows weak pervasive chloritic and
Minerals present 9
Crystal fragments . . I
Plagioclase; 15% (locally 50%), euhedral. crystals, An34, (-0.05 to
0.4 mm), weak dusting of alteration Quartz; -5%, anhedral grain (to 0.3 m) as clusters of grains Mafic; chloritic alteration
Matrix Plagioclase; 35%, euhedral/subhedral laths t o microlites, (-0.01 to
0.05 mm)
K-spar; 35%, anhedral (-0.01 to 0.05 mm) reddish brown alteration dusting
Opaque; 2%, anhedral (-0.01 to 0.05 mm) single grains and aggregates Alteration Carbonate; lo%, irregular masses Chlorite; -5% irregular grains in matrix
35
SD 85-4 11-VI11 i j
Porphyritic trachyandesite flow
c?
cj
MACROSCOPIC Weak porphyr,tic, with fine plagioclase phenocrysts and finer mafic grains in a brick red aphanitic groundmass, Stained slab; indicates a high percentage of K-spar, interstitial to plagioclase and mafic phenocrysts and plagioclase microlites in matrix.
MICROSCOPIC Weakly altered plagioclase and chloritic mafic phenocrysts and aggregates of anhedral quartz grains in an aphanitic groundmass of plagioclase microlites in interstitial K-spar. Matrix has light to medium reddish brown colored dusting of alteration. Opaque dusting of minute flecks and aggregates of flecks; scattered coarser irregular grains.
Minerals present Phenocrysts and segregations Plapioclase; 15%, euhedral/subhedral, (0.1 to 1.5 mm) An34,
Mafic; -5%, chloritic alteration, irregular aggregates (-0.05 to 0.5 mm)
quartz; -5%, anhedral grains and aggregates Opaque; -l%, scattered anhedral grains and irregular aggregates of
slight dusting of alteration, patches of carbonate alteration
(0.05 to 0.5 mm)
grains Matrix Plagioclase; 40%, anhedral microlites (-0.01 to 0.05 mm) K-spar; 35%, interstitial grains, (-0.01 to 0.05 mm)
Opaque; 2%, minute anhedral flecks and aggregates Alteration Carbonate; alteration of plagioclase w r i t e ; alteration of mafics
Sp 85-411-IX Porphyritic trachyandesite flow
As for 85-411-VI11 but slightly coarser grained matrix. hematitic pyrite crystals.
Disseminated
36
MINERALOGRAPHY
Sp 85-402 Pb, Zn, Cu mineralization in carbonate-quartz groundmass.
MACROSCOPIC Mottled pinkish cream intergrowth of carbonate and lesser quartz with irregular discontinuous veinlets and irregular masses of galena, sphalerite with lesser chalcopyrite and pyrite. Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Predominantly carbonate with irregular masses and diffuse veinlets of quartz. opaque and scattered irregular chlorite aggregates. 10% opaque minerals.
Quartz is associated with irregular discontinuous stringers of
Approximately,
Minerals present Carbonate; 60%, irregular intergrown masses Quartz; 30%, irregular stringers and masses, anhedral grains
(-0.05 to 0.5 mm)
Chlorite; -l%, irregular anhedral masses (to +1.0 mm)
Opaques; -lo%, see below Reflected light Minerals present
Sphalerite; 4.5%, anhedral (-0.01 to 3.0 mm), irregular grains and masses, exsolved chalcopyrite, galena,lesser pyrite blebs scattered in crystallographic orientation .
Galena; 40%, anhedral (-0.01 to 2.0 mm) very irregular, cuts pyrite, sphalerite.
Pyrite; 1%, anhedral, scattered euhedral grains, (-0.05 to 0.3 mm)
veined by galena and gangue.
37
c,
I
Chalcopyrite; 0.5%, anhedral (-0.05 to 0.1 mm) minute free blebs and coarser intergrowths with pyrite, galena, sphalerite. Exsolved blebs in sphalerite. Veins pyrite, sphalerite.
Suggested Paragenesis
Pyrite -4
1 apna
I ba I ena I t Chalcopyrite
i
Sp 85-403 Pb, Zn mineralization in quartz and barite
MACROSCOPIC Mottled light to medium grey quartz-chlorite mixture greenish tint, cut bycream barite. Stained slab; no evidence of K-spar.
Scattered irregular blebs of sulphides.
MICROSCOPIC Transmitted light Groundmass mainly quartz, anhedral with crushed zones, interstitial anhedral chlorite. Veined by barite and to a lesser extent carbonate.
Minerals present Quartz; 60%, anhedral grains (-0.05 to 1.5 mm) anhedral Barite; 25%, anhedral, coarse crystals (to +3.0 mm) Chlorite; -5%, anhedral (-0.2 mm) interstitial shredded appearance Carbma te; - lo%, anhedral grains, veinlets and interstitial grains Opaques; 5%, see below
38
Q Reflected-light
Opaques; 5% of sction, clusters of grains
'0
Minerals present SDhalerite; 3.5%, anhedral (-0.05 to 2.0 mm)
Galena; -l%, anhedral (-0.05 to 1.5 mm) irregular grains, cuts sphalerite, pyrite
Pvrite; -0.5%, anhedral/euhedral, (-0.05 to 0.1 mm) scattered grains Chalcopyrite; trace, (-0.0025 to 0.01 exsolved blebs in sphalerite
Suggested paragenesis
Pyrite I Sphalerite
Sp 84-451
Chalcopyrite t------- --I Ga 1 ena
1'- I
Pb, Zn, Ag mineralization in quartz
MACROSCOPIC Mainly quartz groundmass and lesser barite (? ) with diffuse masses of sulphides, mainly sphalerite and galena Stained slab; no evidence of K-spar
MICROSCOPIC Transmitted light Quartz groundmass with varied size crystals and grains ranging from (-0.01 to several mm)
39
Minerals present
Quartz; 65%, crystals grains outlined by "dusty" margins, (-0.Olmm to several mm)
Ouaaues; 35%, see below Reflected light
gDaques &35% of section Sphalerite; 25%, as netted masses (to several ram) and as isolated
grains (-0.05 to 0.5 mm).
irregular grains of galena Containing blebs of chalcopyrite and
Galena; 6 % , irregular grains (-0.05 to several mm) and irregular discontinuous veinlets cutting sphalerite
Chalcouvrite; 3%, anhedral grains and masses, exsolved blebs in sphalerite (-0.05 to 0.3 mm)
Polybasite; 1%, irregular (-0.05 to 0.2 mm) associated with galena, chalcocite and chalcopyrite. reflection
Anisotropic, reddish intemal
Pvrite; trace', anhedral (to 0.15 ram> Covellite; traces, rimming and in fractures in chalcopyrite Reddish
birefringence.
Suggested paragenesis
t - Pyrite
t 1 Sdha le r i t e
I Galena
Chalcopyrit t
-1 +-- - - - Polybasite
P-1
P6-0 to 1 Sp 85-401 Plain light Scale Y 0.lm
Limonitic, oxidized secondary breccia representing hydrothermal centre
r- P6-3 to 4 Sp 85-402-IIIA X nicols Scale Y
0 . l m Trachyandesite flow breccia, very fine felted plagioclase- K-spar-rich matrix/tuffaceous texture containing coarser textured flow fragments. Carbonate veinlet. Chlorite,carbonate alteration.
I P6-4 to 5 Sp 402-LV X nicols Scale I 4
.0.1 IIlIIl Porphyritic trachyandesite flow showing weak sericitic altered plagioclase phenocrysts in a fine felted plagio- and interstitial,K-spar matrix. Mafic altered to mixcure of carbonate and chlorite.
P6-5 to 6 Sp 402-V X-nico 1 s Scale
Porphyritic trachyandesite flow, showing plagioclase phenocrysts in a felted interstitial K-spar. chlorite and carbonate
groundmass of plagioclase with Alteration irregular clots of
Y 0.lmm
X-nicols P6-6 to 7 Sp 402-YI
~ 6 - 7 to a
Scale
Porphyritic andesite flow, altered, plagioclase and lesser chloritized mafic in a fine felted plagio- clase-rich matrix.
Sp 406 X-nicols Scale
Porphyritic andesite, sericitic, lesser carbonate, alteration with albite and very weak quartz alteration/ impregnation
Y 0.lm
H 0.lm
I P6-8 to 9
P6-9t010
W
Scale H 0.lm
Andestitic crystal tuff breccia; lithic fragments are crystal tuff similar to tuff matrix. Groundmass mottled by patches of less altered feldspar (albite) and quartz. Altered biotite (?) mafic.
\ I Sp 409 X-nicols Scale
Porphyritic trachyandesite flow. Altered plagioclase (sericite and carbonate) with lesser chlorite/carbonate altered mafic phenocrysts in a felted matrix of minute plagioclase with strong interstitial K-spar.
H 0.lm
P-5
P6-llto12 Sp 410-1 X-nicols Scale W 0.lm
Porphyritic trachyandesite flow (?) with plagioclase and lesser chloritized remnant mafic and a few rounded resorbed quartz phenocrysts in a fine granular K-spar matrix. Moderate sericite, carbonate, chlorite alteration.
X-nicols Scale P6-13to14 Sp 410-IIB
Crystal tuff polymictic lithic breccia containing flow and crystal tuff fragments in a fine feldspathic matrix Chlorite, epidote and carbonate alteration.
U 0.lm
P-6
I
W
P6-15to16 Sp 410-VA X-nicols Scale H 0.lm
Porphyritic trachyandesite flow, plagioclase pheno- crysts showing strong carbonate, lesser sericite alteration in a felted groundmass of plagioclase laths with interstitial K-spar. Chlorite alteration of biotite (? )
P6- 16t0 17 Sp 410-VB X-nicols Scale H 0.lm
Crystal tuff lithic breccia containing lithic flow fragments in a crystal tuff groundmass. sericite, chlorite alteration. Scattered hematite grains.
Carbonate,
P-7
P6-18to19 Sp 410-VI1 X-nicols Scale U 0.lmm
Crystal tuff lithic breccia; plagioclase and traces of rounded quartz fragments in a tuffaceous feldspar matrix. intensity of sericite, carbonate and chlorite alteration.
Lithic flow and crystal tuff fragments. Varied
P6-19to20
i
Sp 411 X-nicols Scale Y 0.lm
Crystal tuff impregnated by quartz, K-spar and albite(?) and altered by epidote, chlorite, carbonate. Disseminated pyrite crystals.
P-8
I
P6-20t021 Sp 411-1 X-nicol s Scale
Crystal tuff, altered and impregnated by epidote, carbonate chlorite, silica, and K-spar. carbonate and epidote
. Veining by
U 0.lnrm
P6-21t022 Sp 411-111 X-nicols Scale
Andesite ( ? ) flow,altered and impregnated by chlorite, epidote,carbonate and K-spar.
U 0.lm
P7-0
w . .
P7-2
. . . ,
Sp 411-VI X-nicols Scale
Brecciated silicified, epidotized, chloritic altered and impregnated crystal tuff (? )
P-9
Sp 411-VI11 X-nicols Scale
Porphyritic trachyandesite flow, weak carbonate and chlorite alteration.
Y 0.lm
U 0 . l m
P-10
P7-4
P7-5
Reflected l ight Scale Sp 451
Polybasite (P) with sphalerite (S), chalcopyrite (C) galena (G) and cove l l i t e (CV)
Sp 451 Reflected l ight
A s for P7-6 above
Scale
U 0.lm
M 0.lm
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