12. site 42

12. SITE 42

The Shipboard Scientific Party1

SITE BACKGROUND

Site 42 is one of the series of sites selected by thePacific Advisory Panel along the 140th meridian tosample the longitudinal variation in sediment composi-tion in the eastern Pacific. The site is located in anarea of abyssal hills between the Clarion and ClippertonFracture Zones, and is at the northern margin of thethick development of acoustically transparent sedimentextending along the equator.

The average water depth in the site area is about 4800meters. The bottom topography is shown by the Argosurvey to consist of 40 to 60 meter- high abyssal hills,separated with north-south trending groups by narrowV-shaped troughs. The sediments are uniformly dis-tributed over the area above a reflector between 0.1and 0.15 second below the sea floor. Piston cores takenby Argo consist of siliceous ooze overlying calcareousooze and the bottom photographs show scatteredmanganese nodules and current ripple marks.

B.ecause of the uniformity of sediment thickness,little difficulty was experienced in locating the siteduring the approach of Glomar Challenger. The upperflank of one of the groups of abyssal hills was selectedas the drilling site. The underway seismic profilesrecorded the strongest and most continuous reflectorat a depth of 0.15 second with occasionally an indistinct,weak reflector showing below it. The on-site profile(Figure 1) recorded 0.13 second of acoustically trans-parent sediment above the reflector. Subsequent drill-ing revealed this reflector (100 meters) to be chertwhich terminated the drilling and prevented theobtaining of cores from the underlying sediment.Neither from the drilling nor seismic profile canany statement be made on the thickness, age or com-position of the sediment between the 0.13 second

-BOTTOM 4844 m (corr.-0.13 CHERT

—

D. A. McManus, University of Washington, Seattle, Washing-ton; R. E. Burns, ESS A-University of Washington, Seattle,Washington; C. von der Borch, Scripps Institution of Oceanog-raphy, La Jolla, California; R. Goll, Lamont-Doherty Geo-logical Observatory of Columbia University, Palisades, NewYork; E. D. Milow, Scripps Institution of Oceanography,La Jolla, California; R. K. Olsson, Rutgers University, NewBrunswick, New Jersey; T. Valuer, Indiana State University,Terre Haute, Indiana; O. Weser, Chevron Oil Field ResearchCompany, La Habra, California.

Figure 1. On-site seismic reflection profile at Site 42(5 second sweep).

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reflector and an underlying basalt. The nearness of thesite to the magnetic equator renders useless the magneticanomaly method of dating the crust in this region.

Location

Sites 42.0 and 42.1 are located at latitude 13° 50.56'N,longitude 140° 11.3l'W on the upper flank of a groupof abyssal hills.

OPERATIONS

Coring began on 26 May in 4844 meters of water (Table1). Continuous coring proceeded to the depth of theresistant material at 100 meters. The sediment in Cores3 and 4 were somewhat stiffer than in the other cores.The plastic liner collapsed during the taking of Core 3and the sediment in the barrel had to be extruded. Thecoring rate for Core 4 was slower than for the othercores; the remainder of the section was cored rapidly.Coring was stopped upon contact with the resistantmaterial at 100 meters, and the ship was moved 200feet (65.6 meters) to the east after the drill stringhad been pulled up to the mud line.

The first operation at Hole 42.1 was the attempt atgeothermal measurements. This attempt proved unsuc-cessful and was followed by measurements with anaccelerometer in the drill string. The sediment section

was then drilled to the resistant bed and coring wasresumed (Table 2). Core 1 at Hole 42.1 consisted ofthe recovery of 23 feet cut in the chert. Since 26 feetwere recovered, the significance of the ooze whichformed the core is uncertain. Core 2 was taken with avery low rate of penetration and, subsequently, thecenter bit was dropped in order to drill through thechert into softer sediment. Core 3 was attempted insofter sediment, but as the chert was interbedded withthe softer material, the core barrel hit another layer ofchert and penetration ceased. No torque was beingrecorded, and the bit was thought to be worn out. Thehole was abandoned. Later examination showed thatmost of the diamonds on the bit had been lost and thebit had been worn smooth.

LITHOLOGY

Hole 42.0

At Hole 42.0, 100 meters of sediment were cored fromthe sea floor to the bottom of the hole at 100 meters.This interval was continuously cored, and core recoverywas complete except for the 5-foot recovery in Core 3(18 to 27 meters). Resistant beds which proved to besiliceous to cherty well-cemented biogenous sedimentsterminated the coring operations. Most cores had someintervals wherein relatively undeformed sedimentarystructures could be examined.

TABLE 1Drilling Summary of Leg 5, Hole 42.0

Date

26 May

27 May

Core

1

2

3 a

4

5

6

7

8

9

10

11

Depth BelowSea Floor

(m)

0-9

9-18

18-27

27-37

37-46

46-55

55-64

64-73

73-82

82-92

92-100

Depth BelowRig Floor

(ft)

15,950-15,980

15,980-16,010

16,010-16,040

16,040-16,070

16,070-16,100

16,100-16,130

16,130-16,160

16,160-16,190

16,190-16,220

16,220-16,250

16,250-16,279

Totals

(ft)

30

30

30

30

30

30

30

30

30

30

29

329

CoreCut

(m)

9.1

9.1

9.1

9.1

9.1

9.1

9.1

9.1

9.1

9.1

8.8

99.8

CoreRecovered

(ft) (m)

30

30

5

30

30

30

30

30

29

30

29

303

9.1

9.1

1.5

9.1

9.1

9.1

9.1

9.1

8.8

9.1

8.8

91.9

Per CentRecovered

100

100

17

100

100

100

100

100

97

97

100

92

aPlastic liner collapsed in Core 3 and the core was extruded.

Note: Sonic water depth (corrected): 4844 meters; 15,901 feet; 2650 fathoms.Driller's depth: 15,950 feet.

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TABLE 2Drilling Summary of Leg 5, Hole 42.1

Date

28 May

Core

l a

2

3

Depth BelowSea Floor

(m)

100-107

107-109

113

Depth BelowRig Floor

(ft)

16,279-16,302

16,302-16,306

16,322-16,323

Totals

(ft)

23

4

0

27

CoreCut

(m)

7.0

1.2

0.0

8.2

CoreRecovered

(ft) (m)

26.0

0.5

0.0

23.5

7.9

0.2

0.0

8.1

Per CentRecovered

100

13

87

Because of the excessive recovery, much if not all of the core must be considered suspect.

Note: Sonic water depth (corrected): 4844 meters; 15,901 feet; 2650 fathoms. Driller's depth: 15,950 feet.

The sediments at Hole 42.0 consist almost entirely ofvarying percentages of two biogenous components,radiolarians and calcareous nannoplankton. The cal-careous nanonplankton portion is composed mainly ofcoccolithophorids, a lesser number of discoasters andminor amounts of sphenoliths and other forms. Inaddition to the biogenous components, the sedimentscontain small amounts of "red" clay which gives colora-tion to the strata.

The relative proportions of siliceous and calcareousmicrofossils can be used to subdivide the 100 metersof sediments into several lithologic units which aregradational, one into the other.

From Core 1 through the upper part of Core 4 (0 to32 meters), there are beds of pale orange to paleyellow-brown nannofossil ooze and radiolarian nanno-fossil ooze. This is the only unit containing significantamounts of nannofossil ooze.

The next unit which extends from the lower part ofCore 4 to the end of Core 7 (32 to 64 meters), containsa moderate-yellow-brown to moderate-brown nanno-fossil radiolarian ooze and radiolarian ooze. Significantamounts of radiolarian nannofossil ooze are found inCore 6. The radiolarian oozes have their greatest devel-opment in this unit.

The next unit encompasses Core 8 and part of Core 9(64 to 74 meters), and is exclusively a light yellowbrown to light brown gray radiolarian nannofossil ooze.

The lowest unit occurs in the interval 74 to 100 meters.Here, within each bed, radiolarians and calcareousnannoplankton are found in relatively equal percentagesas radiolarian nannofossil and nannofossil radiolarianoozes. One interval of radiolarian ooze is present inCore 10.

The hole apparently terminated in a hard opaline-to-cherty cemented biogenous ooze (see Lithology, Hole42.1).

Two other minor lithologic constituents are foundsparsely throughout the hole. Manganese nodules occurin Cores 5, 6 and 9; and, pumice fragments appear inCores 2, 4, 6, 8, 9, 10 and 11. All the pumice fragmentsare unaltered, except for one in Core 9 which hasdeveloped zeolites along the perimeter of the glassshards.

Most of the bedding seen at this hole occurs in thin-to-medium thick beds. The contacts are sharp to grada-tional. Commonly, slight-to-moderate burrow mottlingcan be seen in the undeformed sediments.

Hole 42.1

At Hole 42.1, 113 meters of sediment were penetrated;the upper 100 meters being drilled. Coring commencedat 100 meters, and three cores were taken to the totaldepth at 113 meters. Core 1 (100 to 107 meters) hadcomplete recovery. Core 2 (107 to 109 meters) onlyhad recovery from the core catcher, and the recoveryfrom Core 3 (109 to 113 meters) was solely from thecenter bit.

One lithologic unit was penetrated at this hole, consist-ing of interbedded hard and soft biogenous layers. Thesoft layers are light gray, light-gray brown and very darkgray-brown radiolarian-nannofossil, nannofossil-radio-larian and radiolarian oozes of which the latter is thedominant lithology. The hard layers are represented byflat dipping beds of hard, dense opaline or chert ce-mented biogenous ooze, similar in composition to thatfound in the soft layers. In addition to beds of thismaterial in the core catcher of Cores 1 and 2, chips andfragments are present in the center bit of Core 3 and inSections 1 and 3, of Core 1. The latter occurrence

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probably reflects material from a bed just above thetop of the cored interval. This bed represents a horizonwhich should be continuous with the hard horizon thatterminated drilling at Hole 42.0. Lithologically, thesediments at this hole represent a continuation of thematerial present near the bottom of Hole 42.0

The undeformed portion of the soft sediments in Core 1and the hard layers in the core catchers of Core 1 and2 had local slight-to-moderate burrow mottling.

PALEONTOLOGY

Nannofossils

Calcareous nannoplankton occur essentially throughoutthe cores from the two holes (42.0 and 42.1) drilledat this site. The calcareous nannofossils are quite abun-dant in the Upper Oligocene portion; they are less com-mon in the more siliceous fossil-rich parts of the LowerOligocene and Middle Eocene sediments; and they arerelatively sparse in the in situ representatives of theUpper Eocene siliceous ooze sequence. Preservation isquite good in the calcareous-rich sediments, thoughsome forms show enlargement or thickened parts dueto some calcification. In the siliceous oozes where thecalcareous forms are less common, some etching anddisaggregation of specimens is present. The preservationis only fair, with considerable overgrowths noted onspecimens scraped from the harder limestones recoveredin Core 2 of Hole 42.1

A few diatoms are present at scattered intervals. Cos-cinodiscus tuberculatus Greville, C. marginatus Ehren-berg, and C. vigilans A. Schmidt occur intermittentlyin the Oligocene in Cores 2, 3 and 4 of Hole 42.0 C.radiatus Ehrenberg, Liostephania spp., and Rhizoso-lenia sp. occur infrequently in the Middle Eocene sedi-ments from Cores 9 through 11 of Hole 42.0

Except for the top and bottom-most portions of theOligocene, an apparently complete sequence represent-ing the remainder of this series was cored (Hole 42.0,Cores 1 to 3 and most of 4). The boundary betweenthe Upper Oligocene and Lower Miocene is not repre-sented; and, possibly, part of the lowest Oligocene ismissing at this site.

Dominant calcareous species which occur throughoutthis Oligocene sequence include Coccolithus pelagicus(Wallich), Cyclococcolithus neogammation Bramletteand Wilcoxon, Discoaster adamanteus Bramlette andWilcoxon and vars., and Sphenolithus morifoπnis(Bronnimann and Stradner). Other calcareous formswhich range throughout this sequence include: Cocco-lithus bisectus (Hay, Mohler and Wade)—morefrequent below the middle of Section 3 of Core 2; C.eopelagicus (Bramlette and Riedel)—more frequent be-low Section 1 of Core 2; C. cf. C. scissurus (Hay, Mohler

and Wade) of Bramlette and Wilcoxon—more commonand with larger specimens occurring below Section 1 ofCore 2; Coronocyclus nitescens (Kamptner); Discoaster deflandrei Bramlette and Riedel—occurring withgreater abundance in the upper part of Core 1; D.adamanteus obtusus Gartner; D. sp. aff. D. aster Bram-lette and Riedel; and, D. woodringi nephados Hay-quite frequent in the upper part of Core 1 and becomesrare with scattered occurrences below the lower part ofCore 2.

Of considerable interest is the lack of certain groups orspecies in this Oligocene section which have been re-ported from comparable Oligocene sections in other lowlatitude areas of the Atlantic and the Indo-Pacific(Bramlette and Wilcoxon, 1967). Most notable is theabsence of the variety of species of Helicopontosphaerain this eastern Pacific area, with the exception of rarespecimens of H. compacta (Bramlette and Wilcoxon)occurring in Core 3. Another peculiarity is the suddendisappearance of Sphenolithus ciperoensis Bramletteand Wilcoxon just above its development from and theextinction of S. distentus (Martini) within the lowerpart of Core 1. It is doubtful that preservation is themain factor as many other forms of equal or less delicacyare represented in these highly calcareous sediments.Biogeographic distributional factors appear to be themore likely reason for absences and exterpations fromthis part of the Pacific during the Oligocene.

A number of calcareous nannofossil species have arestricted distribution through these Oligocene sedi-ments (See Diagnostic Fossils, Hole Summary) whichallows the recognition of several subzones. These speciesare: Coccolithus aff., C. bisectus (Hay, Mohler, andWade) of Bramlette and Wilcoxon, Cyclococcolithuslucitanicus (Black), mostly five-rayed Discoaster tanitani Bramlette and Riedel, mostly six-rayed D. taninodifer Bramlette and Riedel, Pontosphaera vadosaof Hay, Mohler and Wade, Reticulofenestra umbilica(Levin), Sphenolithus abies Deflandre, S. ciperoensis,S. distentus, S. predistentus Bramlette and Wilcoxon,S. pseudoradians Bramlette and Wilcoxon, S. sp. aff. S.belemnos Bramlette and Wilcoxon, and Triquetrorhab-dulus carinatus Martini. Most of the specimens of 7!carinatus are short and narrow triangular rods near thebase of its range, but occasional specimens of the formof this species with extensive wide carinae occur in as-sociation in this interval. In addition to the speciesabove, a few asteroliths appear to have a local limitedstratigraphic distribution. These are Discoaster saunder-si Hay and D. woodringi Bramlette and Riedel—upperpart Core 1, D. woodringi trinidadensis Hay—withinCore 1, and D. woodringi lidzi Hay—Section 1 of Core 1.

The location of the boundary between the Sphenolithusdistentus Subzone and the S. predistentus Subzonebears discussion. An overlapping distribution of Cocco-

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lithus aff. C. bisectus, the Discoaster tani group andSphenolithus pseudoradians occurs over the intervalbetween the basal part of Core 1 and the upper part ofSection 5, Core 2. The coincident limits of thesespecies were given as additional criteria for recognizingthe boundary between the equivalent biostratigraphicunits, S. distentus and S. predistentus Zones (Bramletteand Wilcoxon, 1967, Table 2). Because of this conflict,the original primary criterion based on the evolutionarydevelopment in the lineage of spiked sphenoliths isused, and the boundary is drawn where the charactersof the sphenoliths populations change from dominantS. predistentus to more completely that of S. distentus.This is essentially equivalent to a change in general con-figuration of the coccolith assemblage, with the base ofCoccolithus aff. C. bisectus occurring slightly below.Triquetrorhabdulus carinatus commences slightlyabove this horizon.

Highly contaminated or mixed core material as well asreworked nannofossils or repeated stratigraphic sectionsexist in the more porous and permeable radiolarian-rich siliceous oozes forming the Upper Eocene portionof Hole 42.0 from the lower part of Core 4 down to thelower part of Core 7. This situation creates some diffi-culty in the enumeration of the characteristic nanno-fossil assemblages for this part of the hole and thepositioning of the lower boundary of this subseries.Frequent streaks on areas of light-colored calcareous-rich ooze occur in the more fluid material in the lowerpart of Core 4, and in Cores 5 and 7 and, less frequent-ly, in the firmer material of Core 6. This calcareousmaterial, often containing characteristic Eocene astero-liths, is composed essentially of calcareous nannofossilassemblages representing either the higher parts of theOligocene or the lower part of the Oligocene or mix-tures of both. The intermediate less calcareous areasor less disturbed parts contain an Upper Eocene assem-blage which differs in numbers and preservation charac-teristics over these calcareous ooze streaks. Samplesfrom positions adjacent to these lighter-colored oozeareas often contain minor amounts of this Oligocene ad-mixture. These Oligocene ooze occurrences are consider-ed downhole contamination (see discussion on DrillingDisturbances). Consequently, the occurrences of thecoccoliths common to both the Upper Eocene and theOligocene are recorded from these Upper Eocene coresonly where samples are void of this downhole materialor contain only rare amounts of Oligocene contamina-tion easily recognized by differences in preservation orother characteristics (see Diagnostic Fossils, Hole Sum-mary). The species of calcareous nannofossils usuallyinfrequently present in contamination-free materialinclude: Coccolithus bisectus and C. cf. C. scissurus-as smaller specimens, C. pelagicus and C. eopelagicus,Cyclococcolithuslucitanicus, Reticulofenestra umbilica,and Sphenolithus moriformis-as more delicate speci-mens. The more common and distinctive asteroliths

that characterize the in situ Upper Eocene materials, aswell as being recognizable in most of the downhole con-taminated material, include: Discoaster barbadiensisTan;Z). saipanensis Bramlette and Riedel-distinctivelywith long thin spine-like ray extensions (some whichapproach or encompass the forms named D. leviniHay); long-rayed and larger D. tani tani-mostiy six-rayed though larger five-rayed forms become more fre-quent in the lower part of Core 6; and, D. tani nodifer-mostly with six longer rays. Indeterminate species ofasteroliths that are scattered through this upper Eocenesection include: D. sp. aff. D. gemmifer Stradner, andZλ sp. aff.Zλ sublodoensis Bramlette and Sullivan. Thislatter species has six quite narrow rays with near paral-lel sides and a large disc that is often quite thick andrugose. The ray ends are bluntly pointed to narrowlytruncate; and, this form appears to be intermediatebetween D. sublodoensis and the D. tani group and/orthe form identified asZλ sp. aff.Zλ gemmifer.

Examination of the paleontological samples and interimsmear slides from Section 6, Core 4, shows that bothD. barbadiensis and D. saipanensis occur in significantfrequency to the top of the Eocene at this site. Whereapparent complete sections of the uppermost Eoceneand superadjacent Oligocene have been found, an inter-val occurs above the top occurrence of D. barbadiensiswhich still has diminutive D. saipanensis and relatedforms associated with other calcareous nannofossilsspecies, including fairly common Ismolithus recurvasDeflandre and related forms (Bramlette and Wilcoxon,1967; Maxwell et. al, 1970; and, S. F. Percival Jr.,personal communication, 1969). Some of these species,like /. recurvus, extend up into the lower part of theOligocene. The distribution of these forms and thepresence of a comparable sequence occurs within thegeographic area of the central Pacific (Deflandre andFert, 1954;Leg 9 material presently under investigationby the author). This situation is not present at Site 42,indicating an hiatus at this boundary with the uppermostpart of the Eocene missing and possibly part of theLower Oligocene as well. An additional possible indica-tion of this is the relatively short sections of UpperEocene and Lower Oligocene recovered compared tothe thickness representing the adjacent subseries.

Another anomalous situation in this Upper Eocenesequence occurs in Core 6, where scattered poorly pre-served parts and rims of a Chiasolithus are seen. Morecomplete rims are evident in Sections 4, 5 and the up-per part of 6, where the rims have the characteristicinward "teeth" of C. grandis (Bramlette and Riedel).Extensive searching failed to uncover complete speci-mens with the central structure present. Associatedwith these occurrences in Core 6 are quite commonspecimens of larger, long-rayed Discoaster tani taniand D. saipanensis with distinctive longer pointed rays;both of which are more characteristic of the Upper

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Eocene. The only other indication of Middle Eoceneage for these Core 6 sediments is the possible occur-rence of partial or poorly preserved rare specimens ofD. sublodoensis and Triquetrorhabdulus inversus Bukryand Bramlette in the upper part of Section 6 and thesingle occurrence of Subbotina senni (Beckman) in Sec-tion 3 (see Paleontology—Foraminifera). Nannofossilassemblages restricted to just those forms characteristicof the Discoaster barbadiensis Zone, Upper Eocene,occur below in the basal part of Core 6 and in the un-contaminated samples above the lowest part of Core 7.The present evidence suggests that these anomalous oc-currences in Core 6 are due to reworking of some olderforms into Upper Eocene sediments. The possibility ofhaving a repeated Upper Eocene section due to down-hole slumping with a partial or complete in situ dissolu-tion of characteristic Middle Eocene forms, and theconsequent masking of the boundary is an alternatethat cannot be completely ruled out at this time. Thecharacter of the sediments and the conditon of the coresthrough this interval provide the suspicion in support ofmaintaining this latter possibility; and, if correct, thetop of the Middle Eocene would be at a shallowerdepth than given in this report.

The top of the Chiasmolithus grandis Zone or MiddleEocene is placed within Section 6 of Core 7. Belowthis, complete specimens of C. grandis occur associatedwith other distinctive Middle Eocene species, such as:Campylosphaera bramlettei Kamptner, Sphenolithusfurcatolithoides Locker, Triquetrorhabdulus inversus,and the shorter rayed froms of Discoaster saipanensis.The lowest occurrence of D. tani tani is a short distancebelow this boundary within Core 8, and this subspeciesbecomes a more common constituent of the assemblagesabove in the Upper Eocene.

Except for the bottom part of Core 7, downhole con-tamination is not evident in the sampled parts of theChiasmolithus grandis Zone (lower part of Core 7 tothe lower part of Core 9). The nannofossil assemblagesof the C. grandis Zone are dominated by C. grandis,Coccolithus eopelagicus, C. pelagicus, Cyclococcolithuslucitanicus, Discoaster barbadiensis, Reticulofenestraumbilica, and Sphenolithus moriformis. Less frequentforms include: Campylosphaera bramlette-somewhatlarger with narrower rims in its higher range;Discoasterdeflandreismúl forms; D. saipanensis -with mostlyseven or eight and occasionally five or six shorter rays,which lack the longer spine-like extensions; D. sp. aff.D. sublodoensis; Sphenolithus furcatolithoides; S. rad-ians Deflandre; Thoracosphaera saxea Stradner; and,Triquetrorhabdulus inversus. Rare scattered occur-rences of identifiable specimens of Coccolithus bisectusare present, and a few specimens of Thorocosphaeraprolata Bukry and Bramlette occur in the lower part(Core 9). Six-rayed and occasional seven-rayed Dis-coaster tani nodifer with nodes and truncate and/or

notched ends extend down to the uppermost part ofCore 9. In the lower part of its range, this subspeciesoccurs with a similar form with six-to-eight noded rays,but it exhibits narrow or pointed ray ends. This latter,probably ancestral form is designated D. sp. aff. D.tani nodifer and ranges down through the remainder ofthe zone. The top of A sublodoensis occurs in the lowerpart of Core 8 though a number of thick, more heavilycalcified five- and six-rayed specimens with the generalcharacteristics of this species are included in its upperrange. Within its upper range, it also appears to inter-grade with the form classified as D. sp. aff. D.sublodoensis.

The Chiphragmolithus quadratus Zone extends fromthe lower part of Core 9, Hole 42.0, to the deepestmaterial collected at this site (Core 2, Hole 42.1). Thecalcareous nannofossils of this zone include most ofthe forms found in the zone above. However, the assem-blages are somewhat more diverse and contain additionalspecies including: Chiasmolithus gigas (Bramlette andSullivan), C. solitus (Bramlette and Sullivan), Chiphrag-molithus quadratus Bramlette and Sullivan and vars.,Discoaster martinii Stradner, scattered occurrences ofsmall asteroliths of the D. nonaradiatus Klumpp andD. septemradiatus (Klumpp) group, and Reticulofenes-tra cf. R. umbilica. The upper boundary of this zone isclose to and bracketed by the limits of occurrence ofChiasmolithus solitus, C. staurion and related forms,Discoaster martinii, and the larger, more typical formsof Reticulofenestra umbilica. Scattered rare specimensof Thoracosphaera prolata also occur in this interval.

Slight amounts of downhole contaminants are presentwithin the samples from this zonal interval. Traces arepresent in Hole 42.0 within the basal part of Core 9 andthe upper-most and basal parts of Core 10. More com-mon contamination, especially from Oligocene material,is evident within Section 1 of Core 11. Only traces areevident in the top of recovery from Hole 42.1 (Core 1,Sections 1 and 2).

The Chiphragmolithus quadratus Zone is divisable intotwo biostratigraphic subdivisions at this site with theboundary at about 100 meters depth. The base of thehigher C. quadratus-Chiasmolithus solitus Subzonecoincides with the lowest occurrence of unquestionableDiscoaster saipanensis (as small seven- and eight-rayedforms) and the base of the sensu stricto forms ofChiphragmolithus quadratus which have longer, nearsymmetrical rays and, if present, a narrow-basal platewhich tapers concomitantly with the rays to a pointedend. The lower C. quardatus-Chiasmolithus gigas Sub-zone is found in the recovered cores of Hole 42.1 andcontains frequent C. gigas and a suite of asterolithsthat appear intermediate between Discoaster saipanensisand/), lodoensis Bramlette and Riedel. These somewhatlarger asteroliths have six to seven longer, slightly curved

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rays and lack the distinctive central structure of eitherspecies. Most specimens show more strongly curvedridges on only one or two rays tending toward thecharacter of D. lodoensis, consequently, this plexus isrecorded as D. cf. D. lodoensis. The Chiphragmolithusin this lower subzone is represented only by a smaller,more compact form with a thick, well-developed, widequadrate basal plate which, in combination with theweakly developed spine or ray, is quite asymmetrical-giving an overall imbricate appearance to the fourradiating parts. This C. quadratus var. form is alsofound less frequently in the upper subzone along withtypical forms; and, some specimens there have a slightenlargement or bending of the ends of some of thespines or rays approaching the form described as C.swasticoides (Martini).

Foraminifera, Hole 42.0

Foraminifera occurred sporadically in this hole. Themost fossiliferous parts were in the upper two corebarrels. Selective solution was evident because generallyonly the larger, thicker-walled species were observed.

Species identified in Hole 42.0 include:

Sample 42.0-1-1, 30-32 cm:Planktonic foraminifera absent.

Sample 42.0-1-1, 110-112 cm:Same as above.




Sample 42.0-1-3, 99-101 cm:Globigerinita dissimilis (Cushman and Bermudez), Glo-bigerinita unicava (Bolli, Loeblich, and Tappan).

Sample 42.0-1-4, 8-10 cm:Globigerina euapertura Jenkins, Globigerinita dissimilis,Globigerinita unicava, Globoquadrina baroemoenensis(LeRoy).

Sample 42.0-1-4, 109-111 cm:Globigerinita unicava.

Sample 42.0-1-5, 20-22 cm:Globigerina tripartia Koch, Globorotalia opima nanaBolli, Globorotalia siakensis LeRoy, Globigerinita dis-similis.

Sample 42.0-1-5, 95-97 cm:Globigerina euapertura, Globigerina tripartita, Globo-

rotalia opima opima Bolli, Globigerinita dissimilis,Globigerinita unicava.

Sample 42.0-1-6, 5-7 cm:Globigerina cf. G. galavisi Bermudez, Globigerina tri-partita, Globorotalia opima nana, Globigerinita unicava.

Sample 42.0-1-6, 96-98 cm:Globorotalia opima opima, Globigerinita dissimilis.

Sample 42.0-2-1, 24-26 cm:Globigerina tripartita, Globorotalia opima nana, Glo-borotalia opima opima, Globigerinita dissimilis, Globi-gerinita unicava.

Sample 42.0-2-1, 101-103 cm:Globigerina tripartita, Globorotalia opima nana, Glo-borotalia opima opima, Globoquadrina baroemoenen-sis.

Sample 42.0-2-2, 22-24 cm:Globorotalia opima nana, Globorotalia opima opima,Globigerinita unicava, Globoquadrina baroemoenensis,Globoquadrina cf. G. dehiscens praedehiscens Blowand Banner.


Sample 42.0-2-3, 25-27 cm:Globorotalia opima nana, Globorotalia opima opima,Globigerinita dissimilis, Globigerinita unicava, Globo-quadrina baroemoenensis, Globoquadrina cf. G. dehis-cens praedehiscens.

Sample 42.0-2-3, 93-95 cm:Globigerina tripartita, Globorotalia opima nana, Globo-rotalia opima opima, Globigerinita unicava, Globo-quadrina, Globoquadrina baroemoenensis.

Sample 42.0-2-4, 15-17 cm:Globorotalia opima nana, Globorotalia opima opima,Globigerinita dissimilis, Globigerinita unicava, Globo-quadrina baroemoenensis, Globoquadrina cf. G. dehis-cens praedehiscens.


Sample 42.0-2-5,24-26 cm:Globorotalia opima nana, Globorotalia opima opima,Globorotalia cf. G. siakensis, Globigerinita dissimilis,Globigerinita unicava, Globoquadrina cf. G. dehiscenspraedehiscens.


373

Sample 42.0-2-6, 25-27 cm:Globorotalia opima nana, Globorotalia opima opima,Globigerinita unicava.


Sample 42.04-1, 20-22 cm:Same as above.


Sample 42.0-4-2, 20-22 cm:Globigerinita unicava.

Sample 42.0-4-2, 101-103 cm:Globigerina galavisi Bermudez, Globigerinita unicava.

Sample 42.0-4-3, 30-32 cm:Globigerina galavisi, Globigerina cf. G. tapuriensisBlow and Banner, Globigerinita dissimilis, Globigerinitaunicava.


Sample 42.0-4-4, 30-32 cm:Globigerina galavisi, Globigerinita unicava.


Sample 42.0-4-5, 141-143 cm:Globigerina galavisi.


Sample 42.0-5-1, 90-92 cm:Globigerina galavisi, Globigerina tripartiti, Globigerin-ita unicava.


Sample 42.0-5-4, 51-53 cm:Globigerina galavisi.


Sample 42.0-6-3, 20-22 cm:Subbotina senni (Beckman).


Sample 42.0-8-3, 122-128 cm:Small globigerinids.

Sample 42.0-8-4, 35-37 cm:Subbotina senni.

Sample 42.0-8-5, 18-20 cm:Small globigerinids.












Sample 42.0-11-5, 10-12 cm:Globorotalia bolivariana (Petters), Subbotina senni.



Radiolaria, Hole 42.0

Radiolaria are diverse, common-to-abundant, and well-preserved in all the cores of Site 42.0. The two cores ofSite 42.1 were not examined for Radiolaria. Additional

374

species, wihch were identified but not included on theBiostratigraphy Chart, are listed below with their occur-rence by cores:

Cores

Dorcadospyris costatescensLiriospyris geniculosaTholospyris anthophoraLiriospyris longicornutaDorcadospyris agriscaDorcadospyris confluensLiriospyris clathrataGiraffospyris didicerosDendrospyris stylophoraDendrospyris inferispina

SUMMARY

Hole 42.0

1-31-711

6-116-116-116-116-116-11

Four biogenous units can be identified at Hole 42.0 onthe basis of their proportions of nannofossils andradiolarians (Table 3).

At a total depth of 100 meters, a hard resistant layerof unknown composition was encountered and drillingoperations ceased, to be continued later 200 feet to theeast, in an attempt to continue the section.

Unit 4 (part of Core 9 through Core 11, 74 to 100meters) contains dark, yellow brown to light gray andgray brown interbeds of radiolarian-nannofossil ooze,

nannofossil-radiolarian ooze and radiolarian ooze. Slightto moderate burrow mottling occurs in the undeformedbeds of this Middle Eocene interval.

Unit 3 (Cores 8 through part of 9, 64 to 74 meters) isa radiolarian nannofossil ooze also of Middle Eoceneage. It is light yellow brown to light gray and lightbrown gray, firm to soupy. Again, slight to moderateburrow mottles were noted in the undeformed layers.

Unit 2 (part of Core 4 through Core 7, 32 to 64 meters)ranges in age from Middle Eocene to Early Oligocene.Near the base of the unit are 7 meters of Oligocenesediment within an Upper Eocene sequence. Mostlikely this interval was displaced during drilling opera-tions. The sediments consist of alternating intervals ofmoderate brown to moderate yellow brown nanno-fossil-radiolarian ooze, radiolarian ooze and radiolarian-nannofossil ooze.

Unit 1 (Core 1 through part of Core 4, 0 to 32 meters)is characterized by a predominance of nannofossils,consisting entirely of radiolarian-nannofossil ooze andnannofossil ooze in alternating thin sequences; burrowmottling was still evident. This unit is of Early Oligo-cene age at the base, and Late Oligocene age at the top.

The reason for the basence of younger Cenozoic sedi-ments at this hole is not known. However, the Argosite survey indicated the presence of bottom currentshere.

TABLE 3Stratigraphic Units at Hole 42.0

Units Core AgeDepth(m) Lithology Comments

1,2,3; Upper Oligocene 0-32part of 4 Lower Oligocene

Part of 4; Lower Oligocene 32-645, 6, 7 Upper Eocene

Middle Eocene

8; part of 9 Middle Eocene 64-74

Part of 9; Middle Eocene10, 11

74-100

Nannofossil ooze andradiolarian-nannofossil ooze(pale orange, pale yellowbrown)

Nannofossil-radiolarian ooze,radiolarian ooze, radiolarian-nannofossil ooze (yellowbrown, moderate brown)

Radiolarian-nannofossil ooze(light yellow brown to lightbrown gray)

Radiolarian-nannofossil oozeand nannofossil-radiolarianooze streaks, radiolarian ooze(light gray, gray brown)

Pumice fragments, slightburrow mottles, trace glass.

Manganese nodules, pumicefragments, trace glass.

Manganese nodules, pumicefragments, burrow mottles.

Manganese nodules, pumicefragments, slight to moderateburrow-mottles. Trace glass.

375

The depositional record at Hole 42.0 extends fromMiddle Eocene to Late Oligocene time. During thisperiod only biogenous sediments were deposited, exceptfor minor quantities of red clay. Traces of volcanicash occur in units 1 and 2, whereas, pumice fragmentsare found throughout the section. Some of the volcanicash has become zeolitized. Although manganese nodulesoccur in units 2, 3 and 4, their subsurface occurrencesmay be due to down-hole contamination.

Hole 42.1

A continuation of the stratigraphic sequence drilled atHole 42.0 was encountered at Hole 42.1. Coring com-

menced below the Middle Eocene resistive bed whichhad terminated drilling at Hole 42.0.

Only one major lithologic unit, was encountered (Cores1, 2 and 3, 100 to 113 meters) in the interval coredhere (Table 4). The lithology consists of radiolarian-nannofossil ooze, nannofossil-radiolarian ooze, andradiolarian ooze and is, therefore, similar to unit 4 atHole 42.0. There are local indurated equivalents ofthese sediments which form hard calcareous oozes orstrata which are partially replaced by chert. Burrowmottles are well-developed in the indurated beds.

TABLE 4Stratigraphic Unit at Hole 42.1

Unit Core AgeDepth(m) Lithology Comments

1 1,2,3 Middle Eocene 100-113 Interbedded soft radiolarian-nannofossil ooze, nannofossil-radiolarian ooze, radiolarianooze and hard silica-cementedsediments (fragments andbeds) (light gray, light graybrown, very dark gray brown)

Hard, calcareous fragmentsin Core 1 probably relatedto the layer which terminateddrilling at Hole 42.0. Slightto moderate burrow mottling

is common.

REFERENCES

Bramlette, M. N. and Wilcoxon, J. A., 1967. MiddleTeritary calcareous nannoplankton of the Ciperosection, Trinidad, W. I. Tulane Studies Geol. 5, 93.

Deflandre, G. and Fert, C, 1954. Observations surles Coccolithophoridés actuels et fossils en micro-

scopie ordinaire et electronique. Ann. Paléontol.40, 115.

Maxwell, A. E., von Herzen, R. P., Andrews, J. E.,Boyce, R. E., Milow, E. D., Hsu, K. J., Percival, S. F.and Saito, T., 1970. Initial Reports of the Deep SeaDrilling Project. Volume III. Washington (U. S.Government Printing Office), in press.

376

THE CORES RECOVERED FROM SITE 42

The following pages present a graphic summary of the resultsof drilling and coring at Site 42. Fig. 2, a summary of Site 42is at the back of the book. Figures 3 to 16 are summaries ofthe individual cores recovered. A key to the lithologic sym-bols is given in the Introduction (Chapter 1).

377

DEPTH WET-BULK WATER CONTENT - POROSITY SOUND PENETROMETER NATURAL GAMMAIN DENSITY VELOCITY RADIATION

CORE (gm/cc) (%wt) (%vol) (km/stc) X I0"1 mm (counts/76 cm/1.25 min)

m seel. 10 1.2 1.4 1.6 0 20 40 60 80 100 I 0 1.5 2.0 0 _ 100 200 300CP1000 2000 3000 4000

L_J

Figure 3 A. Physical Properties of Core 1, Hole 42

378

J 3 J

cc

SAMPLEINT

nR

Nannofossil ooze

Smear

Alternating pale orangeto pale yellow

NannosRadsClay

Radio!arian-Nannofossi1 ooze

SmearNannosRadsClay

Alternating nannofossil ooze andradiolarian nannofossil ooze. Mostbeds firm. Local slight burrowmottling.

Figure 3B. Core 1, Hole 42 (0-9 m Below Seabed)

379

SECTION 1

Ocm

Plate 1. Corel,Hole42

380

SECTION 1

Ocm

Plate 2. Core 2, Hole 42

381


CORE (gm/cc) (%wt) (%vol) (km/sec) X I0"1 mm (counts/76 cm/1.25 min)

m sect. 1.0 1.2 14 1.6 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 300CP1000 2000 3000 4000

I i i i - r i

1

\

I i i ii

Figure 4A. Physical Properties of Core 2, Hole 42

382

SUB-ZONE

SAMPLEINT

cc

n f

n f

f n

n R

Nannofossil ooze

Smear

Alternating very paleorange to pale yellowbrown

NannosRadsClayGlass

dr-crr

Firm beds nannofossil ooze withvariable (5-15 per cent) amountsof radiolarians, local glass,shards, and one pumice fragment.Local slight burrow mottling.


383

AGE

SERIESSUB-SERIES

z

LIG

OC

I

oBC

a.—'

ZONESUB-ZONE

αicoNi-t

<U

§ ICO + ^

•S S0 13to S,

CO

to J

r-i O0 s:

1 f1

.2

ó

%

DE

PT

(ME

TI

1 —

2 —

-

_--

4 —-

_

-

_

-_

5 —

-

-

7 —

1 1

I 1

| 1

1 1

1 1

1 1

1 1

Z et.O jg

SE

CT

NU

M

1

cc

>-§0

LIT

Hi

i n

LUa.0

z

NO

II

SEC

SAMPLE

INT

O

PA

LE

nn

α:

SM

EA

R

LITHOLOGY

Plastic core l iner badly damaged incoring operation and al l sedimentsrecovered were put in extra largesize plastic l iner. Exact positionof 150 centimeters of sediment re-covered within 10 meters of corebarrel is not known.

Lithology appears similar toCore 2

Figure 5. Core 3, Hole 42 (18-27 m Below Seabed)

384

SECTION

Ocm

-150Plate 3. Core 4, Hole 42 385


CORE (gm/cci (%wt) (%vol) (km/sec) X I0"1 mm (counts/7.6 cm/1.25 min)

m sect. 1.4 1.6 1.8 2.0 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 300CP 1000 2000 3000 4000

I I I -> 1 I I I

i -Λ I i i i i i i l i i l l I


386

Cores highly distorted

Nannos.Rads.ClayGlass

dc-arr

Nannofossil ooze

Smear

Alternating very paleorange, pale yellowbrown and moderatebrown

Nannofossi1-radiolarian ooze

Smear

Rads.Nannos.ClayGlass

Radiolarian ooze

SmearRads. dNannos. rClay r

Mostly nannofossil ooze in upperpart followed by nannofossil-radi olarian ooze and radi olarianooze. Local burrow mottling, alsoone pumice fragment in Section 4.


387

DEPTH WET-BULK WATER CONTENT • POROSITY SOUND PENETROMETER NATURAL GAMMAIN DENSITY VELOCITY RADIATION

CORE (gm/cc) (%wt) (%vol) (km/sec) X I0"1 mm (counts/76 cm/1.25 min)

m sect. 1.4 1.6 1.8 2.0 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 300CP 1000 2000 3000 4000

1 I I I I I T < I

J

*

I i i π i π r

J

<—.

i -+-» i i i i i i i * - I I I II I I I


388

SAMPLEINT

Core partly soupy

n f

Nannofossil ooze

SmearNannos,Rads.ClayGlass

drrr

Alternating moderatebrown and moderateyellow brown

Nannofossil-radiolarian ooze

SmearRads aNannos. aClay r

n f

Radio!arian ooze

SmearRads. dClay cGlass r

n R

Alternations of firm moderate brownradiolarian ooze and soupy moderateyellow brown nannofossil-radiolarianooze with few nannofossil oozes neartop of core. Manganese nodule inSection 2. Local traces of volcanicglass.

cc


389

SECTION 1

— Ocm

-150


390

SECTION 1

•Ocm


391


CORE (gm/cc) (*wt) (*vol) (km/«ec) × I0"1 mm (counts/7.6 cm/1.25 min)1.0 1.2 1.4 1.6 0 20 40 60 80 100 10 IS 2.0 0 _ 100 200 300CP lOOOl 2000 3000 4000

I i r i r


392

LITHOLOGY


Smear

Alternating moderate brown,moderate yellow brownand dark yellow brown

RadiolarianNannofossilClay

Radio!arian-nannofossil ooze

SmearNannofossilRadiolariaClay

Moderate brown to moderate yellowbrown firm nannofossil-radiolarianooze in upper th i rd .

Moderate yellow brown to darkyellow brown radiolarian-nannofossilooze with minor amount nannofossilradiolarian ooze in lower two-thirds.

Two manganese nodules and onepumice fragment in upper half.


393


CORE (jm/cc) (*wt ) (*vol) (km/sec) × I0"1 nun (counts/7.6 cm/1.25 min)

sect. 1.0 1.2 1.4 1.6 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 MOCPIOOO 2000 3000 4000

I i r

L

L i i i i


394

SAMPLEINT

CC

Sediments soft and soupy and highly deformed.

*Sampled from end of plastic l iner


SmearRads.Nannos.Clay

Radio!arian ooze

SmearRads.Nannos.Clay

Alternating moderate dark brownand moderate yellow brown

Approximately equal amounts moderatedark brown radio!arian ooze andmoderate yellow brown nannofossil-radiolarian ooze. Traces nannofossilchalk ooze.


395


CORE (gm/cc) (%wt) (%vol) (km/sec) X I0*1 mm (counts/7.6 cm/1.25 min)

m sect. 1.0 1.2 1.4 1.6 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 300CP1000 2000 3000 4000

r π

j i i i i


396

Most of core highly deformed with muchof i t soupy

Radiolarian-nannofossil ooze

Alternating l i gh tyellow brown,l igh t gray andl igh t brown gray

SmearNannofossilsRadiolariansClay

Firm to SOUDV radi ol ari an-nannofossilooze with traces of nannofossil ooze.

Local s l igh t moderate burrow mottlingv is ib le where core is undeformed.

Pumice fragment al ter ing to zeoli tein Section 5.

Figure 1OB. Core 8, Hole 42 (64-73 m Below Seabed)

397

Plate 6. Sections of Cores 7 and 8.

398

SECTION

•Ocm

- 1 5 0


399


CORE (gm/cc) (%wt) (%vol) (km/sec) X I0"1 mm (counts/7.6 cm/1.25 min)m sect. 1.0 1.2 1.4 1.6 0 20 40 60 80 100 1.0 1.5 2.0 0 100 200 300CP 1000 2000 3000 4000

I i r

,-? ,

r

i i i i


400

Some beds soupy

RadioTarian-nannofossil ooze

SmearNannofossilsRadiolariaClay

Alternating darkyellow brown andl igh t brown gray


SmearRadiolariaNannofossilsClay

Mainly dark yellow brown nannofossilradiolarian ooze with some l ightbrown gray radiolarian-nannofossilooze.

Strata mostly f i rm, some soupy.

Moderate burrow-mottles visibleless deformed intervals.

Two manganese nodules. One ashfragment altering to zeolites.

in

Figure 1 IB. Core 9, Hole 42 (73-82 m Below Seabed)

401


CORE (gm/cc) (%wt) (%vol) (km/«ec) × I0"1 mm (counts/7.6 cm/1.25 min)m sect. 1.0 1.2 1.4 1.6 0 20 40 60 80 100 10 1.5 2.0 0 100 200 300CP 1000 2000 3000 4000

I I r


402

Radio!arian-nannofossil ooze

Sme'ar (NannofossilsRad.Clay

Alternating lightgray and gray brown


SmearRad.NannofossilsClay

Radiolarian ooze

SmearRad,ClayNannofossils

Light gray and gray brown mostlyf i rm, radiolarian-nannofossil oozeand nannofossil, radiolarian oozein approximately equal amounts.Occasional streaks of radiolarianooze.

Slight to moderate burrow-mottling in places.

Pumice fragments in Section 3.


403


404


405


CORE (gm/cct (%wt) (%vol) (km/sec) X I 0 ' 1 mm (counts/76 cm/1.25 min)

m sect. 1.0 1.2 1.4 1.6 0 20 40 60 80 100 1 0 1.5 2.0 0 100 200 300CP 1000 2000 3000 4000

i r

f

i i i π r

u A , ,


406

AGE

SERIESSUB-SERIES

LU

εocε

r

LU

IIDD

I

2 .

ZONESUB-ZONE

<D

bzo

3LO

to

CO

O 3

3 f»

CO 1

3

* «f•8* 2

|

Jj

-

-

-

-

-

----

----

4 —

_

-

_

_

5 —

—

-

-—

_

_

-

_

7 —

1 1

-

-

8 —

_

-

1 1

-

-

z a:

Siz

1 |

2

3 :

4

5 [

6

cc

>-

§o

ITH

1 É

mii1•USmm1jθ

i1WM•£3

D-O1z

o

LU

j j jgs^Bfiβ

<l i 1 !

QLUz

1-O

PE

=oi—<jCO

SAMPLE

INT.

OLU

<0-

n

R

n

R

n

R

n

n

R

n

pn

nf

n

R

R

n

CH• <

*

*

*

*

LITHOLOGY

Sediments alternating firm and soupy


[Nannofossils aSmear <Radiolaria a

Iciay r

Alternating l ight grayand gray brown


fRadiolaria aJ Nannofossils a

Smear j c 1 a y r

(Glass r

Light gray and gray brown, firm tosoupy, radiolarian-nannofossil ooze,and radiolarian-nannofossil ooze inequal amounts.

Occasional streaks radiolarianooze and nannofossil ooze.

Moderate burrow-mottling wherebeds are underformed.

One pumice fragment inSection 1.

Resistant hard well-cemented limybiogeneous sediments terminatedd r i l l i n g


407

LITHOLOGY

Sediment a l l f i rm and soupy


SmearNannofossilRadiolariaClay

Alternating light gray,light gray brownand very dark graybrown.

Nannofossil radiolarian ooze

SmearRadiolariaNannofossilClay

Radiolarian ooze

SmearRadiolariaNannofossilClay

Alternating radiolari an-nannofossi1ooze and nannofossil-radiolarianooze In upper part. Same lithoiogyin lower part except 50 per centof sediments are radiolarian ooze.

Beds thin-medium thick. Limyhard dense biogenous fragments inSections 1 and 3.

Slight to moderate burrow-mottling common.

Core catcher contained verydark qray hard well-cementedbiogenous ooze, in chips andfragments with conchoidal fracture.Burrow mottling evident.

This cored interval isbelieved to be overlain by thesame hard layer which terminateddrilling at Hole 42.0. It isprobably also the source of the chipsin Sections 1 and 3.

Figure 14. Core 1, Hole 42.1 (100-107 m Below Seabed)

408

SUB-ZONE

SAMPLEINT

LITHOLOGY

Core catcher sample only:Very dark gray and light brown

gray hard, dense to cherty well-cemented siliceous limestone withslight burrow mottles, conchoidalfracture of chips and fragments.

Opaline to cherty material ascementing agent in small to largeamounts, seemingly varying in directproportion to the amount of siliceousfossils originally present. Samematerial as fracture fillings andreplacement of siliceous fossils

Harder fragments withconchoidal fracture have higheramounts of chert.

* Core catcher

Figure 15. Core 2, Hole 42.1 (107-109 m Below Seabed)

409

SERIESSUB-SERIES

ZONESUB-ZONE

SAMPLINT.

LITHOLOGY

After third core was takenunsuccessfully, the center bit wasbrought up. It contained granule-sized chips of well cementedbiogenous ooze and firm pelletsof same.

The lithology is thereforesimilar to the first two cores.

No recovery in core catcher.

Figure 16. Core 3, Hole 42.1 (113 m Below Seabed)

410

12. site 42

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