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Foraminifera from uppermiocene turbidites, Wairarapa,New ZealandPaul Vella aa Geology Department , Victoria University ofWellington , WellingtonPublished online: 12 Jan 2012.

To cite this article: Paul Vella (1963) Foraminifera from upper miocene turbidites,Wairarapa, New Zealand, New Zealand Journal of Geology and Geophysics, 6:5,775-793, DOI: 10.1080/00288306.1963.10423624

To link to this article: http://dx.doi.org/10.1080/00288306.1963.10423624

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FORAMINIFERA FROM UPPER MIOCENE TURBIDITES,W AIRARAPA, NEW ZEALAND

PAUL VELLA

Geology Department, Victoria University of Wellington

(Received for publication, 20 March 1963)

ABSTRACT

Abundant and well preserved Foraminifera in turbidites of Upper Miocene [Kapi­tean) age, at Cleland Creek, were compared with Foraminifera in four differentdepth biofacies of about the same age. The turbidites were deposited in depthscertainly greater than 2,000 ft, and probably between 4,000 and 6,000 ft, and werederived from all shallower depths up to about 400 ft or less. Fragile shells and largeshells are less common in turbidites than in non-turbidites, and many shells are con­sidered to have been destroyed during transport. The basal layer of each turbiditerhythm is considered to consist of "slumped" neritic sediment with little intermixeddeep-water sediment, the intermediate layer to have been deposited by a swift turbiditycurrent, and the upper layer to have been deposited from suspension after theturbidity current ceased flowing. No trace of autochthonous sediment was foundbetween turbidite rhythms.

INTRODUCTION

Strata with well defined graded rhythms, at Cleland Creek, about fivemiles east of Mauriceville township, were mapped and described as turbiditesby Orbell (1962). For turbidites they contain extraordinarily abundant andwell preserved foraminiferal shells which are considered to represent mixedbiofacies (Vella, 1962a) similar to the mixed biofacies found in theVentura Basin, California, in turbidites of about the same age (Natlandand Kuenen, 1951). Like the clastic sediment, the foraminiferal shells aresize-sorted, large shells being concentrated in the lower part of eachrhythm (Vella, 1963).

Generally at the top of each rhythm in the Ventura Basin is anautochthonous layer of mudstone, described by Natland and Kuenen aslithologically and faunally distinct from the underlying mudstone formingthe main upper part of the rhythm. At Cleland Creek no lithologicallydistinct layers were found, and samples from the tops of two rhythmsyielded mixed deep- and shallow-water faunas showing that no autochthonouslayers are present.

BIOFACIES ANALYSIS

Natland and Kuenen were able to use known depth distributions of present­day Foraminifera. This information is not yet known for New Zealand,and the writer is forced to use an inferred sequence of fossil depth biofacies(Vella, 1962b). This method has both disadvantages and advantages, forthough absolute depths represented by biofacies are uncertain, confusion dueto possible changes in depth range of species and genera with time isobviated.

N.Z. J. Geol. Geopbys, 6 : 775-93

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Fossil depth biofacies are determined in three steps. The first is todetermine assemblages of species that lived together (biofacies). The secondis to arrange the biofacies in order of depth. The third is to use knownranges of present-day organisms to estimate absolute depth ranges of thebiofacies. The first two steps are based on direct observation of fossildistributions. The third step is a subjective process of faunal matching,similar to age correlation, and is subject to progressive revision in about thesame measure as age correlation. Only the first two steps are required toshow that turbidites contain a mixture of biofacies.

Foraminifera from the Wairarapa turbidites are compared below withthe Foraminifera in a depth series of four biofacies.

SAMPLE LOCALITIES AND TABLE OF FOSSIL OCCURRENCES

Twelve turbidite samples were examined, all from Cleland Creek, a smallstream flowing parallel to Cleland Road, Sheet District N158 (Fig. 1).Four were ordinary field samples collected by a student, Mr G. Orb ell, torepresent the upper and lower parts of two rhythms. The other eight were

CItEE"

WANGANu,e

FIG. i-Map of the southern part of North Island, showing location of ClelandCreek, and the approximate localities of three non-turbidite samples which aredescribed in the text but are not from Cleland Creek.

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a series of closely spaced samples collected by the writer for the purposeof determining faunal changes within a rhythm and at rhythm boundaries.Roughly equal amounts of material from each sample were examined toobtain the data listed in Table 6.

Three of the non-turbidite samples used for comparison are from SheetDistrict N153 immediately to the north of N158, and are on the oppositeside (north-west) of the Alfredton Fault from Cleland Creek. The localityfurthest from Cleland Creek is about nine miles to the north-west. Theyrepresent different stages of deepening between nil and several thousand feetwhich took place in the area during Kapitean time (Mr G. Neef, pers.comm.) The fourth comparative sample (NI58j610) is from basal Opoitian(basal Pliocene) massive mudstone overlying the Kapitean turbidites atCleland Creek. It was previously determined as Kapitean in age (Vella,1962a; Orbell, 1962) but rare specimens since found of the pelagic speciesTttrborotalia infiata (d'Orb.) indicate an age slightly younger than Kapitean.

Full details of the fossil localities are recorded in the New ZealandFossil Record master file for the Wellington region at the Geology Depart­ment, Victoria University of Wellington. Abbreviated details are given inTable 1. Lithology symbols in this table are those proposed by Wellman(1953, p. 55) with the addition of the symbol R (redeposited) for turbiditefacies. Age symbols are Tk (Kapitean) uppermost Miocene, and Wo(Opoitian) lower Pliocene.

TABLE I-Details of Samples

Fossil GridRecord Locality Ref. Lithology Macrofossi Is AgeNo.

N153

910 Makakahi River 179952 932c nil Tk1155 Mangaoranga 206972 6631c abundant Tk1157 Mangaoranga 205975 R942d common Tk

N15R610 Cleland Creek 260R14 9R42cMM nil Wo624a Cleland Creek 276811 7954jCSSR comminuted Tk

b" "

9851cCSRcom~inuted ik626a Cleland Creek 282808 7964i CQSR

bClela~d Creek " 9R51cCR

comn':inuted Tk630a-h 279RIO

(Lithologies and positions in rhythms of 630a-h are shown in Fig. 2)

All non-turbidite samples used for comparison, and the four turbiditesamples collected by Orbell, were selected for the study because of theirrelatively good foraminiferal faunas. The series of eight closely spacedsamples at locality 630 were taken near a good sample locality of Orbell's.

Occurrences of Foraminifera are shown in Table 6. The four columns onthe left giving species in non-turbidite samples are arranged from left to

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right in order of inferred deepening. Abundances are based on counts ofspecimens on mounted faunal slides. The slides do not contain all thespecimens in each sample, but give reasonably true relative abundances ofmore common species. They probably give greater than true relative abund­ances of rare species because a special search was made for these in eachsample.

BIOFACIES CoNTAINED IN TURBIDITES

Biofacies Represented by the Four Non-turbidite Samples

Each of the four non-turbidite samples contains several species absent fromthe other three. Most of these particular species are facies-restricted anddefine the biofacies represented by each sample. Absolute depths of originof the biofacies are best estimated by comparison with the named Pliocenebiofacies (Vella, 1962a), which have a larger number of Recent species.Diagnostic features and estimated depth ranges are as follows:(1) N153/1155: Sandstone with shell-beds containing abundant Mollusca;the microfauna includes Ostracoda and echinoid spines. The ForaminiferaGuttulina, Sigmoidella, Zeaflorilus, and Notorotalia ct. depressa indicatethe "Zeaflorilus Biofacies" or the "Elphidium Biofacies'(;i;ince Zeaflorilusis not abundant, probably the "Elphidiurn Biofacies". Depth 0 to about400 ft.(2) N153/1157: Sandy mudstone with infrequent scattered Mollusca; themicrofauna includes a few Ostracoda. The presence of abundant Haeus­lerella ct. parri and Robulus calcar, and the absence of persistent veryshallow-water species such as those above and of persistent deep-waterspecies such as Karreriella cylindrica and Hseeslerell« finlayi, indicates the"Haeuslerella Biofacies". Depth 600 --t- 400 ft.(3) N15 3/910: Massive calcareous mudstone with rare Mollusca; no Ostra­coda. Haeuslerella pliocenica, Karreriella cylindrica, and Sigmoilopsiszeaserus indicate a biofacies of greater depth than the "Haeuslerella Bio­facies". The great number of benthonic species (76), relative abundanceof Robulus and Saracenaria, and paucity of pelagic specimens (c. 25%)indicate the "Robulus Biofacies". Depth 2,000 --t- 1,000 ft.(4) N158/61O: Massive calcareous mudstone; no Mollusca or Ostracodafound. Rhabdammina?, Haplophragmoides?, Euuvigerina notobispida, andCibicides aff. robertsonianus, and the absence of many species that occur atN15 3/910, indicate a biofacies distinct from the "Robulus Biofacies". Pelagicspecies make up 50% of the shells and indicate the "Semipelagic Biofacies".Depth, 3,000 --t- 1,000 ft.

Biofacies Contained in Turbidites but not Represented by Non-turbiditeSamples

The turbidite samples contain 39 species of benthonic Foraminifera thatdo not occur in anv of the non-turbidite samples. Most of them areassumed to belong to biofacies different from any of the four comparativenon-turbidite samples. The 39 species can be divided into three depthclasses: probably shallow-water species, probably deep-water species, andspecies of uncertain depth.

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The first class contains: Siphotextulari'a aff. mestayerae, Gaudry;n~

crespinae, Quinqueloculina triangularis, Q. d. lata, Q. kapitiensis, Q.(LachlaneUa) n. sp., Oolina bexayona, G. melo, Sigmomorphina d. lacri­moss, Laryngosigma williamsoni, Virgulopsis d. pustulata, "Bolivina" tur­biditorum, Baliminella elegantissima, B. missilis, Buliminoides williamsoni­anus, Dyocibicides primitiua, Rosaline d. bradyi, Pileolina radiata, P. zea­landica, Elphidium cbarlottensis, E. d. crispum, Elphidium novozealandicum,Notorotalia d. olsoni, Amphistegina sp.

Many of these species are common in shallow water in Cook Strait atthe present day, but comparable fossil faunas are seldom found in theWairarapa. Depth ranges of nearly all probably lie between 0 and 400 ft.Biofacies at these shallow depths are extremely variable, and the shallow­water non-turbidite sample N153/1155 represents only one of a probablylarge number of localised shallow-water sub-biofacies.

The second class, deep-water species, includes only Bulimina trencanellaand Norcottia mioindex, Bulimina truncanella is closely related to the presentday species Bulimina rostrata Brady, which is widespread and restricted tovery deep water (Brady, 1884; Natland, 1957; Bandy and Arnal, 1960).Norcottia mioiudex has no close present-day relative. Both species generallyoccur together in massive calcareous mudstones without macrofossils and withpelagic Foraminifera as the dominant microfossils. They probably representa biofacies of greater depth than any of those represented by the four com­parative non-turbidite samples.

OCCURRENCES OF FACIES-RESTRICTED SPECIES IN TURBIDITES

For brevity in Table 6 facies-restricted species of each biofacies areidentified by the following numbers:

1. Species restricted to N153/1155, and the class of probably shallow­water species contained in turbidites but not in any of the comparativenon-turbidites samples, as listed above.

2. Species restricted to N15 3/1157.3. Species restricted to N153/91O.4. Species restricted to N158/610.5. Probably deep-water species contained in turbidites but not in any of

the comparative non-turbidite samples.

Restricted species from all biofacies occur in two of the turbiditerhythms, and species from four biofacies occur in the other rhythm(Table 2). For comparison the total number of facies-restricted species ineach biofacies is given in the column headed N, and the approximate totalnumber of specimens examined in each biofacies sample or rhythm is givenin brackets. (The figure given in brackets for the shallow-water biofaciesis the number of specimens examined in sample N15 3/1155; but thenumber of restricted species (30) includes only 6 from this sample, theother 24 being found only in the turbidites.)

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TABLE 2-Number of Facies-restricted Species in Turbidites

(Data abstracted from Table 6)

N: Number of restricted species in each biofacies.

Figures in brackets: Approximate total number of specimens examined.

[Nov.

-,--_._~_.

RHYTHMS

BIOFACIES N158/N(Inferred depth increasing downwards) 624 626 630

(700) (350) (900)

1. Shallow-water Biofacies (50) 30 21 14 252. Haeuslerella Biofacies (350) 15 6 4 43. Robulus Biofacies (650) 37 19 18 204. Semipelagic Biofacies (300) 14 3 2 55. Deeper-water Biofacies (-) 2 2 1

The mixing of biofacies indicates that the turbidite fossils were displacedfrom the depths in which they originally lived. The non-turbidite samplescontain 32 species not found in the turbidite samples, but these are rarespecies, fragile species, and large species. All species are less common inturbidites than in non-turbidites; this could be largely due to dilution result­ing from mixing of sediments from different environments with differentassemblages of species.

Species with fragile shells not represented in the turbidites includeVirgulina aff. rotundata, Globobulimina pacifica) Florilus flemingi, Nonien­ella zenitens, and Nonionellu? sp. An equally fragile species, Nonionellamagnalingua, which is common in one of the non-turbidite samples, is repre­sented by rare damaged shells in two of the turbidite samples. Large forms notrepresented in turbidites include Pyrgo and Robulus. Remains of molluscanshells in the turbidities are all finely comminuted, echinoid shells are repre­sented by spines and broken plates only, and ostracode shells are generallydamaged. It is likely that, in general, large foraminiferal shells and fragileshells were not sufficiently protected by the surface tension of water toprevent their destruction during transport, though a few specimens, such asNonionella magnalingua in 624b and 626b, have survived.

Preferential destruction of weaker and larger shells probably accountsfor the generalised kind of fauna usually found in Tertiary turbidites, inwhich the species are all small and strong-shelled and are mostly commonin non-turbidite facies. In some turbidites that are completely barren offossils all shells originally present in the sediments must have been destroyed.

A few species, for example Oolina costate, are small and strong-shelled,and are common in one turbidite rhythm, yet are absent from others. Theytend to be sporadically distributed in non-turbidite facies and suggest thatdifferent turbidite rhythms were not all derived from the same set of environ­ments.

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VARIATIONS WITHIN RHYTHMS

General

781

Although the total number of species in each of the three rhythms isrelatively constant, there is considerable variation in the number of speciesin different parts of each rhythm (Table 3).

TABLE ,3-Number of Species in Each Turbidite Sample

SAMPLES IN EACH RHYTHMRHYTHM TOTAL FOR RHYTHM

a b c d e g

1. N158/624 82 70 97 (includes 6 pelagic spp.)2. N158/626 43 68 73 ( 4 " )3. N158/630 40 60 3 42 48 45 100 ( 5 " )

The foraminiferal shells in all three rhythms are size-sorted, as in therhythm at locality N 158/625 (Vella, 1963), larger shells being concen­trated towards the base and smaller shells towards the top of each rhythm.

The proportion of shallow-water species and specimens decreases from thebottom to the top of each rhythm. This change is probably not related tosize-sorting, because large species are generally represented by juveniles inthe upper parts of rhythms, and the proportions of large and small speciesappear to be about the same in shallow- and deep-water facies.

The vertical faunal changes are most clearly shown by the series ofclosely spaced samples N158/630a-h.

Rhythm Sampled in Detail (N158/630~h)

At locality N158/630, rhythms average about 3 ft and range from about2 ft to 4 ft thick. The basal sandstone is generally about 6 in. thick, andconsists predominantly of medium sand with abundant fragments of mol­luscan shells, is sufficiently permeable to act as an aquifer, and is mottledwith rusty brown limonite stain. Between the sandstone and the overlyingmudstone is a zone of rapid gradation about 6 in. thick, within which,in some rhythms, is a narrow finely banded zone. The upper part of therhythm consists of blue-grey mudstone with no obvious layering, containinginfrequent small particles of molluscan shell.

Sandstone and mudstone bands are almost equally susceptible to erosion,and sole-markings can be seen only obscurely in sectional view. The upperand lower boundaries of rhythms are sharply defined irregular surfaces, themost striking features being twisted, more or less cylindrical borings up toabout 1 inch in diameter, penetrating the upper surface of each rhythm,and filled with sand from the base of the next overlying rhythm.

Eight samples were collected at close (but not equal) intervals, spanningone rhythm and including one sample from the top of the underlyingrhythm, and one sample from the bottom of the overlying rhythm (Fig. 2).

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:. ' Rusty· stalneci blue-grey mudd.y SIC. as below.

Irregu.la.r, bored. surfa.ce - discon.form.i.ty

40 q between. two rh.)'th.11'\.s.--------

F ----

--------30

---- alue -grey rnudston.e wi.th. SO/ll.e rn~n.ute-------- fra.<3"1.enb of rnoUuscQ.l'I. Sh.elts.

e{ -------------_.

~O ----

-------...

lOci) d Poorly developed. micrObed.d.i.nqc.) Zon.e of most rapid. qfa.d.a.tion.a.t chCln.qe..c0~.- Rusty·statneo. blue-9!'ey mud.d.y sst. wi.th abu.n.dar\t

com.mi.nu.teci mottu.scan sh.ens.lrrequ.lar surFace, as above.

aMUdstone, a.s above.

---

FIG. 2-Diagrammatie columnar section of turbidite rhythm sampled in detail atlocality N158/630, Cleland Creek. Relative vertical positions of samples "a" to"h" are shown at the left side of the column.

Table 4 shows the number of facies-restricted species of each biofacies ineach sample, the total number of benthonic and pelagic specimens in eachsample, and for comparison (as in Table 2) the total number of restrictedspecies of each biofacies.

Every sample except "d", which is almost barren, contains Foraminiferafrom at least three different biofacies, most contain Foraminifera from fourbiofacies, and one contains Foraminifera from all five. Sandstone samples("b", "c", and "h'") contain a high proportion of shallow-water species,whereas most mudstone samples ("a", "e", "f", "g") contain a high pro­portion of deep-water species. This unequal distribution of species isparalleled by a more marked difference in the relative numbers of specimens(Table 5, and Fig. 3).

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TABLE 4-Number of Species of Each Biofacies in each Sample (NI58j630)

(Data abstracted from Table 6)

N: Number of restricted species known for each biofacies.

BiofaciesI

NI

Samples

a b c d e f g h

1. Shallow-water Biofacies 30 2 15 13 0 9 4 6 132. Haeuslerella Biofacies 15 0 3 3 0 2 2 1 33. Robulus Biofacies 37 3 3 10 0 8 10 11 44. Semipelagic Biofacies 14 1 2 2 0 1 3 3 05. Deep-water Biofacies 2 0 0 0 0 0 1 0 0

Total number of benthonicspecimens 18 93 192 2 91 146 127 93

Total number of pelagicspecimens 2 8 35 0 13 10 9 1

-------

TABLE 5-Number of Specimens of Restricted Species of Each Biofacies in EachSample (NI58j630)

(Data abstracted from Table 6)--_.._-_. ._-~-- --_.__._ .. - -----------------

Biofacies Samplesa b c d e g h

1. Shallow water 2 39 24 0 20 7 7 462. Haeuslerella Biofacies 0 12 17 0 12 9 7 133. Robulus Biofacies 2 10 30 0 16 41 25 94. Semipelagic Biofacies 1 1 2 0 2 12 3 05. Deep-water 0 0 0 0 0 3 0 0Non-diagnostic specimens 11 31 96 2 41 74 85 25Pelagic specimens 2 8 26 0 13 10 9 1

Total specimens 18 101 195 2 104 156 136 94

Fig. 3, a graphical representation of Table 5, (in percentages), shows arhythmic fluctuation in relative proportions of shallow- and deep-watershells that coincides more or less with the rhythmic fluctuation in relativeproportions of sand and mud. That shallow- and deep-water shells were notcompletely intermixed indicates that the shallow- and deep-water sedimentswere not completely intermixed.

Besides the change in proportions of shallow- and deep-water shells thereis a change in the total number of shells. The basal sandstone and the mud­stone generally have abundant shells, but the gradational zone between thesandstone and mudstone has very few shells. This change is due to differencein the number of shells destroyed during transport and deposition of thesediment forming different parts of the rhythm, and is considered to indicatedifferent modes of transport' and deposition.

The basal sandstone is mostly shallow-water sediment with shallow-waterfossils, and is considered to have been transported as a unit. It was a

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II

I

/ !I I

/ I

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. ..............lilllllll!!!!

............iiE5!!II!I!!

~o30

IIIII

'======~~----------------------

.........iEE!EE!!!!

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I t: I Z :rI I \9 ~UJ I tt I::'! «z I IJJ I

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Almosc bo.rrer\ of fossils.

, , ,. , , ,

\ ,\, ,, ,, , ,

III\ oS' ' en ,

Ill' x : \ J.J \ ) , .J \ J

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:-.: . .:....:.:..:-.....:..-;-----;- ". z.:...:.....:.-:--:.-....._..;

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FIG. 3

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dense, watery slump, which slid rather than flowed turbulently from theupper part of the continental shelf down into much deeper water. During itstransit down the slope, internal movement was sufficient to thoroughlyintermix Foraminifera and sediment picked up on the way, and to partiallyseparate coarser sediment from finer sediment, and larger shells from smallershells, but was not sufficient to destroy more than the largest and most fragileshells.

The intermediate zone between the basal sandstone and the overlying mud­stone, which is nearly barren of fossils, is the only part of the rhythms atCleland Creek that shows any microbedding. Mr S. Kustanovich and thewriter found that much thicker and usually convoluted microbedded layersin Oligocene (Otaiari), turbidites at Ekenui Stream, Tinui, Wairarapa, areinvariably barren of fossils, though fossils are generally present in underlyingnon-microbedded sandstone and overlying non-microbedded mudstone. Themicrobedding indicates sorting and suggests deposition by fairly rapidlymoving water in which abrasion may have been strong. This part of therhythm is considered to have been deposited by the muddy after-current thatwas generated by the initial slump.

The massive mudstone overlying the barren layer was probably depositedfrom suspension after water movement had slowed down. Foraminiferalshells would have been subjected to wear and tear during transport, andprobably the number of shells destroyed would vary from one turbiditerhythm to another, but no shells would be broken during deposition.

No faunal evidence was found for an autochthonous layer of the kindthat occurs between rhythms in the Ventura Basin (Natland and Kuenen,2951). Samples N158/630a and g were taken as close to the top ofrhythms as was possible without contamination from the overlying rhythms,and both contain mixed biofacies. Either no autochthonous sediment wasdeposited in the time interval between rhythms, or more probably autoch­thonous sediment was stripped off by each slump preceding a turbidity flow.The borings in the top of each rhythm are probably merely the lower endsof burrows that originally extended up through the autochthonous sediment,and that were still occupied by living animals after the new rhythm had beenlaid on top. Sand was probably emplaced in the truncated burrows by theburied animals boring upwards in futile efforts to escape.

DEPTH OF DEPOSITION OF THE TURBIDITES

In the absence of autochthonous layers a minimum depth of deposition isthe best that can be determined for the turbidites at Cleland Creek. This isthe minimum depth of the deepest biofacies represented.

FIG. 3-Bar diagram to show differences in relative proportions of shallow-watershells and deep-water shells at different levels in the turbidite rhythms sampledat N158/630. Specimens of restricted species of each biofacies (numbered as inTable 6) are shown as a percentage of total shells. Non-diagnostic species aremarked "X" in Table 6. Sample "d" represents a fairly thin zone almost barrenof fossils.

The ratio of shallow-water to deep-water shells abruptly increases at the baseof each rhythm and decreases somewhat irregularly from the base to the top ofeach rhythm.

GeoIpgy-IO

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786 NZ. JOURNAL OF GEOLOGY AND GEOPHYSICS [Nov.

TABLE 6-Distribution of Foraminifera

Notes: (1) The figures 1 to 9 in the right-hand columns show actual numbers ofspecimens; C indicates 10 to 20; A more than 20; and a dash none.

(2) Samples 1 to 4 are from non-turbidite facies; 1 = NI53/1155, 2 =NI55/1157, 3 = NI53/910, 4 = NI58/610. Corresponding numerals toleft of species names indicate species restricted to each of these samplesor inferred to be restricted to the equivalent biofacies; 5 indicates speciesrestricted to an inferred deeper-water biofacies; X indicates species notrestricted to one biofacies (see Table 2); species (at end of table) without

facies designation are planktonic.

Rhabdammina? sp.

HaplophragfrJojdes? sp.. (crushed)

Textularia kapiteo Finlay

T. off. ensis Vella

X Haeus/erella porri Finlayi

1 2 3 4

2

- A

A

NT 58/630

ab c d e f 9 h

624

a b

626

a b

H.

H.

X H.

morgani Finlayi

finloyi Vella

pliocenica (Finlay)

c

? ?

? ?

c c

? 2

X Siphotextu,laria ihungia Finlay

x S. subcyJindrica Finlay - 3 7

S. off. mestayerae Vella

Gaudryina crespinae Cushman

X Karreriel/a cylind,ica Finlay

Karreriella brady; (Cushman)

X Martinottiella sp.

Sigmoilopsis zeaserus Vella

Quinque/ocu/ina triangularis d'Orb.

A A

c

8 ?

4 -

c

c c

Q.

Q.

d. Iota Terquem

kapitiensis Vella

Q. (LachlanellaJ n. sp.

X Bi/ocu/ina sp.

X Pyrgo sp.

Robu/us colcar Linne

X-R. d. calcar Linne (smell)

A

R. cuitratus Montfort c

R. dicampylus {Frcnaencu}

X R. gyroscalprlJs (Srcche)

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1963J VELLA - FORAMINIFERA FROM TURBIDITES

TABLE 6-continued

N158/630

abcdefgh

624

a b

787

626

a b

X R. locuJosus (Srcche)

X R. spp.

2 Lenticu/ina peregrina (Schwager)

X Saracenaria ita/icc D~france

X Marginulina 5ubbullata Hearken

X Yoginulina sp. A

Vaginulina sp. B

Dentalina soluta Reuss

2 2

7 4

1 -

• 1

X Dentalina sp.

2 Nodosaria affinis Reuss

X D. substrigota Stache 9 -

• 3 • •

- 1 - •

3 -

• 1

N~ d. ca/omorpha Reuss

N. catenu/ata Brady

X N. ho/oserica Schwager

3 N. lamnu/jfera Boomgaart

X N. longiscata d'·Orb.

X ChrysaJogonium verticale (Stcche)

3 Amphicoryne d. scalaris (Botsch)

c

X A.

A.

hlrsuta (d'Orb.)

hirsute var. (smooth)

StiJostomello antipoda (Stach e)

s. d. verneuiJii (d'Orb.)

X StifostomeJla sp. (spinose)

X StilostomeJla spp. indet.

X ParafrondicuJario pe/Jucida (Fin.)

P. wairarapa Vella

Proxifrons vaughani (Cushman)

Awhea subtetragona (finlay)

Lagena distoma Porker & Jones

X L d. laevis (Montagu)

4 L hispido Reuss

X L. d. sulcata Walker & Jacob

2,boJina g/obosa -(Montagu)

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788 N.Z. JOURNAL OF GEOLOGY AND GEOPHYSICS [Nov.TABLE 6-continued

N15S/630 624 626

I 2 3 4 a b c d e I 9 h a b a b

O. hexagona (Williomson) - 2 7 .

O. melo d'Orbigny 4 3 - 2 2

O. costato (Wi II iamson) 2 .X Fissurlna orbignyana Seguenza 2 - 2

I F. yokoyama. (Millett) 2 -X Fissur;nasp. · 4 2 · - 2

Guttulina yobe; Cushman &.Ozawa ? . 3

S;gmomo~phina d. lacrimosa Vella - 2 7

Laryngos;gma williamson; (Terquem)

SigmoiJ.lla d. e/egontissima (P. & J.) 1 - - . 2 4 .4 GlandlJlina symmetrica Stache

3 Ramulina sp,

X P/ectofronc1icuJaria pohana Finlay 6 A · 2 8 - 2 4 3 · 2 5 3 C

X Bo/ivinita pliobliqua Vella · 5 A 5 - 2 7 - . 6

3 B. d. eJegantissima Boomgaart 3 -4 B. pohana Finlay C 4 ? ·3 Bolivina albatross; Cushman · - 2 . 2 . 1 . 3 . 2

X B. al/iliata Finlay A . 3 7 3 A

X B. nurtleroso Vella · 1 1 - 3 - 2 3 2

3 B. d. pacifica Cushman A 6

X Bolivina spp. · 2 6 - · 1 1 - 4 2

"Bo/ivina" turbiditorumVella - 1 . . 2 C C

Rectobolivina sp. 1 . 1 - - 2 2

3 Yirgulina off. rotundata Parr

Virgu/opsis d. pustulate Finlay

Bu/iminella eJegantissjma d'Orb.

B. missi!is Vella 2

Bulim;noides wiJliamsonianus (Brady) - 1 .X Bulimina aculeate d'Orbigny 4 8 - 4 C 2 4

X B. d. australis Vella 3 C · 1 C 2

5 B. truncanella Finlay

B. sp. (smooth) C

2 B. nctevate Chapmen 2

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1%3] VELLA - FORAMINIFERA FROM TURBIDITES

TABLE 6-continued

N158/630 624

789

626

X G/obobu/;mina padfica Cushman

X Neouvigerina vadesc811s (Cushman)

2

c

abcdef a b

3 N.

N.

bellufa Vella

eketahuna Vella

A

A

c

X Halkeruva (H.) taranakiaVeil.

X H. '(Trigonauva) d. zeocuminata Vella

2 H. (Laminiuva) zelamina Vella

3 H. (Tereuva) lutarum Vella

4 Halkeruva (s.1.) delicatula Vella

X Hofkeruva sp. lndet,

E'ulivigerina nofohispicla (Finlay)

Norcotfiamioinclex (Finlay)

X Trifarina brady;Cushman

X Angu/ogerinc spp.

X PJe~rostomella sp.

t:JJipsogfanc1ulina subconica (Kreutz.)

4 Ellipsogiandulinasp,

X Cassiclulina Jaev;gata d'Orb.

X C. neocarinata Thalmann

- A ­

A

c

7 •

• • 4

3 •

4

5 C 7

C

C

5

h 6

2

C

3 Nanio~ella? sp.

2 Florilus flemingiVella

Melonls lutorum Vella

2 Me/onis zeobesus Vella

3 Nonionella magnalingua Finlay

x Cassic1uJina sp.

X CasslrIulinoic!es orientalis (Cushm.)

X Chilostomella ovoidea Reuss

X SpheroirIina bullo/rIes d'Orhigny

3 Pulleniad. bullairIes d'O,higny

3 C.

XP.

X P.

3 N.

subg/obosa Brady

quinque lobo (Reuss)

quadrlloba (Reuss)

zenitens Finlay

• • 4 •

• • 2

• C 5 •

• 9 6 •

• 3 A C

A .

• 4 2 ­

7

• 6 • •

3

C

7

3 -

- 1

2

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790 N.Z. JOURNAL OF GEOLOGY AND GEOPHYSICS

TABLE 6-colltil1ued

N158/630

abc d e

624

a b

[Nov.

626

a b

1 Zeaflorilus parri (Cushman)

X Pacinonion cf. pork; Hornibrook 4

3 P. neefi Yella

3 Pacinonion.n. sp.? C C

X Anomalinoides parvumbilia (Finlay) C A C

2A. d. spherlca (Finlay)

X Cibiciaes de/;quatusFinlay A C 2

Xc. ihungia Finlay . 8 A 2 2

Xc. mediaeris Finlay C A

Xc. moiesrus Hornibrook A A A . 2 C C

C. off. robertsonianus (Brady) - · . A

Dyocibicides primitiv.eVella - 1

Rosaline d. brady; (Cushman) - 2 - 4 A

Pi/colina raeliata Vella 2 .

Pi/colina zec/andica Vella - 5 3 4 ·

X Piscopu!vinu/ino bertheloti (d'Orb.) - ? 1 ·

X Eponieles tenere (Brady) - 2 C C

4 E. d. schreibers; (d'Orb.)

x Gyroidina prominula (Stache) 8 . - 1 1 ·2 Gyroidinoides zeokmdico Finlay A 4 5 4 A 4 5

X Gyroiclinoides sp. (tiny umbilicus) 6 I .3 Valvulinaria sp, · 7

3 Parvicarinina .altocamerata (H·A.& E.) 1 - - 1

Laticarinina ha/ophora (Stcche) 1 .X Epistomina eJegans d'Orb. C 4 6 . · 5 2

3 EpistomineJla sp.• 3

EJphidium charlottensis Vella . 4 2 7 2

1 E. ef. crispum (Linne) 2 2

E. novozealandiciJm Cushmon - 2

Notorotalia cf. depressa Vella A. · 6 6 · A C 7 7

N. olsson; Vella

X N. taranakia Vella A 2 C

1 Amph"istegina sp. - 1 ·

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1963] VELLA - FORAMINIFERA FROM TURBIDITES

TABLE 6-continued

791

Nl58/630 624 626

1 2 3 4 a b c d e f 9 h a b Q b

Globorotalia inflate (d'Orb.) e

Globorotalia n . sp. off miozea Fin. e

G. off. menardii (d'Orb.) 1 1 2 2 3 1 6 1 1

Gfobigerina buJloidesd'Orhigny 3 e A A 2 6 e 7 6 7 A A 1 6

Globfgerina semivera Hcmibrcek 6 e A e 5 3 2 e e

Globigednita sp• 8 e 1 6

Orbulina univecsa d'Orbigny A 4 1

The Semipelagic Biofacies is the deepest recognised with reasonable cer­tainty, the evidence for the Eupelagic Biofacies being only the two benthonicspecies Bulimina truncanella and Norcottia mioindex. The chief evidence ofthe depth ranges of the Semipelagic and Eupelagic Biofacies (discussed morefully by Vella, 1962a, 1962b) is the almost total absence of Mollusca,Brachiopoda, Echinoidea, Bryozoa, and Ostracoda, and the relative abundanceof Foraminifera, and especially, the high proportion of pelagic foramini­feral shells. When freed of sediment the Eupelagic fossil biofacies is similarto Globigerina ooze, with pelagic shells up to more than 90% of all fora­miniferal shells. The Semipelagic fossil biofacies has from 40% to 60% ofpelagic shells. In geographic distribution for any particular time, and instratigraphic sequences, the Robulus Biofacies usually intervenes between theSemipelagic Biofacies and the Haeuslerella Biofacies. The Robulus Biofacieshas from 30% to 50% of pelagic shells, and a highly diagnostic molluscanfauna similar to the deepest present-day archibenthal faunas described byDell (1956) from depths of 1,500 to 1,800 ft. This archibenthal molluscanfauna marks the greatest well-documented depth in the depth sequencedefined by biofacies in the late Tertiary rocks of the Wairarapa. The Semi­pelagic and Eupelagic Biofacies both represent considerably greater depths,but the actual depth ranges attributed to them are tentative, being basedmainly on data given by Phleger (1960).

The minimum depth of the Semipelagic Biofacies is conservatively esti­mated to be 2,000 ft, and this therefore is the least possible depth at whichthe Cleland Creek turbidites could have been deposited. The best estimatethat can be made with the present data is between 4,000 and 6,000 ft.

CONCLUSIONS

Turbidites at Cleland Creek contain mixed deep-water and shallow-waterForaminifera. A typical rhythm consists of three poorly differentiated buthighly distinctive layers: a basal sandstone with abundant fossils, represent-

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792 NZ. JOURNAL OF GEOLOGY AND GEOPHYSICS [Nov.

ing slumped shallow-water sediment with a small proportion of intermixeddeep-water sediment; an intermediate layer that is commonly microbeddedand barren of fossils, representing sediment deposited by the turbidity currentgenerated by the slump; and massive mudstone with abundant fossils, form­ing the upper part of the rhythm, representing sediment that was thrownup in a cloud above the turbidity current and deposited from suspensionafter it had ceased to flow.

No known mode of deposition, other than by submarine slumping andturbidity current, accounts for the simultaneous mixing of deep- and shallow­water shells, size-sorting of shells, and destruction of shells. The turbiditeswere deposited at great depth, probably between 4,000 ft and 6,000 ft, andthe sediments composing them were derived from all shallower depths up toabout 400 ft or less.

This study was begun with the purpose of testing faunal mixing andthe existence of autochthonous layers, and determining depths of deposition.The results, including positive evidence of the different modes of depositionof the parts of the rhythms, exceeded expectations. Study of well exposedTertiary turbidites can supplement data obtainable by oceanographic methods.A more statistical approach is needed than was possible in the presentstudy. More rhythms should be closely sampled at Cleland Creek to testthe consistency of faunal changes and layering, and turbidites elsewhereshould be examined in the same way.

ACKNOWLEDGMENTS

Mr ]. Kennett kindly allowed me to list two microfaunas (N153/1155 and1157) collected and prepared by him for his own research. Sample N153/910 wascollected and prepared by Mr G. Neef. Costs of equipment and field work werelargely defrayed by New Zealand University Research Grants.

REFERENCES

BANDY, O. 1.; ARNAL, R. E. 1960: Concepts of Foraminiferal Paleoecology. Bull.Amer. Assoc. Petrol. Geol. 44 (12) : 1921-32.

BRADY, H. B. 1884: Report on the Foraminifera Dredged by H. M. S. Challengerduring the Years 1873-1876. Rep. Voy. Challanger, Zool. 9 (22): 1-814.

DELL, R. K. 1956: The Archibenthal Mollusca of New Zealand. Dam. Mus. Bull. 18,235 pp., 27 pis.

NATLAND, M. L. 1957: Paleoecology of West Coast Tertiary Sediments. Mem. Geol.Soc. Amer. 67 (2) : 543-72.

NATLAND, M. 1.; KUENEN, PH. H. 1951: Sedimentary History of the Ventura Basin,California, and the Action of Turbidity Currents. Soc. Bean. Min. andPal., Spec. Pub. 2: 76-107.

ORBELL, G. E. 1962: Geology of the Mauriceville District, New Zealand. Trans. Roy.Soc. N.Z., Geol. 1 (17): 253-67.

PHLEGER, F. B. 1951: Displaced Foraminifera Faunas. Soc. Bean. Min. and Pal., Spec.Pub. 2: 66-75.

---- 1960: "Ecology and Distribution of Recent Foraminifera." Johns Hopkins,Baltimore. 297 pp.

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1963] VELLA - FORAMINIFERA FROM TURBIDITES 793

VELLA, P. 1962a: Biostratigraphy and Paleoecology of Mauriceville District, NewZealand. Trans. Roy. Soc. N.Z., Geol. 1 (12): 183-99.

---- 1962b: Determining Depths of New Zealand Tertiary Seas. Tuatara 10(1): 19-40.

---- 1963: Size-sorting of Foraminifera in Graded Beds, Wairarapa, New Zea­land. N.Z. I. Geol. Geopbys, 6 (5): 794-800.

WELLMAN, H. W. 1953: The Geology of Geraldine Subdivision. N.Z. Geol. Surv.Bull. 50. 72 pp.

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