stratigraphy palynologic results general discussion

28. PALYNOSTRATIGRAPHY OF THE BERRIASIAN TO CENOMANIAN SEQUENCE ATDEEP SEA DRILLING PROJECT SITE 535, LEG 77, SOUTHEASTERN GULF OF MEXICO1

L. A. Riley,2 Gearhart Geodata Services Limited, Kirkhill Industrial Estate, Dyce, Scotlandand

J. P. G. Fenton, Robertson Research International Limited, Llanrhos, Gwynedd, North Wales

ABSTRACT

One hundred twenty-seven samples from DSDP Cores 535-18 to 535-79 have been analyzed palynologically and dat-ed using dinoflagellate cysts. The taxa recorded indicate the presence of sediments of late Berriasian/late Valanginian(Sections 535-79-1 to 535-55-6) and Hauterivian (Sections 535-55-4 to 535-47-1) age. These sediments are unconform-ably overlain by Aptian deposits (Sections 535-46-2 to 535-43-3). Sections 535-43-2 to 535-18-1 yielded palynofloras ofAptian to Albian age. Ammonite evidence (Young, this volume), however, suggests reworking of these assemblages intoCenomanian deposits.

INTRODUCTION

Leg 77 of the Glomar Challenger was located in thewestern straits of Florida, southeastern Gulf of Mexico.The drilling conducted during the Leg is part of an over-all program to study the evolution of the western NorthAtlantic passive margin, and to investigate the Mesozoicand Cenozoic history of the area.

PALYNOLOGIC RESULTS

General Discussion

The Cretaceous sequence (Berriasian-Cenomanian) atSite 535 yields rich palynofloras, containing varying pro-portions of dinoflagellate cysts, acritarchs, chlorophyce-an algae and miospores. These palynomorphs occur inassociation with relatively large numbers of microfora-miniferal test-linings and tintinnid loricas. Marine mi-croplankton dominate throughout the sequence, withterrestrially derived miospores making only minor con-tributions to the assemblages.

Miospore assemblages are relatively homogeneous incomposition and display low taxonomic diversity. Pollenof gymnosperm origin predominate, in particular long-ranging species of Callialasporites, Classopollis and bi-saccates. Within the late Berriasian-Aptian interval Clas-sopollis is the most numerous miospore, reticulate angi-osperm pollen first appearing in the Cenomanian.

Foraminiferal test-linings are encountered in veryhigh numbers throughout the Cretaceous at Site 535,being especially prominant in the late Berriasian-earlyValanginian and Aptian-Cenomanian intervals.

Throughout the late Berriasian-Hauterivian, tintin-nid loricas are consistently observed. They occasionallyoccur in large numbers, especially within the late Berria-sian-early Valanginian.

1 Buffler, R. X, Schlager, W., et al., Init. Repts. DSDP, 77: Washington (U.S. Govt.Printing Office).

2 Present address: Gearhart Geoconsultants Limited, Dyce, Aberdeen, Scotland.

Preservation of individual palynomorphs is generallygood, and amorphous organic matter is the dominantkerogen throughout. Terrestrially derived kerogen com-ponents (structured vitrinite and inertinite, plant cuti-cles, and miospores) are present in only minor quantities.

StratigraphyEmphasis during the course of this study has been on

palynomorphs of marine origin, especially dinoflagel-late cysts. Dating is by comparison with known strati-graphic ranges established in accurately dated Europeanonshore sections and local ranges established at previousDSDP sites in the North Atlantic. This information is tobe found in the following publications which deal withvarious aspects of the onshore European and offshoreAtlantic Lower Cretaceous: Davey [1978 (Aptian), 1979b(Portlandian-Barremian), 1979a (Aptian-Albian)]; Da-vey and Verdier [1971, 1973, 1974 (Aptian-Albian)]; Dux-bury [1977 (Berriasian-Barremian)]; Fisher and Riley[1980 (Kimmeridgian-Valanginian)]; Habib [1972 (Ox-fordian-Cenomanian), 1978 (Berriasian-Albian)]; Ver-dier [1975 (Barremian-Albian)]; Williams and Bujak[1979 (Berriasian-Hauterivian)]; and unpublished re-search by the authors on both onshore and offshore Eu-ropean Lower Cretaceous.

The stratigraphic distribution and relative abundanceof the marine palynomorphs recovered during this in-vestigation are shown on Figs. 1-4. In addition, thestratigraphic ranges of 49 "key taxa," which have beenchosen for their chronostratigraphic potential, are shownon Fig. 5.

Late Berriasian-Late Valanginian(Sections 535-79-1 to 535-55-6)

Assemblages are characterized by large percentages ofChytroeisphaeridia sp. A, Diacanthum hollisteri, Gony-aulacysta helicoidea, Hystrichodinium pulchrum, H. aff.pulchrum, Tanyosphaeridium boletum, and Polysphaeri-dium warrenii. Microforaminiferal test-linings and largeleiospheres are also conspicuous components. Many of

675

L. A. RILEY, J. P. G. FENTON

Age

late

Be

rria

sia

n—

late

V

ala

ng

inia

π

Samples

63-4,10-1464-2,92-94

64-6,96-98

65-2,148-150

65-4,69-71

65-5,86-88

66-2,31-34

66-4,17-20

66-5,1-5

67-2,137-139

67-3,77-79

67-4,108-12

68-2,114-16

68-5,120-22

69-1,64-67

69-2,126-128

69-3,91-9369-6,84-87

70-2,44-46

70-3,142-144

70-5,59-61

71-1,107-109

71-1,137-139

71-3,98-100

71-3,100-03

72-4,85-87

72-4,91-93

73-1,89-91

73-3,26-31

74-2,117-119

75-1,24-28

75-3,117-119

76-1,116-119

77-2,44-47

78-1,37-39

79-1,52-53

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Figure 1. Distribution of marine microplankton in Section 535-79-1 to 535-63-4; open circle indicates taxon present, solid circle indicates taxoncommon, solid square indicates taxon abundant. Sample numbers expressed as core-section, interval in cm.

the taxa encountered are either long ranging or notknown from the Lower Cretaceous-type localities in Eu-rope. Broad similarities are, however, seen with the di-noflagellate cyst assemblages present at Sites 391 (Ha-bib, 1978) and 416 (Williams and Bujak, 1979).

Species first appearing in the European upper Berri-asian (Davey, 1979b) and which occur in the basal partof this interval include Achomosphaera neptuni, Mude-rongia simplex, Phoberocysta neocomica, and Pseudo-ceratium peiliferum. Some degree of similarity with theEuropean upper Berriasian is also afforded by the oc-currence of Kieithriasphaeridium cf. fasciatum and vari-ably spinate/tabulate cavate cysts (including Muderon-gia sp. cf. M. simplex of Habib, 1978) included herewithin M. simplex or P. neocomica.

By far the strongest affinities are, however, with theearliest Cretaceous assemblages reported by Habib (1978)from the Blake-Bahama Basin. Druggidium apicopauci-cum first appears in Sample 535-76-1, 116-119 cm, thefirst (lowest) appearance of this species defining theboundary between Habib's (1977, 1978) Biorbifera john-ewingii and Druggidium apicopaucicum zones. The zon-al index B. johnewingii is conspicuous by its absence atSite 535. By comparison with Habib's (1978) data, Sam-ple 535-76-1, 116-119 cm is tentatively considered to ap-proximate the horizon of the Berriasian/Valanginianboundary.

The first occurrence of Spiniferites ramosus in Sam-ple 535-71-3, 98-100 cm indicates an age no older thanValanginian at this level, as this taxon is considered by

676

PALYNOSTRATIGRAPHY OF THE BERRIASIAN TO CENOMANIAN SEQUENCE

Age

angi

nian

y

Hau

teriv

ian

late

Ber

riasi

an—

late

Va

Samples

49-1,123-2749-3,96-9750-2,76-7850-3,27-3450-4,6-8

51-1,101-0352-2,21-2252-3,8-11

52-4,56-6053-2,96-9753-3,23-2453-4,58-6054-1,44-4654-3,48-5055-4,64-6655-6,26-2856-3,53-5656-4,39-4256-4,116-1957-1,98-103

57-3,4-657-4,85-87

58-2,115-1758-3,134-3759-1,68-7159-2,84-8660-1,88-8960-3,67-6961-1,47-4961-1,92-9561-5,68-70

62-1,108-11062-2,64-66

62-5,131-13763-2,34-38

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ra

nept

uni

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dini

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Davey (1979b) not to occur in pre-Valanginian sediments.In addition, Kleithriasphaeridium simplicispinum, whichfirst occurs in Section 535-69-6, is reported to make itsstratigraphic appearance within the lower Valanginian(Davey, 1979b).

The assemblages recovered from above Section 535-68-5 are readily differentiated from the underlying as-semblages by an abrupt reduction in numbers of D. hol-listeri, G. helicoidea, H. pulchrum, P. warrenii, and T.boletum. These features, in association with the occur-rence of the taxa discussed below, tentatively suggest alate Valanginian age for Section 535-68-2 to 535-55-6.Within this subinterval several species are stratigraphi-cally important and include, in alphabetical order, thoselisted below:

1. Aprobolocysta varigranosa has a first stratigraph-ic occurrence within the latest Valanginian of eastern

England (Duxbury, 1977) and is only present in Section535-58-2.

2. Gonyaulacysta kostromiensis occurs, but rarely, atSite 535; its earliest occurrence is in Sample 535-65-2,148-150 cm. In eastern England this species occurs aslow as the basal Hauterivian (Duxbury, 1977), but hasbeen reported from the Valanginian of northern Canada(Mclntyre and Brideaux, 1980).

3. Hystrichodinium furcatum has a first stratigraph-ic occurrence at the base of the Hauterivian in easternEngland, although it has been encountered in Valangini-an assemblages from northwest Europe (Riley, pers.obs.). It occurs throughout this interval, having a basein Section 535-67-4.

4. Muderongia extensiva is restricted to the upperValanginian-lowermost Hauterivian of eastern England(Duxbury, 1977), and occurs rarely in Cores 63 and 62.

677

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41-1,118-2041-2.126-30

41-4,122-12441-6,122-124

42-3,78-8043-1,77-7943-2,139-4143-3,20-22

44-1,117-11844-1,118-11944-1,120-122

46-2,21-2346-2,32-3446-2,39-4046-2,43-4447-1,74-77

47-1,121-2248-1,43-4548-1,76-78

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5. Scriniodinium cαmpαnulum first appears in theBerriasian at Site 416 (Williams and Bujak, 1979), in theValanginian at Sites 391 and 105 (Habib, 1972, 1978)and in Section 535-66-2 in this study. It is often a signifi-cant component of European upper Valanginian-lowerHauterivian assemblages (Riley, pers. obs.).

6. Subtilisphaera sp. A becomes a prominent compo-nent of many assemblages in this interval, and continuedto be numerically significant in overlying intervals. Innorthwestern Europe this genus is generally considerednot to occur in pre-Hauterivian sediments (Duxbury,1977; Davey, 1979b), although large numbers of the ge-nus have been encountered in subsurface sections, datedas Valanginian, in the Gulf of Mexico and onshore U.S.Gulf Coast (C. N. Denison, pers. comm., 1981).

This subinterval also contains the highest stratigraph-ic occurrences of Diacanthum hollisteri (Section 535-61-1) and Leptodinium sp. A (Section 535-63-2). Habib(1972, 1978) considers D. hollisteri to range no youngerthan Valanginian at Sites 391 and 105, whereas bothspecies make their last appearance within the Valangin-ian at Site 416 (Williams and Bujak, 1979).

Valanginian/Hauterivian Boundary

This boundary cannot be defined on palynologic cri-teria with any degree of accuracy because of the paucityof reliable datum horizons or key species in the Europe-an area. Over a wide geographic area throughout west-ern Europe, the Valanginian/Hauterivian boundary is

typically represented within a condensed sedimentary se-quence. In onshore Western Europe and the RussianPlatform the boundary is usually coincident with a ma-jor lithologic change and a corresponding, often abrupt,change in character and composition of dinoflagellatecyst assemblages (Riley, pers. obs.). These may be re-lated to a major eustatic event (Rawson and Riley, 1982).

A significant lithologic change is evident in Section535-55-5, and this equates with the last occurrence ofHystrichodinium aff. pulchrum, an abrupt decrease innumbers of Polysphaeridium warrenii and a reductionin abundance and frequency of Phoberocysta neocomi-ca. These features are, by broad analogy with the Euro-pean area, considered to approximate the Valanginian/Hauterivian boundary.

Hauterivian (Section 535-55-4 to 535-47-1)

The lower limit of this interval and the positioningof the Valanginian/Hauterivian boundary are discussedabove.

Assemblages are characterized by high percentagesof Chytroeisphaeridia sp. A, Oligosphaeridium spp. andSubtilisphaera sp. A. In addition microforaminiferal test-linings and large leiospheres are numerically significantthroughout the Hauterivian.

The following species are considered to be stratigraph-ically important:

1. Callaiosphaeridium asymmetricum, a species thathas a stratigraphic base in the "mid" Hauterivian of

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18-3,45-48

19-2,76-78

20-2,31-34

20-2,140-44

21-3,137-41

21-4,14-17

21-1,52-26

22-6,53-55

23-6,22-24

24-3,46-48

25-3,66-68

27-3,0-3

28-2,100-02

28-6,44-46

30-1,148-50

30-3,143-47

30-4,65-67

31-5,74-77

31-6,141-43

31-7,7-9

32-1,83-85

32-3,44-47

33-5,107-1034-2,109-12

35-1,78-80

35-5,12-14

35-6,38-40

36-1,52-56

36-1,84-86

36-2,40-44

36-3,52-55

37-1,24-26

38-3,81-83

39-4,52-54

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northwest Europe (Davey, 1979b), appears in Sample535-51-1, 101-103 cm.

2. Chlαmydophorellα sp. A of Davey (1979b) has atop stratigraphic occurrence in the late Hauterivian ofeastern England (Davey, 1979b) and occurs up to Sec-tion 535-52-3.

3. Gonyaulacysta kostromiensis has its last occur-rence in Section 535-47-1; in eastern England (Davey,1979b) and the European area (Riley, Fenton, pers.obs.), this taxon becomes extinct in the uppermost Hau-terivian.

4. Hystrichodinium furcatum makes its last appear-ance in Section 535-47-1; in offshore western Europe(Fenton, pers. obs.), this species has a total stratigraphic

range of upper Valanginian to lower Barremian, but ismore numerous within Hauterivian sediments.

5. Muderongia simplex has its last occurrence in Sec-tion 535-53-2. Davey (1979b) and the present authorsconsider that the top occurrence of this species is nor-mally within the upper Hauterivian. Duxbury (1977) has,however, reported it from the lower Barremian of east-ern England and Williams and Bujak (1979) have re-corded the taxon from the Barremian of offshore east-ern Canada.

The change in palynofloras seen in Section 535-51-1corresponds with a lithostratigraphic boundary (UnitsIV/III) and is dated as "mid" Hauterivian. This maycorrespond to a major transgression (possibly of eustat-

679

Λ C θ r e -A g e Section

18-1 -18-3 -

c 19-2 -E 20-2 -c 21-3 -o 21-4 -S 22-1 -" 22-6 -5 23-6 -| 24-3 -

S 27-3 -28-2 -28-6 -

^ 30-1 -s? 30-3 -

N 30-4 -31-5 -31-6 -31-7 -32-1 -32-3 -33-5 -34-2 -35-1 -

£ 35-5 -2 35-6 -™ 36-1 -§ 36-2 -§ 36-3 -O 37-1 -

38-3 -39-4 -40-1 -41-1 -41-2 -41-4 -41-6 -42-3 -43-1 -43-2 -

n 43-3 -S. 44-1 -< 46-2 -

47-1 -48-1 -

Figure 5. Stratigraphic distribution of selected "key taxa," Hole 535.


ic origin) in northwestern Europe (Rawson and Riley,1982).

No positive palynologic evidence has been observedto indicate the presence of Barremian sediments.

Aptian (Sections 535-46-2 to 535-43-3)The base of the Aptian is placed, on palynologic cri-

teria, between Sections 535-47-1 and 535-46-2, and anunconformity between the Hauterivian and Aptian ispostulated. The dinoflagellate cyst assemblages are, as awhole, characteristically Aptian in composition. Severalcharacteristic and stratigraphically restricted Europeanspecies (see Davey and Verdier, 1974), however, are lack-ing. The assemblages are broadly comparable with Apti-an material previously described from Sites 400A, 402A(Davey, 1979a), and 391 (Habib, 1978).

Palynofloras throughout this interval are character-ized by high proportions of Chytroeisphaeridia sp. A,Dingodinium albertii and Subtilisphaera sp. A. in asso-ciation with microforaminiferal test-linings and large lei-ospheres.

The following stratigraphically significant species wererecovered from this interval:

1. Aptea polymorpha restricted to the Aptian in West-ern Europe (Verdier, 1975) and reported from the upperAptian at Hole 402A (Davey 1979a), is restricted to Sec-tion 535-44-1.

2. Dingodinium albertii makes its last appearance inthe lower Aptian at Hole 400A (Davey, 1979a); in theupper Aptian at Hole 402A (Davey, 1979a); and in Sec-tion 535-46-2 in this study.

3. Kleithriasphaeridium simplicispinum has its high-est occurrence in Section 535-44-1 and is reported to havea top stratigraphic occurrence in the Aptian (Verdier,1975). At Hole 400A K. simplicispinum is restricted tothe Aptian, whereas it occurs in the Aptian and Albianat Hole 402A. The occurrence within the Albian at thelatter site appears anomalous and may be due to rework-ing, as suggested by Davey (1979a, p. 549).

4. Muderongia staurota has a top stratigraphic oc-currence in the lower Aptian of northwestern Europe(Verdier, 1975) and is restricted to Section 535-46-2.

5. Nexosispinum hesperum first appears in the up-per Aptian at Hole 402A (Davey, 1979a), is restricted tothe lower Aptian at Hole 400A (Davey, 1979a), and hasa first stratigraphic occurrence in Section 535-46-2.

6. Ovoidinium diversum makes its first appearanceclose to the lower/upper Aptian boundary at Hole 400A(Davey, 1979a), in the lower Aptian at Hole 402A (Da-vey, 1979a), and in Section 535-44-1.

7. Phoberocysta neocomica has a top stratigraphicoccurrence in the lower Aptian at Site 391 (Habib, 1978),in the uppermost Barremian in western Europe (Verdier,1975), and in Section 535-44-1.

8. Pterodinium aliferum first appears in Section 535-46-2 and is considered to appear within the lower Apti-an of western Europe (Verdier, 1975).

The distribution of these species indicates that Sec-tions 535-46-2 to 535-44-1 may be early Aptian in ageand equivalent to the upper part of Habib's (1978) Pho-berocysta neocomica Subzone. Section 535-43-3 is up-per Aptian, probably uppermost Aptian, and equivalent

to the lower part of Habib's (1978) Subtilisphaera perlu-cida Subzone.

Cenomanian? (Section 535-43-2 to Core 30) andMiddle Cenomanian (Core 30 to Section 535-18-1)Rich and diverse microplankton assemblages were re-

covered from these intervals, generally indicative of anAlbian age. Young (this volume), however, reports am-monites of middle Cenomanian age from Core 30 to17,CC. Core 30 to Section 535-43-2 are assigned a ques-tionable Cenomanian age upon the basis of ammonites(Young, this volume). It has therefore been suggestedthat the palynofloras are almost entirely reworked, withlittle in situ kerogen. Major reworking would also haveto be envisaged to account for the recovery of forami-niferal and nannoplankton assemblages of Albian agefrom the same interval. This reworking inference is notacceptable to the present authors who, on the followingcriteria, would maintain an essentially Albian age.

Palynofloras from Section 535-43-2 to 535-18-1 arecharacterized by large numbers of the following taxa:Bacchidinium polypes, Eyrea nebulosa, Oligosphaeridiumcomplex, O. pulcherrimum, Ovoidinium diversum, O.implanum, Spiniferites ramosus s.l., Subtilisphaera sp.A, and Subtilisphaera sp. B. Microforaminiferal test-linings are a significant component through much of theinterval, becoming especially prominent in Sections 535-30-4 to 535-18-1.

Specific age-diagnostic species are discussed below:1. Codoniella psygma first appears in the upper Ap-

tian at Holes 400A and 402A (Davey, 1979a) and is re-stricted to Section 535-43-1. Probable examples of C.psygma, reported as Hystrichosphaeropsis ovum by Ha-bib (1972), also occur in the Aptian-Albian of the west-ern North Atlantic.

2. Florentinia deanii first appears in the uppermostAlbian (Vraconian) of western Europe (Verdier, 1975);in the middle? Albian at Hole 400A (Davey, 1979a); inSection 535-30-1. The species extends stratigraphicallyinto the upper Cretaceous.

3. Ovoidinium implanum first appears in Section535-30-1 and is restricted to the upper Albian at Hole400A (Davey, 1979a). It occurs up to Section 535-18-1.

4. Odontochitina costata appears in the uppermostAlbian (Vraconian) in western Europe (Verdier, 1975)and extends into the Campanian. It appears in Section535-33-5.

5. Palaeoperidinium pyrophorum appears in Section535-31-6 and is considered to make its first appearancewithin the Albian (Fenton, pers. obs.). It is most charac-teristically encountered in late Albian (Vraconian) oryounger sediments.

6. Palaeohystrichophora cf. infusorioides first ap-pears in Section 535-28-2. P. infusorioides makes its firstappearance in the uppermost Albian (Vraconian) of west-ern Europe (Verdier, 1975) and extends up to the Cam-panian. Specimens questionably assigned to P. infuso-rioides have, however, been reported from the upper Al-bian (pre-Vraconian) at Hole 400A (Davey, 1979a).

7. Polysphaeridium pumilum appears in Section 535-21-4 and makes its first appearance in the upper Albianat Hole 400A (Davey, 1979a).

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8. Pterodinium aliferum makes its last stratigraphicoccurrence in the upper Albian (pre-Vraconian) of west-ern Europe (Verdier, 1975) and extends up to Section535-32-1.

9. Xenascus ceratioides makes its first appearancein Section 535-36-3 and first appears in the lower Albianof western Europe (Verdier, 1975). It is consistent in oc-currence at and above Section 535-31-6, a feature char-acteristic of late Albian (Vraconian) or younger depositsin northwestern Europe (Riley pers. obs.).

10. Endoceratium turned, a species that has a totalrange of upper Aptian to upper Albian (pre-Vraconian)of Australia (Morgan, 1980), occurs in Sections 535-43-2 to 535-31-5. Rare occurrences of this taxon havebeen observed within the Cenomanian-uppermost Albi-an of northwestern Europe (Riley, pers. obs.).

11. Aptea securigera occurs in Section 535-43-1 andis generally considered to be stratigraphically restrictedto the Aptian in northwestern Europe (Davey and Ver-dier, 1974).

12. Trichodinium castaneum appears in Section 535-43-1 and has not been recorded from sediments of pre-Albian age in northwestern Europe (Verdier, 1975).

13. Stephodinium coronatum, a species with a totalstratigraphic range of middle Albian-Turonian in north-western Europe (Riley, Fenton, pers. obs.) occurs in Sec-tion 535-35-5.

Although ammonite evidence suggests that the ma-jority of the palynomorphs encountered in Sections 535-43-2 to 535-18-1 are reworked (Young, this volume), lit-tle or no evidence has been found to substantiate this.Within Sections 535-43-2 to 535-18-1, the only positiveevidence for recycling is seen by the presence of rarespecimens of Dingodinium albertii (Section 535-36-2) andDiacanthum hollisteri (Sections 535-34-2 and 535-30-1).The specimens of Nexosispinum hesperum encounteredbetween Sections 535-25-3 and 535-18-3 may also be re-cycled from the Aptian, although the total stratigraphicrange of this taxon has yet to be accurately defined.

The microplankton recovered from Sections 535-43-2to 535-18-1 suggest the following age subdivision is pos-sible, in contrast to that based upon ammonites (Young,this volume). The occurrence of Endoceratium turneri inSection 535-43-2 indicates a late Aptian or younger age.A late Aptian/early Albian age is suggested in Section535-43-1 by the simultaneous occurrences of Aptea se-curigera, Codoniella psygma, and Trichodinium casta-neum. Sections 535-42-3 to 535-31-7 contain taxa gener-ally indicative of an early Albian to late Albian (pre-Vraconian) age. Dinocyst assemblages recorded fromSections 535-31-6 to 535-18-1 suggest a late Albian (Vra-conian) to Cenomanian? age. The presence of the genusOvoidinium in Section 535-18-1, if in situ, tentativelysuggests an age no younger than Cenomanian, althoughthe genus is more characteristic of Aptian to Albian sed-iments.

SYSTEMATIC DESCRIPTIONS

This section is divided in to two parts: The first lists all marinepalynomorph species, in alphabetic order, that have been encounteredduring this investigation. Species figured in the plates are indicated as

PI. X Fig. Y throughout the list below. Taxonomic discussion of cer-tain species is undertaken in the second part.

Taxonomic nomenclature is principally that used by Stover andEvitt (1978), to which reference should be made for further data.

Achomosphaera neptuni (Eisenack, 1958) Davey and Williams in Da-vey et al., 1966

Aptea polymorpha Eisenack, 1958Aptea securigera Davey and Verdier, 1974Apteodinium maculatum Eisenack and Cookson, 1960Aprobolocysta varigranosa Duxbury, 1977Athigmatocysta glabra Duxbury, 1977Avellodinium falsificum Duxbury, 1977Bacchidinium polypes (Cookson and Eisenack, 1962) Davey, 1979aBatioladinium gochtii (Alberti, 1961) Lentin and Williams, 1977. PI. 2,

Fig. 4Caddasphaera halosa (Filatoff, 1975) Fenton, Neves and Piel, 1980Canningia spp.Callaiosphaeridium asymmetricum (Deflandre and Courteville, 1939)

Davey and Williams in Davey et al., 1966Cassiculosphaeridia reticulata Davey, 1969Chlamydophorella sp. A sensu Davey, 1979bChlamydophorella huguoniotti (Valensi, 1955) Davey, 1969Chlamydophorella trabeculosa (Gocht, 1959) Davey, 1979Chytroeisphaeridia sp. A. PI. 2, Fig. 7Chytroeisphaeridia sp. B. PI. 2, Fig. 8Chytroeisphaeridia sp. C. PI. 2, Fig. 5Codoniella psygma Davey, 1979a. PI. 3, Figs. 1, 2Cometodinium sp. A sensu Habib, 1972Cometodinium? whitei (Deflandre and Courtevelle, 1939) Stover and

Evitt, 1978Coronifera oceanica Cookson and Eisenack, 1958Crassosphaera hexagonalis Wall, 1965Cribroperidinium spp.Ctenidodinium scissum Mclntyre and Brideaux, 1980Ctenidodinium sp.Cyclonephelium distinctum Deflandre and Cookson, 1955Cyclonephelium distinctum subsp. brevispinatum (Millioud, 1969) Len-

tin and Williams, 1973Cymatiosphaera delicata Cookson and Eisenack, 1971Cymatiosphaera sp.Dinocyst sp. A. PI. 2, Fig. 9Dinocyst sp. B. PI. 1, Fig. 9Diacanthum hollisteri Habib, 1972. PI. 2, Figs. 1-2Dingodinium albertii Sarjeant, 1966Dinogymnium sp. PI. 1, Figs. 10-11Discorsia nanna (Davey, 1974) Duxbury, 1977Druggidium apicopaucicum Habib, 1973Druggidium rhabdoreticulatum Habib, 1973Endoceratium turneri (Cookson and Eisenack, 1958) Stover and Evitt,

1978. PI. 1, Fig. 4Exochosphaeridium bifldum (Clarke and Verdier, 1967) Clarke et al.,

1968Exochosphaeridium striolatum (Deflandre, 1937) Davey, 1969Eyrea nebulosa Cookson and Eisenack, 1971. PI. 4, Fig. 7Florentinia deanei (Davey and Williams in Davey et al., 1966), Davey

and Verdier, 1973Florentinia laciniata Davey and Verdier, 1973Florentinia spp.Fromea amphora Cookson and Eisenack, 1958Fromea sp. PI. 3, Fig. 3Gonyaulacysta helicoidea (Eisenack and Cookson, 1960) Sarjeant in

Davey et al., 1966Gonyaulacysta kostromiensis (Vozzhennikova, 1967) Sarjeant, 1969Halophoridia cf. xena Cookson and Eisenack, 1962. PI. 3, Fig. 6Heslertonia cf. heslertonensis (Neale and Sarjeant, 1962) Sarjeant in

Davey et al., 1966Heslertonia sp.Hystrichodinium furcatum Alberti, 1961Hystrichodinium pulchrum Deflandre, 1935Hystrichodinium aff. pulchrum Deflandre, 1935. PI. 2, Fig. 6Hystrichodinium voigtii (Alberti, 1961) Davey, 1974Kleithriasphaeridium eoinodes (Eisenack, 1958) Davey, 1974Kleithriasphaeridium corrugatum Davey, 1974

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Kleithriasphaeridium fasciatum (Davey and Williams in Davey et al.,1966) Davey, 1974

Kleithriasphaeridium cf. fasciatum (Davey and Williams in Davey etal., 1966) Davey, 1974

Kleithriasphaeridium simplicispinum (Davey and Williams in Davey etal., 1966) Davey, 1974

Leptodinium sp. A sensu Williams and Bujak, 1979Leptodinium sp. B. PI. 4, Fig. 3Lithodinia cf. bulloidea (Cookson and Eisenack, 1960) Gocht, 1976Lunatodinium cf. dissolutum Brideaux and McKintyre, 1973Maduradiniumi sp. A sensu Davey, 1978Membranilarnacia polycladiata Cookson and Eisenack in Eisenack,

1973Membranosphaera sp. A sensu Davey, 1979aMicrodinium opacum Brideaux, 1971Millioudodinium spp.Muderongia extensiva Duxbury, 1977. PI. 1, Fig. 6Muderongia perforata Alberti, 1961Muderongia simplex Alberti, 1961Muderongia staurota Sarjeant in Davey et al., 1966Muderongia spp.Nexosispinum hesperum Davey, 1979aOccisucysta tentoria Duxbury, 1977Odontochitina costata Alberti, 1961Odontochitina cf. costata Alberti, 1961. PI. 3, Figs. 8, 9Odontochitina operculata (Wetzel, 1933) Deflandre and Cookson, 1955Oligosphaeridium cf. abaculum Davey, 1979. PI. 3, Fig. 5Oligosphaeridium albertense (Pocock, 1962) Davey and Williams in

Davey et al., 1966Oligosphaeridium complex (White, 1842) Davey and Williams in Da-

vey et al., 1966Oligosphaeridium pulcherrimum (Deflandre and Cookson, 1955) Da-

vey and Williams in Davey et al., 1966. PI. 1, Fig. 8Oligosphaeridium totum Brideaux, 1971Oligosphaeridium sp. A sensu Williams and Bujak, 1979Omatia sp. PI. 1, Figs. 1-3Ophiobolus sp.Ovoidinium diversum Davey, 1979b. PI. 1, Fig. 7Ovoidinium implanum Davey, 1979b. PL 3, Fig. 4, PL 4, Fig. 8Palaeohystrichophora cf. infusorioides Deflandre, 1935Palaeoperidinium cretaceum Pocock, 1962Palaeoperidinium pyrophorum (Ehrenberg 1838) Deflandre, 1935Pareodinia ceratophora Deflandre, 1947Phoberocysta neocomica (Gocht, 1957) Millioud, 1969. PL 4, Figs. 1, 4Phoberocysta tabulata Raynaud, 1978Polysphaeridium pumilum Davey and Williams in Davey et al., 1966Polysphaeridium warrenii Habib, 1976. PL 2, Fig. 3Polysphaeridium sp. A sensu Williams and Bujak, 1979Prismatocystis cylindrica Habib, 1970. PL 4, Fig. 6Prolixosphaeridium granulosum (Sarjeant, 1962) Davey et al., 1966Pseudoceratium pelliferum Gocht, 1957. PL 1, Fig. 5Pterodinium aliferum Eisenack, 1958Pterospermella aureolata (Cookson and Eisenack, 1958) Eisenack 1972Pterospermella australiensis (Deflandre and Cookson, 1955) Eisen-

ack, 1972Pterospermella eurypteris (Cookson and Eisenack, 1958) Eisenack,

1972Pterospermella sp. A. PL 4, Fig. 2Pterospermella spp.Scriniodinium campanulum Gocht, 1959Senoniasphaera sp. ASirmiodinium grossii Alberti, 1961Spiniferites ramosus (Ehrenberg, 1838) Loeblich and Loeblich, 1966Spiniferites ramosus ssp. multibrevis (Davey and Williams in Davey et

al., 1966) Lentin and Williams, 1973Stephodinium coronatum Deflandre, 1936Subtilisphaera sp. A. PL 4, Figs. 11, 12Subtilisphaera sp. B. PL 4, Figs. 9, 10Systematophora sp. cf. S. areolata Klement, 1960 sensu Williams and

Bujak, 1979Tanyosphaeridium boletum Davey, 1974Tasmanites spp.Trichodinium castaneum (Deflandre, 1935) Clarke and Verdier, 1967.

PL 4, Fig. 5

Wallodinium krutzschii (Alberti, 1961) Habib, 1970Wallodinium lunum (Cookson and Eisenack, 1960) Lentin and Wil-

liams, 1973Xenascus ceratioides (Deflandre, 1937) Lentin and Williams, 1973.

PL 3, Fig. 7Xiphophoridium alatum (Cookson and Eisenack, 1962) Sarjeant in

Davey et al., 1966

TAXONOMY

Class Dinophyceae Fritsch, 1929Order Peridiniales Haeckel, 1894

Genus CHYTROEISPHAERIDIA Sarjeant, 1962 emendDavey, 1979

Type species. C. chytroeides (Sarjeant, 1962) Downie and Sarjeant,1965 (1964) emend. Davey, 1979.

Chytroeisphaeridia sp. A(Plate 2, Fig. 7)

Description. Cyst subspherical to ovoidal in shape, composed of asingle layer (autophragm) of moderate thickness (0.5-1.5 µm). Theautophragm is smooth and hyaline, and appears unstructured inter-nally. Apical, antapical, and lateral structures are lacking. No para-cingulum and parasulcus were observed. Archaeopyle formed by lossof a single precingular paraplate (probably 3 in.). The detached oper-culum is often seen within the autophragm. Cyst is prone to folding,thereby obscuring the overall shape and archaeopyle.

Dimensions. (Size range with mean dimension in parentheses): cystlength 40 (47) 58 µm (24 specimens measured); cyst width 23 (27)45 µm.

Remarks. This species bears closest resemblance to C. chytroeides,but differs in shape and size. C. chytroeides also appears to possess amore rigid autophragm. Chytroeisphaeridia sp. A differs from C. peri-compsum (Ioannides et al., 1977, 1976; Davey, 1979) in having athicker hyaline autophragm and being smaller in size.

Chytroeisphaeridia sp. B(Plate 2, Fig. 8)

Description. Cyst ovoidal to subspherical in shape, composed of asingle layered wall (autophragm) of moderate thickness (0.5-1.5 µm).The autophragm possesses a reticulate ornament of low relief and ishyaline. Apical, antapical, and lateral structures are lacking. No para-cingulum or parasulcus observed. Archaeopyle formed by loss of asingle precingular paraplate (probably 3 in.). Operculum may remainattached after excystment.

Dimensions. Cyst length 58 (60) 64 µm (10 specimens measured);cyst width 45 (47) 54 µm.

Remarks. This species is possibly conspecific with Pyxidiniopsischallengerensis Habib, 1976. The latter has been recorded from theAptian-Barremian (Habib, 1972) and Berriasian-Hauterivian (Habib,1976) of the western Atlantic.

Chytroeisphaeridia sp. C(Plate 2, Fig. 5)

Description. Cyst ellipsoidal in outline, with a single layered wall(autophragm) of moderate thickness (0.5-1.0 µm). The autophragm issmooth and occasionally hyaline, appearing to be internally unstruc-tured. It lacks apical, antapical, or lateral structures. No paracingu-lum or parasulcus observed. Archaeopyle formed by loss of a singleprecingular paraplate (probably 3 in.). The operculum normally re-mains attached following excystment.


Remarks. This species is similar to Chytroeisphaeridia sp. A ingeneral morphology, but differs in being markedly elongate in outline.

Genus DINOGYMNIUM Evitt, Clarke, and Verdier, 1967

Type species. D. acuminatum Evitt, Clarke, and Verdier, 1967

Dinogymnium sp.(Plate 1, Figs. 10-11)

Description. Cyst biconical to subrounded, single layered wall (auto-phragm). Longitudinal folds ill defined or prominent near paracingu-

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lum becoming indistinct towards the poles. Wall smooth to faintly sca-brate. Paracingulum well defined, broad. Parasulcus indistinct, bestdeveloped upon hypocyst. Antapical pole may rarely become mark-edly pointed. Archaeopyle unobserved.


Remarks. Some variation in outline is observed among the speci-mens encountered. Those from the late Berriasian-early Valanginianappear to possess pointed antapical poles, while those from the Hau-terivian are generally subrounded. Wall canals, which often character-ize Dinogyminium, appear to be absent.

Some of the specimens encountered may be conspecific with Dino-gymnium sp. A. sensu Habib (1972) recorded from the Albian-earlyCenomanian at Site 105.

Dinogymnium usually characterizes Upper Cretaceous sediments,and if not a result of contamination these occurrences may representthe earliest records of the genus.

Genus FROMEA Cookson and Eisenack, 1958Type species. F. amphora Cookson and Eisenack, 1958

Fromea sp.(Plate 3, Fig. 3)

Description. Cyst ellipsoidal to subrounded in outline. Single-lay-ered wall (autophragm), varying between 1.0-1.5 µm in thickness, be-ing smooth and hyaline. Paracingulum faintly indicated, occasionallyreflected by indentation in equatorial outline. Parasulcus unobserved.Circular opening at apex in plan view, concave in lateral view. Opercu-lum occasionally remains attached after excystment.


Remarks. Fromea sp. closely resembles F. amphora, but differs inpossessing a thinner autophragm, smaller dimensions, and being proneto folding so that specimens are seen in oblique or polar compressionsrather than lateral compressions. This results in the circular opening atthe apex being seen in plan view rather than in lateral view as in F. am-phora.

Genus HYSTRICHODINIUM Deflandre, 1935 emend. Clarke andVerdier, 1967

Type species. H. pulchrum Deflandre, 1935

Hystrichodinium aff. pulchrum Deflandre, 1935(Plate 2, Fig. 6)

Description. Cyst subspherical to polyhedral, with thin wall. Sur-face generally scabrate, occasionally becoming graulate. Apex occa-sionally surmounted by low, rounded apical horn. Paracingulum welldefined, parasulcus unobserved. Parasutures vaguely defined by lowridges, with flexuous (often bladelike) processes arising, varying inlength between 10-24 µm. Processes distally closed and pointed. Para-tabulation indistinct. Archaeopyle unobserved.


Remarks. These specimens are distinguished by their small size andrelatively large flexuous processes.

Genus LEPTODINIUM Klement, 1960 emend Stover andEvitt, 1978

Type species. L. subtile Klement, 1960

Leptodinium sp. B(Plate 4, Fig. 3)

Description. Cyst spherical, wall apparently single layered (auto-phragm), scabrate to infrapunctate. Paracingulum distinct, laevorota-tory, apparently undivided. Parasulcus unobserved. Gonyaulacean para-tabulation defined by distinct parasutures. Parasutural crests (approx.3-4 µm high) scabrate, or occasionally minutely perforate surmountedby small rounded spines. Crests upon the hypocyst occasionally be-come markedly trabeculate. Archaeopyle precingular, formed by lossof paraplate 3 in.

Dimensions. Cyst length 48 µm (single specimen); cyst width 46 µm.Remarks. This species differs from other species of Leptodinium

in the morphology of the parasutural crests.

Genus ODONTOCHITINA Deflandre, 1935 emend. Davey 1970

Type species. O. operculata (O. Wetzel, 1933) Deflandre and Cook-son, 1955

Odontochitina cf. costata Alberti, 1961(Plate 3, Figs. 8-9)

Description. Cavate cyst, ceratioid in outline, with apical, antapi-cal, and single lateral horns. Endophragm and periphragm normallyclosely adpressed, except at base of horns. Endophragm thin, smooth,and nontabulate. Small rounded apical protrusion may be present.Periphragm thin, scabrate to faintly granulate, nontabulate. Smallrounded or elongate perforations present on horns, principally devel-oped at their midpoints. Horns frequently possess markedly inflatedlower portions, becoming constricted at their midpoint before taper-ing to pointed or slightly rounded tips. Second, short antapical hornvery rarely developed. Paracingulum and parasulcus indistinct. Ar-chaeopyle apical.


Remarks. These specimens are closely comparable with O. costata,but differ chiefly by the inflated bases of the apical, antapical, and lat-eral horns.

Genus OLIGOSPHAERIDIUM Davey and Williams in Daveyet al. 1966

Type species. O. complex (White, 1842) Davey and Williams in Da-vey et al., 1966

Oligosphaeridium cf. abaculum Davey, 1979(Plate 3, Fig. 5)

Remarks. Two partially fragmented specimens were recovered bear-ing some resemblance to O. abaculum Davey, 1979. Overall morphol-ogy is similar to that of O. complex but the specimens have a paratab-ulation weakly defined by unornamented pandasutural areas. The on-ly species of Oligosphaeridium that possesses a definable paratabula-tion are O. abaculum and O. verrucosum, Davey (1979a), but in theformer species the parasutures are defined by very low ridges, in thelatter by aligned granules.

Genus SUBTILISPHAERA Jain and Millepied, 1973

Type species. S. senegalensis Jain and Millepied, 1973

Subtilisphaera sp. A(Plate 4, Figs. 11-12)

Remarks. Abundant specimens were encountered throughout theLower Cretaceous sequence displaying a wide variety of transitionalmorphological features. Specimens included within Subtilisphaera sp.A may be conspecific with 5. perlucida (Alberti, 1961); S. scabrataJain and Millepied, 1973; S. senegalensis Jain and Millepied, 1973;and S. terrula (Davey, 1974). Because of the occurrence of numeroustransitional morphotypes between the species listed above, no attempthas been made to speciate the specimens incorporated within Subtilis-phaera sp. A.

Subtilisphaera sp. B(Plate 4, Figs. 9-10)

Remarks. Specimens assigned to Subtilisphaera sp. B may be con-specific with S. cheit Below, 1981 and S. ventriosa (Alberti, 1961) sen-su Jain and Millepied, 1973. Wide morphologic variation precludesaccurate specific assignment.

Dinocyst sp. A(Plate 2, Fig. 9)

Description. Cyst ellipsoidal in outline. Wall smooth. Cyst surfaceentirely covered by low muri that form predominantly polygonal lumi-na. Processes (8-10 µm) arise along muri, but principally from gonalareas and support a very thin, delicately perforate ectophragm. Par-cingulum, parasulcus unobserved. Archaeopyle appears to be apical,with the operculum remaining attached.

Dimensions. Cyst length 60 µm (single specimen); cyst width 33 µm.Remarks. This morphotype differs from all other genera by its ov-

erall morphology. Some comparison can be made with Valensiella Ei-

685


seπack, 1963, but the latter differs in possessing a closely adpressedectophragm. Specimens of Dinocyst sp. A have been encounteredwithin the Valanginian of the North Sea area (Fenton, pers. obs.).

Dinocyst sp. B(Plate 1, Fig. 9)

Description. Small, spherical proximate cyst, with faintly scabrateautophragm. Ornament consists of solid, acuminate processes, whichvary in length between 5 and 11 µm. These processes may be partiallyaligned along parasutures or intratabular in distribution. Paratabula-tion indistinct. Paracingulum and parasulcus unobserved. No apical,antapical, or lateral horns present. Archaeopyle formed by loss of anunknown number of precingular paraplates leaving a lingula, com-posed of the anterior sulcal and apical regions.

Dimensions. Cyst diameter 17 (19) 26 µm (10 specimens measured).Remarks. A distinctive feature of this cyst is its small size, which,

when the archaeopyle is undeveloped, makes it appear similar to anacritarch. It differs from other genera, such as Dissiliodinium Drugg,1978 and Lingulodinium Wall, 1967 by its small size, solid processes,and apparent lack of paratabulation.

Incertae SedisGenus HALOPHORIDIA Cookson and Eisenack, 1962

Type species. H. xena Cookson and Eisenack, 1962

Halophoridia cf. xena Cookson and Eisenack, 1962(Plate 3, Fig. 6)

Description. Shell quadrate to rectangular in outline. Thin walledinner body, smooth to faintly scabrate, and subquadrate with weaklyconcave sides. Outer layer quadrate to rectangular in outline, sidesstraight to slightly concave, surface scabrate. No mode of opening ob-served.

Dimensions. Shell length 30-35 µm (2 specimens measured); shellwidth 27-30 µm.

Remarks. H. cf. xena differs from H. xena by possessing a shellthat has a quadrate to rectangular outline rather than circular to sub-circular. The inner body of if. xena also possesses more markedly con-cave sides.

Class PrasinophyceaeGenus PTEROSPERMELLA Eisenack, 1972

Type species. P. aureolata (Cookson and Eisenack, 1958) Eisenack,1972

Pterospermella sp. A.(Plate 4, Fig. 2)

Description. Body sphaerical and smooth, surrounded by equato-rial flange that is smooth to scabrate. Radial folds occasionally devel-oped on flange. Body offset from centre of equatorial flange.

Dimensions. Overall diameter 56-70 µm (3 specimens measured).Remarks. These specimens differ from all published species of Pter-

ospermella in the possession of an offset body.

ACKNOWLEDGMENTS

The authors would like to acknowledge the encouragement and fi-nancial support received from Robertson Research International Ltd.during the course of this work.

REFERENCES

All taxonomic references to dinocysts not listed below are to befound in Lentin and Williams (1981).

Davey, R. J., 1978. Marine Cretaceous palynology of Site 361, DSDPLeg 40, off southwestern Africa. In Bolli, H. M., Ryan, W. B. E,et al., Init. Repts. DSDP, 40: Washington (U.S. Govt. Printing Of-fice), 883-914.

Davey, R. J., 1979a. Marine Apto-Albian palynomorphs from Holes400A and 402A, IPOD Leg 48, northern Bay of Biscay. In Monta-dert, L., Roberts, D. G., et al., Init. Repts. DSDP, 48: Washington(U.S. Govt. Printing Office), 547-578.

Davey, R. J., 1979b. The stratigraphic distribution of dinocysts in thePortlandian (latest Jurassic) to Barremian (Early Cretaceous) ofnorthwest Europe. Am. Assoc. Stratigr. Palynolog. Contrib. Sen,5B:48-81.

Davey, R. J., and Verdier, J.-P., 1971. An investigation of microplank-ton assemblages from the Albian of the Paris Basin. Verh. K. Ned.Akad. Wet., Afd. Natuurk. Reeks, 26:1-58: pi. 1-7.

Davey, R. J., and Verdier, J.-P., 1973. An investigation of microplank-ton assemblages from latest Albian (Vraconian) sediments. Rev.Esp. Micropaleontol., 5:173-212.

Davey, R. J., and Verdier, J.-P., 1974. Dinoflagellate cysts from theAptian type sections at Gargas and La Bedoule, France. Palaeon-tology, 17, 623-653.

Duxbury, S., 1977. A palynostratigraphy of the Berriasian to Bar-remian of the Speeton Clay of Speeton, England. Palaeontograph-ica, 160:1-15.

Fisher, M. J., and Riley, L. A., 1980. The stratigraphic distribution ofdinoflagellate cysts at the boreal Jurassic-Cretaceous boundary.Fourth Int. Palynology Conf., Lucknow (1976-77) Proc, 2:313-329.

Habib, D., 1972. Dinoflagellate stratigraphy Leg 11, Deep Sea DrillingProject. In Hollister, C. D., Ewing, J. I., et al., Init. Repts. DSDP,11: Washington (U.S. Govt. Printing Office), 367-426.

Habib, D., 1978. Palynostratigraphy of the Lower Cretaceous sectionat Deep Sea Drilling Project Site 391, Blake-Bahama Basin, and itscorrelation in the North Atlantic. In Benson, W. E., Sheridan, R.E., et al., Init. Repts. DSDP, 44: Washington (U.S. Govt. PrintingOffice), 887-898.

Lentin, J. K., and Williams, G. L., 1981. Fossil dinoflagellates: Indexto genera and species, 1981 ed. Bedford Institute OceanographyRept., Bl-R-81-12.

Mclntyre, D. J., and Brideaux, W. W, 1980. Valanginian miosporeand microplankton assemblages from the northern RichardsonMountains, District of Mackenzie, Canada. Geol. Surv. Can.Bull., 320:1-57.

Morgan, R., 1980. Palynostratigraphy of the Australian Early andMiddle Cretaceous. Mem. Geol. Surv. N. S. W. Palaeontol., 18:1-153.

Rawson, P. F, and Riley, L. A., 1982. Latest Jurassic/Early Creta-ceous events and "late Cimmerian unconformity" in the North Seaarea. Am. Assoc. Pet. Geol. Bull., 66(12):2628-2648.

Stover, L. E., and Evitt, W. R., 1978. Analysis of pre-Pleistocene or-ganic-walled dinoflagellates. Stanford Univ. Publ. Geol. Sci., 15:1-300.

Verdier, J.-P., 1975. Les kystes de dinoflagellés de la section de Wis-sant et leur distribution stratigraphique au Crétacé moyen, Rev. Mi-cropaleontol, 17:191-197.

Williams, G. H., and Bujak, J. P., 1979. Palynological stratigraphy ofDeep Sea Drilling Project Site 416. In Lancelot, Y., Winterer, E.L., Init. Repts. DSDP, 50: Washington (U.S. Govt. Printing Of-fice), 467-496.

Date of Initial Receipt: August 31, 1982Date of Acceptance: August 15, 1983

686


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•

*

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8

;

i

11

10

t! *'Plate 1. (All magnifications × 750 unless otherwise indicated.) 1-3. Omatia sp., Sample 535-46-2, 32-34 cm. 4. Endoceratium turned, Sample

535-42.CC. 5. Pseudoceratium pelliferum, Sample 535-75-3, 117-119 cm. 6. (×375), Muderongia extensiva, Sample 535-63-2, 34-38 cm.7. Ovoidinium diversum, Sample 535-41-4, 122-124 cm. 8. Oligosphaeridium pulcherrimum, Sample 535-55-6, 26-28 cm. 9. Dinocyst sp. B,Sample 535-76-1, 116-119 cm. 10. Dinogymnium sp., Sample 535-79-1, 52-53 cm. 11. Dinogymium sp., Sample 535-74-2, 117-119 cm.

687


*

ML tit w%

s

'

8

Plate 2. (All magnifications ×750.) 1-2. Diacanthum hollisteri, Sample 535-78-1, 37-39 cm. 3. Polysphaeridium warrenii, Sample 535-78-1, 37-39 cm. 4. Batioladinium gochtii, Sample 535-67-3, 77-79 cm. 5. Chytroeisphaeridia sp. C, Sample 535-50-4, 6-8 cm. 6. Hystrichodinium aff.pulchrUm, Sample 535-79-1, 52-53 cm. 7. Chytroeisphaeridia sp. A, Sample 535-75-1, 24-28 cm. 8. Chytroeisphaeridia sp. B, Sample 535-42.CC. 9. Dinocyst sp. A, Sample 535-75-1, 24-28 cm.

688


:

* - * . . : •

8 9Plate 3. (All magnifications × 750.) 1-2. Codoniella psygma, Sample 535-43-1, 77-79 cm. 3. Fromea sp., Sample 535-19-2, 76-78 cm. 4. Ovoi-

dinium implanum, Sample 535-28-6, 44-46 cm. 5. Oligosphaeridium cf. abaculum, Sample 535-20-2, 31-34 cm. 6. Halophoridia cf. xena,Sample 535-31-6, 141-143 cm. 7. Xenascus ceratioides, Sample 535-36-3, 52-55 cm. 8. Odontochitina cf. costata, Sample 535-30-3, 143-147 cm. 9. Odontochitina cf. costata, Sample 535-30-3, 143-147 cm.

689


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-

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10 n 12

Plate 4. (All magnifications ×750.) 1. Phoberocysta neocomica, Sample 535-57-3, 4-6 cm. 2. Pterospermella sp. A, Sample 535-71-1, 137-139 cm. 3. Leptodinium sp. B, Sample 535-69-2, 126-128 cm. 4. Phoberocysta neocomica, Sample 535-76-1, 116-119 cm. 5. Trichodiniumcastaneum, Sample 535-33-5, 107-110 cm. 6. Prismatocystis cylindrica, Sample 535-75-3, 117-119 cm. 7. Eyrea nebulosa, Sample 535-33-5,107-110 cm. 8. Ovoidinium implanum, Sample 535-28-6, 44-46 cm. 9. Subtilisphaera sp. B, Sample 535-35-6, 38-40 cm. 10. Subtilisphaerasp. B, Sample 535-35-6, 38-40 cm. 11. Subtilisphaera sp. A, Sample 535-59-2, 84-86 cm. 12. Subtilisphaera sp. A, Sample 535-49-3, 96-97 cm.

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stratigraphy palynologic results general discussion

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