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Chapter 83. The biostratigraphy of Cretaceous ostracods from Oman

Chapter 83. The biostratigraphy of Cretaceous ostracods from Oman

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1188 J. ATHERSUCH



SOURCES

OF DATA

The biostratigraphical data presented herein is based on observations of cuttings samples from

6 wells in the western part of Oman bordering Saudi Arabia (Text-fig. 1).

These data are summarised on Text-fig. 2 which records the stratigraphical ranges of the first

downhole occurrences of each species. Selected index species are also depicted in Text-fig. 5.

All the species listed in Text-fig. 2 are illustrated on Plates 1-5.

Text-figures 3 and 4 compare the stratigraphical ranges of each of these species from Oman with

their previously recorded distributions in the Middle East and North Africa. The text provides

information from a variety of sources on their geographical distribution and stratigraphical

significance. The ages quoted from non-BP sources are those provided by the originating authors,

and in the case of the Oman wells, formation “ages” are in-house assignments based on

palaeontological and regional geological considerations.

References to taxomonic names from unpublished literature are enclosed by quotation marks,

thus “ ”. Previously undescribed species have been given BP (Sunbury) reference codes with the

prefix OMN and all of the illustrated specimens are housed in the BP (Sunbury) reference collection.

Text-figure 1 shows a global reconstruction and a lithofacies map of the Arabian Peninsula for



KEY



........

---



APTIAN SHORELINE

MAASTRICHTIAN SHORELINE

CENOMANIAN TETHYAN SHELF AREAS I N

N.AFRICA AND THE ARABIAN PENINSULA

LAND AREAS

MARINE CLASTICS

SHALLOW CARBONATE SHELF

DEEP CARBONATE SHELF

‘BASINAL’ SHALES



TEXT-FIG.

1-Lithofacies map of the Arabian Peninsula during the Cenomanian (data from various sources).



1189



S PEClES



AGE 8 LITHOSTRATIGRAPHY



(Ranges o f t o p occurrences

i n cuttings f r o m several wells:

Ages and lithostratigraphy based

on BP d a t a )



\



Hornibrookella divergens 81-Furaih

Brachycythere sp. (OMN I )

Aphrikanecythere phumatoides Damotte EL O e r t l i

Holcopocythere bassiporosa / f a l s o c u l o t a Al-Furoih

Paragrenocythere g r a v i s / Al Furaih

Phalcocythere r e c t a n g u l a r i s / hebes 81-Furaih

Phyrocythere dextrodigitota Al-Furai h

"Eobuntonia c u r t a " ( S a y y a b )

Buntonia I R E 9 G r o s d i d i e r

Occultocythereis proro Al-Furaih

B r a c h y c y t h e r e sp. ( O M N 2 )

? Mehesella c f . iRC 23 Grosdidier

Soudanella dolabrata Al-Furaih

Reticytheretta sp. ( O M N 8 )

Metacytheropteron I R L 3 Grosdidier

Cytherella posterosuicata Al-Abdul-Razzaq

Brachycythere sp. ( O M N 3)

P t e r y g o c y t h e r e sp. (OMN 7 )

Ovocytheridea cf. producta G r e k o f f

B r a c h y c y t h e r e sp. ( O M N 4)

B r a c h y c y t h e r e sp. ( O M N 5 )

B r a c h y c y t h e r e sp. ( O M N 2 )

Brochycythere cf. sapucariensis Krommelbein

Brachycythere cf. I R E 10 Grosdidier

Veeniacythereiscf. m a g h r e b e n s i s ( Bassoullet a D a m o t t e )

Veeniacytherels j e zzineensls Bischoff

Peleriops elasiodictyota Al-Abdul- Rozzoq

Peleriops u l o s a Al-Abdul-R.azzaq

M e t a c y t h e r o p t e r o n b e r b e r i c u s Bassoullet and D o m a t t e

Cythereis algeriana Bassoullet a Damotte

Veeniacythereis streblolophata Al-Abdul-Razzaq 8 Grosdldier

Cytherella khaiidrazzaqi. AI-A bdul-Razzaq

C y t h e r e l l a ,ahmadiensis Al-Abdul- Razzaq

C y t h e r e l l a kuwaitensis Al-Abdul-Razzoq

" Asciacythere

cf. inpendula" Al-Abdul-Razzaq

Cytherella gigantosulcata Rosenfeld

Eocytheropteron retroversicardinatum Al-Abdul-Razzaq

Glenocythere triangularis Al-Abdul-Razzaq

:ytherella

s p ( O M N) ; 1

Louza amygdalaideo

Al- Abdul - R a z z aq

Glenocythere reticulata 81-Abdul-Razzaq

V e e n i a sp (OMN 12)

Ahmadiura cf. d i c t y o t a Al-Abdul - Razzaq

Meiacytheropteron IR C 10 Grosdidier

Glenocythere bahreinensis A l - A b d u l - Razzaq

Peleriops sphaerommata AI-A bdul-Razzaq

Cythereis cf. f a h r i o n i B l s c h o f f

Cytherella sp ( O M N 11)

Schuleridea I R J 15 Grasdidirr

Schulerideo baidarensis Damotte EL S t Marc

? Schuleridea sp. ( O M N 9 )

indet. sp. I R P 6 Grosdidier

Cythereis cf. IRK 26 Grosdidier

Planileberis cf. malzi ( B i s c h o f f )



4



I

-I

I



4

I

I

I

I

I

4



4



4

4



H

H

4

=I



H

I

I

I



4



c



**

4



c



c

4



H

I



-



TEXT-FIG.

2Stratigraphical distribution of Cretaceous ostracods from Oman.



1190 3. ATHERSUCH



the Cenomanian, with relative positions of Aptian, Cenomanian and Maastrichtian shorelines and

equators. Data used in the compilation of this map come from numerous sources including Murris

(1980), Saint-Marc (1978) and the BP palaeoreconstruction data base.



OSTRACOD

BIOSTRATIGRAPHY

IN OMAN

Only one well yielded ostracods in the Kharaib and Shu’aiba Formations. The sparse fauna

included Cythereis cf. IRK26 Grosdidier and Planileberis cf. malzi Bischoff (Kharaib) and indet. gen.

IRP6 Grosdidier (Shu’aiba). Both of these species have been previously recorded from the Aptian

of Iran. Further work on these formations may identify other species of stratigraphical importance.

The Nahr Umr Formation in Oman has a presumed Early Albian age. It is characterised by

Schuleridea baidarensis Damotte and Saint-Marc and S . sp. OMN 9. According to Standring

(1972), the Nahr Umr in Oman is divisible into three units using ostracods, but the identity of the

index forms used is not known to the present author, and no such subdivision was recognised from

the available material.

Following BP’s practice, the Natih Formation is divided into seven members. Members ‘g’, ‘f’

and the lower part of ‘e’ are thought to be Albian in age; Members ‘g’ and ‘f’ are characterised by

the first downhole occurrence of Cytherella sp. OMN 1 1 and Schuleridea IRJIS Grosdidier in the

lower part and by Metacytheropteron IRClO Grosidier throughout. Member ‘e’ is characterised by

Metacytheropteron IRClO Grosdidier, Cythereis cf. fahrioni Bischoff and Glenocythere spp. together with a number of rarer species. Member ‘d’ typically contains the first downhole occurrences of

Eocytheropteron retroversicardinatum Al-Abdul-Razzaq, Cytherella gigantosulcata Rosenfeld and

“Louza amygdaloidea” Al-Abdul-Razzaq each of which has a well documented Early Cenomanian to Albian age throughout the Middle East. Member ‘c’ and the lower part of the combined ‘a+b’ member are considered to be of Late Cenomanian age and are characterised by a large

number of species in Oman which have been previously recorded from the Middle East and, in

some cases, from N. Africa as well. They include V. jezzineensis (Bischoff), Veeniacythereis cf.

maghrebensis (Bassoullet and Damotte) V. streblolophata Al-Abdul-Razzaq and Grosdidier, Peleriops ulosa Al-Abdul-Razzaq, P. elassiodictyota Al-Abdul-Razzaq, Cythereis algeriana Bassoullet

and Damotte, Metacytheropteron berbericus Bassoullet and Damotte, Cytherella khalidrazzaqi

Al-Abdul-Razzaq, C. ahmadiensis Al-Abdul-Razzaq and C. kuwaitensis Al-Abdul-Razzaq. The

upper part of the combined ‘a+b’ member contains Brachycythere cf. sapucariensis and B. cf.

IRE10 Grosdidier in some wells. These are the only index species from the presumed latest Cenomanian to Turonian in Oman.

Few of the species of Coniacian to Early Santonian age from Iran or elsewhere in the Arabian

Gulf area are also known from Oman. This may be considered as evidence for the absence of

sediments of this age from Oman and supports the notion of a regional unconformity between

Turonian and younger Senonian sediments.

The Fiqa Formation in Oman is probably ?Santonian to Campanian in age and is characterised

by a large number of Brachycythere spp. most of which are not attributable to previously described

species. They are accompanied by Soudanella cf. dolabrata Al-Furaih, Pterygocythere sp., “Mehesella” cf. IRC23 Grosdidier and sometimes by Reticytheretta sp. and Cytherella posterosulcata

Al-Abdul-Razzaq.

The Simsima Formation is probably Maastrichtian in age and contains large numbers of reticulate

trachyleberid ostracods including Hornibrookella divergens Al-Furaih and Paragrenocythere gravis

Al-Furaih as well as Holcopocythere sp., Phalcocythere sp. and Phyrocythere dextrodigitata AlFuraih. Many of the species from this formation are known to cross the Cretaceous/Tertiary



1191



S A N CMP M A A P



1 ?--/I-1:$gI

--?



2



@



B r a c h y c y t h e r e sp

Brachycythere s p



- --?



7-



- - - -7



1 1



Aphrikanecythere phumatoides DarnotteBOertli



?----?a

?--



Pl.+Fi



N A M E



4 - 14



(OMN I )



2 - 5



(OMN2)



2 -1,2

I



1



B r a c h y c y t h e r e sp



(OMN3)



2 - 9,IC



Brachycythere



sp



(OMN4)



2 - 3



Brachycythere



sp



(OMN5)



Buntonia



IRE 9



Grosdidier,



1973



?----$



i

1-14,15



5-1,2

Cytherella posterosulcato Razzaq 1981

I

@



-- - --7



7--



@



"Eobuntonia curtd'sayyab



,



1956



I -17,11

I



~



3- --7



@



~



nolcopocythere bassiporosa/falsoculata AI-Furaih



~~~



I



-



I



I980



1 @@I ?:- ?!?I



Hornibrookella divergens Al-Furaih,



Mehesella'



-.-cf



@



13 -15



I R C 2 3 Grosdidier, 1 9 7 3



-?

Metacytheropteron I R L 3 Grosdldier, 1 9 7 3



@



3??-



1977



- - - -3

7--



Occullocythereis p r o r a



--?- -?



@



?I

7--7



1984



Paragrenocythere g r a v l s AI-Furalh. 1 9 7 7



m 7



@



Al-Furalh,



@



OH



I - 21



1-6, 7



3-16~7



-



Phalcocythere rectangularis/hebes AI-Furaih,

1980



I



Phyrocythere dextrodigitata AI-Furaih, 1980



I - 10



?



I



Reticytheretta sp. ( O M N 8 )



Soudanella dolabrata Ai-Furaih, 1984



2



- 20



1-5



TEXT-FIG.3-Comparison of stratigraphical ranges of Late Cretaceous ostracods in the Middle East and North

Africa (in alphabetical order).

ALGERIA-1, Bassoullet and Damotte, 1969; 2, Bismuth ef al., 1981; 3, Glintzboeckle and Magne,

1959; 4, Dome et al., 1982. EGYPT-5, Van den Bold, 1964. IRAN-6, Grosdidier, 1973. IRAQ-7,

Al-Sheikly, 1980. ISRAEL-8, Rosenfeld and Raab, 1974; 9, Rosenfeld and Raab, 1984; 10, Hirsch ef al..

1983. LEBANON-11, Bischoff, 1963; 12, Damotte and St. Marc, 1972. KUWAIT-13, Al-Abdul-Razzaq,

1977; 14, Al-Abdul-Razzaq, 1979a; 15, Al-Abdul-Razzaq, 1979b; 16, Al-Abdul-Razzaq, 1980; 17, Al-AbdulRazzaq and Grosdidier, 1981; 18, Al-Abdul-Razzaq, 1981. SAUDI ARABIA/% ARABIAN GLJL.F19, Al-Furaih, 1977; 20, Siddiqui and Al-Furaih, 1980; 21, Al-Furaih, 1980; 22, Sayyab, 1956; 23,

Al-Furaih, 1983. OMAN-24, this paper.



1192



APT ALB CEN TUR

7--



..-TO



N A M E



Jl.+Fl



Ahmodiura cf. dlctyolo R o z z o q , I 9 7 7



I - I!

5-9



7--



-@



?.21



-- ?@



Brochycythere ct. sapucariansls Kmmnulbein,

1964(ssnru B i s m u t h e t a l , 1981)



---?@



Brachycythere cf. I R E IOGrosd1diar,1973



-<



z -7,e



2-6

-



D

H

@@

H I2



-00

-a@@



Cythefei6 algeriano Ba8owllet 8 Damotte,



3-12,l:



1969



3-5.6



-



@



Cytheralo cf I R K 2 6 Grosdldler



-15

-



Cytharslla ahmadimsir Rarzaq, 1981



5-10.11



Cytherelia kholidrozzaql Razmq. 1981



5-1 2.1:



Cytherella kuwaitanais Razzaq, h981



j-3,4



Cytherello gigantosulcata Roscnftld, 1981



i-14.1!



@



7--?

@I--7



@



?---?@

H18



4



-



7----7



49



1-7.8



Cytheralla r p . (OMN II 1



i-5,6



Eocy theropteron relrovarsicardinatum Razzaqt

1980



- ?-- @



-



Cytherello sp. ( O M N 10)



Glenocythere bahreinensir Razzoq. 1 9 7 9 0



I



-



II



l-3,4



7 - - - - - ? 2

Glsnocythere roticuIota Rozroq, 19790



7



1 7,&l?m 1 1



@



----'0

?---



Glsnocythen trion~uiorirRozzoq,1979a



1-7.0



4 - I,



&5,6



---p



@?

?---?@

U@



.



"Louza omygdaloided' Rozraq , 1 9 7 7



0 -9



-



TEXT-F~G.

4a-Cbmparison of stratigraphical ranges of Middle Cretaceous ostracods in the Middle East and North

Africa (in alphabetical order).

ALGERIA-1, Bassoullet and Damotte, 1969; 2, Bismuth er al., 1981; 3, Glintzboeckle and Magne, 1959;

4, Dome et al., 1982. EGYPT-5, Van den Bold, 1964. IRAN-6, Grosdidier, 1973. IRAQ-7, Al-Sheikly,

1980. ISRAEL-8, Rosenfeld and Raab, 1974; 9, Rosenfeld andRaab, 1984; 10, Kirsch et al.. 1983.

LEBANON-11, Bischoff, 1963; 12, Damotte and St. Marc, 1972. KUWAIT-13, AI-Abdul-Razzaq, 1977;

14, Al-Abdul-Razzaq, 1979a; 15, Al-Abdul-Razzaq, 1979b; 16, Al-Abdul-Razzaq, 1980; 17, AI-AbdulRazzaq and Grosdidier, 1981; 18, Al-Abdul-Razzaq, 1981. SAUbI ARABIA/% ARABIAN GULF19, Al-Furaih, 1977; 20, Siddiqui and Al-Furaih, 1980; 21, Al-Furaih, 1980; 22, Sayyab, 1956; 23, AlFuraih, 1983. OMAN-24, this paper.



1193

ALE



ICEN ITUR I I



--L



4



N A M E



Metocytheroptemn I R C lo



@



=I::$



z’g



IR.+Fi(



Gmdidier, I 9 7 3



Peldops slassiodictyota Razzoa. 1 9 7 9 b



Peldop. uloso Razzaq



,



1979b



1-8, 9



4-13



4-10.11



3

H@



.--.@



Planileberls malzi (Biachoff), 1963



4 - 16



Schuleridea I R J 15 (Grmdidier),1973



1-23



?



Schuleridea r p (OMN9)



Vaenia sp. (OWN 12)



? - - 7 0



w



e



Vasniacythereis i



o r r h s ~(Bixhoffl.1963



3 -10,ii



7---



O H?@



-0



@@I+



p-”-C‘-?



30-



@-



0

?---PO

El

9



D o m o t t d , I969



@



.--.a



*@



Vaeniacythsrels moghrebmsa (Bassoullet 8



3 -7.8



~-



Veeniacythereia streblalaphdo Rozmq 0



3



Grosdidler ( 0 ;8ubtp.schiatq b; wbap. stretio-



2,3,4



I,



lophato )



Indsl.genua e t . w I R P 6 Grordidier, 1973



4



- 17



TEXT-FIG.4b-Comparison of stratigraphical ranges of Middle Cretaceous ostracods in the Middle East and North

Africa (in alphabetical order).

ALGERIA-1, Bassoullet and Damotte, 1969; 2, Bismuth et al., 1981; 3, Glintzboeckle and Magne,

1959; 4, Dome et a/., 1982. EGYPT-5, Van den Bold, 1964. IRAN-6, Grosdidier, 1973. R

IAQ

7,AlSheikly, 1980. ISRAEL-8, Rosenfeld and Raab, 1974; 9, Rosenfeld and Raab, 1984; 10, Hirsch, et al.,

1983. LEBANON-1 1, Bischoff, 1963; 12,Damotte and St. Marc, 1972. KUWAIT-13, Al-Abdul-Razzaq,

1977; 14, Al-Abdul-Razzaq, 1979a; 15, Al-Abdul-Razzaq, 1979b; 16, Al-Abdd-Razzaq, 1980; 17, AlAbdul-Rauaq and Grosdidier, 1981; 18, Al-Abdul-Razzaq, 1981. SAUDI ARABIA/S. ARABIAN

GULF-19, Al-Furaih, 1977; 20, Siddiqui and Al-Furaih, 1980; 21, Al-Furaih, 1980; 22, Sayyab, 1956;

23, Al-Furaih, 1983. OMAN-24, this paper.



Biostratigraphy of Cretaceous Ostracods from Oman 1195



boundary in Saudi Arabia, but Occultocythereisprora Al-Furaih and Aphrikanecytherephumato ides

Damotte and Oertli apparently signify the presence of Maastrichtian or older sediments. Another

important marker is “Eobuntonia curta” Sayyab,



PALAEOGEOGRAPHICAL

DISTRIBUTION

A comprehensive study of the palaeogeography of Tethyan Cretaceous ostracods is beyond the

scope of this paper which deals principally with the species represented in Oman. Nevertheless, the

data presented herein are sufficient to allow some speculation on the palaeogeographical distribution of these faunas. The following remarks are tentative since the extent to which the known occurrences reflect the actual distributions is uncertain. This is due mainly to incomplete research in

many areas.

As a result of a gradual marine transgressive trend throughout the Aptian to Cenomanian (see

Text-fig. l), a broad carbonate platform developed along the southern shore of Tethys (SaintMarc, 1978). In the Aptian and Early Albian there was some similarity between the ostracod faunas

of Oman, Iran and, to a lesser extent, between Oman, Lebanon and Iraq (see Text-fig. 3).

During Late Albian to Cenomanian times, very similar assemblages of ostracods characterise

a vast palaeogeographical province comprising Algeria, Tunisia, Libya, Egypt, Israel, Lebanon,

Iraq, the Arabian Gulf, Iran, Oman, Somalia and N. Ethiopia. This area is coincident with the

known extent of the southern shelf of Tethys at that time (see Text-fig. 1). A notable exception is the

distribution of the genus Glenocythere which is characteristic of the Arabian Gulf Coast area, but

which is absent from N. Africa and the Levant. The fauna as a whole differs from those known

from France, Spain and Syria to the north, Morocco and Senegal to the west and Tanzania to the

south.

So few ostracods are known from the latest Cenomanian to Turonian of this area that the full

extent of their distributions is largely unknown. This is probably largely due to epiorogenic movements during the Turonian and early Senonian which resulted in widespread nondeposition or

erosion of Turonian sediments. However, Brachycythere sapucariensis and similar forms are known

from Brazil, W. Africa, N. Africa and the Middle East at this time, a fact which has been used to

support the idea of a trans-Saharan marine passage during the Turonian.

In Oman, the study area appears to have been emergent during early Senonian times, as evidence

for Conacian to Santonian sediments is missing.

The great similarity between the faunas of the coastal Fars region of Iran and Oman seen

during the Late Albian to Cenomanian is lost by the ?Santonian/Campanian, presumably as a

result of basinal facies developing throughout the region of the Arabian Gulf and northern Oman

(Saint-Marc, 1978).

During the Campanian and Maastrichtian, essentially the same faunas are seen in Oman, N.

~~



~



~~



PLATE1-Fig. 1. Holcopocythere bassiporosa/falsoculata Al-Furaih. Simsima Fm. Fig. 2. Phalcocythere rectangularislhebes Al-Furaih. Simsima Fm. Figs. 3,4. “Mehesella” cf. M. IRC23 Grosdidier. Fiqa Fm. Fig. 5. Soudanella cf. dolobrata Al-Furaih. Fiqa Fm. Figs. 6, 7. Occultocythereis prora Al-Furaih. Fiqa Fm. Figs. 8, 9.

Metacytheropteron IRClO Grosdidier. Natih ‘f +g’ Fm. Fig. 10. Phyrocythere dextrodigitata Al-Furaih. Simsima Fm. Fig. 11. Eocytheropteron retroversicardinatum Al-Abdul-Razzaq. Natih ‘d‘ Fm. Figs. 12, 13.

Metacytheropteron berbericus (Bassoullet and Damotte). Natih ‘d’ Fm. Figs. 14, 15. Buntonia cf. IRE9

Grosdidier. Fiqa Fm. Fig. 16. Schuleridea sp. [OMN9]. Shu’aiba Fm. Fig. 17. “Eobuntonia curta Sayyab”.

Fiqa Fm. Fig. 18. Eobuntonia cf “E. curta Sayyab”. Fiqa Fm. Fig. 19. Ahmadiura cf “A. dictyota Al-AbdulRazzaq”. Natih ‘e’ Fm. Fig. 20. ?Reticytheretta sp. [OMNS]. Natih ‘a+b’ Fm. Fig. 21. Metacytheropteron

IRW Grosdidier. Fiqa Fm. Fig. 22. Schuleridea baidarensis (Damotte and St. Marc.) Nahr Umr Fm.

Fig. 23. Schuleridea IRJ15 (Grosdidier). Natih ‘e’ Fm. (scale bar = 500 pm). Fm.=Formation.



Biostratigraphy of Cretaceous Ostracods from Oman 1197



Ethiopia, Somalia and Saudi Arabia. No extensive survey of the literature outside these areas was

made, but it would appear that the ostracod faunas of this region are significantly different from

those of the rest of the Middle East and N. Africa at this time (see Text-fig. 4), although there are

apparently some species which are found in TunisiaIAlgeria and Oman (e.g. A. phumatoides and

? ‘Eobuntonia curta’). This marked endemism may result from the irregular submarine topography

which developed on the shelf as a result of tectonism and differential subsidence during Turonian

and early Senonian times, and which may have isolated various parts of the shelf and the associated

ostracod faunas.

Variations in the distribution patterns of ostracods throughout this time may also be related to

changes in oceanic circulation in Tethys or to changes in climate due to the northward drift of the

Arabian plate (see Text-fig. 1).



REMARKS

ON SELECTED INDEXSPECIES

The stratigraphical ranges of index taxa in Oman are shown in Text-fig. 2; distributions and ranges of these taxa for all areas are tabulated in Text-figs. 3 and 4. The following remarks provide

additional data which affect the overall knowledge of stratigraphical and geographical distributions

of these species.



THELATECRETACEOUS

(? SANTONIAN-MAASTRICHTIAN)

Aphrikanecythere phumatoides Damotte and Oertli, 1982 (Pl. 4, fig. 14): First illustrated by

Sayyab (1956) as “Anchycythereis quadrata” from the Upper Cretaceous of the Gulf Coast of Saudi

Arabia and Qatar. Similar to Peleriops levisulcata of Al-Sheikly (1980) and P . nodosa Al-Furaih

(1984a) from the Maastrichtian of Iraq and Saudi Arabia, respectively. Comparable specimens

occur in the Sadi Formation and the Tanuma Formation in Iraq of ?Campanian and ?Coniacian

ages, respectively.

Cytherella posterosukata Al-Abdul-Razzaq (198 1) (Pl. 5, figs. 1, 2): Described by Al-AbdulRazzaq (1977; 1981) from the Santonian Gudair Formation of Kuwait. Also present in Somalia/

Ethiopia, Iran and Iraq where it has a Santonian to Coniacian age range (unpublished data).

“?Eobuntonia curta” Sayyab, 1956 (Pl. 1, figs. 17, 18): Probably identical with Buntonia B816

of Bellion, Donze and Guiraud (1973) from the Campanian of Algeria. Described by Sayyab (1956)

from the Late Cretaceous of the S. Arabian Gulf coast area; occurs in the Campanian Sadi Formation and the ?Coniacian Tanuma Formation, Iraq and the Santonian-Coniacian of Ethiopia

(unpublished data).

Holcopocythere bassiporosalfalsoculata Al-Furaih, 1980 (Pl. 1, fig. 1) : Resembles both H.

bassiporosa Al-Furaih (1980) and H. falsoculata Al-Furaih (1980) from the Late Maastrichtian and

Early Palaeocene of Saudi Arabia.

YMehesella’ cf. ‘Mehesella’ IRC23 Grosdidier, 1973 (Pl. 1, figs. 3, 4): Unpublished data indicate its presence in Somalia and Ethiopia and a stratigraphical range of Santonian to Coniacian.

Occultocythereis prora Al-Furaih, 1984a (Pl. 1, figs. 6, 7): It is similar but not identical to

PLATE 2-Figs. 1, 2. Brachycythere sp. [OMN2]. Fiqa Fm. Fig. 3. Bruchycythere sp. [OMN4]. Fiqa Fm. Fig. 4.

Bruchycythere sp. [OMNS]. Fiqa Fm. Fig. 5. Brachycythere sp. [OMNl]. Simsima Fm. Fig. 6. Bruchycythere

cf. B. IRE10 Grosdidier. Natih ‘a+b’ Fm. Figs. 7, 8. Bruchycythere cf. sapucurier$s Krommelbein (sensu

Bismuth et ul.) Natih ‘a+b’ Fm. Figs. 9, 10. Brachykythere sp. [OMN3]. Fiqa Fm. Figs. 11, 12. Pterygocythere

sp. [OMN 71. Fiqa Fm. (scale bar = 500 pm). Fm. =Formation.



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Chapter 83. The biostratigraphy of Cretaceous ostracods from Oman

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