Palynomorph taxa from the “Lower Coal Measures” deposits (? Campanian-Maastrichtian) of Anambra trough, Southeastern Nigeria

Journal of African Earth Sciences, Vol. 11, No. 1/2, 135-150, 1990. Printed in Great Britain

0899-5362/90 $3.00 + 0.00 © 1991 Pergamon Press pie

Palynomorph taxa from the "Lower Coal Measures" deposits (? Campanian-Maastrichtian) of Anambra Trough, Southeastern Nigeria M. B. SALAMI Department of Geology, Obafemi AwolowoUniversity, Ile-Ife, Nigeria Abstract - Recovered palynomorph taxa from "Lower Coal Measures" deposits of the Anambra trough are largely miospores and few organic - walled mieroplankton. Trilete spores are mainly laevigate form whilst the sculptured varieties are few in the assemblage. Pollen taxa are largely monocolpates whilst other apermral types are few in the assemblage. They show appreciablevariation in the sculpture of the exine. The spores provide evidence of freshwater swamp or marsh environment of deposition. Organic-walled microplankton suite shows, most probably, evidence of normal marine or brackish water incursion into a freshwater swamp or marsh association. The presence of algal stx~es similar to Tasmanites or Pachysphaera support further a freshwater swamp or marsh association. In all 43 species of palynomorphs (11 spores, 26 pollen, 3 dinocysts and 3 incenae sedis) are described and illustrated. One new species of pollen (Longapertites reticulatus) is formallydescribed and illustrated. Some taxa of palynomorphs which appearnew but with few sp~imens are classified as form genera. Stratigraphically significant palynomorph taxa are plotted on a composite diagram. They indicate ?Campanian- Maastrichtian age for the sediments.

INTRODUCTION The "Lower Coal M e a s u r e s " r o c k s a m p l e w h i c h form t h e b a s i s of t h i s s t u d y b e l o n g t o t h e A n a m b r a t r o u g h , one of t h e t e n m a j o r s e d i m e n t a r y b a s i n s o n s h o r e in Nigeria (Whiteman, 1982). T h e y are l o c a t e d b e t w e e n l a t i t u d e s 5 ° 10' - 7 ° 00'N a n d l o n g i t u d e s 7 20' - 8 ° 10'E. T h e y are r o c k s of varying lithologies, p r e v i o u s l y d a t e d b y o t h e r w o r k e r s , o n t h e b a s i s of m e g a f o s s f l s a s C a m p a n i a n M a a s t r i c h t i a n (Simpson, 1954; R e y m e n t , 1965). V a n H o e k e n - E l i n k e n b e r g (1964) in h e r pioneering palynological w o r k , w h i c h w a s b a s e d o n a Geological S u r v e y of Nigeria b o r e h o l e (BH 1001) sited a r o u n d E n u g u , c o n f i r m e d a C a m p a n l a n M a a s t r i c h t i a n age for t h e s e d i m e n t s o b t a i n e d from t h e borehole. S h e b a s e d h e r c o n c l u s i o n on t h e microfloral sLmilarity of t h e Nigerian m a t e r i a l s w i t h t h o s e d e s c r i b e d f r o m C o l o m b i a in S o u t h A m e r i c a b y v a n d e r H a m m e n (1954, 1 9 5 6 a n d 1957). In this w o r k t h e p a l y n o m o r p h t a x a o b t a i n e d from r o c k o u t c r o p s f r o m widely s e p a r a t e d g e o g r a p h i c a l localities of t h e "Lower Coal M e a s u r e s " in t h e A n a m b r a t r o u g h h a v e b e e n studied ( s e e Fig. 1). T h i s a p p r o a c h is c o m p r e h e n s i v e a n d e n a b l e s a s y n t h e s i s of the microflora to b e p r e s e n t e d . More t a x a of palynom o r p h s h a v e t h u s b e e n d e s c r i b e d a n d illustrated in t h i s w o r k c o m p a r e d to t h a t i n v a n H o e k e n - K l i n k e n b e r g (1964). Additionally t h e p a l y n o m o r p h t a x a h a v e b e e n u s e d to d e d u c e the

e n v i r o n m e n t of d e p o s i t i o n a s well a s t h e age of t h e sediments. GEOLOGIC SETTING OF THE ANAMBRA TROUGH T h e A n a m b r a t r o u g h is a geologic f e a t u r e w h i c h t r e n d s in t h e NE to SW direction. It is a n e x t e n s i o n of t h e B e n u e t r o u g h w h i c h t r e n d s in t h e s a m e d i r e c t i o n (Fig. 1). T h e s t r a t i g r a p h y (lithostratigraphy and biostratigraphy), paleogeography and sedimentary tectonics have been d i s c u s s e d b y s o m e earlier w o r k e r s in t h e area. R e y m e n t (1965) d e s c r i b e d t h e s t r a t i g r a p h y of t h e different C r e t a c e o u s a n d Tertiary depositional b a s i n s in t h e c o u n t r y a n d e r e c t e d a large n u m b e r of lithostratigraphic divisions after the geographical localities in w h i c h t h e s e d i m e n t s were first s t u d i e d . In a d d i t i o n h e c r e a t e d s o m e biostratigraphic divisions. Murat (1972) i n t r o d u c e d t h e c o n c e p t of tectonic e v e n t s in his e x p l a n a t i o n of t h e p a l e o g e o g r a p h i c h i s t o r y of t h e S o u t h e r n Nigeria s e d i m e n t a r y b a s i n . His a p p r o a c h emphasised major depositional cycles resulting from t h r e e m a i n tectonic e p i s o d e s a n d t h e r e b y avoided t h e multiplicity of f o r m a t i o n n a m e s in t h e e x p l a n a t i o n of t h e s t r a t i g r a p h y of t h e S o u t h e r n Nigeria s e d i m e n t a r y b a s i n . Kogbe (1976) in his d i s c u s s i o n of t h e p a l e o g e o g r a p h i c h i s t o r y of Nigeria s t r e s s e d t h a t t h e C a m p a n o - M a a s t r i c h t i a n in t h e A n a m b r a t r o u g h b e g a n w i t h a s h o r t Marine t r a n s g r e s s i o n followed b y a regression. The b r o a d ,

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Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) The N s u k k a Formation w h i c h is similar in physical characters to the M a m u Formation and the cream to pinkish well bedded AJalt Formation are not described in this work. The N s u k k a Formation belongs in the "Upper Coal Measures", whilst the AJall Formation is not physically suitable for palynology.

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MATERIALS AND METHODS OF STUDY Thirty-slx surface clastic rock s a m p l e s obtained from localities (CM/MS 1 to 12) s o u t h of E n u g u were u s e d for this study (see Fig. 4). Grey to black shales, clays, m u d s t o n e s , silty s a n d s t o n e s and sandy siltstones were processed for palynomorphs. Limestones were rejected on account of their strong reactions with acids (especially hydrochloric acid), and their low matrix contents, w h i c h were not productive of palynomorphs. The standard technique of maceration for the preparation of acid insoluble microfossils h a s been followed in this study: 32 % Hydrochloric acid, 60 % Hydrofluoric acid, 70 % Nitric acid, 5 % Ammonia solution, separation by Zinc bromide (s.g. 2.1). The palynomorphs were strew m o u n t e d in Hydramount and sealed in Depex. Three slides were made from each studied sample. LeitzOrtholux II microscope and Leitz Orthomat camera unit were u s e d in the s t u d y of the palynomorphs and their photography,

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138

M. B. SALAMI SYSTEMATIC PALYNOLOGY

Classification employed in this work is according to Potonie a n d Kremp {1954-56). Nomenclature follows the rule on priority and typification as laid down by the International Code of Botanical Nomenclature (ICBN-Stadleu et al., 1978). The

"Genera File of Fossil Spores and Pollen Grains" edited by J a n s o n i u s and Hills (1976-1980) was consulted so as to identify those taxa that are n o m i n a n u d a as well as those t h a t are s y n o n y m o u s with previously n a m e d taxa. For the dinoflagellate cysts the terminologies used in their descriptions are after Williams etaL, 1973; Evitt et a/., 1977 and Norris, 1978. No suprageneric classification h a s been used for the dinoflageUate cysts b e c a u s e the data obtained from this s t u d y do not support it. The "Cyst Genus" concept of Stover, 1978 h a s been adopted. No attempt is m a d e in this work to re-describe those taxa that have previously been adequately described by previous other workers. AnteturmaSPoRrrEs, H. Potonid, 1893 Turma TPJLm~S,Reinsch, 1881 S u b t u r m a AZONOT~LZrES,Luber, 1935 I n f r a t u r m a LAEVIGATI(Bennie and Kidston) e m e n d Potoni~ and Kremp, 1970

L o c a t i o n s : CM/MS3a(1), S. 114, Coordinates 28. I,

108.9 (Fig. 9): 25,1, 117.5 {Fig. 13). Cingulattsporites sp. 2 Pl. 1. Figs, 4, 6 D e s c r i p t i o n • Trflete microspore, central body triangular, sides convex, trilete m a r k thin, a r m s long and reaching the equatorial margin of central body; proximal surface smooth, distal surface verrucate, verrucae few a n d low: cingulum wide, of several closely packed gemmae. D i m e n s i o n s : 4 2 x 41 ~ m L o c a t i o n s • CM/MS 6b, S. 123, Coordinates 46.8,

108.4 (Fig. 4); CM/MS 6a, S.122, Coordinates 34.0, 118.6 {Fig. 6).

Cingulattsporites ornah~ van HoekenKlinkenberg. 1964. PI. i, Fig, 2 D i m e n s i o n s : 4 3 x 3 8 p.m, L o c a t i o n : CM/MS 3a{1}. S, 114, Coordinates 29.9,

109.9 Infraturma APICULAT|(Bennie and Kidston) Potoni6, 1958 S u p t u r m a VERRUCATIDybova and Jachowicz, 1968

Distaverrusporites simplex Mtiller, 1968. Leiotriletes cf. adriennis

Pl. l, Figs. 12, 16

(Potoni6 and Gelletich} Krutzsch, 1959. PI. 1, Fig. 3 D i m e n s i o n s : 3 4 x 32 Hm L o c a t i o n : CM/MS 9a(1), S. 129, Coordinates 40.2, 117.9.

D i m e n s i o n s : 3 7 x 3 5 ~m. L o c a t i o n s : CM/MS 8c, S. 128, Coordinates 55.9,

125.1 (Fig. 12); CM/MS 4b, S. 117, Coordinates 34,0, 129.5 (Fig. 16).

Distaverrusporites margaritatus M/iller, 1968 Deltoidospora sp.

Pl. I. Fig. 14

Pl. I, Fig. I0 D e s c r i p t i o n : Small, sub-deltoid trilete spore, with the trilete m a r k s extending almost to the radial corners, "cingulate"; exine laevigate.

D i m e n s i o n s : 30 x 28 ~trn. L o c a t i o n : CM/MS 4b, S, 117, Coordinates 57.9.

D i m e n s i o n s : 2 5 x 2 4 ~rn. L o c a t i o n : CM/MS 6b, S.123, Coordinates 39.0,

P]. I. Fig. 1 D e s c r i p t i o n : Trflete microspore, amb triangular, sides convex, trilete m a r k thin; proximal surface convex, distal surface probably so, both covered by low equidimensional verrucae.

111.9. S u b t u r m a ZONOTRILETESWaltz, 1935 Infraturma CINGULAalPotoni6 and Klaus, 1954 Cingulatisporites sp. 1 Pl. I, Fig. 7-9, 13 D e s c r i p t i o n : Trilete microspore, central body round, occasionally triangular or sub-triangular, sides convex to straight, trflete m a r k long, simple, arms reaching equatorial comers, except the cingulum, cingulum is relatively wide {7.2 - 8.1 lam), uniform, margin sometimes crenulate. D i m e n s i o n s : 48 x 41 Ima, Range 48-42 x 41-35 Ixrn(14 specimens).

128.4.

? Verrucatotriletes sp.

Dimensions : 46 x 30 ~n. L o c a t i o n : CM/MS 9c. S. 133, Coordinates 28.0,

115.0 Remarks

• Specimen is tentatively assigned to

Verrucatotriletes, whose type species appears to have large irregularly shaped verrucae on account of its sparse nature. F u r t h e r m o r e it is not related to such genera as Verrutriletes Potoni6, 1956, Verrucosisporites Ibrahim, 1938 and Convem~osisporites Potoni6 and Kremp, 1954, which have smaller a n d regularly s h a p e d verrucae.

Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian)

139

Plate 1. All photomicrographic illustrations, except where otherwise Indicated, are multiplied by about 1 000 times. They are from unretouched negatives.

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Figures - I. ?Vernlcatotriletes sp. 5, 11, 18. Rugulatisporites caperatus 14. l ~ s t ~ p o r l t e s margarltatus

-2. Cingu/at~porltes o m a t u s -3. LeC0tr//etes of. ornotus -4, 6. C/~ju/atlsporltes sp. 2 -7,8,9,13. C-~ngulatisporltes sp. I -I0. De/tofdospora sp. -12,16. DLstoc~rusporites simplex -15, 19. Ariadnaesporites spblosa

140

M.B. SALAMI

I n f r a t u r m a MURORNATIPotoni~ a n d Kremp, 1954.

119.0

Rugulatisporites caperatus v a n Hoeken-Klinkenberg, 1964. Pl. i, Figs I i . 18 Dimensions : 31 x 30 ~n; 38 x 38 ~n. L o c a t i o n s : C M / M S 13a, S. 140, Coordinates 33.0,

124.1; CM/MS 4b. S. 117, Coordinates 34.0, 129.5. Two v a r i a n t s (one with triangular amb, t h e other with spherical amb} are s o m e t i m e s found in the s a m e palynological preparation. T h o u g h t h e two forms a p p e a r ordinarily to be superficially distinct, t h e y have n o t b e e n separated into individual species, b e c a u s e they are considered d u e to intraspecffic variation. Remarks:

Ephedrepites sp. 2 Pl. 2, Fig. 5 Description

: Prolate. polyplicate small pollen

with m o d e r a t e l y r o u n d e d extremities, ridges narrow, a b o u t 10-12 on e a c h side of grain, ridges a n d valleys of a l m o s t t h e s a m e width t h r o u g h o u t , except at t h e extremities where t h e y t a p e r slightly. D ~ : 3 5 x 21 ~ n L o c a t i o n : C M / M S 12b, S. 139. Coordinates 40.0.

123.1

Gnetaceaepollenites sp. 1 PI. 2, Fig. 8 Elliptical pollen, enclosing a n inner d a r k body a n d a n o u t e r t h i n body with n u m e r o u s ridges a n d valleys, ridges n u m b e r a b o u t 10 on one side of grain, moderately s m o o t h a n d straight; exine thin, n o t d e a r l y differentiated into ectexine a n d endexine, b o t h probably appressed, D i m e n s i o n : 4 8 x 23 I1rn. L o c a t i o n : CM/MS 7a ( 1}. Coordinates 43.2, 127.5 Description:

Zlivisporis blanensis Pacltova, 1959. Pl. 1, Fig. 17, Pl. 2. Figs 1-2 Dimensions : 6 5 x 54 ~rn L o c a t i o n s : C M / M S 8a, S. 126, Coordinates 30.2,

122.3 (Pl. 1, Fig. 17), CM/MS 13b. S.141, Coordin a t e s 21.0, 122.3 (PI. 2, Fig. 1), CM/MS 7b, S. 125, Coordinates 26.1, 120.4 (Pl. 2, Fig. 2). R e m a r k s : The cingulate s t r u c t u r e m e n t i o n e d in Pacltova. 1959 a p p e a r s to represent a residual perisporal m e m b r a n e on o u r specimens. A distinct c i n g u l u m h a s n o t b e e n observed.

GnetaceaepoUenites sp. 2

Gfinther a n d Hills. 1970, Pl. 1. Figs. 15, 19. Pl. 2. Fig. 18

Pl. 2, Fig. 11 Elliptical pollen, enclosing an inner d a r k body a n d an o u t e r light one with a b o u t six "ridges" a n d "valleys"; extne thin, b o t h ectexlne a n d endexine are closely a p p r e s s e d w/thin the ridges.

D i m e n s i o n s : 6 5 x 5 4 ]~m L o c a t i o n s : C M / M S la. S.110, Coordinates 48.0.

Dimensions : 3 0 x 17 ~ n . L o c a t i o n : C M / M S 4b (1}, S.117. Coordinates

125.8 (PI. I. Fig. 19); C M / M S 4a, S . I 1 6 , Coordinates 30.2, 120.1 (Pl. 2, Fig. 18).

38.0. 115.6.

Ariadnaesporites spinosa (Elsik)

Description:

S u b t u r m a MONOCOLPATESIversen a n d

Troels-Smith(1950)

A n t e t u r m a POLLENITES,Potoni6, 1931

Turma POLYPLICATES, E r d t m a n , 1952 S u b t u r m a COSTATES,Potoni6, 1970 I n f r a t u r m a COSTAl, Potoni~, 1970

Arecipites microreticulatus Anderson, 1960 Pl. 3, Fig. 13 Dimensions

Ephedrepites strobilaceous (Kuyl et a/.,1955; Salami,& 1984.

: 3 0 x 27 ~m: Range 38-32 x 27-22 ~rn

Pl. 2, Fig. 3

( 10 specimens). : CM/MS4b(1), S. 117, Coordinates 60.0, 116,1

Dimensions: 68 x 38 ~m. L o c a t i o n : CM/MS 8a, S. 126, Coordinates 39.0,

Auriculiidites reticulatus Elsik, 1964

Location

Pl. 2, Fig, 13; PI. 4, Fig. 3

128.2 Dimensions

Ephedrepites sp. 1 Pl. 2, Fig. 4 : Perprolate pollen with s o m e w h a t r o u n d e d extremities, bears 5-6 straight ridges on one side of t h e grain a n d several small inclined ridges on the opposite side; ectexine more p r o m i n e n t t h a n endexine, w h i c h is restricted to areas between ridges. D i m e n s i o n s : 3 3 x 23 ~rn L o c a t i o n : C M / M S 12b, S. 139, Coordinates 28. I, Description

: 5 4 x 3 0 ~in.

L o c a t i o n : CM/MS 8 (I), S. 128, Coordinates 40.0, 1242.2; CM/MS 12b{I). S, 139, Coordinates 50,9, 128,1 (P1.4, Fig. 3).

Auriculiidites sp. P 1 . 2 , Fig. 17 I ) ~ t z l p t l o u : Ovalpollen grain, probably isopolar, with two auriculate s t r u c t u r e s at the extremities of t h e grain, m o n o s u ~ a t e , s u l c u s long, as long as greatest diameter of grain; exine thin (1.5 - 2.0 I1rn),

141 Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) Plate 2. All photomlcrographlc illustrations, except where otherwise Indicated, are multiplied by about 1 000 times. They are from unretouched negatives

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Figures - ] ,2. ZiWlsporls blanensts -3. Ephedrepltes strobilaceous -4. Ephedrel~tes sp. 1 - 5. Ephedrepites sp. 2 -6. Syncolporltes Incomptx~7. Monoco~pollenites s p h a e r o ~ e s -8. Gnetaoeaepollen~tes sp. 1 -9. Buttlnla andreevl - 10. Aqu~apollenites minor 1 I . G n e ~ n t t e s sp. 2 - 12, 15. NyssapoUenttes pseudocn~'Wlus -13. Aur~,dlldltes r e ~ u / a t u s 14. Pollen i n d e t , x 4 0 0 -16. Aqu//apo//enttes sp. -17. Aurlc~d!~d~tes sp. -18. Ariadnaesporttes spinosa

142

M. B. SALAMI

microreticulate, m u r a t e , m u r i uniform (0.2 - 0.3 ~n), lumina also uniform (about 0.5 ~rn wide), finely columellate. Dimensions : 5 4 x 3 8 ~rn. L o c a t i o n : CM/MS 7b(1), S. 125, Coordinates 40.9,

125.4

Longapertites marginatus van Hoeken-K11nkenberg, 1964 P1,3, Fig. 4; PI. 4, Fig. 8 Dimensions : 5 4 x 4 1 ~rn. L o c a t i o n : CM/MS 8a, S. 126, Coordinates 44.9,

127.0

Longapertites reticulatus n. sp. Pl. 3, Fig. 3 Description : Sub-circular zonosulcate pollen, sulcus long, nearly encircles the grain, proximal surface moderately convex to straight, distal surface prominently convex; exine intectate, conspicuously reticulate, m u t a t e , columella simple, m u r i of uniform width, lumina of various shapes, always wider t h a n muri. D i m e n s i o n s : 6 3 x 48 ~rn; Range 60-72 x 40-55 (5 specimens). R e m a r I r ~ : The specific epithet has been derived from its distinctive coarsely reticulate pattern. Not comparable to Longapertites marglnatus which is micro-foveolate or microreticulate and has a triangular to sub-triangular amb or Longapertites vanendenburgi, which is comparable to L. marginatus but h a s a semi-circular amb.

? Longapertites sp

from the Late Senonian of Gabon, West Africa by Boltenhagen {1976).

Mauriitides crassibaculatus van Hoeken-Klinkenberg, 1964 Pl. 4, Fig. 1 Description : (Emend): Prolate, sometimes oval monosulcate pollen, s u l c u s long, as long as the longest diameter of grain, simple; exine thin, baculate, bacula between 4.5 - 5.5 ~zn long, narrow in width (1.5 - 2.2 ~im), r o u n d at their tips, all indented at their bases by moderately thick exine materials: exine between bacula smooth, distances between adjacent bacula variable. Dimensions : 58 x 38 ~n. L o c a t i o n : CM/MS 9c(I), S. 133. Coordinates 46.9.

115.7. S u b t u r m a T~vTvctms Potoni6, 1970 Infraturma ISOTRICOLPAT[Potonie, 1970

Tricolpites reticulata {Cookson) Couper. 1953 Pl. 3, Fig. 2 Dimensions : 48 x 46 ~m. L o c a t i o n : CM/MS 4bfl). S. 117. Coordinates 29.2,

116.0 S u b t u r m a POLYPTYCHESPotoni6, 1960 Infraturma STEPHA~OCOWA~Potoni~, 1970

Ctenolophonidites costatus van Hoeken-Klinkenberg, 1966 PI. 3, Fi.g. 5 Dimensions

: 47 x 44 ~n

Pl. 3, Fig. 8 D e s c r i p t i o n : Somewhat oval, zonosulcate pollen, sulcus long, nearly encircling the grain, exine intectate, spinose, spines of uniform dimensions, sharply pointed at their tips b u t wide at the bases, spaces between spines uniform.

L c ~ a t i ~ : CM/MS 3a. S. 114, Coordinates 48.0, 122.5

Dimensions : 46 x 39 ~n. L o c a t i o n : CM/MS 9b(1), 5.13 I, Coordinates 38. I,

(van Hoeken-Klinkenberg} Kieser and J a n d u ChOne, 1979 Pl. 3, Fig. 10a., b; P 1 . 4 , Fig. 11

S u b t u r m a SVNCOI2ATESE r d t m a n , 1952

Periretisyncolpites magnosagenatus

127.2

Monocolpopollenites sphaeroidites Jardin6 and Magloire, 1965 PI. 2, Fig. 7 Dimensions

• 22 x 19 ~n.

L o c a t i o n : CM/MS 12a, S, 138, Coordinates 24.3, 125.8

Monosulcites perspinosus Couper 1953

Location

: CM/MS 7a, S. 124. Coordinates 51.9,

122.7 : Figured specimen is fragmentary. No complete specimen was recovered and hence dimensions have not been recorded.

Remarks

S u b t u r m a I>rYCHOTPdVOmNESPotoni6, 1960 Infraturma PROLA~E r d t m a n , 1943

Pl. 3, Fig. 6 Dimensions ; 6 1 x 4 1 ~rn. L o c a t i o n : CM/MS 4a(1), S. 116, Coordinates 55.1,

119.8 R e m a r b : Originally described by Couper (1954) from the Paleocene of New Zealand. Later reported

Nyssapollenites pseudocruciatus Potoni6. 1960 Pl. 2, Figs, 12, 15. Dimensions:

4 3 x 3 2 ~ m (Fig. 12); 3 4 x 1 9 B m

(Fig. 15) - note that specimen is compressed). L o c a t i o n : CM/MS 13a, S. 140. Coordinates 56.0,

143 Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) Plate 3. All photomlcrographlc illustrations, except where otherwise Indicated, are multiplied by about 1 000 times. They are from unretouched negatives

i

¸¸ i =

7

Figures -I. Erlcipltes s p -2. THcolpltes retlculata -3. Longopertltes r e ~ -4. Longopertltes marglnatus ( 1 0 a . . . x 4 0 0 -5. C t e n o / o p h o n k / / t e s co.status -6. Monosulcites p e r s p l n o s u s - 7. Pollen i:ndeL 8. Longapertltes sp. -9. Retldiporites r n a g d a / e n e n s L s l Oa,b. Perb'etlsyncolldtes ~agenatus ) - 1 I. Echitriporltes trianguliformLs - 12. Aqr dlnpoUenltes sp. 2 - 13. Arecipites mlcrorei~ulahcs

144

M. B. SAt,Ar~

109.0; 52.1, 110.3.

T u r m a UG^TESPotoniS, 1960 S u b t u r m a TETRADrrESCookson, 1947

I n f r a t u r m a OBIATIE r d t m a n , 1943

Ericipites sp. Syncolporites incomptus v a n Hoeken,Klinkenberg 1964. PI. 2, Fig. 6 D i m e n s i o n s : 23 x 22 I~rn; Range 23-21 x 22-20 w n ( 16 specimens). L o c a t i o n : C M / M S 4b(1), S. 117, Coordinates 58.9, 121.1 T u r m a POROSAPotoni~, 1960 S u b t u r m a DIeOmNES Potoni~, 1960

Retidiporites cf magdal_enensis van der H a m m e n a n d Garcia de Mutts, 1966 Pl. 3, Fig. 9; PI. 4, Fig. 5 Dimensions : 54 x 41 wn L o c a t i o n s : C M / M S 4b(1), S.117; Coordinates 53.1, 121.1 (PI. 3, Fig. 9), CM/MS 13a(l), S.140, Coordinates 58.9, 127.7 (P1.4, Fig. 5). R e m a r k s : Considerable size variation exists in t h e studied specimens. Whilst PI.4, Fig. 5 m e a s u r e d 54 x 41 ~m, others r a n g e d from 46-41 x 37-32 [~rn. S u b t u r m a TmPom~msPotoni~, 1960

Vl. 4, ~ . 4 ~ n : Tetrahedral ~ I pollen, aperture indistinct b u t short, colpi s h a r e d between adja, cent " g r ~ " ; exine m o d e r a t e (3.0 - 3.5 pan), not sub-dividided into recognisable ectexine a n d endexine layers {both probably appressed), surface smooth. ~ o n s Lo~tlon:

: 3 4 x 3 3 ~rn.

CM/MS 9b(1), S. 131, Coordinates 27.8,

124.5. T u r m a SAccrms E r d t m a n , 1947 S u b t u r m a POLYSACCITESCook,son, 1947

Aquilapo!lenites sp.l PI. 2, Fig. 16 D~e, rlptlon: Sub--at to bipyramidal small pollen with four e q u a t o r i a l ( ? ) p r o t r u s i o n s , sides of central body concave; e x i n e ~ , non-columellate, surface echinate. D i m e n s i o n s : 58 x 42 ~urn. L o c a t i o n : CM/MS 5a(1), S. 118, Coordinates 59.9, 114.4

E c h i ~ t e s trlanguliformis

Aquilapollenites sp. 2

v a n Hoeken-Klinkenberg, 1964. Pl. 3, Fig. 11 D i m e n s i o n s : 35 x 35 ~rn; Range 37-32 x 35-30 ttrn (21 specimens) L o c a t i o n : CM/MS 12a(I), S.138, Coordinates 52.0, 120.3

PI. 3, Fig. 12 D e s c r i p t i o n : S u b t r i a n g u l a r pollen with concave sides, polar area w i t h two m e m b r a n o u s flaps (probably scars from the u n i o n of several grains), "equatorial" a r e a displays three protrusions; exine thin, finely echinate. Dimensions : 4 3 x 3 8 Hm. L ~ a t l o n : C M / M S 12a(1), S.130, Coordinates 32.0, 123.8. R e m a r k s : The above two form species described under the genus Aquilapollenitess F u n k h o u s e r , 1 9 6 1 are so designated b e c a u s e of their s u p p o s e d l y equatorial protrusions. On the r e a l i s a t i o n t h a t undoubtedAquilapollenites belong in t h e n o r t h e r n h e m i s p h e r e , it is probable t h a t they suggest p ~ d evolution in u n r e l a t e d plants.

Echitrlporites sp. PI. 4, Fig. 6 D e s c r l p t l o n : Triangular small pollen, sides convex, triporate; exine thin, covered by n u m e r o u s conical spines, curved at t h e i r tips, distances between adjacent s p i n e s variable, spaces between spines are smooth. Dimensions : 2 9 x 28 ~rn L o c a t i o n : C M / M S 12(b(1), S.139, Coordinates 48.8, 118.3

I n f r a t u r m a ~BEmNI Potoni~, 1970 Tr/or/tes sp. P 1 . 4 , Fig. 9 Description : S u b t r i a n g u l a r small pollen, sides moderately concave, triorate, pores simple; exine thin, finely echinate. Dimensions

: 27 x 21 ~n.

L o c a t i o n : CM/MS 12a(1); S.138, Coordinates 27.2, 125.9

Buttinla andreevi Boltenhagen, 1967 P 1 . 2 i Fig. 9 Dimensions

Loca~: 108.1

: 5 8 x 48 t~n

CM/MSgb(2),S. 132, Coordinates 58.2,

Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) 145 Plate 4. All photomlerographle Illustrations, except where otherwise Indicated, are multiplied by about 1 000 times. They are from unretouched negatives

7

10

ii! Figures -1 M ~ s crasslbacu/atus magda/enensls -6. Echltr/p¢~es sp. 1 I. Perlretlsyncolpltes magnosagenatus AES 11-1/2--J

,

-2. Dyadosporites sp. -3. Aur~dif~l~tes rettculatus -4. Erlclpites sp. 5. Reffdlporttes -7. Spore lndet. -8. Longapertites margtnatus x400 -9. TrIor[tes sp. -I0,14. ?Acrltarch tndet.-12. Polysphaerldtumsp. -13,15. Deflandrea sp. 1 -16,17. DeJlandrva sp. 2

146

M. B. SALAMI Group SPORONrrESH. Potoni6, 1893 Subgroup DICELLASPORONITES Rueda-Gaxiola, 1967 Superdivision I~CELLOSTATES Rueda-Gaxiola, 1967

Dyadoslx~tes sp. Pl. 4, Fig. 2 : Bflocular elliptical fungal spore, with a simple central septum, diporate (?), "pores" located at opposite extremities, spore wall smooth in places except a few parts where it appears punctate (probably due to corrosion). D i m e n s i o n s : 6 0 x 36 lma. L o c a t i o n : CM/MS 4a(1), S. 116, Coordinates 30.2, 120,1 PI. 4, Fig. 7 Spore indet. D e s c r i p t i o n : Subspherical spore, central body s u r r o u n d e d b y a wavy m e m b r a n o u s s t r u c t u r e of uniform width; exine of central body moderate, divided into polygonal areas. Description

D i m e n s i o n s : 2 6 x 2 3 ~rn. L o c a t i o n : CM/MS 13a(I}, S.140,

24.9, 127.5 (Fig. 13); Coordinates 27. I, 118.7 Deflandrea sp. 2 Pl. 4, Figs, 16. 17 D ~ r I p t l o n : Proximate pentagonal peridinioid cyst, subdivided into a low conical epicyst and a somewhat hemispherical hypocyst, both delimited by a paracingulum, eplcyst bears a fairly long apical horn, whilst the hypocyst b e a r s two unequal antapical horns, cyst cavate, periphragm and e n d o p h r a g m closely appressed in the central cyst area, h o r n s are m a d e u p of periphragm alone; archeopyle not very distinct, b u t appears as a broad intercalary hexa type, no paratabulation, except w h e n inferred from the archeopyle. D i m ~ : 111 x 82 ~ (including apical and antapical homs). L o c a t l o m : CM/MS 8c, S. 128, Coordinates 22.1, 109.3 (Fig. 16}. Coordinates 4 5 . 1 . 1 1 0 , 0 (Fig. 17). Remarks : Deflandrea sp. 2 is smaUer w h e n compared to Deflandrea sp. 1. The h o r n s are less robust a n d the overall s h a p e is more pentagonal compared to .Deflandrea sp. 1.

Coordinates

58.0, 123.0

RF.ASULTS OF PALYNOLOGICAL INVESTIGATIONS

Division PrRRHOPHYTAPascher, 1914 Class D[NOPHYCEAEFritsch, 1935

SPINIb-ERATE CYST Polysphaeridiwn sp. Pl. 4, Fig. 12 : Subspherical chorate cyst. with n u m e r o u s processes which do not reflect any clearly defined para-tabulation; processes simple, open distally; wall of a u t o p h r a g m only, no paras u t u r a l features, no paracingulum; archeopyle distinctly apical. D i m e n s i o n s : 28 x 26 fan (excluding processes); processes between 8-10 fan in length. L o c a t i o n : CM/MS 12b(1), S.139, Coordinates 22.0, 110.5 Description

PERIDINIOID CYSTS Deflandrea sp. I Pl. 4, figs. 13, 15 D e s c r i p t i o n : Compressed tricornucavate peri-

dinioid cyst with one apical and two antapical horns, without p a r a s u t u r a l features, except faint lines and ridges, which are not uniformly distributed; paracingulum smooth, indicated by transverse parallel ridges, occasionally by local concavity; periphragm and e n d o p h r a g m smooth; paratabulation indicated by broad hexa type 2a intercalary archeopyle. D i m e n s i o n s : 1 3 5 x 111 ~ma. L o c a t i o n s : CM/MS 2a(1), S.112. Coordinates

The lack of adequate stratigraphical control for the exposed sediments in the A n a m b r a trough, s u c h as the absence of a distinctive maflcer bed to which all height m e a s u r e m e n t s c a n be related, the fact t h a t considerable part of the thickness of beds is unexposed b u t in the subsurface, the luxuriant tropical m a n - m a d e s a v a m m vegetation cover, which obscures the rocks from direct s t u d y except along road cuts and river valleys and a thick mantle of w e a t h e r e d z o n e or o v e r b u r d e n (zone of lateritisation) have imposed severe limitations to detailed palynostratigraphical analysis on the surface rocks in the A n a m b r a trough. Though the sediments are in general sparse in palynomorphs, some of the samples are considerably rich in palynomorphs, as t o allow adequate deductions and observations to be made. Many of the palynomorphs are similar to those described from South Western Nigeria (see Salami. 1983, 1984) whilst a few forms recovered only from the '~ower Coal Measures" could well support Reyment's (1965) observation (based on megafossll evidence) that the "Lower Coal Measures" rocks are in part older t h a n those sediments in s o u t h w e s t e r n Nigeria ascribed to the s a m e age. The E n u g u Shale and M a m u Formation are comparable in age, the Ajall Formation is not palyntferous, whilst the a s s e s s m e n t of the Nsukka Formation (not the subject of this paper) shows t h a t it is y o u n g e r in part at least compared to "Lower Coal Measures" deposits. This is confirmed by the presence in it of

Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) s u c h taxa a s M_a_urtltldes crasslbact~!atus van Hoeken-Klinkenberg, 1964, Retibrevltrlcolpites tr/angol_a_tus v a n Hoeken-Klinkenberg, 1966 a n d Retlbrevltrlcolpltes rotundus v a n H o e k e n Klinkenberg. 1966 w h i c h are a b s e n t from the E n u g u a n d M a m u Formations. Generally, t h e association of m i o s p o r e s indicates a s w a m p or m a n g r o v e vegetation. The m a n g r o v e or s w a m p e n v i r o n m e n t w a s subject to occasional flooding of m a r i n e or b r a c k i s h w a t e r t h e r e b y allowing some organic-walled m i c r o p l a n k t o n to be incorporated in t h e s e d i m e n t s . The observation ofvan Hoeken-Klinkenberg, 1964, (p. 211) on t h e Geological Survey of Nigeria borehole at E n u g u (G.S.N. BH 1001) is p e r t i n e n t here. V a n Hoeken-Klinkenberg (op. tit) illustrated a miospore d i a g r a m w h i c h s u g g e s t e d f l u c t u a t i o n b e t w e e n h e r Monocolpltes medius group a n d Psilatrlletesgroup. S h e attributed the f l u c t u a t i o n s to climatic periodicity in line with v a n der Hamm e n ' s (1957) observation o n rocks of similar age from Colombia, S o u t h America. The Ps~_a__triletes g r o u p , largely p t e r i d o p h y t i c s p o r e s , w h i c h probably inhabited the swamp, whilst the Monocolpites medius group is largely pollen of t h e p a l m a e w h i c h fringed or are closer to t h e m a r g i n of t h e s w a m p s . It is being s u g g e s t e d t h a t there could have b e e n s o m e eustatic c h a n g e s in sea level d u r i n g ? C a m p a n i a n - M a a s t r i c h t i a n w h i c h were responsible for t h e f l u c t u a t i o n s r a t h e r t h a n local c h a n g e s in climate. Unfortunately, t h e dinoflagellate cysts a n d acritarchs w h i c h could have t h r o w n m o r e light on v a n Hoeken-Klinkenberg's palleoecological d e d u c t i o n s were n o t p a r t of t h e fluctuation diagram, n o r were t h e y described or illustrated in v a n Hoeken-Klinkenberg (1964). Based on t h e experience gained from t h e analysis of s e d i m e n t s of a b o u t the s a m e age in S o u t h w e s t e r n Nigeria, t h i s writer is of t h e opinion t h a t t h e frequency f l u c t u a t i o n is a direct result of the general flooding as well as withdrawal of t h e sea in t h e depositional e n v i r o n m e n t . A few dinoflagellate cysts have b e e n recovered a n d t h e y give some credence to the above suggestion. In t h e presence of good stratigraphical control or t h e availability of deep borehole materials, it would have been possible to confirm s u c h a relationship. One peculiarity of t h e miospore distribution is t h a t t h e coarse form of Echltriporltes trianguliformis (cf. Proteacldites Ionglspinosus of J a r d i n 6 a n d Magloire, 1965) w a s recovered from t h e "Lower Coal Measures". This agrees with the observation of Herngreen, 1975 in t h e Brazilian materials. As quoted by H e r n g r e e n (1975), only t h e coarse form of Echitrlpor~s trianguliformls is p r e s e n t in the Senonian. It s h o u l d be highlighted t h a t it h a s b e e n recovered also in the Eocene materials in s o u t h westerla Nigeria. Proteacidltes dehanni quoted by

147

G e r m e r a a d etal. (1968), as ranging d o w n into the MaastrichUan w a s n o t recovered in t h e "Lower Coal Measures" deposits of S o u t h e a s t e r n Nigeria. It is probable t h a t this w a s d u e to s a m p l i n g p r o b l e m s or m a y be d u e to t h e a b s e n c e of the p l a n t s t h a t p r o d u c e d s u c h a pollen in t h e A n a m b r a t r o u g h area. It is therefore p r e m a t u r e to speculate on its terminal range in t h e S e n o n i a n as at the p r e s e n t stage of knowledge. Additional materials m a y therefore be needed, particularly in the "Lower Coal Measures" to d e t e r m i n e t h e d o w n w a r d range of Proteac~_d~_tesdehaanl, PALEOECOLOGICAL DEDUCTIONS The p a l y n o m o r p h assemblage of t h e A n a m b r a t r o u g h of s o u t h e a s t e r n Nigeria p r e s e n t s diverse paleoecological interpretations. Whilst s o m e of t h e s a m p l e s c o n t a i n small sized cuticle a n d few m i o s p o r e s w h i c h will suggest t h a t s u c h s a m p l e s were recycled a n d sorted, o t h e r s w i t h large sized cuticles indicate t h a t they probably have n o t moved m u c h from their original habitat. Algal spores are less c o m m o n in t h e materials. The m i o s p o r e s are n o t numerically a b u n d a n t . The low quantities of m i o s p o r e s m a y be related to shale a n d clay being t h e p r e d o m i n a n t lithology. The occurrence of a fairly diverse miospore assemblage in t h e silty clay p a r t of t h e M a m u F o r m a t i o n could be related to better pore s p a c e s in s u c h a lithology. The m o d e r a t e settling velocity of clay s e d i m e n t s probably allowed various sizes of m i o s p o r e s to be included within it. The miospore association indicates a s w a m p vegetation as s h o w n by a fairly large prep o n d e r a n c e of trilete s p o r e s . T h e s w a m p e n v i r o n m e n t w a s m o s t probably fringed by h e r b a c e o u s a n d other v a s c u l a r p l a n t s w h i c h readily provided pollen to t h e depositional environm e n t . Some of t h e recovered m i o s p o r e s are similar to those ascribed to t h e p a l m a e (e.g. Longapert/tes marginatus, Longapertltes s p . , Arecipites

mlcroreticulatus, Monosulcltes perspinosus, Mauritiides crass/bacu/atus) a n d h e r b a c e o u s p l a n t s (MonocolpopoUenltes sphaeroidites, Syncolporites /ncomptus, Er/c/p/tessp.) b y p r e v i o u s o t h e r workers in other places (Boltenhagen, 1975, 1976; J a r d i n 6 a n d Magloire, 1965; Nichols, A m e s a n d Traverse, 1973; Salard-Cheboldaeff, 1978 a m o n g others). Recovered trflete s p o r e s are morphologically similar to s o m e of t h e extant forms in the families Cyatheaceae, Polypodiaceae, (?) Lycopodiaceae a n d / o r Schizeaceae, s o m e of w h i c h are k n o w n to inhabit fresh water s w a m p s a n d m a r s h e s . The generally low o c c u r r e n c e s of dinoflagellate cysts s u g g e s t a b r a c k i s h w a t e r i n f l u e n c e . The occurrence of poorly preserved m a r i n e bivalves (Ostrea) w h i c h could invoke n o r m a l consideration

148

M.B. ShLA~

of a m a r i n e e n v i r o n m e n t is f u r t h e r a n indication t h a t they are probably stragglers t h a t were leit b e h i n d in local pools after t h e withdrawal of the sea. It is being s u g g e s t e d t h a t except for t h e Nkporo Shale w i t h its h i g h c o n t e n t of e n d e m i c Afrobolivtna afraReyment, other benthic foraminifera a n d some m a r i n e macroinvertebrates, all t h e other deposits of the "Lower Coal Measures" are paralic. Burke, D e s s a u v a g i e a n d W h i t e m a n (1971, 1972) s u g g e s t e d a Late Cretaceous (?CampanianMaastrichtt~n} delta in the A n a m b r a trough, w h i c h is probably d e n o t e d by t h e "Lower Coal Measures" suites of rocks. AGE OF T H E SAMPI,F~ STUDIED

Kieser a n d J a n d u C h i n e (1979), B o l t e n h a g e n (1967, 1975 a n d 1976) a n d Salard-Cheboldaeff ( 1978}. The p a l y n o m o r p h s are generally those t h a t have b e e n described from West Africa (Senegal. Ivory Coast, Nigeria, C a m e r o u n . Gabon} a n d S o u t h America (parts of Colombia. Peru, Brazil, Guinea a n d Surinam}. It is being s u g g e s t e d that the tropical vegetation zone was already established by t h e ? C a m p a n i a n - M a a s t r i c h t i a n times. The overlap in t h e stratigraphic ranges of Butt/n/a

andreevi. Cingulatlsporites ornatus. Distaverrusporites simplex. Distavem~porites margaritatus. Rugulatisporites caperatus, Zlivlsporls blanensis. Arladnaesporites spfftoso, Arectpites microreticulatus. Auricullidites reticula~s, Longapertltes marglnatus, Monocolpopollenites sphaeroldites, a n d Echitriporites

Due to the difficulty of obtaining borehole materials w h i c h w o u l d have formed the basis of tr/angu/~formis is significant. It strongly suggests detailed palynostratigraphical analysis, the fact ? C a m p a n i a n - M a a s t r i c h t i a n for the p a l y n o m o r p h t h a t considerable p a r t of "Lower Coal Measures" assemblage a n d f u r t h e r m o r e for t h e "Lower Coal deposits are in t h e subsurface, the age a s s i g n m e n t Measures" deposits. This age range is in a g r e e m e n t h a d to be b a s e d on the plotting of composite with t h a t of earlier workers in t h e area (Simpson, stratlgraphical r a n g e s of species recovered from 1954; R e y m e n t . 1965) w h o a s s i g n e d a the "Lower Coal Measures" whose ranges are k n o w n ? C a m p a n i a n - M a a s t r i c h t i a n age on t h e basis of elsewhere. The r a n g e s w h i c h are s h o w n on Table 1 m o l l u s c a n ( P e l e c y p o d a , G a s t r o p o d a a n d have b e e n c o m p a r e d with those based on macro- C e p h a l o p o d a ) c o n t e n t s a n d f o r a m i n i f e r a l fossils by S i m p s o n (1954) a n d R e y m e n t (1965) a n d assemblage. It is also in a g r e e m e n t with the they agree. The r a n g e s have b e e n compiled from p i o n e e r i n g p a l y n o l o g i c a l s t u d y of v a n p u b l i s h e d w o r k s by v a n d e r H a m m e n (1954), van Hoeken-Klinkenberg (1964) in the area. except Hoeken-Klinkenberg (1964, 1966), M/tller (1968), that additional taxa of p a l y n o m o r p h s , whose Pacltova (1959), Gtinther a n d Hills (1970), Kuyl, ranges are k n o w n elsewhere have f u r t h e r b e e n Mtiller a n d Waterbolk (1955), Elsik (1964), recovered a n d t h e y f u r t h e r assist in establishing a A n d e r s o n (1960). Jardin~ a n d Magloire (1965). ? C a m p a n i a n - Maastrichtian age for the sediments. Table I. Composite Stratigraphical Ranges of selected species of palynomorphs from the "Lower Coal Measures" of Southeastern Nigeria (adapted from Various authors). C R E T A C E O U $ I

SANTOMIAN

CAMPANIAN

TERTIARY MAASTRICHTIAM

PALEOCENE

AOE

SUMMARY PALYNOHORPH

TAXA

CINGULATISPORITES ORNATU$ O

DISTAVERRUSPORITES SIMPLEX

DISTAVERRUSPORITES MARGARITATUS RUGULATISPORITES ZLIVISPORIS

BLANENSIS

ARIADNAESPORITES ARECIPITES

] II

i

[

.

CAPERATUS

SPINOSA

MICRORETICULATUS

AURICULIIDITES LONGAPERTITES

RETICULATUS

MARGINATUS

MONOCOLPOPOLLENITES

SPHAEROIDITES

ECHITRIPORITES TRIANGULIFORMIS BUTTINIA ANDREEVI

Palynomorph taxa from the "Lower Coal Measures" deposits (?Campanian - Maastrichtian) DISCUSSION

The s t u d y h a s e s t a b l i s h e d t h a t t h e e n v i r o n m e n t of d e p o s i t i o n of t h e "Lower Coal M e a s u r e s " w a s a f r e s h w a t e r s w a m p largely p o p u l a t e d b y f e r n s of t h e families Cyatheaceae, Polypodiaceae, ? L y c o p o d i a c e a e a n d / o r Schlzeaceae. The freshw a t e r s w a m p w a s fringed b y s h r u b s a n d t h e p a l m a e . T h i s f r e s h w a t e r s w a m p or m a r s h w a s i n u n d a t e d b y m a r i n e or b r a c k i s h w a t e r of a s h o r t d u r a U o n . It w a s p r o b a b l e t h a t t h e prevailing salinity after t h e i n c u r s i o n w a s intolerable to m o s t of t h e organic m i c r o p l a n k t o n a n d w o u l d have led to their demise. Microfossfls of t h e "Lower Coal M e a s u r e s " a r e poorly p r e s e r v e d a n d p r o b a b l y indicate f u r t h e r t h a t m o s t of t h e m i c r o p l a n k t o n s u i t e a r e stragglers leil b e h i n d in local p o o l s after t h e w i t h d r a w a l of t h e sea. T h e o c c a s i o n a l recovery of l e n t i c u l a r sideritic l i m e s t o n e s w i t h poorly p r e s e r v e d bivalved m o l l u s c s (especially within t h e E n u g u Shale) i n d i c a t e s t h a t local r e d u c i n g e n v i r o n m e n t of d e p o s i t i o n prevailed at t h e s e times, following t h e views e x p r e s s e d b y K r a u s k o p f (1967). As r e p o r t e d b y K r a u s k o p f (I 967), siderite p r e c i p i t a t e s in a n a r e a w h e r e t h e s u p p l y of f e r r o u s iron is large, a n d / o r a r e d u c i n g e n v i r o n m e n t is m a i n t a i n e d b y a b u n d a n t organic m a t t e r , s u c h a s in deltaic s w a m p s , m a r s h e s a n d m a n g r o v e . B u r k e , D e s s a u v a g i e a n d W h i t e m a n (1971) s u g g e s t e d t h e existence of a delta in t h e E n u g u a r e a d u r i n g ? C a m p a n i a n - M a a s t r i c h t i a n times. B u r k e et aL (1971, 1972) f u r t h e r i n d i c a t e d t h a t delta b u i l d i n g activities h a v e s i n c e t h e n c o n t i n u e d in a s o u t h e m l y p r o g r a d a t i n g direction. S u b s e q u e n t a n c i e n t d e l t a s a s s u g g e s t e d b y t h e m w e r e in Eocene, Oligocene a n d Miocene-Pliocene t i m e s respectively. T h e Miocene-Pliocene delta of t h e p r e s e n t Niger delta is p e t r o l i f e r o u s a n d h a s b e e n of i n t e n s e e c o n o m i c activities for s o m e t i m e s . The few o b s e r v e d b e d d i n g s in t h e "Lower Coal M e a s u r e s " d e p o s i t s are to t h e s o u t h a n d s o u t h w e s t a n d t h e y indicate t h a t t h e a n c i e n t G u i n e a O c e a n w a s t h e s o u r c e of m a r i n e i n c u r s i o n to t h e A n a m b r a t r o u g h r a t h e r t h a n t h e M e d i t e r r a n e a n sea. REFERENCES

Adeleye, D. R. 1975. Nigerian Late Cretaceous Stratigraphy and Paleogeography. Amer. Assoc. Petr. Geol. Bull- 59(12), 2302-2313. Anderson, R. Y. 1960. Cretaceous-Tertlary palynology, eastem side of San J u a n Basin, New Mexico. New Mexico, State Bur. Mines and Min. Res., InsL Min. Tecb., Ment 6,1-58. Boltenhagen, E. 1967. Spores et pollen du Cr6tac6 sup~rieur du Gabon. Po//en et Spores, 9(2 ), 335-355. Boltenhagen, E. 1975. Quelques Spores du Cr6tac6 sup6rleur du Gabon. Rev. MkTopaleontol-. Paris, 18(2), 69 -80.

149

Boltenhagen, E. 1976. La Microflore s~nonienne du Gabon./bzv. Micropa/eontoL, Paris, 18(4}, 191-199. Burke, K. C., Dessauvagie, T. F. J. and Whiteman, A. J. 1971. Opening of the Gulf of Guinea. Nature, (Phys. ScL), 283, 51-55. Burke, ~ C., Dessauvagie. T. F. J. and Whiteman, A. J. 1972. Geological History of the Benue Valley and Adjacent Areas. In. African Geology, Univ. Ibadan Press, Nigeria, 187-205 p. Couper, R. A. 1953. Upper Mesozoic and Cainozoic Spores and Pollen Grains from New Zealand. New Zealand Geo/. Surv. PaleontoL BulL, 22, 1-77. Elsik, W. C. 1954. A new sporomorph genus from eastern Peru. Po//en etSpores, 8(2), 601-604. Evitt, W. R., Lentin, J. K., Mlllioud, M. E., Stover, L. E. and Williams, G. L. 1977. Dinoflagellate cyst Terminology. Geol. Surv. Canada, Paper 76-24, 9 p. Germeraad, J. H., Hopping C. ,~, and Mfiller, J. 1968. Palynology of Tertiary sediments from Tropical areas. Rev. Palaeobotan. PalynoL 6(3/4), 189-348. GCmther, P. and Hills, L. V. 1970. Heterospory in Ariadnaesporites. Po//en et Spores, 12(1), 123-130. Hulbert, E. M. 1963. "I~ne diversity of phytoplankton populations in oceanic coastal and estuarlne regions. Jourrh Mar. Res., 21(2), 81-93. Jain , K. P. and Millepied, P. 1973. Cretaceous microplankton from S~n~gal Basin in N.W. Africa I. Some new genera, species and combinaUons of dinoflagellates. PalaeobotanfsL 20(1), 22-32. Jansonius, J. and Hills, L. V. 1976-80. Genera File of fossil spores and pollen. Spec. Publ. Dept. of Geol., Univ. of Calgary, Canada, 3928 cards. Jardin~, S. and Magloire, L. 1965. Palynologie et strattgraphie du Cr~tac6 des bassins du S~n~gal et de C6te d'[voire Coll. Int. Micropaleontol. (1963), MerrL Bur. GeoL Mb-L,32,187-245. Kieser, G. a n d J a n Du C h i n e , R. 1979. Periretisyncolpites n. gen. and Terscissus Tschudy 1970 grands pollen syncolpes du Maastrlchtien du S~n6gal et du Nlg6ria. Rev. Espano/a de Mk'ropal-, 11{2), 321-334. Krauskopf, IC B. 1967. Introduction to Geochemistry. McGraw-Hill Book Company, New York, 721. Krutzsch, W. 1959. Elnige neue Formgattungen u n d - a r t e n yon sporen u n d pollen a u s der mitteleuropaischen Oberkrelde und dem Terti~ir. P~loeontographfca, abt, B. 105(5-6), 125-155. Kuyl, O. S., Mffller, J. and Waterbo]k, H. T. 1955. The application of palynology to oil geology with reference to Western Venezuela. GeoL Mynbouw 17(3), 49-76. MQller, J. 1968. Palynology of the Pedawan and Plateau Sandstone (Cretaceous - Eocene) in Sarawak Malaysia. Micropaleontology, 14(1), 1-37. Nichols, D. J., Ames, H. T. and Traverse, A. 1973. ArecipitesWodehouse, Mono colpopollenites Thomson and Pflug and the species "Monocolpopollenites tranquillus'. Taxor~ 22(2/3), 241-256. Norris, G. 1978. Phylogeny and a revised supragenerlc classification for Triassic - Quaternary organic-walled dinoflagellate Cysts (Pyrrhophyta), Parts I and II. Neues Jahrb. ft~r Geol. andPalaonL 155(3), 300-17 and 156, 1-30.

150

M. B. SALAMI

Pacltova, B. 1959. On some plant microfossils from freshwater Sediments of the Upper Cretaceous (Senonlan) in the South Bohemian Basin. Sbom/k Ustred, Geol. 28, 38-50. Potoni6, R. 1956. Synopsis der Gattungen der Sporae dispersae. I Tefl: Sporites. BeltL Geol. Jc~hrb., 23, 103 p. Potoni6, R. 1956. Synopsis der Gattungen der Sporae dispersae II Tell: Sporites (Nachtrage). Saccites. Aletes, Praecolpates, Polypllcates, Monocolpates. Be/b. Geol. Jahrb., 31, 114 p. Potoni~, R. 1958. Synopsis der Gattungen tier Sporae dispersae. III Tell: Nachtrage Sporltes, Fotsetzung Pollenites, Mit, General register zu Tell I - III. Be/b. GeoL Jahrb., 8 9 , 189 p. Potoni6, R. 1970 a. Synopsis der Gattungen der Sporae dispersae.VTefl: Nachtrage Zu allen Gruppen (Ttu~ae). BeltL Geol. Jahrb., 87, 172 p. Potoni6, ~ 1970 b. Synopsis der Gattungen der Sporae dispersae Vl Teil. Be/h. Geol. Jahrb., 94, 3-18. Potoni6, R. and Kremp, G. 1954. Die Gattungen der Sporae dlspersae und lhre stratigraphie. Geol. Jahrb.. 69, 194. Potonl6, R. and Kremp, G. 1955. Die Sporae Dispersae des R u h r k a r b o n s ihre m o r p h o g r a p h i e u n d Stratigraphie mit ausblicken auf arten anderer Gebiete und Zeitabschnitte. Palaeontographica, Abt. B., 98, 1-136. Potoni~, ]I. and Kremp, G. 1956. Die Sporae dlspersae des R u h r k a r b o n s ihre m o r p h o g r a p h i e u n d stratigraphie mit ausblicken aufarten anderer Gebiete und Zeitabschnitte. Palaeontographlca, Abt. B., 99, 85-191. Reyment, R. A. 1965. Aspects of the Geology of Nigeria. Univ. Ibadan Press, Nigeria, 145 p. Salami, M. B. 1983. Some Late Cretaceous and Early Tertiary pterldophytic spores from the Southern Nigeria Sedimentary Basin. Rev. EspanoladeMicropaL, 15(2), 257-272. Salami, M. B. 1984. Ephedrepites strobilaceous nov. comb. and polymorphlsm within Ephedroid pollen

grains of the Late Cretaceous and Early Tertiary of Southern Nigeria. Rev. EspanoladeMk'ropal., 18, 425430. Salard-Cheboldaeff, M. 1978. Sur la palynoflore Maestrichtlenne et Tertialre du bassin sL~llmentalre littoral du Cameroun. PolkmetSpc~s, 20(2), 215-260. SarJeant, W. A_ S. 1970. The genus Spinlferltes Mantell, 1850 (Dinophyceae). Grano~ 10, 74-78. Simpson, A. 1954. The Nigerian Coalfield, the geologyof parts of Onltsha, Owerri and Benue provinces. Bull GeoL Surv. of Nkjeria No. 24. Stafleu, F. A. 1978. International Code of Botanical Nomenclature Bohn, Skeltema and Holkema, Utrecht. 457 p. Stover, L. E. and Evitt, W. R. 1978. Analyses of Pre-Pleistocene Organic-walled dinoflagellates. School of Earth Sciences, Stanford Univ., Stanford. California, 300 p. Van Der Hammen, T. 1954. El desarrollo de la flora Colombiana en los periodos geologicos. I. Maestrichtlano hasta terciario mas inferior (Una investigacionpallng~glca de la formaclonde Guaduas y equlvalentes Bo/et/n Geo/og/co, 2(1), 49-106. Van Der Hammen, T. 1956. A Palynological systematic nomenclature. Bo/et/n Geo/og/co, 4(2-3), 63-101. Van Der Hammen. T. 1957. Climatic periodicity and evolution of South American Maestrichtlan and Tertiary floras (a study based on pollen analysis in Colombia). Bo/et/n Geologico, 5(2}, 49-51. Van Hoeken-Kltnkenberg, P. M.J. 1964. Apalynological investigation of some Upper Cretaceous sediments in Nigeria. PoUenetSpores, 8(1), 209-231. Van Hoeken-Kllnkenberg, P. M.J. 1966. Maastrichtian, Paleocene and Eocene pollen and spores from Nigeria. Le/dse Geol. Meded., 38, 37-48. Whiteman, A. J. 1982. Nigeria : Its Petroleum Geology, Resources and Potential, Graham and Trotman. London I/If, 394 p., 306 Figs. Williams, G. L., Sarjeant, W. A. S. and Kidson. E. J. 1973. A glossary of flagellate amphiesmae and cysts and acritarchs. Amer. Assoc. Stratlgr. PalynoL Contrib. Ser., 2, 222 p. 149 Figs.