Journal of Sciences Lithofacies, Palynology and

International Journal of Science and Technology Volume 2 No. 6, June, 2013

IJST © 2013 – IJST Publications UK. All rights reserved. 453

Lithofacies, Palynology and Paleoenvironmental Study of Early

Campanian to Mid-Maastrichtian Deposits of Udi and Environs in the

Anambra Basin, South Eastern Nigeria

Chiaghanam, O.I.*1, Nwozor, K.K. 1, Chiadikobi, K.C. 1, Omoboriowo, A.O. 2, Soronnadi-Ononiwu, C.G. 3,

Onuba, L.N. 1 and Ofoma, A.E. 4 1Anambra State University, Uli, Anambra State, Nigeria.

2University of Port Harcourt, Port Harcourt, Rivers State, Nigeria. 3Niger Delta University, Wiberforce Island, Bayelsa State, Nigeria. 4Haliburton Energy Services, Port Harcourt, Rivers State, Nigeria.

ABSTRACT

Palynological assemblages, lithofacies and facies association were used in the determination of the age and paleoenvironment

of the Enugu and Mamu Formations of Udi area of the Anambra Basin, South east Nigeria. Palynological analysis carried out

in over twenty samples (20) yielded spores/pollens and marine Dinoflagelates that are of Early Campanian to Maastrichtian

for Enugu shale and middle Maastrichtian for Mamu Formation. The main diagnostic species of spores and pollen recovered

includes; Laevigatosporites ovatus, Leiotriletes adriennis, Echitriporites trianguliformis, Longapertites marginatus and

Cyathidites minor. Among the main diagnostic dinoflagellates are Operculodinium centrocarpum, Areoligera senoniensis,

Spiniferites ramosus, Ceratiopsis spp., Paleocystodinium spp., Dinogymniun accuminatum, Spinferites ramosus and

Cordosphaeridium inorders. The coarsening upward sequence of the lithofacies in Mamu Formation is an indication of

decrease in sea level, and the intercalation of Siltstone/Sandstone and Shale in the lithofacies of Enugu Shale with its high

abundance and diversity of Palynomorphs suggest a shallow-marine environment with Tidal influence.

Keywords: Palynomorphs, Dinoflagellate, Lithofacies, Paleoenvironment,Formation

1. INTRODUCTION

Many researchers have studied the lithofacies, palynology

age and paleoenvironments of the Campanian-

Maastrichtian sedimentary fill of Anambra Basin, these

researchers includes Nwajide and Reijers, 1996; Obaje et

al, 1999; Umeji 2006; Ogala et al, 2009; Onyekuru and

Iwagwu 2012; Olusola et al, 2009; Anakwuba and

Onyekwelu, 2012; Onuigbo et al 2012: Soronnadi-

Ononiwu et al, 2012; Onuigbo et al 2012 and Ogala et al

(2009) used palynological data in the study of the Middle

- Upper Maastrichtian Mamu coal facies. Onuigbo et al

(2012) studied the palynology, paleoenvironment and

sequence stratigraphy of the Campanian-Maastrichtian

deposits in the Anambra Basin. Soronnadi- Ononiwu et al

(2012) worked on the palynological and paleovironmental

studies of the Mamu Formation. Onuigbo et al (2012)

applied lithofacies, palynogy and facies association in the

interpretation of paleogeography of the Enugu and Mamu

Formations. Spores and pollens were used in the

determination of age and paleonvironment of the study

area. Dinoflagellate cysts were also applied in the

interpretation of the depositional environmental. (Huan

and Habib, 1996). Palynomorphs recovered from

outcropping sections of Enugu Shale, and Mamu

Formation of the study area were applied in the

determination of paleoenvironment of Early Campanian

to Mid Maastrichtian deposits of Anambra Basin. Fig 1 is

the geologic map of southeastern Nigeria indicating the

study area.

2. GEOLOGICAL SETTING

The studied area lies in the Anambra basin. The Basin is a

NE-SW trending syncline that is part of the Central

African Rift System which developed in response to the

stretching and subsidence of major crustal blocks during a

lower Cretaceous break-up phase of the Gondwana super-

continent (Ogala, et al, 2009). The movement were

reactivated by further plate activity in lower Tertiary soon

after the intermittent Upper Cretaceous rifting (Ogala, et

al, 2009). The separation of the African and South

American plates left the Benue Trough as an Aulacogen, a

failed

Arm of an RRR Triple Junction (Burke, 1972; Olade,

1975; Onyekuru and Iwuagwu 2010; Chiaghanam et al

2012). The Basin is an extensive west and Central African

rift system in which it opened as an extensive sinistral

wrench complex (Emery et al., 1975; Whiteman, 1982;

Genik, 1993). Based on the work done by Murat (1972),

Southern part of the Benue Trough was interpreted to

have longitudinal fault with its eastern half subsiding

preferentially to become the Abakaliki depression.

International Journal of Science and Technology (IJST) – Volume 2 No. 6, June, 2013


The Proto- Anambra Basin was a platform that eventually

became thin sediment- draped at the time the Abakaliki-

Benue sector of the Benue Trough was being filled which

occurred during Albian- Santonian ( Nwajide and Reijers,

1996). There was differential in the rate of subsidence in

the Southern Benue Trough e.g, high in Pre-Albian time,

low in lower Cenomanian and very high in Turonian; the

latter was an important phase of platform subsidence

(Ojoh, 1990). The period of subsidence in Southern

Benue Trough corresponds to the time of the initiation of

the

Anambra Basin, which started during the Coniacian and

reached its peak at the Santonian thermotectonic event

(Nwajide, 2005).

Several authors (Murat, 1972; Nwachukwu, 1972; Weber

and Doukoro, 1975; benkhelil, 1982; Nwajide and

Reijers, 1996; Obi, 2000; Mode and Onuoha, 2001)

demonstrated that the Santonian tectonic pulses dating

back to 84ma, was associated with intensive magmatism.

Folding and faulting which resulted in Abakaliki area

becoming flexurally inverted to form the Abakaliki

Anticlinorium. The Santonian tectonic pulses caused the

displacement of the depocentres to the west and

Southeastwards thereby resulting in the formation of

Anambra Basin and Afikpo Syncline (Murat, 1972;

Burke, 1972). The anticlinorium later became a sediment

dispersal centre from which mineralogically mature

detritus was shed into Anambra Basin and Afikpo

Syncline (Akaegbobi and Schmitt, 1998; Akaegbobi and

Boboye, 1999). Other sources of texturally matured

sediments which finds its way into Anambra Basin

include Southwestern Nigerian Craton, crystalline

basement areas of the Oban Massif and Cameroon

basement granites which had undergone prolonged

chemical weathering ( Hoque and Ezepue, 1977; Amajor,

1987;

Nwajide and Reijers, 1996; Akaegbobi and Schmitt, 1998;

Akaegbobi and Boboye, 1999, Obi, 2000).fig

2(Murat1972)

Fig. 1: Geologic map of south-eastern Nigeria showing the study area



Fig 2: Tectonic map of South – Eastern Nigeria showing Anambra Basin during the Santonian event

(Adapted from Murat, 1972)

Table 1: Stratigraphic Sequence in Anambra Basin (after Nwajide, 2005)

Age Basin Stratigraphic units

Thanctian Niger

Delta

Imo Formation

Danian

Anambra

Basin

Coal

Measures

Nsukka Formation

Maastricthtian

Ajali Formation

Campanian

Mamu Formation

Nkporo

FM

Nkporo

Shale

Enugu

FM

Owelli

Ss

Afikpo

Ss

Otobi

Ss

Lafia

Ss

Santonian Southern

Benue

Trough

Awgu Formation

3. STRATIGRAPHY OF THE STUDY

AREA

3.1 Enugu Shale

The Enugu shale consist of shales and occasionally

sandstones. The shales are grey blue or dark in colour and

contain occasional white sandstones and striped sandy

shale beds. Bands of impure coal occur and nodules and

lenticles of clay ironstones occur at the top of the

Formation (Whiteman, 1982). The Formation is restricted

to the central and northern parts of the Anambra Basin,

with a thickness of about 300ft (Simpson, 1954). The

Enugu shale was assigned Campanian to Lower

Maastrichtian, based on the diagenetic species of

palynomorphs such as Cingulatisporites onatos and

Tricolpites tienebaensis (Reyment 1965; Whiteman 1982

and Soronnadi- Ononiwu et al (2012).

3.2 Mamu Formation (Lower Coal Measures)

Mamu Formation overlies the Enugu shale conformably

and it consists of sandstone, shale, and sandy shale with



coal seams. The sandstones are fine to medium grained

and yellow in colour. The shales and mudstones are dark

blue or grey and frequently alternate with the sandstone to

form a characteristically striped rock. Coal seams vary in

thickness from a few inches to 12ft (Reyment 1965,

Simpson 1956 and Whiteman 1982). The age of the

Formation is Lower-Middle Maastrichtian (Simpson

1954, Reyment 1965). The conditions of deposition and

paleogeography show that the sediments of the Mamu

Formation are shallow water deposits. The Formation was

laid down as part of the paralic facies of a large delta

complex of which the Ajali Sandstone and Nsukka

Formation form part (Whiteman, 1982).

4. METHODOLOGY

Field visit of the studied area was undertaken, during

which outcrop sections of Enugu Shale, and Mamu

Formation within the Udi area were studied and logged

from the base to the top. Rock samples were collected

(basically grey to dark grey Shales) from various

stratigraphic levels and were subjected to palynological

analysis.

Sample preparation was done using the conventional

maceration technique for recovering acid insoluble

organic- walled microfossil from sediments. Each sample

was digested for 30 minutes in 40% hydrochloric acid to

remove traces of carbonate and 72 hours in 40%

hydrofluoric acid for removal of silicate. The extracts

were sieve- wished through 10 microns nylon mesh. The

sieve- washed residues were oxidized for 30 minutes in

70% HNO3 and 5 minutes in Schulze solution to render

the fossils translucent for transmitted light microscopy;

rinsed in 2% KOH solution to neutralize the acid; swirled

to sediment resistant coarse mineral particles and organic

matter; and stained with Safranin- O to increase the

constract for study and photography.

For the coal sample, HCl and HF treatments were not

necessary and treatment started with 30 minutes oxidation

in Schulze solution and continued for the clastic

sediments. Aliquots were dispered with polyvinyl alcohol,

dried on cover- slip and mounted in petro-poxy resin.

Two slides were made from each sample, from which 200

grains were counted. The occurance of each species was

converted to percentage frequency in order to eliminate

differences in counting. Light photomicrographs were

taken with a Kyowa microscope.

5. RESULT AND INTERPRETATION

5.1 The Mamu Formation

5.1.1 Lithofacies and Palynogical Assemblages

Dark Black Fissile Laminated Shale (1)

The facies which was deposited at the basal part of the

outcrop consists of Dark Black fissile horizontally

laminated shales, alternated with a bed of dark brown

sand. Ophiomorpha and Skolithos were found on the

sandstone. Palynological analysis of the sample from this

facies unit (UD/SH/L4/03 table 2) yielded high

abundance of Non marine palynomorphs which includes

Laevigatosprorites ovatos, Leiotriletes adriennis,

Spinizonocolpites baculatus, Echitriporites

trianguliformis, Longapertites marginatus, Cythidites

minor while the marine palynomorphs found includes

Operculodium centrocarpum, Areoligera senoniensis,

Spiniferites ramosus, Legeunecysta hyaline,

Phaelodinium spp, Dinogymium accuminatum,

Senegalinuim spp, Paleocystodinium spp, Ceratiopsis spp.

The unit suggests a back shore (proximal lagoon or

estuary) environment.

Very Fine Sandstone/ Clayey Siltstone (2)

The facie consists of very fine sandstone which is highly

weathered and ferruginized at the top and are brownwish

and well sorted with clay and siltstone layer at the middle

portion of the unit. There are presences of ophiomorpha in

the section which suggest a nearshore, sand dominated

environment, and a setting that are characteristic of

lowstand (Anderson and Droser, 1998). Occurrence and

distributions of palynomorph species in this facie was

very poor.

Table 2: The absolute count of abundance and distributions

of palynomorph species from the analysed samples in Udi

Area

SAMPLE NO PALYNOMORPHS

ud/l4/03 shale

Laevigatosporites ovatus 11

Cyathidites minor 9

Leiotriletes adriennis 15

Schizosporis spp. 6

Foveotriletes margaritae 0

Cingulatisporites ornatus 7

Distaverrusporites simplex 5

Rugulatisporites carperatus 3

Cyathidites australis 0

Azolla cretacea 0

Glechiniidites senonicus 1

Leiotriletes maxoides 0

Ariadnaesporites nigeriensis 0

Spinizonocolpites baculatus 11

Striatopollis catatumbus 0

Retidiporites magdalenensis 3

Liliacidites nigeriensis 6

Echitriporites trianguliformis 11

Longapertites marginatus 53

Constructipollenites ineffectus 7

Psilamonocolpites spp. 6

Echimonocolpites spp. 1

Psilatricolporites operculatus 2



Mauritiidites crassibaculatus 5

Retibrevitricolpites triangulatus 0

Longapertites microfoveolatus 2

Longapertites vaneedenburgi 0

Monoporites annulatus 4

Inaperturopollenites hiatus 2

Monocolpites marginatus 0

Buttinea andreevi 3

Proteacidites miniporatus 0

Tricolpites hains 1

Echitricolporites maristellae 0

Retistephanocolpites williamsi 0

Proxapertites cursus 2

Ericipites equiexinus 0

Operculodinium centrocarpum 1

Areoligera senoniensis 4

Spiniferites ramosus 1

Legeunecysta hyalina 2

Phelodinium spp. 3

Dinogymnium accuminatum. 4

Senegaliniun spp. 2

Cyclonephelium deckonincki 0

Paleocystodinium spp. 3

Andalusiella manthei 0

Cordosphaeridium inordes 0

Ceratiopsis spp. 4

5.2 Enugu Shale

5.2.1 Lithofacies and Palynological

Assemblages

Weathered Clay Facie (3)

The facie consist of highly weathered clay that is dark in

colour which suggests that are the unit was deposited in a

reducing environment in a marine setting. The facie is at

the base of the outcrop.

Palynological analysis (table 3) of the clay sample from

this facie unit (AG/CL/L6/01) yielded abundant and

diverse types of palynomorphs. The non marine

palynomorphs recorded in this unit are Laevigatosporites

ovatus, Leiotriletes adriennis, Echitriporites

trianguliformis, Longapertites marginatus,

Echimonocolpites spp. while the marine palynomorphs

recorded are Operculodinium centrocarpum, Areoligera

senonienis, Spiniferites ramosus, Legeunecysta hyalina,

Phaelodinium spp., Dinogyminum accuminatum,

Senegalinion spp, paleocystodinium spp., Andalusieslla

manthel and Ceratiopsis spp. The facie constitutes the

blackshore (proximal lagoon or estuary) environment.

Well Sorted sandstone and Shale Facie (4)

This facies consist of alternation of well sorted greyish

black fine grained sandstone and Dark-grey fissile,

micaceous shale. The thickness of the sand tends to

decrease upward, the sand display wavy laminations, with

burrows of planoliths and skolithos.

Palynological analysis of samples from this unit

(AG/SH/L6/02, AG/SH/L6/03, AG/SH/L6/04 and

AG/SH/L6/05 in table 3) yielded high abundance of non

marine palynomorphs which includes Laevigatosporites

ovatus, Cyathidites minor, Leiotriletes adriennis,

Echitripodinium trianguliformis, Logaperites marginatus

and Paleocystosdium spp. while the marine palynomorphs

found are Operculodium centrocarpum, Areoligera

senoniensis, spiniferites ramosus, Legeunecysta hyalina,

Pahelodinium spp, Dinogymnium accuminatum,

Senegalinium spp., Cyclonephelium deckoninckl,

paleocystodinium spp, Andalusiella manthei,

cordosphaeridium inordes and Ceratiopsis spp... The

assemblage recovered suggests backshore (Proximal

lagoon or estuary/ coastal swamps).

The Heterolithic Facies (5)

This consists of sandy shale and shale with the sandy-

shale increasing upwards. The shales are greyish brown to

black micaceous fissile shale, while the sandy-shale are

brownish in colour.

Palynoloigical analysis(table 3) of the shale sample from

this facie unit (AG/SH/L6/06, AG/SH,L6/07, AG/SH/

L6/08) yielded high abundance of non-marine

polynomorphs such as Laevigatosporites ovatus,

Cyathidites minor, Leiotriletes adriennis, Echitripodinium

trianguliformis, Logaperites marginatus and

Paleocystosdium spp. while the marine palynomorphs

found are Areoligera senoniensis, spiniferites ramosus,

Legeunecysta hyalina, Pahelodinium spp, Dinogymnium

accuminatum, Senegalinium spp. Paleocystodinium spp,

Andalusiella manthei; Cordospharidium inordes and

Ceratiopsis spp. The unit constitutes the backshore

(proximal lagoon or estuary/ coastal swamp).



Table 3: The absolute count of abundance and distributions of palynomorph species from the analysed samples in Agbogugu (L6)

SAMPLE

NO

PALYNOMORPHS

ag/l6/01

shale

ag/l6/02

shale

ag/l6/03

shale

ag/l6/04

shale

ag/l6/05

shale

ag/l6/06

shale

ag/l6/07

shale

ag/l6/08

shale

Laevigatosporites ovatus 19 11 6 8 13 4 7 9 Cyathidites minor 8 16 5 2 8 3 8 2 Leiotriletes adriennis 22 7 10 7 11 5 5 9 Schizosporis spp. 1 0 2 0 0 3 0 0 Foveotriletes margaritae 2 0 0 1 0 0 0 0 Cingulatisporites ornatus 4 3 2 4 1 0 6 6 Distaverrusporites simplex 3 1 6 2 4 1 3 3 Rugulatisporites carperatus 2 0 0 1 0 0 0 1 Cyathidites australis 1 1 0 0 2 0 2 0 Azolla cretacea 1 0 0 0 0 0 0 0 Glechiniidites senonicus 0 2 0 3 2 0 3 4 Leiotriletes maxoides 0 0 0 0 1 0 0 0 Ariadnaesporites nigeriensis 0 0 0 0 2 0 0 0 Spinizonocolpites baculatus 2 3 4 0 6 3 4 4 Striatopollis catatumbus 2 0 1 0 0 0 0 0 Retidiporites magdalenensis 5 0 2 1 0 1 3 2 Liliacidites nigeriensis 2 0 4 3 1 0 2 2 Echitriporites trianguliformis

47 7 5 9 3 13 7 4

Longapertites marginatus 38 16 27 33 21 24 18 27 Constructipollenites ineffectus

6 2 3 0 4 2 4 2

Psilamonocolpites spp. 2 0 4 2 0 4 2 0 Echimonocolpites spp. 10 0 0 1 0 0 0 0 Psilatricolporites operculatus

3 0 1 2 0 0 1 3

Mauritiidites crassibaculatus

4 1 0 1 0 0 2 0

Retibrevitricolpites triangulatus

3 1 0 0 0 0 0 0

Longapertites microfoveolatus

4 0 1 0 1 2 1 0

Longapertites vaneedenburgi

2 0 0 0 0 1 0 1

Monoporites annulatus 3 0 1 0 3 0 4 1 Inaperturopollenites hiatus 1 2 0 0 1 0 1 0 Monocolpites marginatus 3 2 0 2 4 1 1 2 Buttinea andreevi 2 0 0 1 1 2 0 1 Proteacidites miniporatus 2 0 0 0 3 0 2 0 Tricolpites hains 1 2 0 1 0 0 0 0 Echitricolporites maristellae 0 0 0 0 0 1 0 0 Retistephanocolpites williamsi

0 2 0 0 0 2 1 1

Proxapertites cursus 0 0 1 3 0 1 2 1 Ericipites equiexinus 0 1 0 0 2 0 0 0 Operculodinium centrocarpum

2 0 0 1 0 1 0 0

Areoligera senoniensis 2 4 2 0 3 1 2 0 Spiniferites ramosus 1 1 1 2 2 2 4 0 Legeunecysta hyalina 2 0 2 2 0 0 0 1 Phelodinium spp. 1 1 0 0 4 5 3 3



5.3 Enugu Formation

Lithofacies and Palynological Assemblages

The Greyish to Dark Black Sale Facies (6)

The lithofacies consist of greyish to dark black sub-fissile

to fissile micaceous shale that are horizontally laminated

and were deposited at the basal part of the studied

outcrop. The shale in interbedded with thin beds of thin

siltstone. There is presence of Thalassinoides isp within

the shale. The cyclic sedimentation of these thick layers

of shales with interbedded thin siltstone suggests a marine

environment that was influenced by tide. Weathering on

this unit produced a yellowish earthly coloration

suggestive of mineral pyrite which depicts anoxic

conditions in a marine Environment (Onuigbo E.N et al

2012).

Palynological analysis of samples from this unit

OZ/SH/L5/01, OZ/SH/L5/02, OZ/SH/L5/03,

OZ/SH/L5/04, AND OZ/SH/L5/05) in table 4 yielded

high abundance of Non marine palynomorphs (pollen and

spores) and relatively low marine palynomorphs

(Dinoflagellates). The Non marine palynomorphs present

in this unit are Laevigatosporites ovatos, Leiotriletes

adriennis, Cingulatisporites ornatos, Echitriporites

trianguliformis, Longaperites marginatos,

Constructipollenites inefectos, while the marine

palynomorphs (Dinoflagellated cysts) present which

suggest shallow to open marine deposition environment

are Phelodinium spp., Dinogymnium acuminatum,

Senegalinium spp., Paleocystodinium spp. (muller, 1959;

Sergeant et al, 1987; Oloto, 1992; Cavvaliho, 2004;

Torricelli et al; 2005; John, 2010; Onuigbo et al, 2012).

Sand/shale facies (7)- The unit ovelies (6), it basal part

consists of grayish- brown sandy shale that are micaceous.

Above the sandy shale unit is Black fissile well laminated

shale. Lying above this unit is sandstone that displays

wave lamination with planoilites, skolithos, Terictictious

and nodular concretion at its base and middle portion.

Palynological analysis (table 4) of samples from this

facies (OZ/SH/L5/06) shows that the dominates Non

marine palynomorphs present are laevigatosporites

ovatos, cyathidites miro, Electritriporites triangvliforms,

longaportites spp., while the marine palynomorphs

(Dianoflagallate cycsts) phaelodinium spp., Dinogymnium

accomination, Senegalinium spp. And paleocystodinoium

spp which suggest shallow marine environment (Moller,

1959; Sargeant et al. 1987; Oloto, 1992; Carvalito, 2004;

Torricelli et al; 2005; Johan, 2010; Onuigbo et al 2012).

Table 4: The absolute count of abundance and distributions of palynomorph species from the analysed samples in Ozalla (L5)

SAMPLE NO

PALYNOMORPHS

Oz/l5/01

shale

Oz/l5/02

shale

Oz/l5/03

shale

Oz/l5/04

shale

Oz/l5/05

shale

Oz/l5/06

shale

Laevigatosporites ovatus 39 7 13 6 10 12 Cyathidites minor 0 11 7 7 8 10 Leiotriletes adriennis 4 16 13 8 5 8 Schizosporis spp. 4 0 1 2 0 0 Foveotriletes margaritae 0 1 0 0 1 0 Cingulatisporites ornatus 10 4 2 4 3 7 Distaverrusporites simplex 3 7 5 3 2 1 Rugulatisporites carperatus 6 0 1 2 0 0 Cyathidites australis 2 2 4 4 1 2 Azolla cretacea 1 0 0 0 0 0 Glechiniidites senonicus 4 3 0 0 3 1 Leiotriletes maxoides 2 0 0 0 0 0 Ariadnaesporites nigeriensis 2 1 0 0 0 1

Dinogymnium accuminatum.

3 0 2 3 0 1 4 0

Senegaliniun spp. 2 7 2 4 2 6 3 3 Cyclonephelium deckonincki 0 0 0 1 0 0 0 0 Paleocystodinium spp. 2 8 1 3 0 2 7 3 Andalusiella manthei 1 0 1 0 1 0 0 2 Cordosphaeridium inordes 0 2 0 0 0 2 0 0 Ceratiopsis spp. 1 3 4 5 2 1 4 3



Spinizonocolpites baculatus 0 2 0 1 0 1 Striatopollis catatumbus 0 0 1 0 0 0 Retidiporites magdalenensis 4 2 0 0 1 2 Liliacidites nigeriensis 0 4 3 1 6 3 Echitriporites trianguliformis 24 8 14 10 9 11 Longapertites marginatus 25 27 30 21 31 23

Constructipollenites ineffectus 13 5 2 4 3 2 Psilamonocolpites spp. 3 0 4 2 0 0

Echimonocolpites spp. 0 0 0 0 0 0

Psilatricolporites operculatus 4 1 3 1 3 0

Mauritiidites crassibaculatus 2 3 1 0 1 2

Retibrevitricolpites triangulatus 0 0 1 0 0 0 Longapertites microfoveolatus 0 0 2 0 1 0

Longapertites vaneedenburgi 1 0 1 0 0 1 Monoporites annulatus 2 1 2 0 3 1

Inaperturopollenites hiatus 4 0 0 0 1 0 Monocolpites marginatus 4 2 1 1 3 0

Buttinea andreevi 2 1 0 2 1 0

Proteacidites miniporatus 2 1 1 0 2 0 Tricolpites hains 0 2 0 3 0 1

Echitricolporites maristellae 1 0 0 0 0 1 Retistephanocolpites williamsi 1 0 0 1 0 0

Proxapertites cursus 4 0 1 0 2 0

Ericipites equiexinus 1 0 0 0 0 0

Operculodinium centrocarpum 0 0 0 0 2 0

Areoligera senoniensis 2 0 0 1 3 0

Spiniferites ramosus 2 0 0 2 0 0

Legeunecysta hyalina 0 1 0 2 1 0

Phelodinium spp. 1 1 3 3 1 2

Dinogymnium accuminatum. 6 2 1 4 2 1 Senegaliniun spp. 3 4 2 1 3 4

Cyclonephelium deckonincki 2 0 0 0 0 0 Paleocystodinium spp. 5 1 3 4 6 2

Andalusiella manthei 2 0 1 2 1 0 Cordosphaeridium inordes 2 0 0 0 1 0

Ceratiopsis spp. 2 0 3 1 2 0

5.4 Enugu Shale

The Lithofacies and Palynological Assembles

Black to Grey Shale and Medium Grained

Sandstone Facies (8)

This facies consist of greyish–brown to black sub fissile

to fissile laminated shale with occasional reddish–brown,

medium grained moderately sorted, wavy laminated

sandstone layers.

Palynological analysis (table 5) of sample from this facies

(AG/SH/07/01, AG/SH/07/02, AG/SH/07/03,

AG/SH/07/04) yielded relatively high abundance of non

marine palynomorphs such as Laevigatosporites ovatus,

Cyathidites minor, Echitripodinium trianguliformis,

Longaperitites marginatus while the marine

palynomorphs present are Operculodium centrocarpum,

Areoligera senoniensis, Spiniferites ramosus,

Legeunecysta hyalina, Phaelodinium spp, Dinogymnium

accuminatum, Senegalinium spp. Cyclonephelium

deckonincki, Paleocystodinium spp, Andalusiella

manthei; Cordospharidium inordes and Ceratiopsis spp.

Shale/Coal Facies (9)

The facie consists of reddish brown fissile shale that

consist layers of scattered coal unit. Palynological

analysis (table 5) of the coal sample records



(AG/CO/L7/05). Few Non-marine palynomorphs such as

Cyathidites minor, Leiotriletes adriennis, Glechiniidites

senonicus, Psilamonolopites spp. and Ericipites

equiexinus were recovered in the unit. The unit record no

marine palynomorphs.

Table 5: The absolute count of abundance and distributions of palynomorph species from the analysed samples in Agbogugu (L7)

SAMPLE NO

PALYNOMORPHS

ag/l7/01

shale

ag/l7/02

shale

ag/l7/03

shale

ag/l7/04

shale

ag/l7/05

coal

Laevigatosporites ovatus 15 18 27 12 0

Cyathidites minor 5 0 9 13 49

Leiotriletes adriennis 4 2 0 7 25

Schizosporis spp. 1 0 3 0 0

Foveotriletes margaritae 0 0 0 1 0

Cingulatisporites ornatus 1 4 0 3 0

Distaverrusporites simplex 0 1 3 1 0

Rugulatisporites carperatus 0 0 4 1 0

Cyathidites australis 1 3 1 0 0

Azolla cretacea 0 0 0 0 0

Glechiniidites senonicus 2 1 0 3 7

Leiotriletes maxoides 0 0 1 0 0

Ariadnaesporites nigeriensis 1 0 0 0 0

Spinizonocolpites baculatus 2 1 3 0 0

Striatopollis catatumbus 1 0 1 0 0

Retidiporites magdalenensis 0 0 0 1 0

Liliacidites nigeriensis 3 4 0 3 0

Echitriporites trianguliformis 9 6 7 4 0

Longapertites marginatus 18 27 21 17 0

Constructipollenites ineffectus 3 3 4 3 0

Psilamonocolpites spp. 4 0 1 0 18

Echimonocolpites spp. 0 0 0 2 0

Psilatricolporites operculatus 0 0 1 0 0

Mauritiidites crassibaculatus 3 0 2 0 0

Retibrevitricolpites triangulatus 0 1 0 0 0

Longapertites microfoveolatus 0 0 0 1 0

Longapertites vaneedenburgi 0 0 0 0 0

Monoporites annulatus 3 3 0 0 0

Inaperturopollenites hiatus 0 0 1 2 0

Monocolpites marginatus 2 1 0 0 0

Buttinea andreevi 3 0 1 2 0

Proteacidites miniporatus 2 1 0 0 0

Tricolpites hains 2 4 2 0 0

Echitricolporites maristellae 0 0 0 0 0

Retistephanocolpites williamsi 0 0 0 1 0

Proxapertites cursus 0 0 0 1 0

Ericipites equiexinus 0 1 0 0 8

Operculodinium centrocarpum 1 0 0 2 0

Areoligera senoniensis 2 3 0 1 0

Spiniferites ramosus 0 2 2 3 0

Legeunecysta hyaline 0 0 1 1 0

Phaelodinium spp. 0 1 3 0 0

Dinogymnium accuminatum. 1 2 1 2 0

Senegaliniun spp. 4 5 2 3 0

Cyclonephelium deckonincki 1 0 0 2 0



Paleocystodinium spp. 4 2 1 3 0

Andalusiella manthei 1 1 1 2 0

Cordosphaeridium inordes 0 1 2 0 0

Ceratiopsis spp. 2 2 1 3 0

6. AGE DETERMINATION

The underlisted stratigraphically important Palynomorphs

were recovered from the outcrops studied. The proposed

biostratigraphic age range chart of the selected key

palynomorph species are shown in table (6),the

palynomorph assemblage from the study area which were

recovered from the studied outcrops are shown in fig(3)

1. Proteacidites miniporatus (Upper Campanian- mid

Maastrichtian)

2. Triolites hains (Upper Campanian-Early

Maastrichtian)

3. Laevigatosporites ovatus (Maastrichtian)

4. Buttinea andreevi (Upper Campanian-

Maastrichtian)Atta-peters and Salami (2004)

5. Proxapertites cursus (Maastrichtian)

6. Spinizonocolpites baculatus (Maastrichtian)

Adebayo and Ojo (2004)

7. Psilatricolporites operculatus (Maastrichtian)

8. Ariadnaesporites nigeriensis (Upper Campanian-

Early Maastrichtian)

9. Monocospites marginatus (Early Maastrichtian)Edet

and Nyong (2003)

10. Psilamonocolpites spp (Early- Mid Maastrichtian)

11. Constructidipollenites spp (Maastrichtian)

12. Retidiporites magdalenesis (Mid Maastrichtian)

Germeraad et al 1968

The important Dinoflagellate recovered from the outcrops

studied includes:

a. Senegalinium bicavatum (Upper Campanian) Umeji,

(2006)

b. Phelodinium spp. (Upper Campanian) Umeji, (2006)

c. Areoligera spp. (Upper Campanian – Early

Maastrichtian)

d. Spiniterites ramosus (Upper Campanian –Mid

Maastrichtian)

e. Cyclonephelium spp. (Early Maastrichtian)

Enugu Formation

The age of Enugu Formation was determined based on the

palynomorphs listed below which proposed an Early

Campanian to Early Maastrichtian age. The palynomorphs

and dinoflagellates recovered from the studied are area

which are of Early Campanian to Early Maastrichtian

include; Buttinea andreevi; Proteacidites miniporatus,

Laevigatosporites ovatus, Psilamonocolpites spp.,

Senegalinium spp, Phelodinium spp, and Spiniferites

ramosus.

Mamu Formation

The age of Mamu Formation was determined based on the

polynomophs listed below which proposed Maastrichtian

age. The palynomophs recovered include

Spinizonocolpites baculatus, Monocolpites marginatus,

Proxaperites cursus, Ariadnaesporites nigeriensis,

Laevigatosporites ovatus, Longapertites marginatus,

Retidiporites magdalenesis, Monocolpites marginatus,

Cingulatisporites ornatus, Constructipollenites ineffectus.

Paleoenvironment

The lithofacies and palynological Assemblages

information recovered from the studied suggested Early

Campanian to mid Maastrichtian in the Anambra Basin of

South eastern Nigeria, which represents a transgressive to

regressive setting (Reyment 1965 and Reijers and

Nwajide 1996).

The proposed stratigraphic model (Campanian-

Maastrichtian) in Fig (4) shows a depositional

environment dominated by a transgressive phase with

occasional regressive phase at the base (Enugu Shale) and

a more regressive phase at the top (Mamu Formation)

representing coarsening upward sequence for the section

which also suggests a likely progradational deltaic

environment. The minor regressive phase at the Enugu

Shale is likely to be associated with the alternatively

storm and tide dominated during their deposition. The

Enugu Shale represents the brackish marsh and

fossiliferous deltaic facies of the Campanian early



Maastrichtian depositional cycle (Reijers and Nwajide

1996).

The studied area is a typical deltaic sedimentation in the

Anambra Basin, with the environment showing a build-

out of sediments landward. The general succession is

likely to be a shallow marine deltaic (backshore proximal

lagoon or estuary/ Distal lagoon or estuary) environment

as shown in table (7).

Table 6: Biostratigraphic age range chart of the selected key palynomorph species from the analysed samples in the study area

The high abundance of dinoflagellates species at the base

of the succession represents a transgressive dominated

event shallow to often marine environment) while the

relatively high abundance of spores and pollen is an

indicative of tidal influenced, shallow marine to coastal

swamp environment, which is an indicative of a

regressive event. The presence of coal in the succession

(Mamu Formation) is an indication of Paludal (swamp)

environment in fresh or brackish water (paleosalinity) and

also suggests a decrease in the Dinoflagellate. The relative

presence of Dinoflagellates in the Mamu Formation is an

indication of muddy shoreface separating it from mud

domination shelves (Reijers and Nwajide 1996) or

shallow incursion in the early part of the formation.





Figure 3: proposed Stratigraphic Model of Mamu Formation and Enugu Shale

Table 7: Summary of the palynomorphs distribution, age and palaeoenvironmental inference for the analysed samples



Figure 4: Photomicrographs of some key pollen and spores from Ozalla samples, Enugu shale (x40)

1. Leiotriletes maxoides Tarkahashi & Jux, 1989

2. Echimonocolpites major

3. Araidnaesporites nigeriensis ODEBODE & SKARBY, 1980

4. Cingulatisporites ornatus VAN HOEKEN-KLINLENBERG, 1964

5. Monoporites annulatus VAN DER HAMMEN, 1954

6. Retidiporites magdalenensis VAN DER HAMMEN AND GARCIA, 1965

7. Laevigatosporites ovatus Wilson and Webster, 1946

8. Echitriporites trianguliformis VAN HOEKEN-KLINKENBERG,1964

9. Proteacidites miniporatus GERMERAAD, HOPPING AND MULLER, 1968

10. Cyathidites australis COUPER, 1953

11. Retistephanocolpites williamsi GERMERAAD, HOPPING AND MULLER, 1968

12. Longapertites vaneedenburgi GERMERAAD, HOPPING AND MULLER, 1968

13. Echitricolporites maristellae

14. Longapertites marginatus VAN HOEKEN-KLINKENBERG, 1964



1,2&3. Palaeocystodinium spp. Alberti, 1961

4&7.Dinogymnium accuminatum Clarke and Verdier, 1967

5. Cyclonephelium deckonincki Boltenhagen,1977

6. Cordosphaeridium sp. (Klumpp, 1993) Eisenack,1963

7. Legeunecysta haylina (Gerlach, 1961) Artzner and Dorhofer,1978

8. Operculodinium centrocarpum (Deflandre and Cookson, 1955) Wall, 1967

9. Areoligera senoniensis Legeune-Carpentier, 1938

10. Andalusiella sp.Riegel, 1974



Figure 6: Photomicrographs of some key pollen and spores from Agbogugu & Udi samples, Enugu shale and Mamu

Formation(x40)

1. Spinizonocolpites baculatus MULLER, 1968

2. Mauritiidites crassibaculatus

3. Striatopollis catatumbus Takahashi and Jux, 1989

4. Proteacidites dehaani GERMERAAD, HOPPING & MULLER, 1968

5. Monocolpites marginatus VAN DER HAMMEN, 1954

6. Retibrevitricolpites triangulates VAN HOEKEN-KLINKENBERG, 1964

7. Constructipollenites ineffectus VAN HOEKEN-KLINLENBERG, 1964

8. Echitriporites trianguliformis VAN HOEKEN-KLINKENBERG,1964

9. Monoporites annulatus van der Hammen, 1954

10. Tricolpites sp. S.C.I. 257 Jardine and Magloire,1965

11. Distaverrusporites simplex MULLER, 1968

12. Rugulatisporites carperatus

13. Foveotriletes margaritae (van der Hammen, 1954) GERMERAAD, HOPPING & MULLER, 1968

14. Cyathidites australis COUPER, 1953

15. Leiotriletes adriennis POTONIE & GELLETICH, 1933

16. Cingulatisporites ornatus VAN HOEKEN-KLINLENBERG, 1964

17. Longapertites microfoveolatus ADEGOKE AND JAN DU CHENE,1976



7. CONCLUSION

The Palynological analysis and lithofacies association

which was used to determined the age and

paleoenvironment of the studied are indicates a deltaic

sedimentation in an Anambra basin of a Campanian

maastrichtian sedimentary unit that are characterized with

transgressive and regressive events as reflected the

Abundance and diversity of Palyonomorph and

dinoflagellates that was recorded.

The palynomorphs and dinoflagellates distribution in the

unit shows that Enugu Shales was deposited in a deeper

marine environment than the Mamu Formation is an

indicative of a drop in sea level, possible saline water and

fluvial processes (fresh-water) in a fresh water

swamp/upper deltaic plain.

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