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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
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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
International Journal of Science and Technology (IJST) – Volume 2 No. 6, June, 2013
IJST © 2013 – IJST Publications UK. All rights reserved. 455
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
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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
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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).
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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
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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
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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
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(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
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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
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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.
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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
International Journal of Science and Technology (IJST) – Volume 2 No. 6, June, 2013
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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
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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
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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
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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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