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International Journal of Engineering & Technology IJET-IJENS Vol: 12 No: 03 112

129803-3737 IJET-IJENS @ June 2012 IJENS I J E N S

AGE AND PALEOECOLOGY OF THE NEW NETIM FORMATION CALABAR FLANK, SOUTH EASTERN

NIGERIA

BY

EDOHO D. BASSEY & NSE U. ESSIEN*

DEPARTMENT OF GEOLOGY, UNIVERSITY OF CALABAR, NIGERIA.

ABSTRACT

Diverse benthic and planktic Foraminiferal assemblages of Cretaceous age occur within the shales that

intercalates the New Netim Marl in the Calabar Flank, South Eastern Nigeria. This formation forms marl ridges

across the Calabar Flank from Ikot Nyong (Northeast) to Mbebu village (southwest) . Fifteen fresh samples

were collected from the highly fissile shales that intercalate the marl units (fig 1). They were subjected to

foraminiferal (micropaleontological) and palynological analysis to determine the age and study the

paleoecology of the New Netim Formation. Foraminiferal analysis reveals the occurrence of the following

index benthic forms: Ammobaculites jessensis, Ammobaculites benuensis and Haplophragmodies

bauchensis. Also, the planktic foraminiferal species identified include: Whiteinella inornata, Whiteinella baltica

and Heterohelix reussi. These foraminiferal assemblages point to a Turonian – Coniacian age for the New

Netim Formation. Palynomorphs recovered from the palynological analysis are generally long-ranging

microspores. However, the occurrence of Mid – Upper Cretaceous Trifossapollenites sp. and

Cicatricosisporites sp. indicates a Turonian – Coniacian age for the marl unit under investigation. The above

foraminiferal and palynological assemblages suggest a Turonian- Coniacian age for the New Netim Formation

and a shallow inner- neritic paleo- bathymetric environment for the carbonate build-up..

Keywords: Age, Foraminifera, Palynomorphs, Paleoecology, New Netim Formation.

INTRODUCTION

The New Netim Formation consisting dominantly of marlstones intercalated with highly fissile shale units

(Fig.1) is a new stratigraphic entity erected by Petters et al, 1995. This carbonate build - up was deposited in

the Calabar Flank, Southeastern Nigeria. This work, which focuses on the determination of the age and

paleoecology of the New Netim Formation involved extensive field mapping exercise along its depositional

strike, a distance of 163 km. During the course of the field work, this formation was sampled at various

locations where it outcrops, notably at lkot Nyong, Mfamosing and Mbebu (Fig.2). Altogether, four stratigraphic

sections were studied out, samples collected from the interbeded thin fossilliferous shale beds, ranging from

0.001m to 0.08m in thickness were subjected to foraminiferal and Palynological analysis. This result of this

study is intended to be used to collaborate the result of previous studies (Nyong, 1995, Perch-Nielson and

Petters, 1981).

FIG 1: Nodular-marl and shale intercalation in the New Netim Marl

*Corresponding Author: [email protected]



FIG. 2: Geological map of the Calabar Flank showing sample locations. Inset (2b): Structural elements and

conceptual subsurface distribution of Cretaceous sediments in the Calabar Flank (Modified from the

Geological Map of Nigeria, NGSA, 2007)

GEOLOGIC SETTING OF THE CALABAR FLANK

The Calabar Flank as described by Murat (1972) is an epeirogenic sedimentary basin of Southeastern

Nigeria, which is bounded on the north and south by the Oban massif and Niger delta respectively. In the east,

the flank is bounded by the Cameroon volcanic line and by the Ikpe platform in the west (Fig.2b).

Sedimentation in the flank started during Early Cretaceous (probably Aptian) with the initial deposition of

fluvio- deltaic cross-bedded sandstone of the Awi Formation. This unit overlies the Precambrian Basement

complex of the Oban massif (Adeleye and Fayose, 1978). The Awi Formation is directly overlain by carbonate

platform of the Mfamosing Limestone of Mid – Albian age. During the Cenomanian and Early Turonian,

subsidence of the faulted blocks (horst and graben, Fig. 2b) allowed widespread deposition of shales with

minor marl intercalations which belongs to the Ekenkpon Formation. Deposition of marl increased in



importance in the Coniacian with continued alternate deposition of thin dark shale beds known as the New

Netim Formation (Nyong 1995). Santonian and Early Campanian sediments have not been reported in the

flank and represents with hiatus a period of non – deposition and / or erosion. Nkporo Shales (Late

Campanian- Maastrchtian) overlies the New Netim Formation. The Cretaceous sedimentary succession in the

Calabar Flank is capped by a predominantly continental sands and gravels of Late Tertiary to Recent age

known as the Benin Formation (Essien et al, 2005)

LITERATURE REVIEW

The New Netim Marl has not been widely studied as the earlier deposited carbonate unit, the Mfamosing

Limestone. Nyong (1995) studies on the Cretaceous sediments in the flank describe the marl sequence as

showing lateral facies change from thickly bedded units with dark flaggy shale intercalations rich in burrows

and ammonites to massive sections with almost mono specific assemblage of echinoid to thickly

bedded/massive sections with few burrows and no body fossils. He suggested that deposition of the marl units

probably occurred in a wide variety of near shore marginal marine setting. Akpan and Ntekim, (2004) studies

on Cretaceous bivalves and paleoenvironment of the Calabar Flank using marl as samples and suggested

that the marls were intensively bioturbated by invertebrates. Analysis by Nyong, (1995) using foraminifera and

Perch – Nielson and Petters, (1981) using cocolith suggested Early Coniacian age for the marl unit.

METHODOLOGY

Micropaleontology

Samples for foraminifera studies were collected from the thin shale units that intercalates the New Netim Marl

at different stratigraphic intervals. Altogether, fifteen (15) outcrop samples were collected and subjected to

foraminifera analysis. Each sample was prepared in the laboratory following the standard procedures for

microfossil sample preparation, particularly for foraminifera as outlined by Brasier, (1980). A binocular

microscope with the magnification of 30 to 100 times was used in studying the different forms.

Palynology

The fifteen (15) outcrop samples were also analyzed for palynomorphs. Samples preparation was by the usual

maceration techniques for acid insoluble microfossils using 40% Hydrofluoric acid (HF) (for silica and

silicates), 40% concentrated Nitric acid (HNO3) (for oxidation of humic matter) and 1% Potassium hydroxide

(KOH) (for acid neutralization and dissolution of humic matter). Concentration was by sieving using 200 and

400 mesh nylon screens and pipetting the organic residue from a watch glass. Slides of temporary strew

mounts using Apathy’s medium was made for each of the samples. Optical microscopes were use for studying

the palynomorphs.

RESULT AND DISCUSSION

Foraminiferal occurrence and age determination

A total of eighteen (18) species comprising nine (9) planktics and nine (9) benthics (Plates 1 and 2) were

recovered from the analysed samples. The Foraminiferal range charts for the planktonic and benthonic

foraminifera are as shown in Figs 3 and 4 respectively. The result shows the dominance of long and short

ranging taxa. Diversified Cretaceous benthic and planktic foraminiferal assemblages were identified in the

shale intercalations. At Ikot Nyong (location MS1 - Fig. 2) along Calabar - Itu highway ( km 34), samples

Sh A 1-4 show a wide occurrence of planktic foraminifera assemblage (Fig 5). Age interpretation was therefore



based on the diagnostic planktic assemblage identified and recorded in the samples. The predominant

assemblages include: Hedbegerella holmdelensis, Hedbegerella planispiral, Hedbegerella delrioensis,

Heterohelix moremami, Heterohelix ressui, Whiteinella inornata and Whiteinella baltica. Heterohelix ressui and

Whiteinella inornata points to the Turonian-Coniacian age (Boli et al, 1989). Samples belonging to outcrop

section Sh B1-4 (location MS4 – Fig. 2) at Mfamosing (Fig.6) belong to the Turonian-Coniacian age because

of the single occurrence of Heterohelix reussi. Arenaceous benthic foraminiferal assemblage occur in the

entire interval sampled in the marl outcrop in Sh C 1-4 at Mbebu (location MS5 - Fig. 2) -Fig.7. Benthic forms

with very minor occurrence of planktic foraminifera (hedbegerella delrioensis) were also recorded. The benthic

foraminifera noted here are Ammobaculites jessensis, Ammobaculites sp, Ammobaculites suberetaceus,

Ammobaculites coprolithiformis, Ammobaculites amabensis, Ammobaculites benuensis, Ammotium borunm,

Haplophragmodies sp. and Haplophragmodies bauchensis. Ammobaculites jessensis and Haplophragmoides

bauchensis points to the Turonian-Coniacian age (Petters, 1982). Outcrop samples belonging to section Sh D

1-3 (location MS3 - Fig. 2) at Mfamosing (Fig. 8) were very poor in foraminiferal recovery. However, very rare

occurrence of Ammobaculites jessensis which points to the Turonian - Coniacian age for the anlysed samples

were recorded (Petters, 1982).

NEW NETIM MARL FORMATION

AGE

PLANKTONICFORAMINIFERALZONE

Hedbergella plamispira

Whiteinella b tica

Whiteinella inornata

Heterohelix moremani

reussi

globulosa

Hedbergella holmdelensis

Hedbergella dolrioensis

al

Heterohelix

Heterohelix

ALBIAN CENOMANIAN TURONIAN CONIACIANSANTONIANEARLY

CAMPANIANLATE MAASTRICHTIAN

R. appenn

inicaR

. ticinen

sisR

. subticinensisB

. subticinensisT. p

rimulea

R. cushm

ani

R. reich

eliR

. brotzeni

M. sig

aliH

. helvetica

W. arch

aeocretaca

D. C

oncavataD

. primitive

D. asym

etrica

G. calvarata

G. ventricosa

G. elevata

A. m

ayeroen

sisG

. ganssery

G. aegyptiaca

G. h

avanensis

FIG. 3: Planktonic foraminiferal range chart



NEW NETIM MARL FORMATION

AGE

BENTHONICFORAMINIFERALZONE

Haplophragmoides bauchensis

Haplophragmoides sp

Ammobaculites amabensis

Ammobaculites benuensis

Ammobaculites coprolithiformis

Ammobaculites jessensis

Ammobaculites bauchensis

Ammobaculites subcretaceus

Ammotium bornum

ALBIAN CENOMANIAN TURONIAN CONIACIANSANTONIANEARLY

CAMPANIANLATE MAASTRICHTIAN

AN

OM

AL

INA

PL

UM

ME

RA

E-

TR

OC

HA

MIN

AW

ICK

EN

DE

NI

PL

AN

UL

INA

BE

AD

NE

LL

IA

MM

OA

ST

UT

AN

IGE

RIA

NA

NE

OB

UL

IMIN

AS

UB

RE

GU

LA

RIS

GA

BO

NIT

AL

AT

A

BO

LIVIN

A A

FRA

HA

PLOP

HR

AG

MO

IDE

STA

LOK

AE

NS

E

FIG. 4: Benthonic foraminiferal range chart



3.0

4.0

2.0

1.0

0

5.0

6.0

ShA

NE

W N

ET

IM M

AR

LFormation Sample No Depth

(m)

1

ShA2

Sh

Sh

A

A

3

4

Lithology

0 0 X X X 0 0 0 00 0 0

0 0 X X X 0 X X X 0

0 XX 0 X 0 XX 0 X 0 0

X 0 X 0 XX XX 0 X XX

Hed

bege

rella

hol

mde

lens

is

Hed

bege

rella

pla

nisp

ira

Hed

bege

rella

del

rioe

nsis

Hed

bege

rella

Sp

Het

eroh

elix

Reu

ssi

Het

eroh

elix

glo

bulo

sa

Het

eroh

elix

Sp

Het

eroh

elix

mor

eman

i

Whi

tein

ella

bat

tica

Whi

tein

ella

Sp

Whi

tein

ella

inor

nata

Am

mo

bacu

lites

bau

chen

sis

00Dark grey Laminated Shales

Weathered SedimentsMould and Cast of Organisms

Weathered Over Burden

Present

Absent

X

o

Nodular Marl with very thin shale bed

Keys

FIG, 5: Foraminiferal distribution in the interbedded shales within the New Netim Marl outcrop (Sh A 1-4 ) at Ikot

Nyong (location MS1)



2.0

1.0

0

3.0

4.0

5.0

6.0

7.0

ShB

NE

W N

ET

IM M

AR

L

FormationSample

NoDepth

(m)

1

ShB 2

Sh

Sh

B

B

3

4

Lith o logy

Dark grey Laminated ShalesMarl

Highly Weathered Shales

Keys

PresentAbsento

BE

NT

HO

NIC

PL

AN

KT

ON

IC

Am

mob

acul

ites A

mab

ensi

s

Am

mob

acul

ites

Bau

chen

sis

Het

eroh

elix

Reu

ssi

X 0 0

0 00

0 00

0 X XNodular Marl with very thin shale bed

FIG. 6: Foraminiferal distribution in the interbedded shales within the New Netim Marl outcrop ( Sh B1-4 ) at

Mfamosing (location MS4

X Present

0 Absent



4.0

3.0

2.0

1.0

0

NEW

NET

IM M

AR

L

S h C1

S h C2

S h C3

S h C4

D ark grey Lam inated S hales

M arl

Weathered S ed im ents

Weathered O ver B urden

K eys

P resentA bsent

X

o

X

X

X

X

0

0

X

X

0

0

X

X

X

X

0

X

X

X

X

X

0

0

X

X

X

X

X

0

0

0

X

0 0 0 0

0 0 0

X 0 X

0 X X

BEN

TH

ON

ICAm

mob

acul

ites C

opro

lithi

form

is

Amm

obac

ulite

s Ben

uens

isA

mm

obac

ulite

s Am

oben

sis

Amm

obac

ulite

s Sub

erct

aceu

s

Amm

obac

ulite

s Bau

chen

sisAm

mob

acul

ites S

pA

mm

obac

ulite

s Je

ssen

sisA

mm

otiu

m B

ornu

mH

aplo

phra

gmoi

des B

auch

ensis

Hap

loph

ragm

oide

s Sp

Hed

bege

rella

Del

rioe

nsis

PL

AN

KTO

NIC

Form ation S am p leN o

D ep th(m )

L itho lo g y


FIG. 7: Foraminiferal distribution in the interbedded shales within the New Netim Marl section

( Sh C 1-4 ) at Mbebu (location MS5)



2.0

0

1.0

3.0

4.0

ShD

NE

W N

ET

IM M

AR

L

Formation Sample NoDepth

(m) Lithology

1

ShD 2

ShD 3

0

X

0

0

X

0

BENTHONIC

Am

mob

acu

lites

Jess

ensi

s

Am

mob

acu

lite

sSP

.

X

0

Present

Absent

Dark grey Laminated Shales

Marl

Weathered Sediments

Weathered Over BurdenKeys


FIG. 8: Foraminiferal distribution in the interbedded shales within the New Netim Marl outcrop

(Sh D 1-3 ) at Mfamosing (location MS3)

Palynomorph occurrence and age determination

Results obtained from palynormophs in this study is not very impressive (Plate 3). Range chart for

Palynomorphs in the analyzed samples is as shown in Fig.9. Samples belonging to outcrop section ShA 1-4

yielded only few palynomorphs namely Ephedripites, sp., Ephedripites procerus, Cicatricosisporites sp.,

Steevesipollenites gigantus, and Trifossapollenites sp. All these forms range from Albian – Cenomanian, with

exception of Trifossapollenites sp. and Cicatricosisporites sp. which is of Upper - Mid Cretaceous age (Fig 9).

In samples ShB 1-4 at Mfamosing (Fig11), palynomorphs recorded for ShB 1 were only Steevesipollenites

giganteus and Steevesipollenites sp of Albian – Turonian age. Ephedripites procerus was found only in ShB2

while ShB3 and 4 were barren of pollen and spores. Samples ShC1-4 from Mbebu (Fig 12) recorded

abundant palynomorphs ranging from Albian –Turonian in age. The identified species were: Classopollis



jardinel, Cicatricosisporites sp., Ephedripites procerus, Steevesipollenites giganteus, Ephedripites sp. and

Gemmatriletes clavatus. Sample ShD 1 from Mfamosing (Fig. 13) had only two palynomorphs namely

Ephedripites procerus and Steevesipollenites giganteus ranging from Albian – Turonian. ShD2 and 3 from the

same location were barren, with only abundant foram lining.

Generally, most of the palynomorphs identified are of Early Cretaceous age: Classopollis jardinel and

Gemmatriletes clavatus. Ephedripites procerus, Ephedripites sp., and Steevesipollenites giganteus forms are

long-ranging species. Trifossapollenites sp. and Cicatricosisporites sp. occur in Upper to Mid Cretaceous and

point to a Turonian-Coniacian age for the New Netim Marl. According to Jan Du Chene et al (1978),

Trifossapollenites sp. has been found in Upper Cretaceous in Canada and Mid Cretaceous in Peru and

Cicatricosisporites sp. has also been found in Accra (Upper Cretaceous). From the above result, abundance

and diversity of Turonian-Coniacian palynomorphs remained low in the New Netim Marl. However, the

association of Trifossapollenites sp. and Cicatricosisporites sp. suggests a Turonian – Coniacian age for the

New Netim Marl (Jan Du Chene et al, 1978) .

Studies similar to that carried out in this investigation were conducted by Harold and Frerich (1997) in Mexcala

Formation which is part of the southern arm of the Laramide fold-thrust belt of Mexico. It forms a comparative

evaluation for this study. In their evaluation, a total of 15 planktic foraminiferal species from 35 productive

shale samples demonstrate that the Mexcala is assignable to the Coniacian to Santonian Age Dicarhella

concavata biozone. Thus, local Laramide onset occurred during Coniacian time (88 Ma).

E

phed

rip

ites

Pro

ceru

s

Cla

sso

polli

s J

ardi

nel

Ste

eves

ipol

leni

tes

gig

ante

ns

Trifo

ssap

olle

nite

s

Eph

edri

pite

s S

p

Ste

eves

ipol

leni

tes

Sp

Gam

mat

rile

tes

Cla

vatu

s

Cic

atri

cosi

spor

ites

Sp

AG

E

SU

PE

RZ

ON

E

ZO

NE

13 Proteacidites dehanni

12 Crassitricolpontes subprotatus

11 Aurianliidites reticeilaris

10 Droseridites Senonians

9 Interval zone

8 Triorites africaensis

7 Elaterosporites - Afropollis

ER

A

PE

RIO

D

EP

OC

H

ME

SO

ZO

IC

CR

ETA

CE

OU

S

LAT

EE

AR

LY

6 Elateropollenites jardinei

5 Tricolpites - E. Tumulus

4 J. Crisopolensis - Afropollis3 A. Spinulosis - E. Tumulus2 Densoisporites perinatus1 Alisporites - D. Etrusaus

Maastrichtian

Aptian

BarremianBarre. / Neoc

Maast / Camp

Sant. / Coniac

Turonian

LATECENOMANIANMIDDLECENOMANIANCENOM. / ALBIAN

MIDDLE ALBIAN

EARLY ALBIAN

VI

V

IV

III

II

I

FIG. 9: Range Chart for Palynomorphs



3.0

4.0

2.0

1.0

0

5.0

6.0

ShA

NE

WN

ETI

MM

AR

L

1

ShA2

Sh

Sh

A

A

3

4

Lithology Pal

yno

mo

rph

s

Cic

atr

ico

sis

po

rite

ss

p.

Ep

hed

rip

ite

sp

roc

eru

s

Ep

hed

rip

ite

ss

p

Ste

eve

sip

oll

enit

esg

igan

teu

s

Tri

fos

sap

olle

nit

essp

0 0 0 0 0

X 0 0 0 0

X X 00 0

X X X00

Formation Sample No. Dep

th (

m)

Weathered overburdenDark grey laminated shalesNodular marl with very thin shale bedWeathered sedimentsMould and cast of organismsPresentAbsent

Keys

FIG. 10: Palynomorph distribution in interbedded shales of New Netim Marl outcrop Section ( Sh A1-4 ) at Ikot

Nyong (Location MS1)

X Present

0 Absent



2.0

1.0

0

3.0

4.0

5.0

6.0

7.0

Pa

lyn

om

orp

hs

Ep

hed

rip

ites

pro

ceru

s

Ste

eve

sip

olle

nit

es

sp

Ste

eve

sip

olle

nit

es

gig

nat

eu

s

X0 X

0X

X0 X

0 0 0

0

ShB

NEW

NET

IMM

ARL

1

ShB2

Sh

Sh

B

B

3

4

LithologyFormation Sam

ple

No.

Dep

th (

m)

Weathered over burdenDark grey laminated shalesNodular marl with very thin shale bedWeathered sedimentsPresentAbsent

Keys

FIG. 11: Palynomorphs distribution in the interbedded shales within the New Netim Marl outcrop ( Sh B1-4 ) at

Mfamosing (location MS4)

X Present

0 Absent



4.0

3.0

2.0

1.0

0

PALY

NOM

OR

PHS

Ephe

drip

ites

pro

ceru

s

X 0X

Ephe

drip

ites

sp

Cica

tric

osis

porit

essp

.

Ste

eves

ipol

len

ites

gig

ante

us

Clas

sopo

llis

jard

inal

Gem

mat

rilet

escl

avat

usTr

ipoj

ecta

cite

ssp

Psila

tric

olp

ites

X XX 0 0

X X X X X

X

X X0

X X X XX 0 0

X X XX 0X0 0

NEW

NETI

MM

ARL

ShC1

ShC2

ShC3

ShC4

Lith o log y

o

Form

atio

n

Sam

ple

No.

Dep

th (

m)

Weathered over burdenDark grey laminated shalesMarl Nodular marl with very thin shale bedWeathered sedimentsPresentAbsent

Keys

FIG. 12: Palynomorph distribution in interbedded shales of New Netim Marl outcrop Section ( Sh c1-4 ) at

Mbebu (Location MS5)

X Present

0 Absent



2.0

0

1.0

3.0

4.0

PALY

NO

MO

RPH

S

Ephe

drip

ites

proc

eru

s

Stee

vesi

pol

leni

tes

gig

ante

us

X

0

X

00

0

ShD

NE

WN

ETI

MM

AR

L

Lithology

1

ShD2

ShD3

Weathered over burdenDark grey laminated shalesMarl Nodular marl with very thin shale bedWeathered sedimentsPresentAbsent

Keys

Sam

ple

No.

Dep

th (

m)

For

mat

ion

FIG. 13: Palynomorphs distribution in the interbedded shales within the New Netim Marl outcrop ( Sh D1-3 ) at

Mfamosing (location MS3)

X Present

0 Absent



PALEOECOLOGY

The poor occurrence of benthic foraminifera in ShA 1-4 (Ikot Nyong- Fig 5) is suggestive of an anaerobic

bottom conditions at those intervals, which was unfavourable for the development of benthonic communities

(Petters 1982). Abundant of planktonic forms (Fig.3) in outcrop sections dominated by Heterohelix and

Hedbegerella with only a few keeled forms signifies flooding of the region during this period by a sea that was

characterized by shallow water depth and restricted ecological circulations. Petters (1980) and Eicher and

Worstell (1970) had noted that the Heterohelicids and the simple globigerine-shaped Hedbergellids dominated

Cretaceous shallow water environments, as they constitute the first planktonic species to colonize new

seaways and also the last to disappear. Based on these considerations, a middle-outer neritic (prodelta)

paleo-water setting environment of deposition is suggested for location ShA 1-4 (Ikot Nyong) outcrop section.

An entirely arenaceous benthic foraminiferal assemblage occur at sampled intervals Sh C 1-4 (Mbebu – Fig 7).

Diversed arenaceous taxa with very minor occurrence of planktic foraminifera, represented by Hedbegerella

delrioensis was observed. Foraminfera, particularly the benthics are among the most sensitive group of

organisms that could respond to even slight changes in their environmental conditions. According to Brasier

(1980), high – diversity foraminiferid assemblages strongly suggest a wide range of available food resources.

The predominance of this similar benthic assemblage in ShC 1-4 (Mbebu) is indicative that the sediments were

deposited within the middle (prodelta) neritic paleo – water depth.

Similar foraminiferal assemblage occurs in ShB1 – 4 (Fig. 6 )and ShD 1 – 3 (Fig. 8) at Mfamosing village.

Samples were generally very poor in foraminiferal recovery. However, abundant and diversified species of

Ostracoda (Brachycythere cf. sapucariensis) were observed to dominate the sections. Their abundant cannot

be ignored in the paleo - ecological studies of a sedimentary formation and its depositional environment.

These organisms have adapted to various niches as the ocean water surface, sea floor, freshwater ponds and

even humid forest soils. They are however known to be shallow marine benthos, where they may be less than

the foraminifera amongst the fossil microfauna. Ostracods are particularly useful for the biozonation of marine

strata on a local or regional scale. It is second to none as indicators of ancient shorelines, salinities and

relative sea floor depths (Brasier, 1980). Ostracods today are predominantly benthic or pelagic throughout

their life history. Deduction from the analysis of ShB1 – 4 and ShD 1 – 3 (Mfamosing), whose foraminiferal

association is characterized by low planktic/benthic ratios and abundance of ostracods, shows that the

sediments (New Netim Marl) were deposited within a shallow - inner neritic setting.

CONCLUSION

Foraminiferal analysis reveals the occurrence of benthic and planktic index forms. These forms are

Ammobaculites jessensis, Ammobaculites benuensis, Haplophragmodies bauchensis, Whiteinella inornata,

Whiteinella baltica and Heterohelix ressui. The above fossil assemblage points to a Turonian – Coniacian age

for the New Netim Formation. Palynological analysis of the shale samples shows that all the recovered

palynomorphs were long ranging palynofloral assemblage, mostly from Albian – Turonian. Of note, is the

occurrence of the Mid – Upper Cretaceous Trifossapollenites sp. and Cicatricosisporites sp. which points to a

Turonian – Coniacian age for the rocks under investigation. The Turonian – Coniacian age deduced in this

study for the New Netim Formation is in conformity with earlier Coniacian age by Perch-Nielsen and Petters,



(1981) based on cocolith. Also, the paleoecological study indicates a shallow - inner to middle-outer neritic

(prodelta) paleo-water depositional environment for the New Netim Formation.

EXPLANATION OF PLATE 1: Benthic Foraminifera (Redrawn from Petters, 1982)

1 – 2: Haplophragmoides bauchensis. (Petters, 1979) umbilical view, side view.

3: Haplophragmoides sp. seen only in ShC4 Loc. MS5.

4: Ammobaculites bauchensis (Petters, 1979) × 120. Spiral view.

5: Ammobaculites benuensis (Petters, 1979) × 120.

6 – 7: Ammobaculites coprolithiformis (Schwager, 1868). × 96,

8: Ammobaculites subcretaceus (Cushman & Alenxander, 1930) × 120.

9: Ammobaculites amabensis (Petters, 1979) × 101.

10: Ammobaculites jessensis (Petters, 1979) × 71.

11: Ammobaculites sp. × 58.

12-13: Ammotium Bornum × 58.



EXPLANATION OF PLATE 2 :Planktonic foraminifera (Redrawn from Bolli et al, 1989)

1 – 2: Whiteinella baltica (Douglas & Rankin, 1969) × 60. Spiral view, 2, umbilical view.

3 – 4: Whiteinella inornata (Bolli, 1957) × 60 Spiral view, 4, umbilical view.

5: Hedbergella delrioensis (Carsey, 1926) × 96. Umbilical view.

6: Hedbergella holmdelensis (Oysson, 1964) × 96. Umbilical view,

7 – 8: Hedbergella Planispira (Tappan, 1940) × 120. 7, spiral view, 8, umbilical view.

9-10: Heterohelix moremani (Cushman, 1938) × 160. Side views.

11- 12: Heterohelix reussi (Cushman 1938) × 160. Side views.

13 - 16 Heterohelix globulosa (Ehrenberg, 1840) × 180. side views, 14, edge view.



1 2

3 4

5

EXPLANATION OF PLATE 3 (Edited after Jan Du Chene et al, 1978).

1: Steevesipollenites giganteus

2: Classopollis jardinel.

3: Ephedripites procerus.

4: Cicatricosisporites sp.

5: Steevesipollenites sp.



REFERENCES

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Brasier, M. D. (1980). Microfossils. London: George Allen and Unwin.

Cushman, J. A. (1911). Monograph of the foraminifera of the North Pacific Ocean. Astrorhizidae and Lituolidae United States Natural Museum Bulletin, 71(1): 1 – 134.

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Essien, N. U.; Ukpabio, E. J.; Nyong, E. E. & Ibe, K. A. (2005). Preliminary organic geochemical appraisal of cretaceous rock units in the Calabar Flank, Southeastern Nigeria. Journal of Mining and Geology, 41(2): 185 – 191.

Jan Du Chene, B. E.; De Khasz, I. & Archibong, E. E. (1978). Biostratigraphic study of the borehole. Ojo-1, Nigeria, with special emphasis on the Cretaceous microflora. Revue de Micropaléontologic. 21(3): 123 – 138.

Lang, H. R. & Frerich, W. E. (1997). New planktic foraminifera data document Coniacian age (88ma) for Laramide orogeny onset and paleooceanography in Southern Mexico . Jet propulsion laboratory technical report server, United States (1- 16)

Lipps, J. H. (1979). Ecology and paleoecology of planktonic foraminifera. In: J. H. Lipps, W. H. Berger, M. A. Buzas, R. D. Douglas and C. A. Ross (Eds.), Foraminiferal Ecology and paleoecology (62 – 104). Houston: SEPM.

Murat, R. C. (1972). Stratigraphy and paleogeography of the Cretaceous and Lower Tertiary in Southern Nigeria. In: T. J. Dessuavagie (Ed.), African Geology (251 – 266). Ibadan: University Press.

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Petters, S. W. (1982). Central West African Cretaceous – Tertiary benthic foraminifera and stratigraphy. Paleontologica, 179: 1 – 104.

Petters, S. W., Nyong, E. E., Akpan, E. B. & Essien, N. U. (1995). Lithostratigraphic revision of the Calabar Flank, South East Nigeria: Proceedings of the 31st Annual Conference of the Nigerian Mining and Geosciences Society, Calabar.

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