Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria

Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria
IJGM
Foraminiferal Approach to Palaeoenvironmental Interpretations:
Case Study of Priabonian – Rupelian Sediments of the Niger Delta,
Nigeria
1Ukpong, Aniediobong Jonah, 2Ekhalialu, Ogie Macaulay*
1,2
Department of Geology, University of Calabar, Calabar, Cross River State, Nigeria
Palaeoenvironmental analysis was carried out on eighty (80) ditch cutting samples of the Late
Eocene-Early Oligocene sediments from two wells (well C consist of 13 samples collected at
30metres interval from depth range of 2410 -2770m while well F consists of 67 samples collected
at 20metres from depth range of 2000-3320m) in the Northern Depobelt of the Tertiary Niger Delta.
This study was carried out using standard micropalaeontological sample procedures and
analysis as well as interpretation of the foraminiferal biofacies assemblages taking into
consideration the qualitative and quantitative approaches. The qualitative method involved
comparison of the recovered foraminifera with extant forms while the quantitative method
involved the use of tau index, palaeowater depth (Pwd), percent of calcerous to arenaceous
benthic foraminifera ratios (%FOBC: %FOBA), Fisher diversity and foraminifera/ ostracoda ratio.
The palaeoenvironmental analysis indicates that the sediments were deposited in a non-marine
to outer neritic environmental setting with salinity conditions fluctuating between normal marine
and slightly hypersaline.
Keywords: Foraminifera, palaeoenvironment, palaeowater depth, tau index, Fisher diversity, Niger delta,
palaeobathymetry, palaeosalinity
INTRODUCTION
Palaeoenvironmental analysis uses microfossils among
other indices to provide direct evidence for the interpretation
of ancient environments. Different sedimentary rocks are
deposited in a wide range of environments that look very
similar; the microfossils found in the sedimentary rocks are
often a diagnostic feature in determining the ancient
environments (Armstrong and Brasier, 2005). The presence
of microfossils in sedimentary rocks therefore helps to
precisely predict the depositional environment.
Palaeoenvironmental analysis from microfossils perspective
appears to be the most reliable method of studying the past
environments. This is further confirmed by the study of
Boltovskoy and Wright (1976), Boersma (1978), Brasier
(1980), Murray (1971, 1976, 1991, 2006), Armstrong and
Brasier (2005).
Palaeoenvironmental studies most often depend on the
previously established / proven relationship that exists
between the biota and the ambient environment. This can
be achieved with the use of abundant well-preserved
foraminifera and other microfossils. The purpose of most
studies including this current study is to attribute the
change in living activities to actual environmental
variations. Armstrong and Brasier (2005) suggested that
ecological sensitivity of microfossils makes them
particularly useful in studies of recent and ancient
environmental conditions. Murray (2000) went further to
establish that foraminifera are very dependable and
extremely useful in analysing, determining and
understanding recent and ancient marine environments.
Changes in the composition of foraminiferal assemblages
may be used to determine changes in sea-water depth. A
range of factors (physical, chemical and biological) affect
the ecological behaviour of foraminifera and should be
considered during palaeoenvironmental studies.
Furthermore, foraminifera have a wide habitation range,
from terrestrial to deep sea and from polar to tropical belt
(Armstrong and Brasier, 2005).
*Corresponding Author: Ekhalialu Ogie Macaulay,
University of Calabar, Calabar, Cross River State, Nigeria.
E-mail: ansmacaulay@gmail.com
International Journal Geology and Mining
Vol. 4(2), pp. 165-178, June, 2018. © www.premierpublishers.org. ISSN: 3019-8261
Research Article

Ukpong and Ekhalialu 166
Figure 1: Map of the Niger Delta showing the depobelts and location of the study wells (C and F)
This current study is the first report in the Niger Delta using
different foraminiferal palaeoenvironmental methods and
harmonizing with the established depth range of the
recovered foraminifera.
Location of the study wells
The study wells (wells C and F) were drilled in the Northern
Delta depobelt of the Niger Delta which forms a segment of
the Niger Delta petroleum province of Nigeria (figure. 1).
The Niger Delta Basin is a prolific hydrocarbon province
that contains enormous hydrocarbon both on the onshore,
shallow and deep offshore areas and it is located between
Latitudes 3° and 6° N and Longitudes 5° and 8° E
respectively in the Gulf of Guinea, on the margin of West
Africa (Reijers, 2011; Doust and Omatsola, 1987).
The Niger Delta is described by Doust and Omatsola
(1990) as one of the largest deltaic systems in the world.
The formation of the Niger Delta basin began in the Early
Cretaceous; it was developed at the triple junction between
South Atlantic, Gulf of Guinea Margin and Benue Trough
(Burke, 1972). The Niger Delta deltaic system is known to
prograded over an area of three hundred kilometers (300
km) since the Late Eocene (Short and Stauble, 1967;
Burke, 1972; Evamy et al., 1978; Whiteman, 1982;
Stacher, 1995).
The study by Evamy et al. (1978), Ejedawe (1981), Knox and
Omatsola (1987) and Stacher (1995) point out that the
evolution of the Niger Delta is controlled by pre- and
synsedimentary tectonics. The delta has prograded
southwestward, forming depobelts known as the most active
sections / portions of a delta during each stage of its
development (Doust and Omatsola, 1990). Kulke (1995)
and Hospers (1965) defined the Niger Delta as one of the
largest regressive deltas in the world and it covers an area
of approximately 300,000 km2
with a sediment volume of
500,000 km3
respectively. Kaplan et al. (1994) proposed a
sediment thickness of over 10 km in the basin depocenter.
The Niger Delta is a delta at equilibrium state due to the
equal contribution from fluvial, wave and tide influence.
Research by Evamy et al. (1978) and Doust and Omatsola
(1990) suggested that the structural configuration and the
stratigraphy of the Niger Delta were largely influenced by
the interaction between the rates of sediment supply and
subsidence.
Three (3) main vertically stacked lithologic units are known
and defined in the Niger Delta by various workers (Doust
and Omatsola, 1990; Weber, 1971; Weber & Daukoru,
1975; Evamy et al., 1978; Ejedawe, 1981; Knox and
Omatsola, 1987) and they correspond to the three-fold
lithostratigraphic subdivision proposed by Short and
Stauble (1967) for the subdivision of the Niger Delta viz:
i. Benin Formation (indicating continental environment)
(youngest)
ii. Agbada Formation (indicating transitional
environment) and
iii. Akata Formation (indicating marine environment)
(oldest)
Numerous authors have published papers on the geology
of Niger Delta. Examples include the following: Short and
Stauble (1967), Evamy et al. (1978), Ejedawe (1981),
Knox and Omatsola (1987) Petters (1979, 1981, 1982,
1983, 1984, 1995); Doust and Omatsola (1990), Stacher
(1995), Reijers et al. (1997), Reijers (2011), Ukpong et al
(2017a, 2017b, 2017c)

Int. J. Geol. Min. 167
MATERIALS AND METHODS
Materials
A total of eighty (80) ditch cutting samples were used for
this study. Well C ranges from depth 2800m – 2410m
consisting of thirteen (13) samples at 30metres interval
while well F ranges from depth 2000m – 3320m consisting
of sixty-seven (67) samples at 20metres interval
respectively.
Foraminiferal analysis
The anhydrous sodium carbonate method was utilized for
the separation of foraminifera in this study as outlined by
Brasier (1980) and Armstrong and Brasier (2005). 20 - 40g
of the ditch cutting was used in the sample preparation.
The sample preparation was made in three (3) phases:
soaking, wet sieving and drying of residues. The residues
obtained after the extraction of foraminifera from the
prepared samples were properly stored in well labelled
sample bags for lithologic/sedimentologic analysis.
Identification of the foraminifera extracted from the
samples was done by comparing picked forms with
previously published forms.
Palaeoenvironmental analysis
The current approaches used in foraminiferal
palaeoenvironmental studies are mainly based on
concepts in vogue in modern foraminiferal studies mostly
on empirical comparison of living and death forms in
modern assemblages. The studies of Murray (1971, 1973,
1976 and 2006) and Murray and Wright (1974) have
proven this fact. The palaeoenvironmental interpretation
also relies on the use of planktonic and benthic
foraminifera as well as other accessory taxa such as
ostracoda, pelecypoda and gastropoda.
The palaeoenvironment interpretations of this study rest
on three basic assumptions (after Douglas 1979):
i. The physiological adaptations of species do not
change with time
ii. The depth distribution of foraminifera species do not
change with time
iii. The palaeoenvironemental requirements of
foraminifera species are fixed and do not change with
time.
These assumptions are made with the view that, as new
bathymetric zones are generated in the marine
environments, the new depth range of the foraminifera
species either remain unchanged or remain somewhat
similar to their parent species due to development of
similar morphological features that can be attributed to the
transfer of genetic information from parents to offspring.
Douglas’s (1979) study of form, structure and environment
of living species and fossil fauna correlates and supports
these assumptions.
Foraminiferal palaeoenvironmental methods used in this
study include:
i. Species diversity patterns: Species diversity shows an
upsurge from the shoreline to the edge of the
continental shelf and then declines or remains
unchanged on the continental slope (Bandy, 1953a,
b).This is probably due to prevailing of tougher
conditions in the coastal area such as clastic influx and
mixing at the coast. The species diversity index
adopted in this study is the Fishers- index developed by
Fisher et al., (1943) taking into account the species
abundance as well as the number of species. Fisher
index (α) of species diversity is given as α=n1:x. X is a
constant with a value of <1, n1= N(1-x), N denotes the
number of individuals. The measure of the distribution
of species abundance can be approximated using the
Fisher’s log series. The Fisher’s log series used here is
after Wright (1972). Species diversity has a multiple
purpose. It is a pointer to palaeosalinity (Valchev, 2003) of
sediment using the recovered foraminiferal information
and it is also informative for palaeobathymetry (Valchev,
2003). The values of Fisher-index increase as the depth
increases. Outer shelf is characterized by α=5-19, the
slope – by α=5-25.
The highest values of α demonstrates the lowermost
continental slope (Murray, 1976).
Salinity levels of a water body influence the species
diversity value. Values of α>5 suggest normal salinity
(Murray, 1991). Hyposaline and hypersaline conditions
are generally characterized by low species diversity
(Valchev, 2003). Species diversity can also be useful in
determining the dissolved oxygen levels. Low
oxygenated environment demonstrate low species
diversity (α<7) and they are dominated by 2-3 species
comprising over 80 percent of the total number of
individuals in the samples (Valchev, 2003).
ii. Palaeowater depth (Pwd): Palaeowater depth is a
significant descriptor in reconstructing
palaeoenvironment. Planktic/Benthic (P/B) ratio is the
measure of the ratio between the planktic and benthic
foraminifera. Grimsdale and Morkhoven (1995) observed
that the abundance of planktic foraminifera increases
beyond the outer shelf depths; this also validates the use
of P/B ratio as depth estimators and can be easily
determined as it requires no taxonomic identification apart
from the separation into planktic and benthic groups. Lipps
(1979) observed that there is preferential elimination of
some foraminifera species towards the shoreline. The use
of P/B ratio is based on the fact that planktic foraminifera
are depth-stratified and are very sensitive to certain
environmental (limiting) factors such as hydrostatic
pressure, temperature, salinity and light which are
dependent on water depth (Douglas, 1979). However, it is
pertinent to state in clear terms that water depth per se is
not a limiting factor to the survival of foraminifera species.

The palaeowater depth was measured using
recalculated equation of Van der Zwaan et al. (1990)
instead of the traditional method.
Depth (m) = e3.58718 + (0. 03534 x percent P)
.
According to Murray (1976), inner shelf is
characterized by up to 20percent planktic individuals,
the middle shelf – 10-60 percent, the outer shelf – 40-
70percent, and the upper slope - >70percent. The
highest values 90percent are known in the lowermost
slope (Boersma, 1978).
iii. Triangular plot for foraminifera assemblages: This is
based on the three major groups of wall structure
(shell composition) of foraminifera: the agglutinated/
arenaceous (Textulariina), the porcellanous
(Miliolina) and the hyaline (Rotaliina). The first group
(Suborder Textulariina) builds their test from sea/
ocean particles held together with organic calcerous
/ siliceous cements. The second group (Suborder
Miliolina) and the third group (Suborder Rotaliina)
secrete calcerous shells that vary in chemical
components, microstructure and even in surface
lustre. The relative proportion of shell types found in
benthic foraminifera assemblages varies from one
sample to another. The Miliolina, Rotaliina and
Textulariina (MRT) plot can be used to discriminate
ranges of palaeosalinity of deposition (Murray, 1971,
1973, 2006; Murray and Wright, 1974; Petters, 1982).
iv. Percent of calcerous to arenaceous benthic
forminifera ratios (%FOBC: %FOBA): this is an
indirect measures of salinity conditions (Douglas,
1979). The percent ratio of calcareous to arenaceous
benthic foraminifera (%FOBC: %FOBA) is a good
pointer for palaeoenvironmental studies, the high
values of %FOBC: %FOBA suggests shallower
palaeowater depths while higher %FOBA: %FOBC
suggests deeper palaeodepths (Boersma, 1978).
v. Tau-index: Gibson (1988) was the first to introduce the
use of Tau-index as a bathymetrical indicator from data
obtained from the Gulf of Mexico. Tau index tends to
increase with depth and can be calculated using the
formula: Tau index = b. %p. Where b is the number of
benthic individuals and %p is the percent of the number
of planktic individuals in a sample, both converted into
%. Depths of up to 40m has a tau value of<100, depths
range between 40 and 1000 m are characterized by tau
values between 100-1000 while depths up to 2000m
has tau values between 1000-10000 (Gibson, 1988).
vi. Percent Foramininfera: percent Ostracoda (%F: %O):
This can also be used as an environmental indicator.
The percentF: percentO tends to increase with depth
from lagoonal areas into Open Ocean and offshore
areas (Bandy, 1963). The P/B ratio of offshore areas
is usually hundred times higher than the ostracoda
recovery (Brady, 1967).
The palaeoenvironment of deposition of the sediment
penetrated by the study wells are interpreted based on
quantitative methods (such as tau index, pwd, percent
FOBA/ percent FOBC and Fisher’s diversity) and
qualitative method (depth range of living form). The study
of Petters (1982,1995) have proven that the formations
that comprises the Niger Delta contain
palaeobathymetrically significant benthic foraminifera that
characterized different environments of deposition from
shallow (coastal) to very deep (bathyal).
The indicator foraminiferal assemblages and individual
specimens for different depths described by Bandy
(1953a, 1953b, 1963), Murray (1971, 1973, 2006),
Boltovsky and Wright (1976) are used to characterize the
palaeobathymetric environments.
For convenience and for clarification purposes, the
terminology of palaeobathymetric subdivision adopted by
Petters (1995) has been used in this study (Figure 2).
Neritic will be depth range of 0-200m (comprising of
shallow inner neritic = 0-10m, inner neritic = 0-40m, middle
neritic = 40-100m, outer neritic = 100-200m). Bathyal will
be > 1000m.
RESULTS AND DISCUSSION
The study wells (well C: interval 2410 – 2800m and well F:
interval 2000 – 3320m sampled at 30m and 20m depth ranges
respectively) penetrated sediments characterized by
alternation of sandstone/sand and shale, the shale is dark
grey in colour, sub fissile – fissile, micromicaceous and
moderately hard - hard. The sand is smoky white – brown,
fine - coarse grained, sub-angular - rounded, poorly
- well sorted and occasionally ferruginized, carbonaceous,
glauconitic and predominantly unconsolidated –
consolidated. These sediments of heterogeneous
sequence of alternating shale and sand/sandstone belong
to the Middle - Lower units of the paralic Agbada Formation
described by Short and Stauble (1967), Doust and
Omatsola (1990) and Whiteman (1982) as a
lithostratigraphic subdivision of the Niger Delta subsurface.
Foraminiferal analysis was carried out on eighty (80)
samples obtained from the two wells (C and F). The
foraminifera forms recovered include planktonic and
benthic foraminifera (calcareous benthic and arenaceous
benthic foraminifera). Some foraminifera forms are long
ranging in terms of stratigraphic occurrence while others
have restricted stratigraphic occurrence with regional –
cosmopolitan distribution. Foraminifera distribution chart of
the wells C and F are presented in appendix. The total
count of picked foraminifera prior to description was four
thousand and twenty two (4022) specimens but due to
poor preservation most of the recovered foraminifera could
not be described and it is strongly associated with the
Eocene – Oligocene transition. A total count of one

Figure 2: Foraminiferal biofacies model for the Niger Delta (Petters,1995).
thousand, eight hundred and seventy-two (1872)
foraminifera specimens were described from the two wells
(wells C and F). Also recovered were seventy-two (72)
ostracods, two (2) pelecypods and one (1) gastropod
which were collectively classified as miscellaneous.
The Eocene – Oligocene boundary was detected based on
the recovered foraminifera from the study wells. The age
(biozonation and biochronology) and the transition oxygen
changes across the Eocene – Oligocene boundary of the
study wells (wells C and F) have been discussed in Ukpong
et al. (2018) and Ukpong and Ekhalialu (2017c)
Palaeobathymetry
The foraminiferal distribution chart of the two wells (wells
C and F) is presented in figure 3 and 4 respectively.
The palaeoenvironmental analysis of the study wells (wells
C and F) show a range of environment from non-marine,
shallow inner neritic, inner neritic, mid neritic and outer
neritic settings based on the foraminiferal biofacies
assemblages (planktonic and benthic forms) obtained and
the use of some quantitative methods (such as tau index,
pwd, percent FOBA / FOBC, Fisher diversity). Table 1 and
2 (in appendix) show the summary of the quantitative
foraminiferal distribution of wells C and F.

Figure 3: Foraminiferal chart of well C

Figure 4: Foraminiferal chart of well F

Palaeobathymetry of Well C
In Well C, intervals 2410-2440m, 2530-2560m, 2590-
2680m, 2710-2741m were inferred to have been deposited
in shallow inner neritic settings based on the calculated
indices (table 1), absence of planktic foraminifera and the
abundance of shallow marine foraminifera such as Nonion
spp., Nonionella spp., Hanzawaia spp., Hopkinsina
spp.,Eponides spp., Epistominella spp. etc within the
interval.
In well C, interval 2560-2590m was deposited in a non-
marine setting based on the calculated indices (table 1 in
appendix) and absence of foraminifera.
In Well C, interval 2440-2530m indicated to be deposited in
inner – mid neritic settings based on the calculated indices
(table 1 in appendix), paucity of planktic foraminifera and the
co-occurrence of shallow marine foraminifera (Nonion spp.,
Nonionella spp., Hanzawaia spp., Hopkinsina spp. Eponides
spp., Epistominella spp.) and few deep marine foraminifera
(Bolivina spp. and Uvigerina spp.) within the interval. This
corresponds to the study of Petters (1995)
Palaeobathymetry of Well F
In well F, intervals 2020-2240m and 2860-2880m were
inferred to have been deposited in a non-marine setting
based on the calculated indices (table 2 in appendix) and
absence of foraminifera. Intervals2000-2020m, 2320-
2340m, 2400-2420m, 2760-2780m, 2880-2920m, 2980-
3000m, 3080-3100m, 3200-3220m,3240-3300min well F
were also inferred to have been deposited in shallow inner
neritic settings based on the calculated indices (table 2 in
appendix), absence of planktic foraminifera and the
abundance of shallow marine foraminifera such as Nonion
spp., Nonionella spp., Hanzawaia spp., Hopkinsina
spp.,Eponides spp., Epistominella spp. etc within the
interval. Similar assemblages have been used by Petters
(1995).
Sediment deposited in Well F, intervals 2260-2320m,
2340-2360m, 2380-2400m, 2440-2500m, 2540-2720m,
2740-2760m, 2780-2800m,2820-2840m, 2920-2980m,
3000-3080m, 3100-3200m, 3220-3240m were also
indicative of inner – mid neritic depositional settings based
on the calculated indices (table 2 in appendix), paucity of
planktic foraminifera and the co-occurrence of shallow
marine foraminifera (Nonion spp., Nonionella spp.,
Hanzawaia spp., Hopkinsina spp., Eponides spp.,
Epistominella spp.) and few deep marine foraminifera
(Bolivina spp., Uvigerina spp., Praeglobobulimina spp.)
within the interval. This corresponds to the study of Petters
(1995).
In Well F, interval 2340-2360m, 2420-2440m, 2500-2540m,
2720-2740m were also indicative of an outer neritic
depositional setting based on the calculated indices (table 2
in appendix), moderate planktic foraminifera recovery and the
co-occurrence of some shallow marine
foraminifera (Nonion spp., Nonionella spp., Hanzawaia
spp., Hopkinsina spp.,Eponides spp., Epistominella spp.)
and abundance deep marine foraminifera (Bolivina spp.,
Uvigerina spp.). This corresponds to the study of Petters
(1995).
Palaeosalinity
Foraminifera have successfully conquered most habitats
and live in all marine environments from the shallowest
intertidal area to the deepest ocean (Murray, 1971). All
these areas are characterized by different salinity values
and can be distinguished and interpreted based on the
Fisher’s log series plot of Wright (1972) and Foraminifera
shell-type (morphogroup) ratio (triangular plot) of Murray
(1973).
Palaeosalinity analysis of well C
The Miliolina, Rotaliina and Textulariina (MRT) plot (Figure of
well C reveals the dominance of the Rotaliina / hyaline
calcareous with frequent but minor occurrence of
arenaceous test and minute miliolina shell type,
suggesting a range of environment based on varying
salinity viz: normal marine shelf sea – continental slope as
well as hyposaline - hypersaline environment while the
Fisher’s log series plot (Fig. 6) suggests hypersaline
setting. Comparison with modern microfaunas based on
the study of Murray (1973, 1991 and 2006) and Valchev
(2003) assisted in constricting the results. The
microfaunas of the sediments penetrated by well C are
essentially of those that are indicative of a normal-marine
– slightly hypersaline shelf. The dominance of the
calcareous benthic foraminifera (FOBC) with over
90percent of total foraminifera forms; suggest normal
marine condition (Nagy et al., 1988) and the presence of
few Miliolids affirm slightly hyper marine conditions.
Armstrong and Brasier (2005) further reaffirms this
interpretation.
Figure 5: MRT plot for well C (Modified from Murray, 1973)

Figure 6: Fisher’s log series plot for well C (modified from
Wright, 1972)
Palaeosalinity analysis of well F
The Miliolina, Rotaliina and Textulariina (MRT) plot (Figure
7) of well F reveals the dominance of Rotaliina / Hyaline
calcerous with frequent but minor occurrence of arenaceous
test and minute miliolina suggesting a range of environment
based on varying salinity viz: normal marine shelf –
continental slope as well as hyposaline – hypersaline
environments while the Fisher’s log series plot (Figure 8)
suggest hypersaline - normal marine shelf setting.
Comparison with modern microfaunas based on the study of
Murray (1973, 1991, and 2006) and Valchev (2003) assisted
in constraining the results. The microfaunal content of the
sediments penetrated by well F are essentially of those that
characterize a normal-marine – slightly hypersaline
environmental setting. The dominance of the calcareous
benthic foraminifera (FOBC) with over 90percent of total
foraminifera forms, suggest normal marine condition
(Nagy et al., 1988) and the presence of few Miliolids
affirms the slightly hyper marine conditions. Armstrong and
Brasier (2005) further reaffirms the interpretation
presented in this study.
Figure 7: MRT plot for well F (modified from Murray (1973)
Figure 8: Fisher’s log series plot for well F (modified from
Wright, 1972)

SUMMARY AND CONCLUSION
The palaeoenvironment of deposition (palaeobathymetry
and palaeosalinity) of two wells from the Niger Delta
encompassing Priabonian – Rupelian sediments was
attempted based on qualitative and quantitative methods.
The qualitative method involved comparison of the
recovered foraminifera with extant forms or living relatives
while the quantitative method involved the use of tau index,
pwd, percent FOBA/ percent FOBC, Fisher diversity,
foraminifera / ostracoda ratio. The palaeoenvironmental
analyses reveal that the sediments were deposited in a
non-marine to outer neritic environmental setting with
salinity conditions fluctuating between normal marine to
slightly hypersaline.
ACKNOWLEDGEMENT
We (the authors) wish to express our profound gratitude to
the management of Nigerian National Petroleum
Corporation (NNPC) and Nigerian Agip Oil Company
(NAOC) for providing the ditch cuttings for this study. Many
thanks to the Department of Geology, University of
Calabar, Calabar for the encouragement. The authors are
grateful to the following reviewers: Prof. Om N. Bhargava.
(Centre of Advanced Geology, Panjab University, India),
Dr. Kamil Zágoršek (Technical University of Liberec,
Czech Republic), Dr. Lluís Checa Soler (Institut Català de
Paleontologia "M.Crusafont", Spain), Dr. Sanjay Kumar
Mukhopadhyay, (formerly, Geological Survey of India) and
Dr. Andrey Yu. Gladenkov (Geological Institute, Russian
Academy of Sciences, Russia) for their useful comments
that greatly improved this paper.
REFERENCES
Armstrong H. A. And Brasier M. D. (2005). Microfossils.
Second Edition. Blackwell Publishing.
Bandy, O. L. (1953a). Ecology and paleoecology of some
California foraminifera; Part I, the frequency distribution
of Recent foraminifera off California. Journal of
Paleontology, 22, 161-182.
Bandy, O. L. (1953b). Ecology and paleoecology of some
California foraminifera; Part II, foraminifera evidence of
subsidence rates in the Ventura basin. Journal of
paleontology, 27, 183-203.
Bandy, O. L. (1963). Dominant parallic foraminifera of
Southern California and Gulf of California. Contribution
Cushman Foundation for Foraminiferal Research, 14
(4), 127-134.
Blow, W. H. (1969). Late - middle Eocene to recent
planktonic foraminiferal biostratigraphy. In P.
Bronnimann, & H. H. Renz (Eds.), Proceedings of first
international conference on planktonic microfossils
(pp. 199-422). Geneva: Leiden.
Boersma, A. (1978). Foraminifera. In B. U. Haq & A.
Boersma (Eds.), Introduction to Marine
Micropaleontology (pp. 19-77). North Holland:
Elsevier.
Boltovskoy, E., & Wright, R. (1976). Recent Foraminifera:
The Hague: Springer Science Media.
Brasier, M.D. (1980). Microfossils. Kingtons-upon-Hull :
University of Hull Press.
Burke, K. (1972). Longshore drift, submarine canyons and
submarine fans in development of Niger Delta.
American Association of Petroleum Geologists
Bulletin, 56, 1975-1983.
Channel. Paleontology Association. London:
Douglas, R. G. (1979). Benthic foraminiferal ecology and
paleoecology: a review of concepts and methods.
Society of Economic Paleontologist and Mineralogists
short course, 6, 21-53.
Doust, H., & Omatsola, E. (1990). Niger Delta. In J. D.
Edwards, & P. A. Santogrossied, (Eds.), Divergent /
passive margin basins (pp. 201-238). American
Association of Petroleum Geologists.
Ejedawe, J. E (1981). Patterns of incidence of oil reserves
in Niger delta basin, American Association of Petroleum
Geologists Bulletin, 65, 1574-1585.
Evamy, B.D., Haremboure, J., Kamerling, P., Knaap, W.A.,
Malloy, F.A, & Rowlands, P.H. (1978). Hydrocarbon
habitat of Tertiary Niger Delta. American Association of
Petroleum Geologists Bulletin, 62, 1-39.
Fisher, R. A., Corbet, A. S., & Williams, C. B. (1943). The
relation between the number of species and number of
individuals in random samples of an animal population.
Gibson, T. G. (1988). Assemblage characteristics of
modern benthic foraminifera and application to
environmental interpretation of Cenozoic deposits of
Eastern North America. Review of Paleobiology
Colloquium Special, 2, 777-787.
Grimsdale, T., & Markhoven, F. (1955). The ratio between
pelagic and benthonic foraminifera as a means of
estimating depth of deposition of sedimentary rocks. 4th
World Petrology Congress Proceedings Section, 473-
491.
Hampshire and Paris Basins and the English
Hospers, J. (1971). The geology of the Niger Delta area.
In P. M. Delany (Ed.), The geology of the east Atlantic
continental margin (pp. 125-142). London: International
Council for Scientific Unions.
Journal of Animal Ecology, 12, 42-58.
Kaplan, A., Lusser, C.U., & Norton, I. O. (1994). Tectonic
map of the world. American Association of Petroleum
Geologists, panel 10.
Knox, G. J., & Omatsola, E.M. (1989). Development of the
Cenozoic Niger Delta in terms of the ‘escalator
regression’ model and impact on hydrocarbon
distribution. In W. J. M. Van der Linden, S. A. P. L.
Cloetingh, J. P. K. Kaasschieter, J. A. M. Van der Gin.
Coastal Lowlands, Geology and Geotechnology (pp.
181-202). Dordrecht: Kluwer Academic Publishers.
Kulke, H. (1995). Nigeria, In H. Kulke (Ed.), Regional
petroleum geology of the world. Part II: Africa, America,
Australia & Antarctica (pp. 143-172). Berlin: Brüder
Borntraeger.
Lipps, H. J. (1979). Ecology and paleoecology of planktic
foraminifera. Society of Economic Paleontologist &
Mineralogists (SEPM) short course, 6, 62-104.

Murray, J. W. (1976). A method of determining proximity of
marginal seas to an ocean. Marine Geology, 22, 103-119.
Murray, J. W. (2006). Ecology and applications to benthic
foraminifera. Cambridge: Cambridge University Press.
Paleontology, 14, 1-129
Murray, J. W., & Wright, C. A. (1974). Paleogene
11oraminiferida and paleoecology,
Murray, J.W. (1971). Ecology and paleoecology of
benthicforaminifera. New York: John Wille & Sons.
Murray, J.W. (1973). Distribution and ecology of living benthic
foraminiferids. New York: Crane, Russak & Company.
Murray, J.W. (1991). Ecology and paleoecology of benthic
foraminifera. New York: Longman Scientific and Technical.
Murray, J.W. (2000). When does environmental variability
become environmental change? The Proxy Record of
benthic Formanifera. Environmental Micropaleontology,
Topics in Geobiology. New York, Kluwer
Academic/Plenum Publishers.
Nagy, J., Lofadli, M., & Backstrom, S.A. (1988). Aspects of
Foraminiferal Distribution and Depositional Conditions in
Middle Jurassic to Early Cretaceous Shales in Eastern
Spitsbergen. Abh Geology Journal, 41, 287-300.
Petters, S. W. (1979). Some late Tertiary foraminifera from
parabe-1 well, eastern Niger Delta. Revista Espanola de
micropaleontologia, 11, 119 – 133.
Petters, S. W. (1981). Eocene foraminifera from clastic and
phosphatic beds of the Gulf of Guinea. In J. W. Neale, &
M. D. Brasier (Eds.), Microfossils from recent and fossil
shelf Sea (pp. 214-230). Chichester, England: Ellis
Horwood.
Petters, S. W. (1983). Gulf of Guinea planktonic foraminiferal
biochronology and geological history of the South Atlantic.
Journal of Foraminiferal Research, 13, 32 – 59.
Petters, S. W. (1984). An ancient submarine canyon in the
Oligocene – Miocene of the western Niger Delta.
Sedimentology. 31, 805-810.
Petters, S. W. (1995). Foraminiferal biofacies in the Nigerian
rift & continental margin deltas. In M.N. Oti & Postma
(Eds.), Geology of deltas (pp. 219-235). Rotterdam:
Balkema.
Petters, S.W. (1982). Central West African Cretaceous –
Tertiary benthic foraminifera and stratigraphy.
Palaeontographica, 179, 1-104.
Reijers, T.J.A (2011). Stratigraphy and sedimentology of the
Niger Delta. Geologos, 17 (3), 133-162
Reijers, T.J.A., Petters, S.W., & Nwajide, C.S. (1997). The
Niger Delta Basin. In R.C. Selley (Ed.), African basins (pp.
145-168). Sedimentary Basins of the World.
Short, K. C., & Stauble, A. J. (1967). Outline of Geology of
Niger Delta. American Association of Petroleum
Geologists Bulletin, 51, 761-779.
Stacher, P. (1995). Present understanding of the Niger Delta
hydrocarbon habitat. In M.N. Oti, & G. Postma, (Eds.),
Geology of deltas (pp. 257-267). Rotterdam: Balkema.
Ukpong, A. J. & Ekhalialu, O. M. (2017c). Evaluation of
palaeo-oxygen conditions of Priabonian – Rupelian
sediments of the Agbada Formation, Niger Delta based on
Fisher’s diversity index and benthic foraminifera oxygen
index. EPRA International Journal of Research and
Development (IJRD), 2 (12): 65-80.
Ukpong, A. J., Ekhalialu, O. M., Osung, W. E., & Omoko,
E. N. (2018). Foraminiferal biozonation and
biochronology of Priabonian – Repulian sediments of
the Agbada Formation, Niger Delta. International
Journal of Scientific and Research, 8 (1), 425-441.
Ukpong, A. J., Ikediasor K. C., Anyanwu, T. C., Osung E.
W., & Ekhalialu O. M. (2017a). Foraminiferal
biozonation of “Well K-27”, greater ughelli depobelt,
Niger Delta basin, South Eastern Nigeria. International
Journal of Multidisciplinary Research, 3 (10), 23-32.
Ukpong, A. J., Ikediasor, K.C., Ekhalialu, O. M., & Osung,
E. W. (2017b). Sequene stratigraphic analysis of Well
“X2” in the Niger Delta, Southeastern Nigeria.
International Journal of Scientific and Technology
Research, 6 (10), 342-351.
Valchev, B. (2003). On the potential of small benthic
foraminifera as paleoecological indicator: recent
advances. 50 years University of Mining and Geology
“St. Ivan Rilski” Annual, 46, Part I, Geology and
Geophysics, 189-194.
Van der Zwaan, G. J., Jorissen F. J., & de Stigter H. C.
(1990). The depth dependency of planktonic / benthic
foraminiferal ratios: Constraints and applications.
Marine Geology, 95, 1-16.
Weber, K. J., & Daukoru, E. M. (1975). Petroleum Geology
of the Niger Delta. In Proceedings of the 9th World
Petroleum Congress, Geology 2 (pp. 209-221).
London: Applied Science Publishers Limited.
Weber, K.J. (1971). Sedimentological aspects of oil fields
in the Niger Delta. Geologie enMijnbouw 50, 559-576.
Whiteman, A. (1982). Nigeria- its petroleum geology,
resources and potential. London: Graham & Trotman.
Wright, C. A. (1972). Foraminiferids from the London Clay
at Lower Swanwick and their paleoecological
interpretation. British Geology Association, 83 (3), 337-
348.
Accepted 28 June 2018
Citation: Ukpong A.J, Ekhalialu O.M (2018). Application of
Foraminiferal Study to Palaeoenvironmental Analysis of
Priabonian – Rupelian Sediments of the Niger Delta,
Nigeria. International Journal Geology and Mining 4(2):
165-178.
Copyright: © 2018 Ukpong and Ekhalialu. This is an open-
access article distributed under the terms of the Creative
Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium,
provided the original author and source are cited.

APPENDIX
Table 1: Quantitative foraminifera distributions of well C
Depth (m) M R TC BC A B P TFC %P %B %M %A %R %FOBC %FOBA T Pwd Α %F %O
2410-2440 0 3 3 3 0 3 0 3 0 100 0 0 100 100 0 0 36.13 0.6 100 0
2440-2470 0 5 5 5 0 5 0 5 0 100 0 0 100 100 0 0 36.13 1 100 0
2470-2500 0 37 37 37 0 37 0 37 0 100 0 0 100 100 0 0 36.51 2.6 100 0
2500-2530 0 9 9 9 0 9 1 9 11.11 88.89 0 0 100 100 0 9 53.51 1.6 100 0
2530-2560 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 0.6 100 0
2560-2590 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0
2590-2620 0 6 6 6 0 6 0 6 0 100 0 0 100 100 0 0 36.13 1.4 75 25
2620-2650 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0
2650-2680 0 6 6 6 0 6 0 6 0 100 0 0 100 100 0 0 36.13 1 100 0
2680-2710 1 11 12 12 1 13 0 13 0 100 7.69 7.69 84.62 92.31 7.69 0 36.13 1.8 100 0
2710-2740 0 4 4 4 0 4 0 4 0 100 0 0 100 91.67 8.33 0 36.13 0.6 100 0
2740-2770 1 10 11 10 1 11 1 12 8.33 91.67 8.33 8.33 83.33 90.91 9.09 11 48.50 1.8 92.31 7.69
2770-2800 0 53 53 53 5 58 0 58 0 100 0 8.62 91.38 91.38 8.62 0 36.13 3 100 0
Keys: M=Miliolina/Porcelaneous , R= Rotaliina/Hyaline, TC= Total calcerous, BC = Calcerous benthic, A= Textulariina/Arenaceous, B=Benthic, P=Planktic,
TFC=Total foraminifera count, %P= percentage of planktic, %B= percentage of benthic, %M= percentage of Miliolina, %A= percentage of Arenaceous, %R=
percentage of Rotaliina, %FOBC= percentage of Benthic Calcerous Foraminifera, %FOBA= percentage of Benthic Arenaceous Foraminifera, T = Tau index,
Pwd=Palaeowater depth, P/B ratio= Plantkic/Benthics ratio, α= Fisher diversity index,% F/O = percentage of Foraminifera to Ostracoda ratio.
Application of Foraminiferal Study to Palaeoenvironmental Analysis of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria

Table 2: Quantitative foraminifera distribution of well F.
Depth (m) M R TC BC A B P TFC %P %B %M %A %R %FOBC %FOBA T- Pwd α %F %O
index
2000-2020 0 1 1 1 0 1 0 1 0 100 0 0 100 100 0 0 36.13 0.2 100 0
2020-2040 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2040-2060 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2060-2080 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2080-2100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2100-2120 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2120-2140 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2140-2160 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2160-2180 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2180-2200 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2200-2220 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2220-2240 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2240-2260 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2260-2280 0 77 77 77 1 78 0 78 0 100 0 1.28 98.72 98.72 1.28 0 36.13 5 93.98 6.02
2280-2300 0 43 43 43 0 43 0 43 0 100 0 0 100 100 0 0 36.13 5 100 0
2300-2320 0 4 4 3 0 3 1 4 25 75 0 0 100 100 0 3 87.42 1 80 20
2320-2340 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 0.4 100 0
2340-2360 0 62 62 62 0 62 0 62 0 100 0 0 100 100 0 0 36.13 2.8 95.39 4.61
2360-2380 0 118 118 114 0 114 4 118 3.39 96.61 0 0 100 100 0 456 40.73 8 100 0
2380-2400 0 44 44 43 1 44 1 45 6.67 93.33 0 2.23 97.78 97.28 2.22 44 45.74 6 100 0
2400-2420 0 1 1 1 0 1 0 1 0 100 0 0 100 100 0 0 36.13 0.2 100 0
2420-2440 0 26 26 22 0 22 4 26 15.38 84.62 0 0 100 100 0 96 62.22 5 100 0
2440-2460 0 14 14 14 1 15 0 15 0 100 0 6.67 93.33 93.33 6.67 0 36.13 2 100 0
2460-2480 0 10 10 10 0 10 0 10 0 100 0 0 100 100 0 0 36.13 1.8 100 0
2480-2500 0 14 14 14 1 15 0 15 0 100 0 6.67 93.33 93.33 6.67 0 36.13 2 100 0
2500-2520 0 170 170 169 1 170 1 171 0.85 99.4 0 0.58 99.4 99.42 0.58 170 36.88 3.6 93.44 6.55
2520-2540 0 297 297 278 19 307 9 316 2.85 97.15 0 6.61 94.30 93.99 6.01 27.63 39.96 16 96.04 3.96
2540-2560 0 27 27 27 2 29 0 29 0 100 0 6.90 93.10 93.60 6.40 0 36.13 4 100 0
2560-2580 0 12 12 12 4 16 0 16 0 100 0 25 75 75 25 0 36.13 3 100 0
2580-2600 0 17 17 17 3 20 0 20 0 100 0 15 85 85 15 0 36.13 3 95.34 4.76
2600-2620 0 51 51 50 1 51 1 52 1.89 98.11 0 1.95 98.08 98 2 52 40.64 8 98.07 1.92
2620-2640 0 30 30 30 0 30 0 30 0 100 0 0 100 100 0 0 36.13 4.6 100 0
2640-2660 0 25 25 24 1 26 0 26 0 100 0 3.85 96.15 96 4 0 36.13 3.6 100 0
2660-2680 0 26 26 26 0 26 0 26 0 100 0 0 100 100 0 0 36.13 5 74:28 25.72
2680-2700 0 56 56 56 0 56 0 56 0 100 0 0 100 100 0 0 36.13 7.8 100 0
Keys: M=Miliolina/Porcelaneous , R= Rotaliina/Hyaline, TC= Total calcerous, A= Textulariina/Arenaceous, BC = Calcerous benthic, B=Benthic, P=Planktic,
TFC=Total foraminifera count, %P= percentage of planktic, %B= percentage of benthic, %M= percentage of Miliolina, %A= percentage of Arenaceous, %R=
percentage of Rotaliina, %FOBC= percentage of Benthic Calcerous Foraminifera, %FOBA= percentage of Benthic Arenaceous Foraminifera, T = Tau index,
Pwd=Palaeowater depth, α= Fisher diversity index, %F/O = percentage of Foraminifera to Ostracoda ratio.

Table 2 cont.
Depth (m) M R TC BC A B P TFC %P %B %M %A %R %FOBC %FOBA T- Pwd α %F %O
index
2700-2720 0 18 18 17 0 17 1 18 5.80 94.20 0 0 100 100 0 32 53.51 3.2 90 10
2720-2740 0 44 44 40 2 42 4 46 10.87 89.14 0 4.35 95.65 95.22 4.88 220 53.03 7.8 97.87 2.13
2740-2760 2 18 20 20 0 20 0 20 0 100 10 0 90 100 0 0 36.13 3.2 97.87 2.13
2760-2780 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 1 89.74 11.26
2780-2800 0 8 8 8 0 8 0 8 0 100 0 0 100 100 0 0 36.13 1.8 100 0
2800-2820 0 1 1 1 0 1 0 1 0 100 0 0 100 100 0 0 36.13 0.2 100 0
2820-2840 0 10 10 10 0 10 0 10 0 100 0 0 100 100 0 0 36.13 2 100 0
2840-2860 0 35 35 35 0 35 0 35 0 100 0 0 100 100 0 0 36.13 2 100 0
2860-2880 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 0
2880-2900 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 1 100 0
2900-2920 0 1 1 1 0 1 0 1 0 100 0 0 100 100 0 0 36.13 0.2 100 0
2920-2940 0 9 9 9 0 9 0 9 0 100 0 0 100 100 0 0 36.13 1.6 100 0
2940-2960 0 21 21 21 0 21 0 21 0 100 0 0 100 100 0 0 36.13 1.8 95.45 4.55
2960-2980 0 17 17 17 0 17 0 17 0 100 0 0 100 100 0 0 36.13 1.8 89.47 10.53
2980-3000 0 18 18 18 0 18 0 18 0 100 0 0 100 100 0 0 36.13 1 100 0
3000-3020 0 35 35 35 0 35 0 35 0 100 0 0 100 100 0 0 36.13 2 100 0
3020-3040 0 42 42 42 0 42 0 42 0 100 0 0 100 100 0 0 36.13 3.6 100 0
3040-3060 0 43 43 43 0 43 0 43 0 100 0 0 100 100 0 0 36.13 5.4 100 0
3060-3080 0 36 36 36 0 36 0 36 0 100 0 0 100 100 0 0 36.13 3 100 0
3080-3100 0 12 12 12 0 12 0 12 0 100 0 0 100 100 0 0 36.13 1.6 100 0
3100-3120 1 76 77 77 0 77 0 77 0 100 1.29 0 98.70 100 0 0 36.13 3.6 97.47 2.53
3120-3140 0 37 37 37 0 37 0 37 0 100 0 0 100 100 0 0 36.13 3.6 94.87 5.13
3140-3160 0 5 5 5 0 5 0 5 0 100 0 0 100 100 0 0 36.13 1 83.33 17.67
3160-3180 0 14 14 14 0 14 0 14 0 100 0 0 100 100 0 0 36.13 1.6 100 0
3180-3200 0 24 24 24 0 24 0 24 0 100 0 0 100 100 0 0 36.13 2 100 0
3200-3220 0 1 1 1 0 1 0 1 0 100 0 0 100 100 0 0 36.13 0.2 100 0
3220-3240 0 18 18 18 0 18 0 18 0 100 0 0 100 100 0 0 36.13 1.6 100 0
3240-3260 0 7 7 7 0 7 0 7 0 100 0 0 100 100 0 0 36.13 0.6 100 0
3260-3280 0 7 7 7 0 7 0 7 0 100 0 0 100 100 0 0 36.13 0.6 100 0
3280-3300 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 0.6 100 0
3300-3320 0 4 4 4 0 4 0 4 0 100 0 0 100 100 0 0 36.13 1 100 0
3320-3340 0 10 10 10 0 10 0 10 0 100 0 0 100 100 0 9 36.13 2 100 0
Keys: M=Miliolina/Porcelaneous , R= Rotaliina/Hyaline, TC= Total calcerous, BC = Calcerous benthic, A= Textulariina/Arenaceous, B=Benthic, P=Planktic, TFC=Total
foraminifera count, %P= percentage of planktic, %B= percentage of benthic, %M= percentage of Miliolina, %A= percentage of Arenaceous, %R= percentage of
Rotaliina, %FOBC= percentage of Benthic Calcerous Foraminifera, %FOBA= percentage of Benthic Arenaceous Foraminifera, T = Tau index, Pwd=Palaeowater
depth, α= Fisher diversity index, %F/O = Foraminifera to Ostracoda ratio.

Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria

Similar to Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria (20)

More from Premier Publishers

More from Premier Publishers (20)

Recently uploaded

Recently uploaded (20)

Foraminiferal Approach to Palaeoenvironmental Interpretations: Case Study of Priabonian – Rupelian Sediments of the Niger Delta, Nigeria