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Geotechnical and Chemical Evaluation of Tropical Red Soils in a Deltaic Environment: Implications for Road Construction

TL;DR: Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction.
Abstract: Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2 . Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to A-2-4 subgroups of the AASHO classification. The overall implication of these composite engineering properties is that the non-lateritic soils rate as poor to fair subgrade materials.

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Journal of Geography and Geology; Vol. 8, No. 3; 2016
ISSN 1916-9779 E-ISSN 1916-9787
Published by Canadian Center of Science and Education
42
Geotechnical and Chemical Evaluation of Tropical Red Soils in a
Deltaic Environment: Implications for Road Construction
Akaha C. Tse
1
& Adunola O. Ogunyemi
1
1
Department of Geology, University of Port Harcourt, Nigeria
Correspondence: Akaha C. Tse, Department of Geology, University of Port Harcourt, Nigeria. Tel:
234-8055-364-149. E-mail: akaha.tse@uniport.edu.ng
Received: December 10, 2015 Accepted: December 30, 2015 Online Published: August 30, 2016
doi:10.5539/jgg.v8n3p42 URL: http://dx.doi.org/10.5539/jgg.v8n3p42
Abstract
Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated
using combined conventional engineering geological investigation with major oxide geochemistry to determine
their properties and evaluate their engineering performance in road construction. Laboratory test results indicate
that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values
of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific
gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are
soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9%
respectively whereas the average undrained shear strength is 172kN/m
2
. Maximum dry density and optimum
moisture content values fall between 1680 to 1880kN/m
2
and 13-16% respectively. Generally the soils classify as
A-7-6 to A-2-4 subgroups of the AASHO classification. The overall implication of these composite engineering
properties is that the non-lateritic soils rate as poor to fair subgrade materials.
Keywords: geotechnical, red soils, sesquioxide, lateritic, subgrade, Niger Delta
1. Introduction
The Niger Delta wetland area in Nigeria consists of three geomorphologic zones including the coastal or Lower
delta zone, Transition or Mangrove zone and the Upper deltaic plain or freshwater zone. The freshwater zone
consists of dry flatlands and plains (Akpokodje 1989 and Teme 2002) and its subsurface soil profile consists of a
top lateritic clay layer underlain by silty clays and sands which are in turn succeeded by poorly graded sand and
gravel. Akpokodje (1989) described the lateritic layer as a reddish brown/brown soft to firm clay which becomes
stiffer with depth and is mottled with shades of grey or brown and also tends to contain reddish, lateritic gravelly
concretions with a varying proportion of silt and clay. Although all of the Niger Delta area is characterized by
tropical rainfall conditions, annual rainfall ranges from 2000mm in the freshwater zone to over 4000mm at the
coast which also accounts for nearly 85% of the annual rainfall. Thus the coastal and mangrove zones contain
nearly 70% of the numerous marshes and back swamps that occupy as much as 50% by area of the entire delta
region. Also they are usually submerged during the wet season (April to October). However the relatively less
“wet” conditions in the freshwater zone coincide with the occurrence of lateritic or tropical red solids. These
deltaic lateritic soils differ markedly from the other lateritic soils because of some mode of formation related
peculiarities (Omotosho, 2015). Alabo et al. (1984) studied these soils in Port Harcourt area and its environs
which belong to the freshwater zone. They referred to the soils as ‘deltaic red soils’ on the basis of their colour,
one of the several identifying criteria for laterites and lateritic soils. These tropical red soils occur exclusively in
the freshwater zone and are widely used in highway and other earthen work constructions, and as back fill
materials. The performance of the soils for engineering construction in the delta region is varied. Early failure of
pavements constructed with these soils is common. Studies by Alabo et al. (1984) showed that locally in Port
Harcourt area, the soils belong to the A-2-7 class of AASHO classification and this correlates well with their
good performance as fill materials. Adeyemi (2002) has emphasized the imperative of a comprehensive
evaluation of any lateritic soils prior to utilization for any engineering purpose. This is because of the unique set
of physical, chemical and engineering properties the soils exhibit in response to the different climatic,
geomorphologic and geological conditions of their origin. Due to the abundance of these soils and ready
availability, they have been widely used in the construction of foundations, roads, airfields, low-cost housing,

jgg.ccsenet.org Journal of Geography and Geology Vol. 8, No. 3; 2016
43
and compacted fill in earth embankments. This affects their variable performance as soil materials for road
earthwork, and often require stabilisation (Omotosho and Eze-Uzomaka 2008, Ugbe 2011, Adeyemi et al. 2015)
compared to other matured tropical lateritic soils (Elarabi et al. 2013, Elsharief et al. 2013, Carvalho et al 2015,)
which achieve better success under mechanical compaction in engineering construction. Therefore, for
engineering purposes it is important that the geological and engineering properties as predicted or derived from
testing are reliable (Kamtchueng et al. 2015). This paper will attempt to determine the major oxide geochemistry
and geotechnical properties of these red soils. The new data will help to classify the lateritic nature of the
examined soils and also determine their quality as fill materials.
2. Geological Setting
The studied area is located in the freshwater geomorphologic zone of the eastern Niger which lies between
latitudes 4
o
30
and 5
o
20
and longitudes 6
o
15
and 7
o
35
(Fig.1). The geology of the Niger Delta including its
tectonic framework, stratigraphy and sedimentation pattern is well known from the published accounts of several
authors, including Allen (1965) and Short and Stauble (1967), Doust and Omatsola (1990), Reijers et al 1997,
Reijers (2011) and Nwajide (2013). The Niger Delta is a large arcuate delta of the destructive, wave dominated
type. Its development is a function of the balance between the rate of sedimentation and the rate of subsidence.
Tectonic evolution of the delta was controlled by Cretaceous fracture zones formed during the triple junction
rifting and opening of the south Atlantic. The sedimentary fill of the southern Nigeria sedimentary basin was
controlled by three major tectonic stages together with epirogenic movements which led to major episodes of
transgressions and regressions. The cycles accounted for the sedimentary units in both the Cretaceous and
Tertiary Southern Nigerian sedimentary basins, among which is the Niger Delta (Odigi, 2007). The delta
represents the regressive phase of the third cycle of deposition which began during the Paleocene and has
continued to the present day. The basin contains Cenozoic to Recent deposits emplaced in high energy
constructive deltaic environments. The delta is underlain by three lithostratigraphic units comprising from
bottom of Akata Formation deposited under marine conditions and consisting of shale. The formation has an
approximate range of thickness from 0 6,000m and ranges from Paleocene to Holocene in age. It is the main
source rock in the petroliferous Niger Delta. Shale diapirism due to loading of poorly compacted, over-pressured,
prodeltaic and delta-slope clays resulted in the deposition of the Akata Formation. It is overlain by a paralic
facies of shale and sand intercalation known as Agbada Formation deposited under mixed marine and continental
environments. This sequence consists of an upper predominantly sandy unit with minor shale intercalations and a
lower shale unit which is thicker than the upper sandy unit. The Agbada Formation is over 10,000ft thick and
ranges in age from Eocene to Recent. All hydrocarbon accumulations in the Niger Delta are found in this
formation. It is a pro-delta deposit characterized by gravity tectonics structures such as shale diapirs, roll-over
anticlines, collapsed growth fault crests, and steeply dipping closely spaced flank faults. The top Benin
Formation, Oligocene to recent age, is predominantly sandy although some shale intercalations are common. It
was deposited under continental conditions. Various types of Quaternary deposits overly the Benin formation
especially in the coastal and Mangrove zone and their nature have been discussed extensively by Akpokodje
(1989) and Tse and Akpokodje (2013). Generally they consist of a top stratum of clay, silt or organic matter and
sand, silt-clay mixture overlying a sandy/sand substratum which occurs at variable depths, ranging from 5 to
30m or more in the subsurface.

jgg.ccsenet.org Journal of Geography and Geology Vol. 8, No. 3; 2016
44
Figure 1. Map of Niger Delta showing geomorphologic zones and sampling points
In the freshwater zone, the Benin Formation is covered by appreciable thicknesses of red soils. Assez (1976)
suggested they were formed as a result of the weathering of sedimentary deposits of sands and poorly cemented
sandstones with some clay and their subsequent ferrugenisation. The dry flat land and plains is characterized by
freshwater rivers, creeks and seasonal marshes. Soil profiles comprises of a top lateritic clay layer succeeded by
poorly graded sand and gravel. The zone is comparatively the best drained of all the other geomorphic zones and
is thus relatively drier. The permeability of soils is low to high and aquicludes, perched and normal aquifers are
common. Overall, the soils have variable foundation potentials as discussed by Akpokodje (1979), Teme (2002),
and Tse and Akpokodje (2013).
3. Materials And Methods.
Soil samples used for this study were obtained along major roads in areas which geomorphologically lie in the
dry flatland and plains in the eastern Niger Delta along an east-west direction as shown in Fig. 1. The samples
were collected from active and abandoned borrow pits used for mining of backfill and pavement materials by
civil construction companies. The soils range from light yellow to greyish brown to reddish brown
clayey-silty-sandy earth materials. At each location, three disturbed samples were collected at the bottom, middle
and top in a vertical profile along the face of the pits which were first scraped to obtain fresh samples. The soils
were described by visual inspection in the field and were subjected to laboratory tests according to methods and
procedures specified by BS 1377 of 1990. Classification and strength tests carried out included particle size
distribution, Atterberg limits, linear shrinkage, specific gravity by density bottle method, standard proctor
compaction test, quick undrained unconsolidated triaxial test in standard triaxial test cells 76mm high and 38mm
in diameter, and soaked and unsoaked California Bearing Ratio (CBR). Sieve analysis first involved washing of
the soil samples through ASTM sieve number 200 (0.075mm mesh) to separate sand fraction from the fines (clay
and silt) fraction. Thereafter, mechanical sieve analysis was performed to separate the sand into the various

jgg.ccsenet.org Journal of Geography and Geology Vol. 8, No. 3; 2016
45
particle sizes. The moisture content density relationships of the soils were determined by the standard Proctor
test where 3kg of the soil was compacted in 3 equal layers in a cylindrical metal mould of volume 0.00956m
3
using a 4.5kg rain falling through a height of 0.45m. Linear shrinkage tests were carried out to determine the
water content at which no further decrease in the volume of the soil masses will not be experienced. The major
oxides composition of the soils was determined by X-ray fluorescence analysis using Thermoscientific Advant
1200 model equipment. Results were used to determine the lateritic nature of the soils using the silica
sesquioxide ratio presented by Rossiter (2004) as described in Alayaki (2015). Finally statistical regression
analysis was performed on the test results and correlation coefficients tests were used to establish the
relationship among the properties tested.
4. Results
A field examination and visual observation shows that the soils range from light yellow to greyish brown to
reddish brown clayey-silty-sandy earth materials. The major oxides composition of the soils are shown in Table 1.
The soils are made up of 62.66 to 69.94 wt.% of SiO
2
, 0.11 to 0.32 wt.% of Fe
2
O
3
, and 27.20 to 34.12 wt.% of
Al
2
O
3
. Thus quartz, iron and aluminium oxides are the dominant components of the soils. Results of the
geotechnical properties of these tropical red soils which consist of variable proportions of gravel, sand, and fines
fraction are shown in Table 2. Typical particle size distribution curves of the soils shown in Fig. 2 reveal that the
amount of fines ranges from 22 to 76%. Soils in Ulakwo and Ogrike have the least amount of fines while
Igwuruta and Emohua have the highest. A quantitative measure of the range of soil particles in a given sample is
the uniformity coefficient. This varies from 2 to 9 with most of the samples having values of below 5 indicating
that the soils are poorly graded. The moisture-density relationship results are summarized in Fig. 3. Maximum
dry density of 1680 to 1880 kg/m
2
were obtained at optimum moisture content (OMC) of 13 to 16%. Soils in the
northern and western northern parts of the study area attained the least MDD of approximately 1700kg/m
3
at
OMC of 15%, while the ones in the south eastern axis from Igwuruta to Tabaa gave the highest MDD of
approximately 1850kg/m
3
at an average OMC of 13%. Lateritic soils which give OMC between 8-10% and
above 10% are rated by Philips (1952) as average to poor respectively for use under bituminous surfacing.
Atterberg limits are important factors in the use of lateritic soils in pavement construction as sub-grade and
sub-base materials. The average values of liquid limit of 26 to 48% classifies as clays of low to intermediate
plasticity. Plasticity index range from 5 to 15%. These are soils of low swelling potentials according to the Ola
(1982) rating. Thus, when the Skempton activity was calculated from the results of the plasticity index and
percentage of clay obtained from the hydrometer tests, values of 1.01 to 5.56 with an average of 1.23 were
obtained (Table 3). These classify as normal to active clays of low to medium sensitivity (Skempton, 1953). The
California Bearing Ratio (CBR) test is used in the empirical estimation of the bearing capacity of sub-grade and
sub-base materials under soaked and dry conditions. The soaked and unsoaked CBR values range between 3-9%
and 14-38% respectively, and their relationship is graphically shown in Fig. 4.
Table 1. Major oxide geochemistry and silica:sesquioxide ratios
Location %
SiO
2
%
Fe
2
O
3
%
Al
2
O
3
%
MgO
%
CaO
%
NaO
%
K
2
O
%
MnO
2
%
T
i
O
2
%
P
2
O
5
%
Total
SSR
Ogrike 69.94 0.11 27.20 0.08 0.19 0.08 0.10 0.08 2.02 0.020 99.82 4.37
Ahoada 68.43 0.13 28.60 0.05 0.25 0.10 0.13 0.10 2.02 0.023 99.83 4.06
Elele Alimini 65.51 0.15 31.55 0.04 0.21 0.08 0.11 0.10 2.12 0.026 99.90 3.52
Igwuruta 66.43 0.18 30.60 0.11 0.25 0.10 0.13 0.07 2.01 0.017 99.90 3.69
Ulakwo 67.08 0.16 29.75 0.10 0.30 0.12 0.10 0.08 2.15 0.022 99.85 3.82
Eleme 68.22 0.20 28.45 0.06 0.37 0.10 0.16 0.05 2.24 0.030 99.88 4.07
Nonwa 66.83 0.32 30.09 0.10 0.29 0.11 0.15 0.06 2.05 0.029 99.88 3.74
Bori 62.66 0.24 34.12 0.07 0.28 0.14 0.14 0.09 2.19 0.018 99.95 3.09
Tabaa 64.88 0.17 31.80 0.08 0.33 0.09 0.12 0.05 2.21 0.032 99.76 3.45
SSR = silica:sesquioxide ratio
Table 2. Geotechnical properties of the soils

jgg.ccsenet.org Journal of Geography and Geology Vol. 8, No. 3; 2016
46
S/
No
Location GS LL
(%)
PL
(%)
PI
(%)
LS
(%)
%
Fines
%
Sand
CU Cohesion
(kN/m
2
)
FA
(
O
)
OMC
(%)
MDD
(Kg/m
3
)
Soaked
CBR
Unsoaked
CBR
1 Ogrike 2.68 30 23 7 7.7 31 69 9 160 3 15 1780 3.61 18.79
2 Obite 2.66 35 24 11 7.5 50 51 7 20 23 16 1680 2.71 13.83
3 Abarikpo 2.67 26 21 5 7.6 53 47 2 35 17 16 1710 3.61 15.48
5 Elele
Alimini
2.65 47 35 12 7.5 58 42 4 30 22 15 1700 5.11 14.13
6 Emohua 2.67 41 32 9 7.7 76 22 3 60 14 15 1730 6.61 18.49
7 Ibaa 2.68 44 33 11 7.5 51 51 5 135 5 15 1770 3.41 17.89
8 Omagwa 2.68 48 33 15 7.5 60 41 1 60 14 15 1770 4.36 19.39
9 Igwuruta 2.67 42 29 12 7.5 69 38 2 115 8 15 1820 5.56 24.80
10 Ulakwo 2.67 40 33 7 7.5 37 67 5 120 12 14 1850 9.17 25.54
11 PH 2.67 39 28 12 7.6 51 49 6 30 17 16 1690 3.76 13.68
12 Eleme 2.66 34 24 10 7.7 43 58 7 150 6 14 1820 5.86 23.00
13 Nonwa 2.67 28 24 10 7.7 51 49 6 40 25 14 1860 6.31 16.68
14 Bori 2.67 34 28 12 7.7 46 54 5 130 10 14 1880 7.21 29.16
15 Taabaa 2.66 40 29 11 7.8 62 39 2 100 7 13 1880 7.67 37.76
Average results for 3 samples at each location. GS = specific gravity, LL = liquid limit, PL = plastic limit, LS =
linear shrinkage, CU = coefficient of uniformity, FA = frictional angle
Table 3. Classification and description of soil activity (after Skempton 1953)
S/No Location Clay
amount
%
Plasticity Index
(%)
Activity
value
Activity classification Activity
description
1 Ogrike 5.73 7.4 1.29 Active Low sensitivity
2 Obite 4.30 11 2.56 Active Medium sensitive
3 Abarikpo 4.86 4.9 1.01 Normal Insensitive
5 Elele Alimini 5.08 12.8 2.51 Active Medium sensitive
6 Emohua 4.03 9.2 2.28 Active Medium sensitive
7 Ibaa 2.52 11 4.37 Active sensitive
8 Omagwa 2.68 14.9 5.56 Active sensitive
9 Igwuruta 5.08 12.4 2.47 Active Medium sensitivity
10 Ulakwo 1.38 7.2 5.21 Active sensitive
11 Port Harcourt 7.88 11.7 1.48 Active Low sensitivity
12 Aleto Eleme 6.11 10.2 1.66 Active Low sensitivity
13 Nonwa 4.28 8.00 1.87 Active Low sensitivity
14 Bori 6.41 9.7 1.86 Active Low sensitivity
15 Taabaa 10.08 10.60 1.05 Normal Low sensitivity

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Cites background from "Geotechnical and Chemical Evaluatio..."

  • ...Shale diapirism due to loading of poorly compacted, over-pressured, prodeltaic and delta-slope clays resulted in the deposition of the Akata Formation, the continental intercalaire (Abija, 2019; Tse and Ogunyemi, 2016) by the higher density delta-front sands of the Agbada Formation (Bakare, 2006)....

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Abstract: Deltaic laterite is the most suitable and most widely used soil material for road embankment in the Niger Delta. Usually, its natural characteristics fall short of the minimum requirements for such applications hence it has to be stabilised to improve its properties. In this study, samples of deltaic lateritic soils were subjected to mechanical (with or without controlled sand addition), cement and cement-sand (composite) stabilisation methods to improve strength for improved engineering applications. Mechanical stabilisation was found to satisfy subgrade requirements while the addition of sand produced sub-base material quality at best depending on compacted maximum dry density (MDD), which itself is dependent on the optimum sand content (OSC). The OSC was also shown to affect the optimum moisture content (OMC) and the soaked California bearing ratio (CBR) of stabilised specimens. Combination of the test results produced a graphical model to predict the influence of mechanical stabilisation on the soil materials using the percentage fines (that is, passing through a 75 mm sieve) obtainable from wet sieving. Cement stabilisation of the soil (by indigenous highway standard) produced base-course quality materials with cement content in excess of 12 %, which is economically unviable. However, the addition of controlled proportions of sharp sand (also abundant in the Niger Delta) to the soilcement mixtures produced base-course quality materials with 6 % cement (less than half of that obtained through only cement stabilisation) and about 40 % sand content. A model was also presented to predict the other constituents of sand-cement stabilisation using the percentage fines obtainable from wet sieving.

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References
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Journal ArticleDOI
TL;DR: In this paper, a new threefold lithostratigraphic subdivision for the Niger delta subsurface is introduced, comprising an upper sandy Benin Formation, an intervening unit of alternating sandstone and shale named the Agbada Formation, and a lower shaly Akata Formation.
Abstract: The coastal sedimentary basin of Nigeria has been the scene of three depositional cycles. The first began with a marine incursion in the middle Cretaceous and was terminated by a mild folding phase in Santonian time. The second included the growth of a proto-Niger delta during the Late Cretaceous and ended in a major Paleocene marine transgression. The third cycle, from Eocene to Recent, marked the continuous growth of the main Niger delta. A new threefold lithostratigraphic subdivision is introduced for the Niger delta subsurface, comprising an upper sandy Benin Formation, an intervening unit of alternating sandstone and shale named the Agbada Formation, and a lower shaly Akata Formation. These three units extend across the whole delta and each ranges in age from early T rtiary to Recent. They are related to the present outcrops and environments of deposition. A separate member of the Benin Formation is recognized in the Port Harcourt area. This is the Afam Clay Member, which is interpreted to be an ancient valley fill formed in Miocene sediments. Subsurface structures are described as resulting from movement under the influence of gravity and their distribution is related to growth stages of the delta. Rollover anticlines in front of growth faults form the main objectives of oil exploration, the hydrocarbons being found in sandstone reservoirs of the Agbada Formation.

1,036 citations


"Geotechnical and Chemical Evaluatio..." refers background in this paper

  • ...The geology of the Niger Delta including its tectonic framework, stratigraphy and sedimentation pattern is well known from the published accounts of several authors, including Allen (1965) and Short and Stauble (1967), Doust and Omatsola (1990), Reijers et al 1997, Reijers (2011) and Nwajide (2013)....

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404 citations


"Geotechnical and Chemical Evaluatio..." refers background in this paper

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170 citations


"Geotechnical and Chemical Evaluatio..." refers background in this paper

  • ...According to Gidigasu (1976), the high aluminum oxide content compared to iron oxides in soils is one of the features common with soils formed in a continuously wet climate characteristic of the Niger Delta....

    [...]

Journal ArticleDOI
01 Sep 2011-Geologos
TL;DR: An updated biostratigraphic scheme for the Niger Delta is presented in this paper, which takes into account local and delta-wide effects of sea-level cyclicity and delta tectonics.
Abstract: Stratigraphy and sedimentology of the Niger Delta During the Cenozoic, until the Middle Miocene, the Niger Delta grew through pulses of sedimentation over an oceanward-dipping continental basement into the Gulf of Guinea; thereafter progradation took place over a landward-dipping oceanic basement. A 12,000 m thick succession of overall regressive, offlapping sediments resulted that is composed of three diachronous siliciclastic units: the deep-marine pro-delta Akata Group, the shallow-marine delta-front Agbada Group and the continental, delta-top Benin Group. Regionally, sediment dispersal was controlled by marine transgressive/regressive cycles related to eustatic sea-level changes with varying duration. Differential subsidence locally influenced sediment accumulation. Collectively, these controls resulted in eleven chronostratigraphically confined delta-wide mega-sequences with considerable internal lithological variation. The various sea-level cycles were in or out of phase with each other and with local subsidence, and interfered with each other and thus influenced the depositional processes. At the high inflection points of the long-term eustatic sea-level curve, floodings took place that resulted in delta-wide shale markers. At the low inflection points, erosional channels were formed that are often associated, downdip, with turbidites in low-stand sediments (LSTs). The megasequences contain regional transgressive claystone units (TST) followed by a range of heterogeneous fine-to-coarse progradational or aggradational siliciclastic (para)sequence sets formed during sea-level high-stand (HST). An updated biostratigraphic scheme for the Niger Delta is presented. It also updates a sedimentation model that takes into consideration local and delta-wide effects of sea-level cyclicity and delta tectonics. Megasequences were formed over time intervals of ~5 Ma within individual accurate megastructures that laterally linked into depobelts. The megasequences form the time-stratigraphic frame of the delta and are the backbone for the new delta-wide lithostratigraphy proposed here. Such a new lithostratigraphy is badly needed, in particular because of the vigorous new activity in the offshore part of the Niger Delta (not covered in this contribution). There, as well as in the onshore part of the delta, the traditional lithostratigraphic subdivision of the Cenozoic Niger Delta section into three formations is insufficient for optimum stratigraphic application; moreover, the various informal subdivisions that have been proposed over time are inconsistent.

167 citations


"Geotechnical and Chemical Evaluatio..." refers background in this paper

  • ...The geology of the Niger Delta including its tectonic framework, stratigraphy and sedimentation pattern is well known from the published accounts of several authors, including Allen (1965) and Short and Stauble (1967), Doust and Omatsola (1990), Reijers et al 1997, Reijers (2011) and Nwajide (2013)....

    [...]

Book ChapterDOI
01 Jan 2009

166 citations