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A PAPER REVIEWED BY

AGBAJE TITUS MAYOWA

Email Address: feelmayor@gmail.com

AT THE UNIVERSITY OF ILORIN, KWARA STATE, NIGERIA

GRANULOMETRIC ANALYSIS AND

HEAVY MINERAL STUDIES OF BIMA

SANDSTONE, UPPER BENUE

TROUGH: IMPLICATION FOR

PALEOENVIRONMENTAL

RECONSTRUCTION

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TABLE OF CONTENT

INTRODUCTION……………………………………………………………………………………………… 3

LITERATURE REVIEW ……………………………………………………………………………………… 4

LOCATION OF STUDY AREA…………………………………………………………………………….. 6

GEOLOGY OF THE STUDY AREA……………………………………………………………………….. 7

STATEMENT OF PROBLEM ……………………………………………………………………………… 11

JUSTIFICATION ……………………………………………………………………………………………….. 12

AIM & OBJECTIVES …………………………………………………………………………………………. 13

METHODOLOGY…………………………………………………………………………………………….. 14

EXPECTED RESULT AND VALUE ADDITION………………………………………………………. 17

TIMELINE ……………………………………………………………………………………………………….. 18

BUDGET/SPONSORS ………………………………………………………………………………………. 19

DISSEMNINATION TECHNIQUE……………………………………………………………………….. 20

REFERENCES…………………………………………………………………………………………………… 21

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INTRODUCTION

Sedimentary rocks are classified generally based on texture, cement and groups. These groups

can be subdivided into three such as detrital/clastic, biogenic and chemical sediments. These

sediments belong to the clastic group, which could be clean having silica cement, matrix rich-

greywacke and the arkosic type. The Benue Trough is a 1,000 km long, 50 to 150 km wide

intracontinental NE – SW trending rift depression in Nigeria. The basin (Benue Trough) is filled

with continental and marine sediments (about 6,500 m). The Benue Trough is divided into three

segments: the lower, middle and upper Benue regions.

The Upper Benue is an extensive sedimentary basin, with an area extent of about 203,000 km2

and occupies the upper reaches of the Benue valley. Its main drainage network comprises

numerous streams and rivers flowing into the River Benue from the north and south. The major

system includes the Gongola, Kilunga and Pai to the north and the Faro and Taraba from the

south of the River Benue. The ground slopes from the west, northeast and eastern areas into

the centre of the valley, but regionally sloping towards the southwest, the direction of flow of

the River Benue.

Bima sandstone is the name given to the continental Intecalaire in the Chad Basin and Upper

Benue Trough of Nigeria. It is the oldest sedimentary deposit in these regions. The composition

of Bima sandstone, mainly Arkose to quartz arenite and its depositional structures have

generated wide speculations as to the source and environment of deposition. This geologic

formation reaches hundreds of meters in thickness and is of significant interest in the Chad

basin as it is assumed to be the potential reservoir rock for petroleum storage and it is of hydro

geological significance in the upper Benue trough.

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LITERATURE REVIEW Obiefuna G.I. et al (2010) Geochemical and Mineralogical Composition of Bima Sandstone

Deposit, Yola Area, NE Nigeria.

The results of the log of ratio of the major oxide groups indicate that Bima Sandstone of the

study area can be classified as greywacke, arkoses and lithic arenite including sub-greywacke

and protoquartzites. The abundant alkali values as shown by the relatively high log K2O/Na2O

ratio in most of the samples indicated immature sandstones whereas low alkali values in

other samples revealed mature sandstones. The enrichment of silica (quartz) over Al2O3 (log

SiO2/Al2O3<1.5) indicate that Bima Sandstone has undergone long period of transportation

and have been subjected to intense weathering resulting in the destruction of other minerals

especially plagioclase and potassium feldspars during transportation. Microscopic examination

of about sixteen slides (16) of Bima Sandstone under both plane and cross polars revealed the

following average mineralogical composition: quartz (65%) feldspars (14%), mica (9%), iron

oxide (5%), calcite (3%) further confirms quartz/lithic arenites and greywackes as some of the

predominant sedimentary rocks in the study area.

Bakari A., (2014) Granulometric Analysis of Bima Sandstone around Chekole in Gombe Sub-Basin of the Upper Benue Trough, Nigeria. The study investigates the grain size distribution of Bima sandstone formation exposed around

Chekole in North-eastern Nigeria and determines the condition of their deposition. The result of

the granulometric analysis indicates that the grain size of the Bima formation is continental in

origin which is dominated by coarse grains and some fine to medium grains which indicates an

evidence of change in depositional energy medium from moderate to high. Kurtosis values

ranged from Platykurtic to leptokurtic. The positive skewness values indicate fluvial process

under high energy condition. The sandstone has high storage capacities for hydrocarbon

accumulation, good aquifer characteristics and excellent economic value as aggregates for

construction.

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Obiora F.I. et al (2014) Depositional Environment of Bima Sandstone in Hinna Community in

Yamaltu/Deba Local Government Area of Gombe State, Nigeria and its Economic Importance in

Construction

The result of the sieve analysis indicates that the grain size, the formation ranges from fine to

medium then coarse grains which are evidence of change in depositional energy medium from

moderate to high. The positively skewness and bivariate plot show river origin also the grain

size proper proportions suggest that the sandstone has economic value. It can be mined for

engineering construction purpose thereby reduce cost compared to that of present day river

sand with a doubtable gradation for construction.

Saka A.O. (2012) Lithofacies Association in the Bima Sandstone of the Upper Benue Trough,

Nigeria

Facies association of the Bima Sandstone in the Upper Benue Trough reflects the tectonic

evolution of the basin. The concept of pull apart basin fits the rapidly changing alluvial facies

from coarser grained marginal to finer grained axial deposits. The stacking patterns of the

deposits are mainly of fan and fluvial channel sedimentation. While alluvial fan was deposited

as gravity and debris flow, a high sinuosity stream flow leading to a low sinuous form, probably

due to rejuvenation in the competence of the stream, was the basis of channel deposition of

the point/transverse bar as well as braided deposits in the basin. Four major Facies association

identified are: conglomeratic facies association – FA I; tabular sandstone facies association – FA

II; Soft sediment deformed beds FA III and medium bedded lenticular sandstone association- FA

IV.

LOCATION OF STUDY AREA

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The study area is located about 10 kilometers east of Hinna community in Gombe state which corresponds to latitudes 10° 20’ and 10° 24’ North and longitudes 11° 37’ and 11° 40’ East. The area falls in the (Gombe sub-basin) upper margins of the upper Benue Trough. It is characterized by undulating terrain with few flat plains. The climate is semi-arid with three distinct seasons: a long hot dry season from April to May.

Day time temperatures are in the range of 36 to 40°C and night time temperatures fall to 10 to

17°C. This is followed by a short rainy season from May to September with a daily minimum

temperature of 20°C and a maximum of 31°C with relative humidity of 40 to 60% and annual

rainfall from 860 to 900 mm. Finally, the cold (harmattan) season runs from October to March

when temperatures fall to about 20°C and a dry dusty wind blows from the Sahara desert

Figure 1 Map showing the location of study area

GEOLOGY STUDY OF THE AREA

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The Upper Benue Trough is made up of two arms, the Gongola Arm and the Yola Arm (Obaje,

2009). However, some authors have sub-divided the Upper Benue Trough to include a third

central Lau-Gombe sub-basin. In both arms of the basin, the Albian Bima Sandstone lies

unconformably on the Pre-Cambrian Basement. This formation was deposited under

continental conditions (fluvial, deltaic, lacustrine) and is made up of coarse to medium grained

sandstones, intercalated with carbonaceous clays, shales, and mudstones.

The Bima Sandstone is the most extensive earliest continental sediments deposited on the

floor of the entire basins of northeast Nigeria as a basal unit of the Cretaceous series soon after

crustal rifting. It lays discomformably on the basement complex. The first major study on the

formation was carried out by Carter, et al. (1963), based on the structural and Sedimentological

framework of the Lau sub-basin. The Bima Sandstone was subdivided by (Carter, et al., 1963)

into a Lower, Middle and Upper Bima. The Middle Bima is reported to be shaley in most parts

with some limestone intercalations and was assumed to be deposited under a more aqueous

anoxic condition (lacustrine, brief marine). Consequently, marine transgression episode caused

the deposition of Yolde, Dukul, Jessu, Sekule and Numanha sedimentary formations, which are

found in the Upper Benue Trough.

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Figure 2: Geological map of the Upper Benue Trough. 1, quaternary alluvium: 2, tertiary to

recent volcanism: 3, kerri kerri formation: 4, Gombe sandstone: 5, pindiga formation: 6, yolde

formation: 7, Bima sandstone: 8, burashika group (Mesozoic volcanism): 9, granitoids

precambrian (modified after Maurin et al., 1985).

Stratigraphic Units of the Bima Sandstone

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The Bima Sandstone is dominantly a quartz arenite occupying the base of the Cretaceous

succession in both the Upper Benue Trough and the Borno basin of Nigeria. The sediments

were mainly derived from juxtaposed basement suites of older granite and gneisses which were

subjected to humid conditions that accelerated the weathering processes. Despite the

dominance of quartz arenite as the main lithology, the field relationships of the beds made it

possible to differentiate the formation into three members; the Lower Bima (Bima – 1) the

Middle Bima (Bima – 2) and the Upper Bima (Bima – 3) (Carter, et al., 1963; Allix, 1983).

The Lower Bima was directly affected with the tectonic events (Guiraud, 1993) as large clasts

with muddy matrix were straddled as sediments within the fractured horst and graben of the

marginal rift structure. The unit is revealed at the exposed core of Lamurde anticline consisting

of shale intercalated with Feldspathic and calcareous sandstone (Carter, et al., 1963). The

middle and upper Bima beds overstep the lower Bima syn-rift deposits and in some places the

marginal horst of the rifted basement (Guiraud, 1990) (Figure 3). The clasts of the middle Bima

are coarse to medium grained with well marked pebbly lag deposits at the base of successive

beds while the upper Bima sediments are mainly of medium to fine grained clasts.

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Figure 3: Schematic Diagram of Lithostratigraphic Sequences of Bima Sandstone in Relation to

the Basement (Guiraud, 1990)

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STATEMENT OF PROBLEM Previous studies in this area have investigated grain size distribution; geochemistry and geology

of sandstone formation exposed around Chekole in North-eastern Nigeria and determined the

condition of their deposition.

This proposed research is therefore expected to focus on Granulometric and Heavy mineral

analysis of sandstone in Hinna community.

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JUSTIFICATION The knowledge of particle size distribution and the assemblages of heavy minerals in

Sedimentary rocks particularly in the earth crust make it possible to effectively locate and use

essential minerals to predict their dispersal pattern when they re-enter the natural

environment and information about the source of the sediment, provenance of the material as

well as the environment of deposition and mineral composition of Bima sandstone.

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AIM & OBJECTIVES The aim is to provide a better understanding of the petrological characteristics of the

sedimentary environment.

OBJECTIVES: Investigate the grain size distribution of the Bima Formation on the basis of their

physical characteristics

Determine the conditions of the deposition.

Paleoenvironment Reconstruction

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METHODOLOGY A total number of twenty sandstone samples were collected randomly at different locations

from exposed Bima Sandstone deposits. Twenty samples were subjected to grain size analyses

out of which ten (10) of the finest residues were randomly selected for heavy mineral analysis.

The mineralogical analyses was carried out petrographically with the prepared thin sections

and viewed under both plane and cross polarized microscope in Department of Geology of the

University of Ilorin Nigeria in May to June 2015.

LABORATORY ANALYSIS

In the case of grain size analysis (granulometric); the samples will be effectively disaggregated

by squeezing them between fingers and paper sheets. The sand samples will be observed under

the binocular microscope in order to view the proportion of aggregated sands. A weight of

100gm will be obtained using a weight balance as a measuring instrument. Sieving analysis will

be achieved by using a sieve shaker of nine sieves agitating for about 10min. The sieve sizes to

be used for this operation are as follows; 4.00mm, 2.36mm, 1.60mm, 1.00mm, 0.50mm,

0.30mm, 0.25mm, 0.112mm, 0.09mm, 0.063mm, <0.0063mm. The corrected weight of each

fraction will be used to calculate individual percentage. Each cumulative percentage will be

obtained as a percentage of the cumulative of the cumulative corrected weight to the total

corrected weight. The grain size of the 5th, 16th, 25th, 50th, 75th, 84th and 95th percentiles

will be obtained from each cumulative curve drawn. These are used to calculate statistical

parameters for the Graphic Mean (M), Standard Deviation (sorting) (SD), Graphic Kurtosis (K)

and Graphic Skewness (SK) based on (Folk et al 1957) as follows:

Graphic Mean (M) = Ø16+Ø50+Ø84

3

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Standard Deviation (Sorting) (SD) = Ø84-Ø16 + Ø95- Ø5

4 6.6

Graphic Kurtosis (K) = Ø95- Ø5

2.44(Ø75- Ø25)

Graphic Skewness (SK) = (Ø84+ Ø16-2 Ø50) + (Ø95+ Ø5-2Ø50)

2(Ø84- Ø16) 2(Ø95- Ø5)

HEAVY MINERAL ANALYSIS

Ten samples will be selected from the twenty samples used for sieve analysis.

The prepared slides will be examined petrographically for non-opaque heavy minerals and on

reflected light for opaque heavy minerals. Identification of mineral type is based on optical

characteristics such as color, pleochroism, absorption, relief, extinction, and birefringence;

others are size, crystal form, and elongation. The “ZTR” index which is a quantitative definition

of mineral assemblage is calculated using the percentage of the combined Zircon, Tourmaline

and Rutile grains for each sample according to the formula below.

ZTR index = ZIRCON + TOURMALINE + RUTILE

TOTAL NO. OF NON OPAQUE HEAVY MINERALS

This formula is referred to as Hubert’s (1962) scheme. The calculated index is expressed in

percentage to ascertain the mineralogical maturity of the sediment.

Accordingly, ZTR <75% implies immature to sub mature sediments and ZTR >75% indicates

mineralogically matured sediments

.

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EXPECTED RESULT From the analyses carried out, we will be able to deduce the following:

Energy of the Depositional Environment

Maturity and Transportational History of the sediment.

To determine the Hydrocarbon potential of the proposed area.

Source prediction through correlation.

VALUE ADDITION From the result gotten,

Granulometric will help in paleoenvironmental reconstruction of Bima Sandstone and

also evaluate the Hydro-geological potential of the formation.

By carrying out Heavy minerals analysis, we will be able to determine if the Minerals are

commercial thereby developing the community industrially.

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TIMELINE

WORKPLAN MAR 2015

APR 2015

MAY 2015

JUN 2015

JUL 2015

AUG 2015

SEP 2015

OCT 2015

NOV 2015

DEC 2015

LITERATURE REVIEW

FIELD WORK

GRANULOMETRIC ANALYSIS

THIN SECTION ANALYSIS

HEAVY MINERALANALYSIS

INTERPRETATION & REPORT

SUBMISSION

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BUDGET

STEPS NAIRA (#)

FIELD WORK # 100,000 . 00

SAMPLING # 50, 000. 00

GRANULOMETRIC ANALYSIS #20,000. 00

THIN SECTION &

HEAVY MINERAL ANALYSIS

#20,000 .00

#200,000.00

REPORT TYPING #10,000.00

MISCELLANEOUS # 20,000.00

TOTAL #420,000. 00

SPONSORS

Ministry of Solid Minerals, Gombe State

TETFUND

Personal Savings.

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DISSEMINATION TECHNIQUES Workshop/In-house seminar

Conferences

Publications

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REFERENCES Allix P., (1983), “Environments Mezosoique de la partie nord-orientale du fosse de la Benoue

(Nigeria). Stratigraphie- Sedimentologie. Evolution dynamique. These 3emecycle.” Trav. Lab.

Sci. Terre. Marseille: St-Jerome, France. 21. 200p.

Bakari A., (2014), Granulometric Analysis of Bima Sandstone around Chekole in Gombe Sub-

Basin of the Upper Benue Trough, Nigeria, international journal of scientific & technology

research volume 3, issue 9.

Carter J.D., W. Barber, E.A. Tait, and G.P. Jones. (1963), “The Geology of Part of Adamawa,

Bauchi and Borno Provinces in Northeastern Nigeria”. Bull. of Geol. Surv. of Nigeria. 30:109.

Folk R.L, Ward W.C., (1957). Brazos river bar: a study in the significance of grain size

parameters. J. Sediment petrol., 27: 3 – 26.

Guiraud M., (1990), “Tectono-Sedimentary Frameworks of the Early Cretaceous Continental

Bima Formation (Upper Benue Trough, NE Nigeria)”. Jour. of African Earth Sciences. 10:341-353.

Guiraud M., (1993), “Late Jurassic Riftng- Early Cretaceous Rifting and Late Cretaceous

Transpressional Inversion in the Upper Benue Basin (in Nigeria)”. Bull. Centres Rech. Explor.-

Prod. Elf Aquataine. 12(1):29-128.

Hubert J.T., (1962). Zircon-tourmaline-rutile maturity index and interdependence of the

composition of heavy minerals assemblages with the gross composition and texture of

sandstones. J. Sed pet. 32:440–450.

Maurin J.C., Benkhelil J., Robineau B (1985), Fault rocks of the Kaltungo Lineament

(Northeastern Nigeria) and their relationship with the Benue Trough. J. Geol. Soc. London

143:587-599.

Obaje N.G., (2009), Geology and Mineral Resources of Nigeria‖. Springer, Berlin, London, pp:

69-72, 2009.

Obiefuna G.I., and Orazulike D.M. (2010), Geochemical and Mineralogical Composition of Bima

Sandstone Deposit, Yola Area, NE Nigeria, Research Journal of Environmental and Earth

Sciences 3(2): 95-102.