DETERMINATION OF THE SEDIMENTOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE SEDIMENT IN THE NIGER DELTA BASIN

DETERMINATION OF THE SEDIMENTOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE SEDIMENT IN THE NIGER DELTA BASIN

CHAPTER ONE
INTRODUCTION

The mineralogical and chemical composition of classic sedimentary rocks are controlled by various factors,
including (1) the composition of their source rocks, (2) environmental parameters influencing the weathering of
source rocks (e.g., atmosphericchemistry, temperature, rainfall and topography), (3) duration of weathering
(4)transportation mechanisms of clastic material from source region to depocenters, (5)depositional environment
(e.g., marine versus fresh water), and (6) post-depositional processes (e.g., diagenesis, metamorphism) (Hayashi
et al., 1997). Numerousinvestigations are substantiating the above aspects pertaining to genesis of both ancient
andmodern siliciclastic sediments (e.g., Dickenson et al., 1983; Nesbitt and Young, 1982, 1984; Bhatia, 1983;
Roser and Korsch, 1988; McCann, 1991; Condie et al., 1992; Condie, 1993; McLennan et al., 1993; Nesbitt et
al., 1996; Cullers, 2000; Hessler and Lowe 2006; Nagarajan et al., 2007; Spalletti et al., 2008). Several studies
have also been focused on the identification of palaeotectonic settings of provenances based on geochemical
signatures of siliciclastic rocks (e.g., Dickinson and Suczek, 1979; Bhatia, 1983; Bhatia and Crook, 1986; Roser
and Korsch 1986; McLennan and Taylor, 1991). Among the terrigenous sedimentary rocks, shales are
considered to represent the average crustal composition of the provenance much better than any other siliclastic
rocks (e.g., McCulloch and Wasserburg, 1978). Shales retain most of the mineral constituents of the source and
their bulk chemistry preserves the near-original signature of the provenance and more faithfully reveal
palaeoweathering conditions (e.g., Pettijohn, 1975; Graver and Scott, 1995). The present note examines the
geochemistry of sediment from part of the subsurface Niger Delta Basin province, attempts to constrain there
paleo redox and tectonic setting and provenance. Owing to limitations of analytical facilities, the present work is
based on chemical analyses data of major and select trace elements of the investigated sediment of the study
area.

DETERMINATION OF THE SEDIMENTOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF THE SEDIMENT IN THE NIGER DELTA BASIN