CARBONATE SEQUENCE OF PINDIGA FORMATION IN ASHAKA QUARRY, UPPER
CARBONATE SEQUENCE OF PINDIGA FORMATION IN ASHAKA QUARRY, UPPER
No Thumbnail Available
Date
2014-12
Authors
ABDULKARIM, SA’ID
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Two lithologic sections of limestone/shale deposits within the Pindiga Formation
which is exposed at the Ashaka Cement Quarry which are 4 km apart were studied. The
succession is such that the 8-9 m lowermost limestone deposit in the quarry overlies the
continental Bima Sandstone, the two being separated by a ferrugineous layer which represents
the lower sequence boundary and is characterized by sub-aerial exposure and erosion. The
upper part of the section is made up of intercalated limestones and shales representing
alternation in the depositional settings with oxic and anoxic conditions for the limestone and
the shale deposits respectively. Deposition was in a shallow marine environment which is, in
most cases of low energy, although there is evidence of high energy of the depositional
medium represented by the cross bedding in some limestone facies,
A transgressive systems tract which is represented by two parasequence sets in the
southern section, three parasequence sets in the northern section and a highstand systems tract
represented by two parasequence sets in both the southern and northern sections make up the
stratigraphic sequence at the quarry; the two systems tracts are separated by a maximum
flooding surface. The marine flooding surfaces and minor marine flooding surfaces were
identified. The lowstand systems tract is missing in the quarry and the upper sequence
boundary is inferred to be within the Deba Fulani Member of the Pindiga Formation. Fossils
present in the limestones include bivalves, ostracods, foraminifers, gastropods, and
vertebrates. Extraclast such as quartz and feldspar as well as glauconite were also found in
some of the limestones. The limestones are generally affected by neomorphism and are
mostly wackestone and packston. Porosity is moderate to low, decreasing from top to the base
of the profile and is mostly of biomoldic and vuggy type.
Description
A THESIS SUBMITED TO SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, ZARIA
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF A
MASTER DEGREE IN GEOLOGY
DEPARTMENT OF GEOLOGY,
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
DECEMBER, 2014
Keywords
CARBONATE SEQUENCE,, PINDIGA FORMATION,, ASHAKA QUARRY,, UPPER,, NIGERIA.