FORAMINIFERAL AND OSTRACODE BIOSTRATIGRAPHY AND PALEOECOLOGY OF KALAMBAINA FORMATION, SOKOTO BASIN; SOKOTO STATE, NIGERIA
FORAMINIFERAL AND OSTRACODE BIOSTRATIGRAPHY AND PALEOECOLOGY OF KALAMBAINA FORMATION, SOKOTO BASIN; SOKOTO STATE, NIGERIA
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Date
1994-03
Authors
OBIOSIO, ENAM O.
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Abstract
A total of 22 samples collected from the Upper Paleocene
Kalambaina Formation, yielded 31 species of benthonic, 2
species of planktonic foraminifers, and 18 species of
ostraeodes. One foraminifera species, Nonion planaturn has
just been reported from the Formation. Benthonic
foraminiferal and ostracode assemblages were investigated with
respect to their stratigraphy, paleoecological and
paleobiogeographical significance.
The Kalambaina Formation is correlated by means of
benthonic and planktonic foraminifers, and ostraeodes. Those
foraminifers and ostraeodes are referable to the Thanetian age
on the basis of known ranges of these species. The benthonic
foraminiferal faunas are similar to the Paleocene Tethyan-type
fauna, and are associated with planktonic foraminifers
referable to zones P4 and P5 of the standard planktonic
foraminiferal zonation. These zones are correlated with the
Operculinoides bermudezi and Trachyleber is teiskotensis units
recognized for the benthonic foraminifers and ostraeodes
respect ively.
The interpretation of the paleoecology of Kalambaina
Formation is based on quantitative study of the distribution
of the foraminifers and ostraeodes in the sections. The
foraminifers and ostraeodes are abundant and fairly
diversified, a circumstance which tend to increase their
usefulness as paleoecological indicators. Paleoenvironments
interpreted from foraminiferal assemblage suggest a shallow
depth of approximately 10 metres with open marine conditions.
The presence of planktonic foraminifers in some samples
corroborates the open marine conditions interpreted from the
benthonic assemblage. The ostracode assemblage point towards
an open marine, shallow depth of relatively low hydrodynamic
energy.
A comparison of paleobiogeographical pattern between the
Kalambaina and Ewekoro formations showed the existence of two
foraminiferal paleobiogeographic province separated by a
barrier. The comparison of ostracode assemblages between the
two formations shows that similarity exists. The presence of
a barrier implies that there was no communication between the
seas. The results obtained in this study support the
hypothesis that the Saharan sea that occupied the Sokoto area
moved in southeast wards from the Tethys sea.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL, AHMADU BELLO
UNIVERSITY, IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
AWARD OF THE DEGREE OF MASTER OF SCIENCE.
Department of Geology
Faculty of Science
Ahmadu Bello University,
Zaria
Keywords
FORAMINIFERAL,, OSTRACODE,, BIOSTRATIGRAPHY,, PALEOECOLOGY,, KALAMBAINA,, FORMATION,, SOKOTO BASIN,, NIGERIA