GRAVITY SURVEY OF THE OLDER GRANTS PLUTONS IN ZARIA AREA OF KADUNA STATE NIGERIA
GRAVITY SURVEY OF THE OLDER GRANTS PLUTONS IN ZARIA AREA OF KADUNA STATE NIGERIA
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Date
1987-06
Authors
OMOLAYO, OLUSEGUN ADENIYI
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Abstract
A gravity survey over the Precambrian "Older
Granite" intfrusives in Zaria area of northern Nigeria
was carried out. The survey was aimed at investigating
the structure, depth and extent, and the mode
of occurence of the Older Granites.
A LaCoste - Romberg gravimeter (model G468) was
used in collecting gravity data while station elevation
determinations were accomplished using 2 altimeters.
In all, 279 stations were established at intervals of
1 to 2 km. Laboratory density determination was
carried out on 118 rock samples collected from the
area.
Interpretation of the gravity anomaly shows that
the area is characterised by prominent residual gravity
lows of -12. mGal to -8 mGal relative to a N-S trending
regional anomaly of gradient 0.07 mGal/km. Three -
dimensional modelling of the residual gravity shows
that there are 3 batholiths in the area, with floors
which are located at depths 2,3 and 1.7 km respectively,
and the walls of the batholiths are, in general, inward
dipping. Five prominent plugs in the survey area
extended to depths of beweenn 2 and 8 Km locally.
The general configuration of the modelled bodies
and pattern of the gravity anomalies suggest that the
area is characterised by a multiple batholith which
were magmatically emplaced with the 5 plugs acting as
conduits for the ascent of the magma
Description
A thesis submitted to the Postgraduate School,
Ahmadu Bello University, in partial fulfillment of the
requirements for the degree of Master of Science in
(Applied Geophysics).
Department of Physics
Faculty of Science
Ahmadu Bello University
Zaria - Nigeria.
June, 1987
Keywords
GRAVITY, GRAVITY, OLDER, GRANTS, PLUTONS, ZARIA AREA, KADUNA