GEOLOGY OF SHEET 79 MALUMFASHI SOUTH EAST, GEOCHEMISTRY AND MINERALIZATION POTENTIAL OF TUDUN KAYA - DANZAU AREA NW, NIGERIA
GEOLOGY OF SHEET 79 MALUMFASHI SOUTH EAST, GEOCHEMISTRY AND MINERALIZATION POTENTIAL OF TUDUN KAYA - DANZAU AREA NW, NIGERIA
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Date
2011-06
Authors
RUFA’I, SHAFI’U AHMAD
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Abstract
ABSTRACT
Field mapping, petrographic and geochemical analysis of rocks in sheet 79, Malumfashi SE was
carried out in this study. Field mapping on a scale of 1:50,000 reveals that the area is composed
of banded gneiss, Older Granite, diorite as the major rock types. Pegmatite veins, aplite dykes
and quartz veins occur as minor intrusives. Alluvium. Laterite and soil occur as superficial
deposits. The pegmatite zone was further mapped on a scale of 1:10,000 for detailed study.
Structural analysis indicates that some of the rocks are deformed, either folded or faulted
trending N-S to NNE-SSW, which coincides with the disposition of the Pan African Basement
structures. North- East trending fractures and faults were also documented and are exploited by
most of the pegmatitic veins and dykes.
Petrographic analysis using transmitted light microscopy shows that the granites contains
quartz, feldspar(microcline) and biotites as the major minerals, the diorite is seen to contain
oligoclase as the dominant feldspars with biotite, chlorite and quartz. The pegmatite also
contains predominantly feldspar, quartz mica and beryl. The banded gneiss was highly weathered
that they could not allow for a petrographic analysis of the rock.
Geochemical analysis of eleven representative samples of the major rock types granite,diorite
and the pegmatite from the study area was carried out at the Activation Laboratories Ontario,
Canada. The analytical methods used by Actlabs include the Inductively Coupled Plasma Mass
Spectrometry (ICP-MS) for major and trace element analysis, the Instrumental Neutron
Activation Analysis (INAA) for trace and rare earth elements analysis. The major elements from
the analysis shows SiO2 for Granites to be 72.3 – 74.3 wt%, Diorites 57.96 – 74.77 wt% and
pegmatites 62.6 – 74.While K2O for granites is 4.71 – 4.85 wt%, diorite 4.39 -5.02 wt% and 0.86
– 9.64 wt% for the pegmatites. TiO2 in all the samples is between 0.01 -0.908 wt%.
The trace element composition for all the samples was Ba 27.4 – 2073ppm, Sr 14.0 – 603, Rb
41.0 – 1000ppm, Cs 5.1 – 30ppm. The rare earth elements in the samples are Ce 4.6 – 107, Eu
0.05 – 2.07ppm.
The granites were found to be peraluminous in nature and on a chondrite normalized REE
pattern plots shows enrichment in LREE and a depletion in HREE. The Eu anomaly is negative
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and well pronounced typical of the other granitic rocks from other parts of northern Nigeria. The
pegmatites also show an enriched LREE and a more enriched HREE with a negative Eu
anomaly. The K/Rb ratio and a plot of the discrimination diagram K/Rb Vs Rb suggest only a
slight enrichment of the REE in the pegmatites.
An evolution model for the rock types and other intrusives in the study area is being proposed.
As no major mineralization was observed on the major rock types yet the associated minerals
most especially for the pegmatites could be exploited industrially, prospects for tapping the
alluvium deposits, laterites and rock aggregates are high.
Description
DEPARTMENT OF GEOLOGY
AHMADU BELLO UNIVESITY
ZARIA - NIGERIA.
Keywords
GEOLOGY,, SHEET,, MALUMFASHI,, SOUTH,, EAST,, GEOCHEMISTRY,, MINERALIZATION,, POTENTIAL,, TUDUN,, KAYA,, DANZAU,, AREA,, NEW., NIGERIA.