[01] Efosa Udinmwen, Department of Geology, University of Calabar, Calabar, Nigeria. [02] Michael Ikpi Oden, Department of Geology, University of Calabar, Calabar, Nigeria. [03] Rufai Ayuba, Department of Earth Science, Kogi State University, Anyigba, Nigeria. [04] Asinya Enah Asinya, Department of Geology, University of Calabar, Calabar, Nigeria.

The Igarra schist belt in the southwestern basement complex of Nigeria is part of the 3000 Km long Trans – Saharan belt. It contains Pre – Cambrian rocks with fractures and foliations commonly filled with aplite and quartz. Foliation planes in the Igarra schist belt are basically oriented in the N – S and NW – SE directions with moderate – high dip angles while the fractures dips steeply but have a more complex orientation with a dominant E – W and N – S trend. The mineral veins within the schist belt have a somewhat consistent orientation and like the structures, dip moderately/steeply. The similarities of attitudes of the veins and the structures (fracture and foliation) suggest that these structures are conduits for mineralizing fluids. The thickness and orientation of aplite and quartz veins suggest that mineralization in this schist belt was not a random process. These veins are often a few centimeters wide however the widest veins that grew to widths in excess of one meter (> 1 m) are parallel to the E – W direction. Analysis of 174 veins from metasediments and granites in the Igarra schist belt show that fracture – filling mineralizations are dominant and widest in this area. Fractures constitute the main plane of weakness in this area and they are usually parallel to the E – W direction which seems to be favoured for wide vein formation. This knowledge should guide researchers carrying out exploration for minerals in the region.

Fracture, Foliation, Mineral Veins, Igarra, Quartz

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