Updates on the Geological Map of Paiko Sheet 185, North Central, Nigeria

Abstract

Geological mapping of Paiko Sheet 185 was carried out on a scale of 1:100,000 to update the existing geological map of the area. Traverse as well as green line methods of mapping were employed. At each location, the lithology, color, texture, and nature of contact between lithologies and structures were noted and documented. Field observations show that the area is composed of migmatitic gneiss (66.15%), Porphyritic biotite granite (14.23%), medium-grained biotite granite (13.06%), sandstone (4.18%), tonalite (2.14%), ironstone (0.09%), Talcose rock (0.09%) and marble (0.06%). The modifications made to the existing map which was produced in 2009 and updated in 2015 include; the replacement of the alluvial lithology with the bedrock (migmatite) and the renaming of talc-tremolite-actinolite schist to Talcose rock due to the absence of schistosity. Other modifications include the removal of the Phyllite, mica schist interlayered with amphibolite in the northeastern part of the area because it is located on the adjacent Abuja Sheet; the inclusion of the Sakpe Formation around Lapai as well as harmonising of the marble occurring around Kwakuti as one unit. Structures such as folds, faults, joints, unconformities, exfoliations, strain-slip cleavage, trace fossils, bedding, and bedding planes were observed and recorded. The result of joint direction measurements shows that the principal joint direction is in the northwest-southeast. The economic geological resources within the area include gold, lead, zinc, marble, Talcose rock, rocks, laterite, clay, sand, and gravel.