The Geology of Southern Akor and Its Environment

Department of geology

ABSTRACTS

The study area is located within latitude 050 271 4611N and longitude 0080 431 46E, and the elevation of the place is 156m. The major rock types encountered in the area include gneisses, quartzite, amphibolites and marbles. These are intruded by pegmatite, quartz vein and aplite. The latest metamorphic episode occurred during the Pan-African Orogeny (600 ± 15ma) and the deformation left a structural trend of NS and NE-SW on the rocks. The occurrence of NW-SE structural trend are also shown on some rocks indicating that the Pan-African event did not completely alter earlier structural imprints. The study area is highly forested, undulating in slope and is a characteristic of a tropical rain forest in the area.

Chapter One: Introduction

The geology of southern Akor and its environs lies within the Oban Massif, a component of the crystalline basement of Nigeria. The Nigeria crystalline basement in turn forms a part of the African crystalline basement and covers over 50% of the total land surface of Nigeria . The rock assemblages encountered and identified consists of mainly schists, gneisses, Amphibolite, Charnockite, Marble and Quartzites and pegmatite, Quartz vein and Aplite emerging as Igneous intrusive rocks. The area mapped and studied (Akor) is predominated by intrusive rocks and these rocks are very well exposed where the topographyis slopy along streams and river channels.

Ekwueme et al (1992) proposed that charnockite rock’s occur in both the eastern and western Oban Massif. The rocks occur as large coarse-grained, rounded and, massive bodies deformed together with the bounded gneisses. Ekwueme (1992) has shown that the diorities and charnockite are similar in composition and that the former may be retrogressive product of the latter.

The occurrences of weathering and tectonic activities were observed to have greatly affected the exposed outcrop and such effects from wet season had deformed these outcrops to boulders with reference to their shapes and sizes.

1.1 Location and accessibility

The area is located in the Eastern part of Akamkpa local Government area of theCross River State of Nigeria. It covers an estimated area of about 85sq.KM and constitutes part of the Oban Massif of the South-eastern Nigeria. The map area is largely made up of Ntebachot Akor. New Ntebeji and Ayip Eku all located in Akamkpa Local Government area of Cross River state.

About 90 percent of the area is inaccessible due to thick vegetation, steep valleys and hilly terrains. The only access road across the area is the Calabar-Ekang Road while hunters tracks provide minimal access into the area.