Abstract
The study aims at differentiating lithologic units, general structural trends and orogenic implications of crystalline rocks within part of Oban Massif, Southeastern Nigeria. Field study involve geological mapping, rock description and structural measurement, while laboratory analysis covered photomicrograph. Field observation and microscopic analysis reveal five petrological units; gneisses, schists, granodiorite, pegmatite and quartz veins. The rocks are generally siliceous and quartzo-feldspathic. The schist show foliation planes trending majorly in the NE-SW direction. The gneisses were highly fractured, indicative of a polyphase deformation. Structural elements such as joints, fractures, foliations and veins show series of deformational episodes that affected the area. Rose diagram plot for these structures show the NE-SW direction indicative of the Pan-African orogeny (600±150 Ma) and interpreted as the most recent event affecting the area. NW and NE trending joints are consideredto be tectonic in origin based on their alignments with major structures of the area. Furthermore, the structures also showed weak NW-SE and E-W trends, an imprint of older (Kibaran orogeny) deformational episodes.
Highlights
IntroductionDescription Of Study Area: The study area is situtated in Akamkpa, Cross River (Nigeria), covering about 38.3 km
Ekwueme (1987) reported that the crustal evolution of the Oban massif was affected by Kibaran orogeny, which was dated 1313 – 1315 Ma and that this event imprinted a weak NW-SE trending foliation on the rock
This study aims to contribute to the scientific discussion on the petrology and structural settings of the study area
Summary
Description Of Study Area: The study area is situtated in Akamkpa, Cross River (Nigeria), covering about 38.3 km. Description Of Study Area: The study area is situtated in Akamkpa, Cross River (Nigeria), covering about 38.3 km2 It lies between latitude 8 15' to 8 22'30''N and longitudes 5 12'30" and 5 18'30''E and includes villages such as Awi and Ayiebam, Isang-Inyang, Mbarakom and parts of Calaro oil palm estate camps. The dominant structures encountered in the study area are; joints, faults, lineations and foliations. Joints were mapped by observing areas in outcrops where cohesion is lost with no relative movement of the rocks along the fracture plane. Linear (lineations) and planar structures (foliations) were mapped carefully by identifying their trends or orientations. Laboratory study involved preparing thin section of fresh samples collected for petrographic studies using the microscope This petrographic work was carried out to determine the major rock types and mineral contents. A geologic map of the area with emphasis on structures was produced
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
