_____________________________________________________________________________________________________ *Corresponding author: E-mail: udinmwenefosa@gmail.com; Asian Journal of Chemical Sciences 1(1): 1-9, 2016; Article no.AJOCS.30077 SCIENCEDOMAIN international www.sciencedomain.org Structures and Petrology of the Rocks around Ekori, Western Ikom – Mamfe Embayment, Southeastern Nigeria Efosa Udinmwen 1* , E. A. Amah 1 , B. E. Ephraim 1 , A. N. Ugbaja 1 and P. A. Udofia 2 1 Department of Geology, University of Calabar, PMB 1115, Calabar, Nigeria. 2 Department of Geology, Akwa Ibom State University, Ikot Akpaden, PMB 1167, Uyo, Nigeria. Authors’ contributions This work was carried out in collaboration between all authors. Author EU designed the study, wrote the first draft of the manuscript and analyzed the data. Author EAA checked the protocol of the study and managed literature searches. Author BEE appraised data quality. Authors ANU and PAU checked the grammar and language. All authors read and approved the final manuscript. Article Information DOI: 10.9734/AJOCS/2016/30077 Editor(s): (1) Georgiy B. Shul'pin, Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russia. Reviewers: (1) Kasturi Bhattacharyya, Indian Institute of Technology, India. (2) Ram Chandra Tewari, Lucknow University, India. Complete Peer review History: http://www.sciencedomain.org/review-history/17263 Received 15 th October 2016 Accepted 9 th November 2016 Published 17 th December 2016 ABSTRACT Ekori and adjoining areas is located in western part of the Ikom – Mamfe embayment. Sedimentary rocks such as sandstones, limestone, shale and few mudstones make up the sedimentary units in this area while intrusive bodies like dolerite sills and gabbro plutons constitutes the igneous rocks in the area. The sedimentary rocks of the study area contain different types of fossils most notably bivalves and brachiopods in sandstones and burrows in limestone. The calcareous sandstone sometimes form semi – caves beneath which grey shale occur. Fresh limestone usually occurs as thin beds within weathered sandstone. The presence of limestone and black shale suggests shallow and deep marine transgression events while the variation in sediment grain size from coarse to fine implies an intercalation of high and low energy depositional environment. Igneous bodies (dolerite and gabbro) intruded the sandstones and shale which baked some of the shales. The gently dipping sedimentary rocks are intensely fractured with NW – SE/ESE – WNW, NNW – SSE, ENE – WSW and NNE – SSW oriented fractures. The complex behaviour of tectonic fractures in this area implies Original Research Article