PROVENANCE AND TECTONIC SETTING OF SOME PALEOPROTEROZOIC SEDIMENTARY ROCKS IN THE CHAGUPANA AND TARKWA AREAS OF GHANA: PETROGRAPHIC AND STRUCTURAL CONSTRAINTS
Journal: Earth Science Malaysia (ESMY)
Author: Blestmond A. Brako, Gordon Foli, Etornam B. Fiadonu, Chiri Amedjoe, Derrick Aikins, Simon K.Y. Gawu
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Paleoproterozoic sedimentary rocks associated with the Man Shield of West Africa are perceived to be similar, irrespective of their locality. This research seeks to establish the provenance and tectonic setting of these rocks to ascertain any such similarity perception, based on information from two localities. The study uses modal mineral estimations to reconstruct the source, paleocurrent, paleoclimate and relief of some conglomerates and sandstones from Chagupana and Tarkwa areas in Ghana. Chagupana conglomerate has igneous and metamorphic provenances, while Kawere conglomerate has metamorphic provenance. Average mineralogical composition of Chagupana sandstone is Q53-F45-R3 and classify as arkose. Tarkwa suites of Huni, Kawere and Banket sandstones are composed of Q48-F34-R18, Q51-F25-R23 and Q76-F7-R17, and classify as lithic arkose, lithic arkose-feldspathic litharenite, and sublitharenite, respectively. Detritus of all the sandstones suggest acid igneous rock source, with minor sedimentary and metamorphic imprints, with an order of maturity as Banket>Kawere>Huni>Chagupana. Detritus in the Chagupana, Huni and Kawere sandstones are from the transitional continental margin. The Chagupana is from the cold arid climate, while the Huni and Kawere are from the semi-arid/semi-humid climates. The Banket sandstone mobilises from craton interior with recycled orogenic materials in a humid environment. The angular-subangular feldspars in Chagupana sandstone indicate low relief and low-moderate recycling close to the source. Huni, Kawere and Banket sandstones derive from low-moderate reliefs with multiple recycling episodes. The Chagupana and Huni sandstones show paleo-current directions from the north and east, respectively. Similarities between the Chagupana and Tarkwa rocks can only be limited to the tectonic setting and not from source area, paleo-climate, paleo-current and relief.