Petrography and Geochemistry of Upper Paleozoic Sandstone around Kuch Area, Blue Nile Basin, Central Ethiopia: The implication for Provenance, Paleoclimate and Tectonic

Tigist Birhanu

dc.contributor.author	Tigist Birhanu
dc.date.accessioned	2021-02-24T09:24:05Z
dc.date.available	2021-02-24T09:24:05Z
dc.date.issued	2021-02-24
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/11953
dc.description.abstract	Paleozoic sedimentary rocks in the Blue Nile of central Ethiopia are related to two major Gondwana glaciations: namely, the Late Ordovician- Silurian and the Carboniferous- Permian glaciation. The present study investigates sandstone sections cropping out in the BokotaboSentom and Daguja town, both of which are found around the Kuch area, in the western parts of Blue Nile basin, central Ethiopia. The upper Paleozoic sandstones are composed of mudstones, siltstones, and sandstones in the Bokotabo-Sentom area and deposited as sandstone-siltstoneand tillite in the Daguja area. The present study is aimed at investigating the petrography and geochemistry of these sandstones to evaluate the provenance, the tectonic setting, and the paleoclimate conditions under which the upper Paleozoic sandstones were deposited. The study was conducted using a transmitted microscope, inductively coupled plasma mass spectrometry (ICP-MS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Based on major, trace and rare earth element analysis and petrographic data, the upper Paleozoic sandstones are dominated by Quartz (on average of 64.5% in Bokotabo-Sentom area and 58.4% in Daguja area) and followed by feldspars (on average of 31.0% in Bokotabo-Sentom area and 36.6% in Daguja area) and rock fragment (on average of 3.2% in Bokotabo-Sentom area and 4.9% in Daguja area). The sandstone is medium- to coarse-grained, texturally immature to submature, and poorly to moderately sorted. The sandstone was derived from transitional continental and basement uplift rocks. The sandstone could be classified as arkosic and lithicarenite. The chemical index of alteration, plagioclase index of alteration, and chemical index of weathering values identifythe upper Paleozoic sandstone has moderate to high weathering history in the Bokotabo-Sentom area and low to moderate in the Daguja area. Based on trace and rare earth element concentrations, its sources possibly are juvenile material, the basement nearby. Keywords: upperPaleozoic, Sandstone, Blue Nile basin, Petrography, Geochemistry, Provenance	en_US
dc.language.iso	en	en_US
dc.subject	Petrology	en_US
dc.title	Petrography and Geochemistry of Upper Paleozoic Sandstone around Kuch Area, Blue Nile Basin, Central Ethiopia: The implication for Provenance, Paleoclimate and Tectonic	en_US
dc.type	Thesis	en_US