Petrography and geochemistry of the Middle Miocene Gebel El Rusas sandstones, Eastern Desert, Egypt: Implications for provenance and tectonic setting

Abstract

Petrography and bulk rock geochemistry of the Middle Miocene sandstones of the lower and upper members of Gebel El Rusas Formation along the Egyptian Red Sea Coastal plain, have been investigated to determine the provenance, tectonic setting, and weathering condition of this formation. The Lower Member is formed mainly of sandstones and conglomerates with clay interbeds. The Upper Member is more calcareous and formed mainly of sandstones and limestones with marls and clays intercalations. Petrographically, the Lower Member sandstones are mostly immature and classified as arkoses with an average framework composition of Q 66 F 29 R 5 , and the Upper Member sandstones are partly submature (more quartzose, less feldspathic) and classified as subarkoses with an average framework composition of Q 80 F 17 R 3. The Gebel El Rusas sandstones are enriched in Sr, Ba, Zr and Rb and depleted in Co and U, as compared to UCC. The chemical index of alteration (CIA) values suggest moderate weathering conditions. The geochemistry results revealed that the Gebel El Rusas sandstones were derived from felsic-granitic source rocks and deposited in a passive margin of a synrift basin. The inferred tectonic setting for Middle Miocene Gebel El Rusas sandstones in the study area is consistent with the regional geology of the Eastern Desert of Egypt during Middle Miocene.

Petrography and geochemistry of the Proterozoic sandstones of Somanpalli Group from Pomburna area, Eastern Belt of Pranhita–Godavari Valley, central India: Implications for provenance, weathering and tectonic setting

“…Many authors have successfully established the tectonic environment using the proportions of frame work grains by petrographic studies (Dickinson and Suczek 1979;Taylor and McLennan 1985;Periasamy and Venkateshwarlu 2017). The frame work grain properties of quartz and feldspar of studied samples are consistent with those of sediments deposited in a passive continental margin (e.g., Zaid 2015Zaid , 2017. Pomburna sandstones that fall within the passive continental block are chiefly derived from exposed shield areas of Bastar craton.…”

“…The tectonic setting discrimination diagrams proposed by Bhatia (1983) and Roser and Korsch (1986) for clastic sediments were used in many studies to identify the tectonic setting of unknown basins (Zaid 2017). Many researchers cautioned against the use of these previously proposed discrimination diagrams (e.g., Armstrong-Altrin and Verma 2005).…”

“…The original composition of weathered source rocks has a dominant control on the makeup of terrigenous sediments, and therefore, geographic and stratigraphic variations in provenance can provide important constraints on the tectonic evolution of the region (e.g., Clift et al 2000;McLennan et al 2003;Rahman and Suzuki 2007;Absar et al 2009;Absar and Sreenivas 2015;Nagarajan et al 2017;Tawfik et al 2017;Zaid 2017). The geochemistry of clastic sedimentary rocks is widely studied to the tectonic setting, weathering, source rock compositions, provenance and 1 diagenesis (Dickinson and Suczek 1979;Nesbitt and Young 1982;Bhatia 1983;Roser and Korsch 1986;McLennan 1989;Condie 1993;Armstrong-Altrin et al 2004;Absar et al 2009;Moosavirad et al 2011;Saeed et al 2011;Randive 2012;Zaid 2012Zaid , 2015Sharma et al 2013;Srivastava et al 2013;Absar and Sreenivas 2015;Absar et al 2016;Madhavaraju et al 2016;Nagarajan et al 2017;Pandey and Parcha 2017;Periasamy and Venkateshwarlu 2017;Zaid 2017). The chemical composition of clastic sedimentary rocks is a function of a complex relationship of several variables, including the source rock composition, the extent of weathering, transportation and diagenesis (Taylor and McLennan 1985;Bhatia and Cook 1986;Roser and Korsch 1986;…”

Geochemical Application in Unraveling Paleoweathering, Provenance and Environmental Setting of the Shale From Chia Gara Formation, Kurdistan Region, Iraq

“…The chemical analyses of the major, trace and rare earth elements of the clastic sediments were widely used to distinguish the source rock identity (Armstrong-Altrin et al, 2015;Tobia and Shangola, 2016;Tobia and Mustafa, 2016;Zaid, 2017). In order to deduce the provenance of the rocks, several discrimination diagrams were proposed based on major and trace elements (Roser and Korsch, 1988;Floyd et al, 1989;McLennan et al, 1993;Armstrong-Altrin, 2013, 2016;.…”