Geochemical and Mineralogical Characteristics of Recent Clastic Sediments from Lower Godavari River: Implications of Source Rock Weathering

Abstract

The major, trace and rare earth elements geochemistry and clay mineral compositions in the river bed sediments from lower reaches of Godavari river suggest that they are derived from weathering of felsic rocks. Trace and rare earth elemental compositions indicate evidence of sedimentary sorting during transportation and deposition. Lower concentrations of transition elements, such as V, Ni and Cr imply enrichment of felsic minerals in these bed sediments. The REE pattern in lower Godavari sediments is influenced by the degree of source rock weathering. The light rare earth elements (LREE) content are indicating greater fractionation compared to the heavy rare earth elements (HREE). A striking relationship is observed between TiO2 and ΣREE content suggesting a strong control by LREE-enriched titaniferous minerals on REE chemistry. Shale-normalized REE pattern demonstrate a positive Eu anomaly, suggesting weathering of feldspar and their secondary products, which are enriched in Eu. Chondrite-normalised REE pattern is characteristic of felsic volcanic, granites and gnessic source rocks. Trace elemental compositions in sediments located near urban areas suggest influence of anthropogenic activity. Chemical Index of Alteration (CIA) is high (avg. 65.76), suggesting a moderate chemical weathering environment. X-ray diffraction analysis of clay fraction shows predominance of clay minerals that are formed because of the chemical weathering of felsic rocks.

Climatic and Tectonic Control on the Bengal Fan Sedimentation Since the Pliocene

“…10.1029/2020GC009448 (Brass & Raman, 1990;Joussain et al, 2016) and rivers including Ganga (Heroy et al, 2003;Khan et al, 2019), Brahmaputra (Heroy et al, 2003;Khan et al, 2019), lower Meghna (Brass & Raman, 1990), Krishna (Naidu et al, 1985), Godavari (Vuba et al, 2013(Vuba et al, , 2015, and Mahanadi (Naidu et al, 1985).…”

A Geochemical and Mineralogical Study of the Sediments Transported through Wadi Al-Qassab and Wadi Al-Murr, South Mosul City, Northern Iraq

“…SiO2, Al2O3, K2O, MgO, and Fe2O3 have strong +ve relationships that reflect the presence of a minerals group of quartz, K-feldspar, and clay minerals. The relationship between SiO2, Al2O3 and K2O represents the presence of feldspar and illite phases (Vuba et al, 2013), Considering the low molar ratios of Al2O3 substituted for Si and Mg in chlorite and palygorskite in tetrahedrons and trioctahedrons, respectively (Van Olphen and Veniale, 1981). TiO2 have a strong correlation with above oxides owing to the presence of Ti-oxide phases as anatase and /or rutile that found commonly with clay minerals as erodible products, respectively (Van Olphen and Veniale, 1981).…”

“…All these processes produce sediments that differ from the origin rocks in regarded of chemical and physical characteristics . In general, several factors control these characteristics, such as type of source rock and quality, water activity, weathering intensity, leaching, mobility of ions as soluble load colloidal solution (as colloid load), climate elements, vegetation activity and intensity, the hydrological characteristics of the valleys (Dinelli et al, 2005;Vuba et al, 2013;Chen et al, 2020) and the frequency of the effect of these factors on source rocks and sediments in the valleys .…”

“…It should be noted that some elements have been depleting as a result of leaching processes during weathering, this is mainly due to the ability of these elements to move in the ionic phase in the aqueous environment ( Vuba et al, 2013;He et al, 2015). Aluminum, silicon and titanium elements are not affected by movement in the aqueous environment, but are changed to other metal phases as a result of hydrolysis, such as the transformation of feldspar minerals into clay minerals (Van Olphen and Veniale, 1981).…”