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Geochemical signatures of surface sediments from the Mahanadi river basin (India): Chemical weathering, provenance, and tectonic settings
Author(s) -
Bastia Fakira,
Equeenuddin Sk Md.,
Roy Priyadarsi D.,
HernándezMendiola Ernesto
Publication year - 2020
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3746
Subject(s) - geology , provenance , weathering , geochemistry , continental crust , fluvial , continental margin , sediment , igneous rock , structural basin , tectonics , geomorphology , crust , paleontology
The Mahanadi river basin (MRB) is one of the eight major fluvial basins of India. This paper presents a very first systematic study of geochemical characteristics, including rare earth elements of surface sediments collected from the riverbed at different parts of this basin to infer the chemical weathering, provenance, and tectonic settings. Lower mean values of major elements (except for SiO 2 and K 2 O) are observed compared with that of the upper continental crust (UCC). It is attributed to the dominance of quartz and orthoclase in sediments and removal of mobile elements from the sediment during the transportation. The concentrations of Rb, Ba, Cu, Th, and Pb are elevated with respect to the UCC. The higher concentration of K 2 O and Rb, the ratio of Al 2 O 3 to TiO 2 , and other bivariant plots indicate that the sediments are derived mostly from acidic to intermediate igneous rock. Majority of the sediments have geochemical similarity with the arkose and litharenite sandstones. The chemical index of alteration (CIA) values of the MRB sediments varies between 52 and 69 with most of the samples having CIA < 60 suggesting the lower degree of weathering which is further supported by the mineralogy. The eroded sediments have compositional maturity comparable to sediments deposited under semi‐arid climatic conditions. Sediments show both positive and negative Eu anomalies based on the source rock. Based on the commonly used discrimination diagrams, it is concluded that the MRB has a tectonic setting similar to the passive continental margin.