Open AccessInvestigations of the spatial and temporal variations of S r and N d isotopes in sediments from two I ndian R ivers: Implications to source identification
Author(s) -
Pradhan Sonali,
Zhang Jing,
Baskaran Mark,
Shirodkar Prabhaker Vasant,
Wu Ying,
Pradhan Umesh Kumar
Publication year - 2017
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2016gc006669
Subject(s) - radiogenic nuclide , provenance , geochemistry , geology , sediment , weathering , sedimentary rock , archean , silicate , gneiss , tributary , proterozoic , geomorphology , metamorphic rock , chemistry , paleontology , cartography , mantle (geology) , geography , organic chemistry , tectonics
Radiogenic isotopes of Sr and Nd provide crucial information on chemical and physical erosion processes, therefore used as tracers for fingerprinting the sources of fluvial sediments. Moreover, elemental geochemistry, 87 Sr/ 86 Sr and 143 Nd/ 144 Nd signatures in silicate fractions of sediments primarily reflect intricate controls of characteristics and provenance of sediment. A suite of sediment samples collected from two rivers of India, Narmada (large) and Netravati (small) were analyzed for elemental concentrations, 87 Sr/ 86 Sr and 143 Nd/ 144 Nd in silicate as well as acid‐leachable fractions. 87 Sr/ 86 Sr in acid‐leachable sediment fractions from both the rivers (0.7094 ± 0.0002 for Narmada and 0.7158 ± 0.003 for Netravati) showed more radiogenic 87 Sr/ 86 Sr in Netravati compared to Narmada indicating influence of source rocks in their watersheds. Weak correlation of sedimentary 87 Sr/ 86 Sr and 143 Nd/ 144 Nd with Al and Chemical Index of Alteration (CIA) in silicate fraction indicates that isotopic compositions are primarily controlled by their sources and not by chemical weathering in both the rivers. Provenance of sediments in Narmada is dominated by their supply from Deccan deposits with secondary supply from mid‐late Proterozoic Vindhyan along with Mesoproterozoic to MesoarcheanT DM Ndages. Sediments from Netravati reflected signatures of peninsular gneisses dominant with gneisses schists and granodiorite along with PaleoarcheanT DM Ndages. Based on variability of 87 Sr/ 86 Sr and 143 Nd/ 144 Nd, present study highlight that sediment supplies from tributaries to the mainstream in Narmada is inadequate as compared to that in Netravati. 87 Sr/ 86 Sr and 143 Nd/ 144 Nd signatures in Narmada and Netravati are comparable with Global Rivers.