Sources of sulfur in Deccan Trap rivers: A reconnaissance isotope study

作者：Das Anirban^*; Pawar N J; Veizer Jan

来源：Applied Geochemistry, 2011, 26(3): 301-307.

DOI：10.1016/j.apgeochem.2010.12.003

Sulfur isotopic composition (delta(34)S) of dissolved SO(4)(2-) was measured in waters of rivers draining the Deccan Trap basalts in order to elucidate the source(s) of elevated SO(4)(2-) content in some of these rivers, observed in an earlier study. The delta(34)S values range from 8.7 parts per thousand. to 19.5 parts per thousand, with an average of 14.5 +/- 2.8 parts per thousand, values generally enriched in (34)S compared to data available from other Indian rivers. The Bhima River (a tributary of the Krishna) and most of its tributaries have (delta(34)S within the 14 +/- 2 parts per thousand range and high dissolved SO(4)(2-) concentrations (256-1556 mu M). Measured delta(34)S of 7 of the saline/alkaline soils suggest that the high dissolved SO(4)(2-) in the Bhima river system is likely derived from this source and/or gypsum concretions in the soils. The (delta(34)S-SO(4) relationship for the Krishna River and its smaller tributaries follows a mixing pattern of two end-members, rainwater with low SO(4)(2-) and low delta(34)S and an unknown, likely a pollution, source with intermediate SO(4)(2-) content and heavy delta(34)S. The most important finding that this study brings out is the minimal role that the weathering of basalt-sulfides play in contributing to the dissolved SO(4)(2-) in the rivers. This rules out the role of H(2)SO(4-), and supports H(2)CO(3)-mediated weathering as the dominant process in the Deccan settings.

• 出版日期2011-3