Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal

Journal Article · Mon May 01 00:00:00 EDT 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90205-6· OSTI ID:5097306

Sarin, M M; Krishnaswami, S; Dilli, K; Somayajulu, B L.K. ^[1]; Moore, W S ^[2]

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1. Physical Research Laboratory, Ahmedabad (India)
2. Univ. of South Carolina (USA)

The Ganga-Brahmaputra, one of the worlds's largest river systems, is first in terms of sediment transport and fourth in terms of water discharge. A detailed and systematic study of the major ion chemistry of these rivers and their tributaries, as well as the clay mineral composition of the bed sediments has been conducted. The chemistry of the highland rivers are all dominated by carbonate weathering; (Ca + Mg) and HCO{sub 3} account for about 80% of the cations and anions. In the lowland rivers, HCO{sub 3} excess over (Ca + Mg) and a relatively high contribution of (Na + K) to the total cations indicate that silicate weathering and/or contributions from alkaline/saline soils and ground waters could be important sources of major ions to these waters. The chemistry of the Ganga and the Yamuna in the lower reaches is by and large dictated by the chemistry of their tributaries and their mixing proportions. The highland rivers weather acidic rocks, whereas the others flow initially through basic effusives. The Ganga-Brahmaputra river system transports about 130 million tons of dissolved salts to the Bay of Bengal, which is nearly 3% of the global river flux to the oceans. The chemical denudation rates for the Ganga and the Brahmaputra basins are about 72 and 105 tons{center dot}km{sup {minus}2}{center dot}yr{sup {minus}1}, respectively, which are factors of 2 to 3 higher than the global average. The high denudation rate, particularly in the Brahmaputra, is attributable to high relief and heavy rainfall.

• OSTI ID: 5097306
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 53:5; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
54 ENVIRONMENTAL SCIENCES
GANGA RIVER
IONIC COMPOSITION
WATER CHEMISTRY
SEDIMENTS
ENVIRONMENTAL TRANSPORT
BANGLADESH
CARBONATE ROCKS
CHEMICAL COMPOSITION
CLAYS
GEOCHEMISTRY
HYDROLOGY
INDIA
WATER
WEATHERING
ASIA
CHEMISTRY
DEVELOPING COUNTRIES
HYDROGEN COMPOUNDS
MASS TRANSFER
OXYGEN COMPOUNDS
RIVERS
ROCKS
SEDIMENTARY ROCKS
STREAMS
SURFACE WATERS
580000* - Geosciences
540320 - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)