Computer Science
Scientific paper
May 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992gecoa..56.2099p&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 56, Issue 5, pp.2099-2111
Computer Science
35
Scientific paper
Strontium concentrations and isotope ratios have been measured in river and ground waters from the Ganges, Orinoco, and Amazon river basins. When compared with major element concentrations, the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments: 1. (1) "typical" drainage basins containing limestones, evaporites, shales, and alumino-silicate metamorphic and igneous rocks; 2. (2) shield terrains containing no chemical or biogenic sediments; and 3. (3) the floodplains that constitute the largest areas of many large rivers. The strontium concentration and isotope composition of river waters are largely defined by mixing of strontium derived from limestones and evaporites with strontium derived from silicate rocks. The strontium isotope composition of the limestone endmember generally lies within the Phanerozoic seawater range, which buffers the 87 Sr / 86 Sr ratios of major rivers. A major exception is provided by the rivers draining the Himalayas, where widescale regional metamorphism appears to have led to an enrichment in limestones of radiogenic strontium derived from coexisting silicate rocks. The strontium isotope systematics of rivers draining shield areas are controlled by the intense, transportlimited, nature of the weathering reactions, and thereby limits variations in the strontium flux from these terrains. Floodplains are only a minor source of dissolved strontium to river waters, and precipitation of soil salts in some floodplains can reduce the riverine flux of dissolved strontium to the oceans. The most effective mechanisms for altering the isotope ratio and flux of riverine strontium to the oceans are increased glaciation and large-scale regional metamorphism of the type produced during continental collision. Both mechanisms provide a means for increasing the 87 Sr / 86 Sr ratio of the global riverine flux.
Edmond John M.
Palmer Martin R.
No associations
LandOfFree
Controls over the strontium isotope composition of river water does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Controls over the strontium isotope composition of river water, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Controls over the strontium isotope composition of river water will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1516338