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- Title
Dolomite Controls on Phanerozoic Seawater Chemistry.
- Authors
Arvidson, Rolf S.; Guidry, Michael W.; Mackenzie, Fred T.
- Abstract
We investigate the potential role of dolomite as a long-term buffer on Phanerozoic seawater composition. Using a comprehensive model of Phanerozoic geochemical cycling, we show how variations in the formation rate of sedimentary marine dolomite have buffered seawater saturation state. The total inventory of inorganic carbon reflects the sum of fluxes derived from continental weathering, basalt-seawater exchange, alumino-silicate diagenesis (reverse weathering), and global deposition of calcium carbonate. Although these fluxes are approximately balanced, model results indicate that seawater saturation state is sensitive to the marine dolomite depositional flux. This conclusion is consistent with and constrained by independent proxy data for seawater ion ratios, paleo-atmospheric CO concentrations, and paleo-pH data, and dolomite mass-age distribution through Phanerozoic time. Abundant research indicates that dolomite's occurrence in marine sediments is sensitive to many factors: temperature, seawater composition, paleogeographic setting, continental organization, etc. Although the complexity of the process of dolomite formation prevents a complete understanding of the relative role of these factors, our model results clearly underscore the importance of this mineral in the chemical history of Phanerozoic seawater.
- Subjects
SEAWATER composition; DOLOMITE; GEOCHEMICAL cycles; SEDIMENTATION &; deposition; CALCIUM carbonate; DIAGENESIS; WEATHERING
- Publication
Aquatic Geochemistry, 2011, Vol 17, Issue 4/5, p735
- ISSN
1380-6165
- Publication type
Article
- DOI
10.1007/s10498-011-9130-7