HR: 17:40h
AN: OS14A-07 INVITED     [Abstracts]
TI: Marine Barite Formation - Pathways, Processes, and Product
AU: * Paytan, A
EM: apaytan@pangea.stanford.edu
AF: Stanford University, Geological and Environmental Sciences, Stanford, CA 94040 United States
AB: The seawater is generally under-saturated with respect to barite. The mineral barite however, is observed in sinking oceanic particulate matter worldwide. It has been suggested that marine barite forms authigenically within microenvironments in association with organic matter and other biogenic debris. Barite can also precipitate diagenetically within sulfate reducing sediment at the oxic anoxic front or from hydrothermal or other Ba rich solutions when they encounter sulfate rich seawater. Barite is widely used to reconstruct ocean chemistry (87Sr/86Sr, del34S, Sr/Ba) and export production. To reliably record seawater chemistry and water column processes it is essential that the authigenic mineral will precipitate in seawater. Moreover, parameters affecting the chemistry (trace element substitution, isotope incorporation) of the mineral such as temperature, pressure, salinity and precipitation rate should be well constraint. Some of these requirements are met for marine barite but not all. A discussion of what controls the chemistry of marine barite and how this can affect potential use of this mineral for paleoceanographic reconstruction will be presented.
DE: 4805 Biogeochemical cycles (1615)
DE: 4825 Geochemistry
DE: 4835 Inorganic marine chemistry
DE: 4875 Trace elements
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting