Degree of supersaturation and precipitation of organogenic dolomite

Journal Article · Fri Apr 01 04:00:00 EST 1988 · Geology; (United States)

DOI:https://doi.org/10.1130/0091-7613(1988)016<0318:DOSAPO>2.3.CO;2· OSTI ID:7018052

Compton, J S

This paper integrates the degree of carbonate saturation into a general model for the origin of dolomite in organic-rich marine sediments. Degradation of organic matter by sulfate-reducing bacteria promotes early dolomite precipitation by simultaneously increasing the carbonate alkalinity and lowering the sulfate ion concentration to near zero. The interstitial water in organic-rich sediments of several Deep Sea Drilling Project sites where dolomite is believed to be precipitating is up to 10/sup 3/ times supersaturated with respect to near-ideal dolomite and up to 10 times supersaturated with respect to calcite. The highly supersaturated interstitial waters appear to overcome low-temperature kinetic barriers to precipitate a nonideal, fine-grained calcian dolomite. The degree of supersaturation with respect to dolomite decreases, and the interstitial water approaches carbonate equilibrium with increasing burial depth at several of these sites. Removal of sulfate ion is important because sulfate ion may inhibit dolomite precipitation. A calcareous sediment is not required, but the presence of calcite or aragonite appears to greatly enhance dolomitization by providing an additional source of Ca and carbonate ions.

• Research Organization: Univ. of South Florida, St. Petersburg (USA)
• OSTI ID: 7018052
• Journal Information: Geology; (United States), Journal Name: Geology; (United States) Vol. 16:4; ISSN GLGYB
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
&amp; Exploration
ALKALINE EARTH METAL COMPOUNDS
BACTERIA
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATE ROCKS
CARBONATES
DOLOMITE
GEOLOGIC MODELS
GROUND WATER
HYDROGEN COMPOUNDS
INTERSTITIAL WATER
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MICROORGANISMS
MINERALIZATION
MINERALS
ORGANIC MATTER
ORIGIN
OXYGEN COMPOUNDS
PRECIPITATION
ROCKS
SATURATION
SEDIMENTARY ROCKS
SEDIMENTS
SEPARATION PROCESSES
SULFATE-REDUCING BACTERIA
WATER