New distribution coefficient for the incorporation of strontium into dolomite and its implications for the formation of ancient dolomites
- Univ. of Miami, FL (USA)
Late Tertiary dolomites form the Bahamas exhibit a strong inverse correlation between Sr and mol% MgCO{sub 3}. It is proposed that this relation is a result of a distribution coefficient dependent on the concentration of Ca in dolomite. Because these dolomites precipitated from water with a Sr{sup 2+}/Ca{sup 2+} ratio similar to that of seawater, a distribution coefficient (D{sub Sr}{sup dolomite}) of 0.0118 is calculated for Sr in stoichiometric dolomite. This coefficient increases by about 0.0039 for every additional mol% CaCO{sub 3} in nonstoichiometric dolomite. These data have three important implication. First, the new D{sub Sr}{sup dolomite} is substantially lower than previously suggested. Second, a relation has been established among the Sr{sup 2+}/Ca{sup 2+} ratio of dolomite-forming waters, the major element composition of dolomites, and the Sr content of dolomites, allowing the determination of the Sr{sup 2+}/Ca{sup 2+} ratio of fluids involved in the formation of ancient dolomites. Third, some published data sets on dolomites show a similar relation between Sr content and major element composition suggesting that these dolomites may also have formed from seawater. Other data sets deviate from the correlation defined by Little Bahama Bank dolomites, indicating either dolomitization in fluids other than seawater or changes of the Sr{sup 2+}/Ca{sup 2+} ratio of seawater through time.
- OSTI ID:
- 6140594
- Journal Information:
- Geology; (USA), Journal Name: Geology; (USA) Vol. 18:5; ISSN GLGYB; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580000* -- Geosciences
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
BAHAMA ISLANDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
CHEMISTRY
DEPOSITION
DEVELOPING COUNTRIES
DISTRIBUTION
DOLOMITE
ECOLOGICAL CONCENTRATION
ELEMENTS
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
HYDROGEN COMPOUNDS
ISLANDS
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
METALS
MINERALS
OXYGEN COMPOUNDS
PRECIPITATION
QUANTITY RATIO
SEAWATER
SEPARATION PROCESSES
STOICHIOMETRY
STRONTIUM
TERTIARY PERIOD
WATER
WEST INDIES