Formation of diagenetic dolomite in coastal sabkha along Arabian (Persian) Gulf
- Univ. of Petroleum and Minerals, Dhahran, Saudi Arabia
Aragonitic intertidal sediments are being dolomitized in the subsurface supratidal environment of a sabkha along the south shore of the Arabian (Persian) Gulf as a result of the percolation of wind-driven marine-derived brines. The development of abundant diagenetic dolomite results from a optimum combination of high mMg/sup 2 +//mCa/sup 2 +/ ratio fluids, a rapid flow rate which is related to the flooding frequency and sediment permeability, and a shoreline configuration that maintains the proper conditions for a sufficient length of time. Most diagenetic dolomite forms at the expense of primary aragonite according to the reaction: Mg/sup 2 +/ + 2CaCO/sub 3/(arag) ..-->.. CaMg(CO/sub 3/)/sub 2/ + Ca/sup 2 +/. Dolomite forms under the following conditions: (a) chloride concentration between 3.25 and 3.75 mCl/sup -//Kg; (b) mMg/sup 2 +//mCa/sup 2 +/ greater than about 6; (c) pH between 6.3 and 6.9; (d) minimum P/sub CO2/ of 10/sup -2/ to 10/sup -3/ atm; (e) temperature between 25 and 40/sup 0/C; (f) saturation with respect to gypsum; and (g) reducing environment in association with hydrogen sulfide. Other recent dolomite occurrences in the Bahamas, Florida, and Bonaire are significantly different in terms of stratigraphy, degree of lithification, and evaporite mineral association from those in the Arabian Gulf.
- OSTI ID:
- 5386129
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 66:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
DOLOMITE
DEPOSITION
PERSIAN GULF
ARAGONITE
CALCITE
DIAGENESIS
GEOCHEMISTRY
GYPSUM
ORIGIN
SEDIMENTATION
ALKALINE EARTH METAL COMPOUNDS
ARABIAN SEA
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CALCIUM SULFATES
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHEMISTRY
INDIAN OCEAN
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALS
OXYGEN COMPOUNDS
SEAS
SULFATE MINERALS
SULFATES
SULFUR COMPOUNDS
SURFACE WATERS
580100* - Geology & Hydrology- (-1989)
020200 - Petroleum- Reserves
Geology
& Exploration