Dolomite occurrence in Coorong region, south Australia

Conference · Mon Feb 01 04:00:00 EST 1988 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5720874

Rosen, M; Warren, J K ^[1]

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1. Univ. of Texas, Austin (USA)

Lakes in the Coorong region are filled with a diverse suite of Holocene carbonates; mineralogies include aragonite, calcite, magnesium-calcite, magnesite, hydromagnesite, and dolomite. Dolomite is the main mineral of concern in this paper, yet it makes up no more than 5% of the carbonate minerals forming surficial deposits in the coastal plain of southeast South Australia. Coorong dolomite occurs as three stratigraphically and mineralogically distinct forms. Volumetrically, the most important type of dolomite is an evaporative dolomite laid down as the last episode of sedimentation in those Coorong Lakes that contain dolomite. In most lakes, dolomite is a capstone unit no more than a meter thick, although in a few lakes it has infilled the lakes to form dolomitic units up to 4-5 m thick. Evaporative dolomite is usually magnesian-rich. In some lakes, a calcian-rich dolomite occurs along the edges of the lake. Like the evaporative upper dolomite, this dolomite is not intergrown with other carbonate phases and appears to define areas where continental ground waters first enter the lake. A third type of dolomite occurs in some Coorong lakes. A basal dolomite, which is more crystalline than the other two forms of dolomite, appears to have formed some 6000 years ago when the rising Pleistocene water table (driven by a transgressing sea) first caused continental ground waters to outcrop and evaporate at the surface.

• OSTI ID: 5720874
• Report Number(s): CONF-880301--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 72:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALKALINE EARTH METAL COMPOUNDS
AUSTRALASIA
AUSTRALIA
CALCITE
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CENOZOIC ERA
DOLOMITE
GEOLOGIC AGES
GEOLOGY
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALOGY
MINERALS
OXYGEN COMPOUNDS
QUATERNARY PERIOD
STRATIGRAPHY