Intra-platformal organic-rich facies of the Alpine Triassic
During the Middle and Late Triassic, large areas of the Alpine-Mediterranean region were blanketed by carbonate-platform systems that developed prior to the initiation of major rifting that ultimately produced the Ligurian Tethys Ocean. Field studies reveal that the stratigraphic record of these platforms includes a number of locally developed beds, in particular of Ladinian and late Norian-Rhaetian age, characterized by the preferential preservation of organic carbon in a range of facies, from subtidal right through to stromatolitic units conventionally referred to as inter/supratidal environments. This heightened carbon preservation is most strikingly developed in Ladinian and Norian-Rhaetian deposits of intraplatformal depressions with limited area (up to 1,000 km/sup 2/). These successions can approach 500 m thick and commonly consist of dark interbedded shales, limestones, and/or dolomite with 1 to 5% organic carbon, depending on carbonate dilution. With hydrogen indices up to 500 mg HC/g and S/sub 2/ pyrolysis yields in the range of 5-20 kg/MT, they clearly have considerable bulk petroleum source potential. In condensed sections these values may be greatly exceeded. The carbon-rich sequences were usually associated with Mesozoic structural highs which received relatively thin post-Triassic cover and as a consequence were commonly pushed into the oil window in the latest flysch phases, i.e., post-Alpine deformation. Thus not only were the source horizons surrounded by abundant carbonate reservoirs, but also any secondary migration should have occurred at a time when potential structural traps were stable.
- Research Organization:
- Oxford Univ. (England)
- OSTI ID:
- 5848749
- Report Number(s):
- CONF-8809346-
- Journal Information:
- AAPG Bull.; (United States), Vol. 72:8; Conference: Mediterranean Basins conference and exhibition, Nice, France, 25-28 Sep 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MEDITERRANEAN SEA
GEOLOGIC HISTORY
PETROLEUM DEPOSITS
ORIGIN
CARBONATE ROCKS
DOLOMITE
GEOLOGIC TRAPS
LIMESTONE
SHALES
STRATIGRAPHY
TRIASSIC PERIOD
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MESOZOIC ERA
MINERAL RESOURCES
MINERALS
OXYGEN COMPOUNDS
RESOURCES
ROCKS
SEAS
SEDIMENTARY ROCKS
SURFACE WATERS
020200* - Petroleum- Reserves
Geology
& Exploration