Deep burial dolomitization driven by plate collision: Evidence from strontium-isotopes of Jurassic Arab IV dolomites from offshore Qatar
- Shell Research, Rijswijk (Netherlands)
The use of strontium-isotope ratios of dolomites to constrain timing and mechanism of diagenesis has been investigated on Jurassic Arab IV dolomites from offshore Qatar. Reservoir quality is determined by two types of dolomites, which were differentiated geochemically (cathodoluminescence, fluid inclusions, and carbon and oxygen stable isotopes): (1) stratigraphically concordant sucrosic dolomites with high porosity formed during early near-surface diagenesis (Jurassic) and (2) stratigraphically discordant cylindrical bodies of massive, porosity-destroying dolomites formed late during deep burial diagenesis (Eocene-Pliocene). Detailed Sr-isotope analysis of dolomites from the Arab IV confirms an Early Jurassic age of the sucrosic, high porosity dolomites ({sup 87}Sr/{sup 86}SR = 0.70707 for NBS 987 = 0.71024) with magnesium and strontium being derived from Jurassic seawater. Late Tertiary compressional orogeny of the Zagros belt to the north is proposed to have caused large-scale squeezing of fluids from the pore system of sedimentary rocks. A regional deep fluid flow system developed dissolving infra-Cambrian evaporites upflow and causing large-scale deep burial dolomitization downflow.
- OSTI ID:
- 7271617
- Report Number(s):
- CONF-910403-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
58 GEOSCIENCES
PETROLEUM DEPOSITS
RESERVOIR ROCK
QATAR
DIAGENESIS
GEOCHEMISTRY
POROSITY
CARBONATE ROCKS
CHEMICAL COMPOSITION
DOLOMITE
GEOLOGIC FORMATIONS
JURASSIC PERIOD
OFFSHORE SITES
PLATE TECTONICS
STRATIGRAPHY
STRONTIUM ISOTOPES
TERTIARY PERIOD
ALKALINE EARTH ISOTOPES
ASIA
CARBONATE MINERALS
CENOZOIC ERA
CHEMISTRY
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGY
ISOTOPES
MESOZOIC ERA
MIDDLE EAST
MINERAL RESOURCES
MINERALS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
TECTONICS
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences