Geologic setting for hydrocarbons in Tunisia

Conference · Tue May 01 00:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6634987

Schamel, S ^[1]

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1. Univ. of South Carolina, Columbia (USA)

Hydrocarbon habitats on the Tunisia-Sicily shelf result from the complex interplay of three factors: (1) proximity to a source of terrigenous sediments, (2) eustatic sea level changes resulting in major transgression/regression events, and (3) a varied and ever-changing structural mosaic involving successive transtensional, transpressive, and compressional tectonic phases. The stratigraphy, structure, and petroleum resources of the shelf are linked to the crustal template created during the middle Mesozoic rifting of the Tethyan margin of North Africa. Transtensional stretching and crustal fragmentation forming the Tunisia-Sicily passive margin occurred in the Late Triassic-Jurassic at the juncture of the South Saharan and Gibraltar shear zones, creating a complex array of ridges and furrows and localized pull-apart basins. During the Cretaceous and early Tertiary, the subsident block-faulted shelf was buried beneath a varied stratigraphy ranging from a thin pelagic limestone succession devoid of terrigenous components in Sicily to a considerably thicker neritic Tunisian succession composed of mixed terrigenous and carbonate strata. Differences in stratigraphic character across the shelf relate to the relative position of Sicily and Tunisia between the unstable and subsident Tethyan margin and the stable and emergent Saharn platform. Beginning in the middle Cretaceous, the region experienced localized tectonic instability expressed as transtensional faulting, crustal inversion, salt diapirism, and submarine volcanism. These events profoundly altered bathymetry and facies distribution on the shelf. As the North African continental margin subducted northward beneath the Kabyle-Calabrian accretionary complex in the late Cenozoic, the thin competent carbonate successions of Sicily responded by detaching in a series of southward migrating thrust sheets. The thrusts die out along strike in Tunisia.

• OSTI ID: 6634987
• Report Number(s): CONF-900605-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:5; Conference: Annual convention and exposition of the American Association of Petroleum Geologists, San Francisco, CA (USA), 3-6 Jun 1990; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
PETROLEUM DEPOSITS
GEOLOGY
SICILY
TUNISIA
CARBONATE ROCKS
CONTINENTAL MARGIN
CRETACEOUS PERIOD
GEOLOGIC FAULTS
GEOLOGIC HISTORY
OFFSHORE SITES
RIFT ZONES
STRATIGRAPHY
TECTONICS
AFRICA
DEVELOPING COUNTRIES
EUROPE
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
ITALY
MESOZOIC ERA
MINERAL RESOURCES
RESOURCES
ROCKS
SEDIMENTARY ROCKS
WESTERN EUROPE
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences