A Sequence Stratigraphic Reference Section for the Tithonian of Lebanon
Christopher Toland, 2000. "A Sequence Stratigraphic Reference Section for the Tithonian of Lebanon", Middle East Models of Jurassic/Cretaceous Carbonate Systems, Abdulrahman S. Alsharhan, Robert W. Scott
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Central Lebanon provides some of the best exposed and most readily accessible Upper Jurassic (Kimmeridgian-Tithonian) sections in the Middle East, and is one of the few places where lateral equivalents of the prolific Arab Formation (Kimmeridgian-Tithonian) reservoirs of Peninsular Arabia can be studied at outcrop.
At the Bikfaya outcrop section (35 km ENE of Beirut), the uppermost Jurassic comprises at least two disconformity-bounded third-order depositional sequences. Sequence 1 (“Falaise de Bikfaya”) is 61 m+ thick and comprises a progradational succession (highstand systems tract) of foreshoal micropeloid packstones, shoal-crest stromatoporoid floatstones, back-shoal Permocalculus wackestones, and (?attached mainland-) shoreface facies culminating in tidal-flat deposits. This interval is of Early to Middle Tithonian age.
Sequence 2 (“Calcaire de Salima”) is ca. 63 m thick, and commences with an abrupt transgressive surface and an associated influx of calcareous dinocysts. The lower part of this sequence comprises strongly argillaceous micropeloidal packstones and occasional peloid-intraclast packstones, interpreted as an offshore transition zone facies association. The initial marine flooding event is of late Middle Tithonian (upper fallauxi-ponti Zone) age. A candidate maximum flooding surface (MFS) is recognized within the late Middle Tithonian ponti Zone, coincident with calcareous dinocyst species and abundance maximum. (A ponti Zone MFS has also been identified elsewhere in the Middle East.) The recessive middle part of Sequence 2 is largely unexposed, whereas the upper cliff-forming part comprises ca. 22 m of Upper Tithonian ooid-skeletal grainstones that coarsen and thicken up-section. These grainstones are characterized by pronounced planar cross-stratification with set heights of up to 3.6 m, and are interpreted as a wave-dominated shoal complex culminating in emergent foreshore facies. Sequence 2 is terminated by a prominent paleo-karst (Type 1 sequence boundary) corresponding to the Jurassic-Cretaceous boundary, and is overlain by basal Cretaceous wacke-ironstones that form the lower part of the Chouf Sandstone Formation.
The lower part of the Chouf Sandstone Formation lacks age-diagnostic fossils. The timing of initial Cretaceous onlap is thus only poorly constrained by the presence of Late Tithonian taxa in the underlying “Calcaire de Salima” and the presence of Barremian spores in the upper part of the Chouf Sandstone Formation.
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Middle East Models of Jurassic/Cretaceous Carbonate Systems
This volume will interest tectonic modelers, stratigraphers, sedimentologists, and explorationists. It is the product of the international conference of “Jurassic/Cretaceous Carbonate Platform-Basin Systems, Middle East Models” that was convened in December 1997 jointly by SEPM (Society for Sedimentary Geology) and the United Arab Emirates University in Al Ain, United Arab Emirates. The twenty-three papers present new data and interpretations arranged in three sections: 1) sequence stratigraphy, cyclostratigraphy, chronostratigraphy, and tectonic influences, 2) depositional and diagenetic models of carbonate platforms, and 3) hydrocarbon habitat and exploration/development case studies. New tectonic models of the Arabian Basin, new stratigraphic and sequence stratigraphic reference sections, new geochemical and source rock data, and new reservoir data are presented. New geologic models make this set of papers relevant to geoscientists working outside of Arabia also.