Fringing carbonate platforms at the Arabian Plate margin in northern Oman during the Late Aptian–Middle Albian: Evidence for high-amplitude sea-level changes - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Sedimentary Geology Année : 2005

Fringing carbonate platforms at the Arabian Plate margin in northern Oman during the Late Aptian–Middle Albian: Evidence for high-amplitude sea-level changes

Résumé

The Aptian–early Middle Albian margin of the Arabian Platform is exposed in Wadi al Assyi (northeast of Jebel Akhdar in northern Oman), and exhibits remarkable geometries testifying to the sedimentary history during the subaerial exposure of most of the Arabian Platform. Detailed analysis of the depositional geometries allows the reconstruction of sea-level fluctuations during the studied time interval, and an estimation of their amplitude. The final progradation of the Lower Cretaceous Arabian carbonate Platform (uppermost part of Kahmah Group) coincides with the deposition of the uppermost Salil Formation whereas the Al Hassanat Formation mostly developed at the margin during the exposure of the Arabian Platform in the Late Aptian to Middle Albian, and thus corresponds to a 2nd-order shelf-margin wedge. During the Early Aptian, km-scaled clinoforms constituted the prograding part of the partly bioconstructed Lower Shuaiba Member. Close to the Early–Late Aptian boundary, the Arabian Platform became exposed and a forced regression took place as evidenced by strong erosion and deposition of a channelized clinoform. These preceded the formation of at least seven, km-scaled, carbonate sequences in the Upper Aptian– lowermost Middle Albian Al Hassanat Formation that, by their geometries and palaeoenvironmental setting, look like fringing coral reefs. These carbonate sequences are therefore described as fringing carbonate platforms that developed laterally and/or above each other. Their internal architecture is mainly retrogradational and aggradational due to rapid, 3rd-order sea-level fluctuations of high amplitude, which forced the carbonate systems to migrate basinward after a sea-level fall and aggraded during sea-level rise, and to the fact that these systems were partly bioconstructed. Five major sea-level falls (30 to 100 m) possibly correlate to sequence boundaries identified in other palaeotectonic/palaeogeographic settings, and are interpreted as resulting from glacio-eustatism or, alternatively, an unknown mechanism.

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Dates et versions

hal-00181343 , version 1 (23-10-2007)

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Benjamin Gréselle, Bernard Pittet. Fringing carbonate platforms at the Arabian Plate margin in northern Oman during the Late Aptian–Middle Albian: Evidence for high-amplitude sea-level changes. Sedimentary Geology, 2005, 175, pp.367 - 390. ⟨10.1016/j.sedgeo.2004.11.007⟩. ⟨hal-00181343⟩
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