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Titre : Sedimentology, Sequence stratigraphy and Spatial-temporal Patterns of the late Paleocene Succession, western Sirt Basin, Libya

Auteur : ELKANOUNI, IBRAHIM,ELTAIB,DAW

Université de soutenance : Durham University

Grade : Doctor of Philosophy (2014)

Résumé partiel
In the western Sirt Basin, sedimentation during the Late Paleocene was characterized broadly by shallow-marine carbonates, local build-ups and deeper-water shales and marls on the Dahra Platform and in the Dor al Abid/Zallah Troughs. Seven lithofacies and eleven associated microfacies have been recognised within the Selandian/Thanetian carbonate succession in the study area, and these range from mud-supported carbonates to grain-dominated facies. The Dahra Formation on the Dahra Platform was deposited on a homoclinal carbonate ramp with inner, mid and probably outer ramp facies, each with distinctive sub-facies and microfacies. The similarity of facies and associated microfacies throughout the Dahra Formation suggest deposition under similar conditions throughout the east and west Dahra Fields on the Dahra Platform, and these persisted during deposition of the Zelten and Harash Formations. The Mabruk Member, which consists mainly of shallow-water carbonates bounded above and below by deeper-marine shale and marl, accumulated in lagoonal and reefal environments, probably in a rimmed-shelf setting. Different types of diagenetic alteration occurred at various stages in the Paleocene sedimentʼs history including dissolution, cementation and compaction. Primary and secondary types of porosity were developed within the studied rocks, particularly in the Dahra Formation, where the depositional facies, diagenesis and the pattern of carbonate cycles played an important role in porosity creation and preservation.

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