--> Abstract: Distribution of Carbonate Cements within Depositional Facies and Sequence Stratigraphic Framework of Shoreface and Deltaic Sandstones: Evidence from Lower Miocene Succession, the Gulf of Suez Rift, Egypt, by Mohamed A. El-Ghali, Essam El-Khoriby, Sadoon Morad, and Howri Mansurbeg; #90105 (2010)

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Distribution of Carbonate Cements within Depositional Facies and Sequence Stratigraphic Framework of Shoreface and Deltaic Sandstones: Evidence from Lower Miocene Succession, the Gulf of Suez Rift, Egypt

Mohamed A. El-Ghali1; Essam El-Khoriby2; Sadoon Morad3; Howri Mansurbeg4

(1) Geology and Petroleum Geology, Universiti Brunei Darussalam, Bandar Seri Begawen, Brunei Darussalam.

(2) Department of Geology, Mansoura University, El-Mansoura, Egypt.

(3) Department of Petroleum Geosciences, The Petroleum Institute, Abu Dhabi, United Arab Emirates.

(4) AGR Reservoir Evaluation Services AS, AGR Reservoir Evaluation Services AS, Oslo, Norway.

The shoreface-offshore (transgressive systems tract TST and highstand systems tract HST) and coarse-grained deltaic (lowstand systems tract LST) calcarenite and hybrid arenites of the Mheiherrat Member of the Rudeis Formation, Early Miocene, the Gulf of Suez, Egypt were pervasively cemented by carbonate cements and less amounts of zeolite, palygorskite, pyrite and iron oxides. The spatial and temporal distribution of carbonate cements were constrained within a sequence stratigraphic framework. The shoreface-offshore TST and HST calcarenite and hybrid arenites, particularly below parasequence boundaries (BP’s), transgressive surface (TS) and maximum flooding surface (MFS) were pervasively cemented by (i) grain-coating and inter- and intragranular pore-filling microcrystalline calcite (e.g. circumgranular isopacheous acicular, and columnar and small amounts of circumgranular equant) and inter- and intragranular pore-filling coarse-crystalline calcite (e.g. poikilotopic and overgrowths) with δ18OVPDB = -3.6 to -0.3 ‰ and δ13CVPDB = -2.3 to -0.7 ‰, and (ii) non-ferroan rhombic dolomite (δ18OVPDB = -3.9 to +0.9‰; δ13CVPDB = -2.5 ‰ to -0.7 ‰). The coarse-grained deltaic LST calcarenite and hybrid arenites was pervasively cemented by (iv) grain-coating calcite (e.g. columnar and circumgranular equant) and inter- and intragranular pore-filling coarse-crystalline calcite (e.g. poikilotopic and overgrowths) with δ18OVPDB = -4.4 to -2.3 ‰; δ13CVPDB = -2.8 to -1.3 ‰, and (v) small amounts of non-ferroan rhombic dolomite (δ18OVPDB = -4.8 to -2.5 ‰; δ13CVPDB = -3.3 to -1.5 ‰). Such extensive cementations by carbonates i.e. calcite and dolomite particularly below BP’s, TS and MFS were being facilitated by the presence of detrital carbonates and bioclasts. This study demonstrates that the spatial and temporal distribution of diagenetic alterations in deltaic and shallow marine calcarenite to hybrid arenites can be better predicted when linked to depositional facies and sequence stratigraphy.