Reconstruction of Middle and Late Cretaceous Sequence Stratigraphic Framework in South-Eastern Abu Dhabi
A. Farid1, M. Ali1, and M. Iqbal1
Five sequence boundaries and four sequences have been identified on seismic records between Cenomanian and Upper Maastrichtian. Sequence boundary FS(SB1) has been identified on the seismic sections as a clear angular unconformity, generated due to basement activity during the Cenomanian. This basement activity is the major cause of uplift along many structures which pushed the structures above the sea level. Tectonic activity due to the obduction of Semail Ophiolite and resulting flexural buldge lead to incision in the older sediments during Turonian. This unconformity is another sequence boundary in the Middle Turonian, MT (SB2) lying between Halul and Shilaif sequences, is most evident in south of Abu Dhabi along the structural highs where it has cut through the Mishrif and Shilaif sediments. This event is followed by a general sea level rise with the deposition of Halul and Laffan Formations. The regression patterns seen in different sediments lead to the tectonic activity along different structures in different ages. The sequence boundary FS (SB3) is an erosional unconformity on the top of Halul sequence is generated due to the ongoing tectonic activity and resulting changes in the sea level. This unconformity is traced in synclines as a correlative conformity by the onlapping patterns where Fiqa Formation is well developed above this unconformity. Another tectonic episode has resulted in an erosional unconformity between Fiqa and Simsima sequences and is considered to be the fourth sequence boundary FS (SB4). This unconformity can be recognized on the seismic section by the onlaps and truncation patterns of base Simsima. The Cretaceous-Tertiary boundary KT (SB5) is taken as the fifth sequence boundary and marks the closure of the Late Cretaceous Simsima sequence.
AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain