Abstract

Tracking sequences in hemipelagic facies is complicated because of the rather monotonous appearance of the hemipelagic deposits, lack of subaerial exposure, and absence of typical sequence stratigraphic geometries. This study addresses how the sequence stratigraphic model can be applied in hemipelagic environments. Eight latest Maastrichtian to early Eocene hemipelagic sections from central East Sinai have been recorded and biostratigraphically and paleobathymetrically studied by means of planktic and benthic foraminifera, calcareous nannofossils and sedimentological observations. Sea-level changes were reconstructed using the foraminiferal planktic/benthic ratio, hiatuses, hard calcareous marl beds, and benthic foraminifera. Correlation of the observed paleobathymetric cycles yielded a sea-level history for the region consistent with the existing literature. Candidate systems tracts boundaries were interpreted using a simple model that provides an approximate relationship between relative sea level and systems tracts. Sequence stratigraphic history was compared with regional sea-level curves from central/southern Egypt, Tunisia and Texas, as well as with European (Hardenbol and others, in press) and "global" (Haq and others, 1987) sequence charts. Correlation is excellent for the early and middle Paleocene (K/T boundary to mid Globanomalina pseudomenardii Zone). Deposition in central Sinai during this time may, therefore, have been predominantly controlled by eustatic sea level rather than local tectonics. Interpretation of sea-level development in the late Thanetian is more ambiguous. The study demonstrates the applicability of the sequence stratigraphic concept in suitable hemipelagic environments. The Paleocene hemipelagites of Sinai represent a paleobathymetric interval suitable for sea-level changes to be recorded in the foraminiferal faunal composition in terms of the planktic/benthic ratio.

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