Upper Cretaceous-lower Paleocene subsurface sequence, Farafra Oasis, Western Desert, Egypt: stratigraphical and paleoenvironmental inferences

摘要

This work presents details litho-, bio-, and sequence stratigraphy and paleoenvironmental studies on the Upper Cretaceous-lower Paleocene subsurface rocks of Sahl Baraka at Farafra Oasis, Western Desert, Egypt. Lithostratigraphically, two rock units were recognized: the Wadi Hennis (at the base) and the Khoman (at the top) formations. Ten planktonic foraminiferal zones were identified from the Khoman Formation covering the Campanian-Danian chronostratigraphic interval. Using the R-mode hierarchical cluster analyses, four benthonic foraminiferal biofacies (A, B, C, and D) were recognized. The data indicates that the sediments of the Khoman Formation were deposited in marine environments ranging from deep marine (outer neritic-upper bathyal setting) for the lower and middle parts to shallow marine one (middle-outer neritic setting) for the upper part. The Sahl Baraka area was located in a sedimentary basin subjected to three tectonic events during the Late Cretaceous-early Paleocene time which were related to the Syrian Arc Orogeny. These tectonic events interrupted the eustatic sea-level curve. The integrated data led to define three depositional sequences (sequence-1 to sequence-3) separated by three sequence boundaries (SB1-SB3) throughout the Late Cretaceous-early Paleocene time.