Maastrichtian-Paleocene successions at Kharga-Dakhla stretch, Western Desert, Egypt: Paleoenvironmental and basin evolution interpretations

Abstract

Detailed field, litho-, bio-stratigraphic and paleoenvironmental studies on the Maastrichtian-Paleocene successions exposed at El-Qasr, Abu Tartur, Gabal El-Aguz and Darb Gaga sections at Kharga-Dakhla region, Western Desert, Egypt are attempted. Three rock units are recognized; Dakhla, Kurkur and Tarawan formations. Eight calcareous nannofossil and ten planktonic foraminiferal zones are recorded and integrated to determine a precise age dating. Four benthonic foraminiferal biofacies (A, B, C and D) are reconstructed using the R-mode (species) hierarchical cluster analysis. These biofacies along with the relative abundance of the calcareous nannofossil species are used to interpret the paleoenvironmental conditions as well as the depositional settings prevailed during deposition of the studied successions. The integration of these data led to the identification of significant hiatuses which could be linked to two syn-sedimentary tectonic events (Tectonic Event I and II). Tectonic Event I at the Cretaceous/Paleogene (K/Pg) boundary has a regional effect and led to expose the southern part of the Tethys margin which is represented by the present study area. Throughout the Early Danian, the sedimentary basin could be divided into two sub-basins at El-Qasr and G. El-Aguz sections separated by two sub-marine paleohighs at Abu Tartur and Darb Gaga sections which represented the northern extensions of the southern shallow Garra El-Arbain Facies. The effect of Tectonic Event II initialized at Danian and continued throughout Thanetian. This event is restricted to the eastern part at Darb Gaga and G. El-Aguz sections forming an areal paleohigh at Darb Gaga and a sub-marine paleohigh at G. El-Aguz sections.