Reply to Ruban and Zorina’s (2015) discussion on the paper: “Danian/Selandian unconformity in the central and southern Western Desert of Egypt” by S. Farouk and E. El-Sorogy (2015; Journal of African Earth Sciences, 103, 42–53)

Abstract

A global sea-level fall during the Latest Danian Event (LDE) is observed in a regional and worldwide context in widely-separated locations with different tectonic and depositional settings (Clemmensen and Thomsen, 2005). A similar trend in the central and south-western Desert of Egypt is synchronous with a weak tectonic event, which results in the absence of the upper portion of the regressive phase during the LDE, of the P3b Subzone which is seen in “tectonically stable” areas. This weak tectonic event is linked to more intense deformation of the Syrian Arc (Swell) of the Bahariya Oasis, which is synchronous with the global Laramide orogeny. Over the entire Dakhla Basin, the similar vertical sequence tracks can be traced across the area and indicate relative sea-level changes rather than shoreline shifts, and consequently reflect a eustatic origin. Correlation with the Arabian Plate charts (Sharland et al., 2001, 2004; Haq and Al-Qahtani; 2005; Simmons et al., 2007) do not match with the regional reconstruction of Farouk and El-Sorogy (2015) because these Arabian Plate charts are based on mega-sequences controlled by a dramatic tectonic event with erosion along the northeast Arabian plate (Haq and Al-Qahtani, 2005). Recently, after recalibration of many eustatic charts the conclusions made by Farouk and El-Sorogy (2015) concerning the late Danian sea-level fall (e.g., Haq et al., 1987; Hardenbol et al., 1998; Lüning et al., 1998; Guasti et al., 2005; Clemmensen and Thomsen, 2005; Schmitz et al., 2011; Gradstein et al., 2012) have been confirmed.