Int Journ Earth Sciences (2000) 88 : 708±724  Springer-Verlag 2000 ORIGINAL PAPER C. Scheibner ´ J. Kuss ´ A. M. Marzouk Slope sediments of a Paleocene ramp-to-basin transition in NE Egypt Received: 9 November 1998 / Accepted: 6 October 1999 Abstract Sedimentary structures, microfacies and stratigraphy of a late Paleocene ramp-to-basin transi- tion have been studied in the Galala Mountains in the northern part of the Eastern Desert of Egypt. Three phases of ramp progradation were observed. During non-progradation hemipelagic sediments were inter- calated. These progradational phases are indicated by mass-transport deposits of glides slumps and debris flows which came from different directions except from the south. At least two of these mass-transport deposits may reflect deposition during sea-level low- stands, whereas the hemipelagic intercalations indicate transgressive phases. Microfacies analysis provided evidence of a change in the origin of the debris flow deposits. They show a transition from a basinal-to-out- er-ramp setting to a middle-to-inner-ramp setting and a change in organism distribution. While coralline red algae prevailed on the inner ramp in the Selandian to Thanetian, nummulitids dominated in the late Thane- tian. Key words Middle to Late Paleocene ´ Glides ´ Slumps ´ Debris flows ´ Microfacies analysis ´ Algal shoals ´ Nummulitidae shoals Introduction The area of the Galala mountains (Eastern Desert, Egypt) has been the focus of numerous studies mostly dealing with biostratigraphy and lithostratigraphy (Is- mail and Abdallah 1966; Abdou et al. 1969; Abdel Kireem and Abdou 1979; Strougo et al. 1992; Faris 1994). Only a few studies have dealt with the overall architecture of the depositional system (Bandel and Kuss 1987; Kuss and Leppig 1989; Kulbrok 1996; Gietl 1998; J. Kuss et al., submitted). These authors propose a stuctural high during late Cretaceous times, situated at the central and southern parts of the North Galala including the Wadi Araba area to the south. Late Cre- taceous slope deposits of the mid-outer ramp are exposed at the monastery of St. Anthony (Fig. 1); however, they are not present further south at the monastery of St. Paul where only their basinal equiv- alents occur (Kulbrok and Kuss 1995). Ramp progra- dation continued during the Paleogene. The first ramp-derived allochthonous sediments were trans- ported during the Selandian from northerly directions to the St. Paul area. The sections studied, west of the monastery of St. Paul, represent a segment of a ramp to basin transition within that southward-prograding ramp system. This paper concentrates on an excellent, continuous outcrop near the monastery of St. Paul, 360 m wide and 50 m high, including a massive layer (20 m) com- posed of various units of mass-transport sediments (Figs. 1, 2). They exhibit multiple transitions between glides and debris flows (DFs), composed mainly of carbonates with only minor contents of quartz. Thin- section analysis of allochthonous carbonates indicates a wide spectrum of components originally formed in different environments of the Paleogene carbonate ramp situated further north. Many limestones within the different allochthonous units are comparable to shallow-water autochthonous ramp environments described previously by Gietl (1998). Moreover, we discuss various stages of ramp progradation during the late Paleocene. C. Scheibner ( ) ) ´ J. Kuss Department of Geology, Bremen University, Fachbereich 5, P.O. Box 330440, D-28334 Bremen, Germany e-mail: scheibne@uni-bremen.de Fax: +0421-2184515 A. M. Marzouk Department of Geology, Faculty of Science, Tanta University, ET-31527 Tanta Egypt