Paleozoic glaciation in NE Africa: field and remote sensing-based evidence from the South Eastern Desert of Egypt

ABSTRACT

Exhumed Paleozoic glacial deposits and landforms of the North Gondwana are reported here for the first time from the South Eastern Desert (SED) of Egypt. Using field observations and remote sensing datasets (Advanced Land Observing Satellite [ALOS], Phased Array L-band Synthetic Aperture Radar [PALSAR] radar, multispectral Landsat TM datasets, and digital elevation models [DEMs]), we mapped the distribution of Paleozoic glacial features (i.e. deposits and landforms) in the SED. Two main glaciogenic facies were identified in three locations in the SED: (1) massive, poorly sorted, matrix supported, boulder-rich diamictites in Wadi El-Naam and Korbiai, and (2) moderately-sorted, occasionally bedded outwash deposits in Betan area. Inspection of radar, DEMs, and Landsat Operational Land Imager (OLI) images revealed previously unrecognized ENE-WSW trending glacial megalineations (MLs) over the peneplained Neoproterozoic basement rocks in the central sections of the SED, whose trends align along their projected extension with those of glacial features (tunnel valleys and striation trends) reported from Saudi Arabia. The glaciogenic features in the SED are believed to be largely eroded during the uplift associated with the Red Sea opening, except for those preserved as basal units beneath the Nubia Sandstone Formation or as remnant isolated deposits within paleo-depressions within the basement complex. The apparent spatial correlation of the SED glacial features with well-defined Late Ordovician deposits in North Africa and in Saudi Arabia, and the reported thermochronometric analyses and fossil records are consistent with a Late Ordovician age for the SED glaciogenic features and support models that call on the continuation of the Late Ordovician (Hirnantian) ice sheet from the Sahara into Arabia through the SED of Egypt.

KEYWORDS:

• Late Ordovician
• Hirnantian
• megalineations
• megagrooves
• Paleozoic glaciation
• North Gondwana
• South Eastern Desert
• diamictite

Acknowledgments

The authors thank Professor John Menzies for his contribution in identifying and interpreting the paleosol layer, and Mr. Eid Nour, Mr. Nasser Awad, and Shiekh Sir El-Khatam (the head of the Ababda tribe) for facilitating fieldwork. We extend our gratitude to the IGR Reviewers (William Bosworth and an anonymous reviewer) for their constructive comments that significantly improved this work, along with Robert Stern for his suggestions and for handling the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the Egyptian Cultural Affairs and Missions Sector, Ministry of Higher Education (Plan 2015-2016), and by the Earth Sciences Remote Sensing (ESRS) facility, Department of Geological and Environmental sciences, Western Michigan University.