Red Sea tectonics unveil one of the largest terrestrial ice streams: New constraints on Late Ordovician ice sheet dynamics

Mega-streamlined landforms on Earth and Mars have been attributed to aeolian, glaciogenic, fluvial, and tectonic processes. Identifying the forces that shaped these landforms is paramount for understanding landscape evolution and constraining paleo-climate models and ice sheet reconstructions. In Arabia, eastnortheast trending, kilometer-scale streamlined landforms were interpreted to have been formed by Quaternary aeolian erosion. We provide field and satellite-based evidence for a Late Ordovician glacial origin for these streamlined landforms, which were exhumed during Red Sea-related uplift. Then we use Late Ordovician paleo-topographic data to reconstruct the Late Ordovician ice sheet using identified and previously reported glacial deposits and landforms. Our reconstruction suggests these glacial features are part of a major, topographically controlled, marine-terminating ice stream, with a minimum length of 1000 km extending from the southeast Egypt to northern and central Arabia and possibly more than twice this length if the glaciomarine and iceberg deposits in the present-day western Iran are part of this system. Our results support models that advocate for a single, major, and highly dynamic ice sheet and provide new morphological-based constraints for Late Ordovician climate models. (c) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

This study provides evidence for a Late Ordovician glacial origin of streamlined landforms in Arabia and reconstructs the Late Ordovician ice sheet. The results support the existence of a significant and dynamic ice sheet during the Late Ordovician period and provide new morphological constraints for paleo-climate models.