FROM LIMITED PLACER OUTCROPS TO MAPPING THE LARGEST TERRESTRIAL ICE STREAM: ALAN KEHEW'S CONTRIBUTIONS TO LATE ORDOVICIAN GLACIATION IN THE SAHARAN-ARABIAN DESERT

The significant contributions and achievements of Alan Kehew to the Midwestern glacial geology, geomorphology, and hydrology are evident and unmistakable. Nevertheless, Alan's contributions extended beyond the continental USA. One of his significant contributions, and those of the students he supervised, was mapping previously unrecognized Late Ordovician glacial mega-streamlined landforms in southern Egypt and their extension in northern Arabia. The latter was misinterpreted as mega-yardangs in Arabia. These landforms were proven to be part of a major, topographically controlled, marine-terminating ice stream that extends from southern Egypt to northern Arabia and ends in western Iran. The initial objectives of this research were to understand the origin of a newly discovered conglomerate-hosted gold placer deposit in the southern sections of the Eastern Desert of Egypt. Thanks to Kehew's contributions, the research goals and tasks were developed to accomplish the following: (1) identify the origin and age of the associated mega-streamlined landforms in southern Egypt and northern Arabia using remote sensing and field-based techniques, (2) develop paleo-topographic reconstructions of the Late Ordovician ice sheet using PaleoDem datasets and Gplates software, (3) understand the Late Ordovician ice sheet extension and dynamics, (4) define the distribution of the paleo-ice streams within the eastern part of the Late Ordovician ice sheet, and (5) identify the exploration criteria that control the distribution of glacial (conglomerate-hosted) placer deposits as a source for mineral deposits. These objectives were successfully met and published in two papers in International Geology reviews 2020 and Earth and Planetary Earth Sciences 2022.