Abstract
Spectacular erratic boulders, polymictic conglomerates, and sedimentary structures are discovered in many localities at the Midyan Peninsula, east of the Gulf of Aqaba. These deposits are discontinuous, and they unconformably overlie older lithological units of Proterozoic, Cretaceous, Paleogene, and Neogene ages. The erratic boulders are composed of basement rocks, sandstone, and limestone. Some of the boulders exceed 2 m (6 ft) in diameter. The boulders are sub-rounded to rounded, striated, polished, grooved, and faceted. The polymictics are composed of heterogeneous coarse clastics (ranging from boulders to conglomeratic sandstones) of various rock types and fill incised paleovalleys. The sedimentary structures include polished, faceted, and striated boulders, pavements, U-shaped valleys, slumps, and fan-shaped structures. These deposits are herein informally named the Midyan Formation. A Pleistocene age is assigned to the formation based on its stratigraphic position. The polymictic conglomerates are interpreted as glaciogenic tillite, and the erratic boulders and sedimentary structures are considered to have been deposited by glacial erosion, deposition, and possibly tectonics. This interpretation raises the question; did glaciers exist during Pleistocene in the Midyan region? If this interpretation is valid, then recognition of Pleistocene glaciation in Arabia fills a blank spot in the global map of the “Ice Age”. Pleistocene glacial features were reported in Yemen and regions in north Iraq.