Assessment of bauxite, clay, and laterite deposits in Afghanistan

Abstract

Bauxite-bearing rocks are present in several regions of Afghanistan; specifically, the southeast segment of the North Afghanistan Platform, the eastern parts of South Afghanistan, and within the Afghanistan-North and -South Pamir Fold Regions. Bauxite-bearing rocks occur at various stratigraphic levels, in lithologically different sequences of sedimentary rocks. The bauxites are paleosols and represent previous, rather than recent, weathering events. Bauxites and bauxite-type horizons are most common at the base of carbonate rock units, where they form the basal horizons of sedimentary rock sequences separated by erosion and stratigraphic unconformity surfaces. Less common are zones in redeposited weathering developed on igneous rocks. At present there are five known stratigraphic intervals with significant bauxite and bauxite-type deposits and occurrences: the lower Permian, the upper Permian, the Upper Triassic, the Lower Jurassic, and the base of the Upper Jurassic. This report summarizes a compilation and review of geological data for regions in Afghanistan that contain bauxite deposits and occurrences based on work conducted during 2009 to 2011 by the U.S. Geological Survey, the U.S. Department of Defense Task Force for Business and Stability Operations, and the Afghanistan Geological Survey. Permian strata contain bauxites and bauxite-like rocks that are recognizable at various stratigraphic intervals within several areas of southern Afghanistan and in the Central Afghan Massif in central Afghanistan. The main zones of known bauxite occurrences are the Haftqala bauxite zone (late Permian and Late Triassic), Shewa bauxite zone (early Permian), Qarghanaw bauxite zone (late Permian and Late Triassic), Arghandab block in Zabul Province (middle through late Permian), Arghandab block in Ghazni Province (early Permian), Surkhob bauxite zone (Early Jurassic), and Tirin block in Uruzgan, Zabul, and Kandahar Provinces (Late Jurassic). Although some bauxite occurrences were sampled in the course of reconnaissance exploration by Soviet workers in the 1960s and 1970s, the bauxite areas in Afghanistan generally are underexplored. The Obatu Sheila area is a known field of bauxite deposits of Late Jurassic age that had been studied in more detail than other known bauxite deposits and occurrences in Afghanistan. Obatu Sheila has an estimated reserve of 7.2 million tons.