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Secondary Minerals From Extrapedogenic Per Latus Acidic Weathering Environments At Geomorphic Edges, Eastern Nebraska, Usa, Robert Matthew Joeckel, K.D. Wally, B.J. Ang Clement, P.R. Hanson, J.S. Dillon, S.K. Wilson

Conservation and Survey Division

Acidic weathering of the sulfidic Upper Cretaceous Carlile and Pierre Shales in Nebraska has led to the precipitation of the Al sulfate–hydroxide minerals aluminite, alunite, “basaluminite”/felsöbányaite (e.g.,), the aluminum hydroxides gibbsite and bayerite, and the rare Al phosphate hydroxide vashegyite. Kaolinite has also been produced as a result of this acidic weathering. These minerals do not appear as neoformed constituents in any extant soils in the region, and their existence underscores the ability of pyrite oxidation to produce major changes in mineralogy on a Holocene to Recent time scale. Jarosite, hydronium jarosite, gypsum, halotrichite, and melanterite also appear as secondary …