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8152994 
Journal Article 
Mineralogy of Rohrer's Cave, Lancaster County, Pennsylvania 
White, WB; Scheetz, BE; Atkinson, SD; Ibberson, D; Chess, CA 
1985 
47 
1 
17-27,34-35 
English 
The cave is 275 m long and floored in places with a brown mud, overlying an intricately layered sequence of white, yellow, and grey sediment. In place of the usual calcite speleothems, the cave contains a collection of white and black soft mushy coatings and hanging forms resembling pinecones. It also contains brown stalactites and stalagmites of hydrated iron oxides. The iron oxide speleothems are relatively pure but non-crystalline at the XRD scale. There is no evidence for other heavy metals. The black coatings consist of manganese oxides with exceptional concentrations (approx 20 wt.%) of Ni, Co, Cu and Zn in approximately equal proportions. The white opaline-like deposits consist in part of non-crystalline hydrated Al silicates and Al phosphates. Their chemical composition and microstructure identify them as allophane. The blue flowstone found in a few patches in the cave is also allophane containing a few % of Cu. The layered sediments consist mainly of allophane with minor Fe and Mn oxide forming pigmenting layers. All deposits contain large proportions of unbound water which is lost on drying to form loose fine-grained powders or thin flakes. (Authors' abstract)-C.N.