MINERALIZATION IN RELATION TO SPELEOGENESIS IN AMAZING MAZE CAVE

Amazing Maze Cave, in Pecos County, Texas, located approximately 30 miles east of Fort Stockton, is the third longest cave in the state. It is a large, rectilinear maze cave that appears to have been formed by hypogene speleogenesis. The cave is formed in the Lower Cretaceous Fort Terrett Formation (Fredericksburg Group), in approximately one-meter thick beds of mudstone, wackestone and packstone facies. Several mineral species are found in the cave that are indicative of sulfuric acid speleogenesis, such as secondary gypsum, halloysite 10Å (endellite, a clay mineral similar to kaolinite), tyuyamunite (hydrated uranyl vanadate) and manganese oxides. Most secondary minerals are spatially limited, but common throughout the cave; however, secondary gypsum forms massive bodies often filling passages near intersections. The angular maze shape of the cave, along with the appearance of speleogens such as cupolas, risers, and ceiling channels, are definitive characteristics of morphometric suite of rising flow indicative of mixed convection flow regimes associated with hypogene speleogenesis. Because the cave has been breached and is no longer in a semi-confined speleogenetic setting, it is actively being overprinted by epigene processes; however, this is limited to a few a localized regions where epigigene solutional overprinting and carbonate speleothems are present. The occurrence of secondary minerals and morphological features in Amazing Maze Cave supports a sulfuric-acid, hypogenetic model for spleogenesis, similar to that of the large cavernous porosity of the Guadalupe Mountain Caves.