, Auditorium
The epigenetic model of speleogenesis was a product of observations and measurements in caves of Indiana and Kentucky. In his transformative work starting in Indiana, Art Palmer combined the mode and pace of recharge enhanced with soil carbon dioxide and the physical distribution of porosity in the host rock as a deductive model for the shape and distribution of resulting caves. The predictive power of Art's synthesis was an important step to understanding the evolution of caves.
Transformative science and comprehensive models are laced with anomalies. In Kentucky, seeps of petroleum in caves and unusual passage morphologies, secondary minerals, and rock textures revealed hypogene speleogenesis from sulfide oxidation. Soon, similar hypogene influences were also detected in Indiana caves. What is now clear is that cave evolution is polygenetic and multigenerational and may include hypogene cave development overprinted by epigenetic processes. Caves have formed at multiple stages throughout the history bedrock.
What is also apparent is the association of caves with geologic structures. At the largest scale, regional structures position the carbonate outcrop. At localized scales, fractures and faults are pathways for meteoric recharge and can guide groundwater movement and the orientation of cave passages. Faults are also preferred pathways for rising basin fluids and thus the locus of hypogene speleogenesis. Geochemistry studies of groundwater demonstrate the influence of sulfur in some caves of the Mitchell Plateau. Analysis of drilled cores, geologic mapping, LiDAR data, and cave maps characterized extensions of the Mount Carmel Fault zone in southern Indiana.
Lee J. Florea – Washington Geological Survey, Bloomington
Indiana Grotto, & Oregon Grotto