THE QUINLAN CLASSIFICATION OF KARST: HOW HAS It HELD UP?

The unpublished 1978 PhD dissertation of James F. Quinlan was built around a highly detailed classification of karst that was a scholarly tour de force drawing on world literature over a long historical period. Although available only as a published abstract, the classification scheme was widely used in the karst literature. Now, 30 years later, it is of interest to examine the Quinlan classification scheme in light of present day developments in karst geomorphology.

The classification scheme continues to work well for epigenetic karst - karst landforms formed by descending (top down) meteoric water. A major new concept, largely unknown when the classification was written, is hypogenetic karst - karst landforms, mostly caves, formed by ascending (bottom up) fluids which may be hot, at high CO₂ pressures, or contain sulfuric acid. Many examples of paleokarst, which was a minor category in the original scheme, are now known to be formed by hypogenetic processes.

Most in need of refinement, even in the original classification, is interstratal karst - karst development beween older cover rocks. Quinlan restricted the category to lateral dissolution along beds but excluded cave development under cover rocks, a distinction that seems arbitrary. Maze caves formed by lateral flow under cover tocks have been offered as evidence for hypogenetic karst development. More attention needs to be given to the distinction beween down-and-under flow paths as contrasted with up-and-over flow paths.

Overall, it appears that the Quinlan classification has survived very well.