Abstract
Paleocollapse structures represent a major obstacle to be overcome by organizations engaged in site evaluations for the location of large surface structures and underground facilities in the midcontinent of North America. Paleocollapse structures range in size from a few acres to over a mile and are places where large blocks of bedrock have moved downward many feet along high angle, normal faults. They are believed to have formed by the collapse of the cavern-roof and the overlying column of Pennsylvanian age strata into caverns formed by dissolution in thick Mississippian age limestone and dolomite beds that underlie the region at a depth of several hundred feet. Paleocollapse structures were formed during an earlier interval of geologic time and are covered by the regolith. Consequently, they are commonly unnoticed until the intensely folded and faulted bedrock units are uncovered in excavations. Paleocollapse structures are best located by a systematic program of core test drilling but the presence of a paleocollapse structure can be anticipated in reconnaissance mapping from the steep dip of bedrock units exposed by stream erosion, and the modification of stream drainage patterns as seen on topographic maps. Three paleocollapse structures are described from the Longview region near Kansas City, Missouri.
