The NSS Bulletin
- ISSN 1090-6924
Volume 51 Number 2: 101-119 - December 1989
A publication of the National Speleological Society
Evidence of Quaternary
Tectonic Activity, and for Regional Aquifer Flow at Wind Cave, South Dakota
Thomas E. Miller
Radiometric dating of extensive sub-aqueous precipitates from Wind Cave, South Dakota, shows deposition in the period from 350,000-1,250,000 years BP, and establishes a minimum age of 350,000 years for the cave. Tilting and faulting of these precipitates demonstrate tectonic activity in the Black Hills at least since the mid-Pleistocene. A local dike intrusion beneath the cave is indicated by geophysical evidence, and could possibly relate the present high geothermal gradient in the cave, the dated precipitation event, and the recent tectonic activity.
In the lower cave levels, the well-known "boxwork" of Wind Cave is covered by the calcite precipitates, and therefore predates them.
The hydrochemical survey of surface and cave waters undertaken in Wind Cave National Park (1976-1978) shows the chemical similarity of cave waters to nearby artesian well waters, and supports the idea that they are part of a regional flow system, rather than merely local. Seasonal solutional enlargement also appears to be possible well into the aquifer.
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17 May, 2002 11:11
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