Stability of paleosinks and karstic carbonates in the Southern Fire Clay Mining District of Missouri

<p>"The Southern Fire Clay District of Missouri was intensely mined during the late-1800’s to mid-1900’s for its valuable resource of high refractory clays deposited within Pennsylvanian sinkholes “paleosinks”. Mining operations have produced modifications in the Ozark aquifer, which in effect has possibly increased the instability of this paleokarst terrain and the potential of further environmental impacts to the land. Evidence supporting this hypothesis are: (1) A southerly shift in the regional groundwater divide relative to the topographic divide. This possibly is caused by the distribution of leaking clay pits, which suggests that the bedrock permeability or hydraulic conductivity has been increased towards the north. (2) Stratigraphic and geohydrologic unites thin in areas related to clay pit distribution. It is speculated that meteoric water is being recharged through paleosinks and is causing further dissolution along fractures, carbonate bedding planes and paleoconduits. (3) Clay pits are interconnected and are possibly undergoing enhancement of secondary permeability in the subsurface. This hypothesis is supported by missing (dissolved) rock sections in water wells, seismic data, obvious pit drainage of collapsed clay pits, and connective dye trace evidence. (4) Seismic reflection data of paleosinks and field observations of known collapsed clay pits show a potentially unstable setting in the vicinity of clay pits. (5) Clay pits in-filled with refuse and unconsolidated material show evidence of recent subsidence. Many clay pits filled with water leak into the subsurface and have the potential for catastrophic collapse. Open pits and unplugged boreholes increase the potential of surface runoff entering the subsurface aquifer and thereby contaminating the ground-water supply of the district"--Abstract, page iii.</p>

Name thesis:degree_name

Ph. D. in Geology and Geophysics

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Dillon, Robert Weiser

• Geology
• Geophysics and Seismology

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/1334

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-2336