| Description |
viii, 83 leaves : illustrations, maps ; 29 cm |
| Format |
Photocopy. Rolla, Missouri : Missouri University of Science and Technology, 2011. Photocopied from microfilm copy of the original thesis. |
| Summary |
"In order to analyze the effects of pumping groundwater from underground lead mines upon present groundwater resources of the New Lead Belt area, the geology and hydrogeology of that area must first be determined. The primary method of investigation of this analysis was interpretation of ecologic and hydrogeologic data taken from water well logs and mineral exploration well logs, with supplemental information supplied by published and unpublished literature sources. From all these sources of data, structural contour maps of the Precambrian erosional surface; the tops of the Lamotte, Bonneterre, and Davis Formations; isopachous maps of the Davis and the Lamotte/Bonneterre Formations; a generalized clastic to carbonate ratio map of the Davis Formation; and a shallow aquifer potentiometric surface map were constructed. Structural contour maps of the Cambrian Lamotte, Bonneterre, and Davis Formations show that the general regional dip of sandstones and dolomites that lap onto Precambrian igneous intrusive and extrusive rocks is toward the southwest, except where influenced by normal faulting and initial dips of as much as 15 to 20 degrees around Precambrian knobs. Isopachous maps of these formations show that thinning and thickening of sediments around a buried Precambrian erosion surface had diminished by the time the Davis Formation was deposited. The clastic to carbonate ratio map of the Davis Formation indicates that there is a lithologic facies change within this formation. The shallow aquifer potentiometric surface map, when compared to the structural contour maps, illustrates that the regional hydrogeologic gradient within the Black River basin is at an oblique angle to the regional geologic gradient. Another prominent feature of this map is the "Logan Creek sink" located in T. 30 N., R. 1 W. Three hydrogeologic groups have been established to qualitatively evaluate the recharge of groundwater into mines. These groups are the shallow aquifer, the Davis Formation, and the deep aquifer. The concepts of the Davis Formation "leaky aquiclude facies" and "aquifer facies" have been introduced in accordance with the variable lithology of the Davis Formation. Using these groups, three primary methods of recharge to the deep aquifer are discussed. These methods are vertical leakage through the Davis Formation "leaky aquiclude facies", which includes both intergranular leakage and leakage through faults and fractures; migration of groundwater from the deep aquifer outcrop area; and migration of groundwater down the shallow aquifer gradient to the Davis Formation "aquifer facies". Groundwater is being pumped both from the shallow aquifer and deep aquifer. However, the most significant source of pumping within the New Lead Belt area is from mines within the deep aquifer"--Abstract, leaves ii-iii. |
|
