| Description |
iv, 34, 1-14, 2-4 leaves : illustrations ; 29 cm |
| Summary |
"Values of heat flow through a Precambrian mineral deposit were determined in the Boss area of Missouri, where 350 meters of Paleozoic sedimentary rocks overlie a complex series of rhyolite flows which have been altered and contain a copper bearing magnetite deposit. Geothermal data were obtained from a closely spaced grid of 17 diamond drill holes penetrating to depths of 1000 meters below ground surface. Temperature measurements were made at 5 meter intervals in the Precambrian section of all holes. These and thermal conductivity measurements made on representative core samples from 300 to 400 meters below the top of the Precambrian gave a regional heat flow of 1.) microcalories/cm²sec. Core from one hole was sampled at approximately 5 meter intervals from 350 to 1000 meters. Comparison of the regional flux with the vertical components of heat flow in the deeper portions of the intensively sampled hole indicated the presence of a low conductivity zone with a flux 25 percent below the regional and a high conductivity zone with a flux 10 percent above the regional. The calculated attitudes of these zones led to an interpretation of the geologic structure that, previously, had not been considered. The low conductivity corresponds to a tabular zone of prophyllitic alteration dipping 72 degrees, and the high conductivity corresponds to a granite dike dipping 50 degrees"--Abstract, leaf ii. |
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