Locatable Mineral Reports for Colorado, South Dakota, and Wyoming Provided to the USDA Forest Service in Fiscal Years 2006-2009

摘要

The U.S. Geological Survey is required by Congress (under Public Law 86509) to provide Locatable Mineral Reports to the USDA Forest Service whenever National Forest System lands are sold or exchanged. This volume is a compilation of the reports already provided to the Forest Service by the author in fiscal years 2006-2009 (October 2006 September 2009). Altogether, the reports describe the geology and locatable mineral resource potential of 57 properties offered in 10 land-exchange proposals. Approximately 41,084 acres were evaluated: 19,068 acres in Federal parcels and 22,016 acres in non- Federal parcels. The parcels are located in eight National Forests and one National Grassland in three States. Locatable Mineral Reports provide a summary of the geology and a subjective appraisal of the mineral resource potential of land parcels considered for exchange. Information in each report is based on a review of published maps and reports, unpublished data in U.S. Geological Survey files, the professional expertise of the writer, and interviews with other knowledgeable geoscientists. No visits were conducted to support the reports included in this volume. The mineral resource information provided is used in making relative comparisons of the potential future mineral value of lands being offered in an exchange and in appraising the value of the land. Future mineral potential value is subjectively expressed in qualitative terms using a three-tier nomenclature of high, moderate, and low. In general, high is applied where mineral deposits are present on the property or adjacent to it or there are other indications that the area has been mineralized. Moderate is applied where mineralization is only suspected or where an area possesses some of the same geologic characteristics that are common to areas around known mineral deposits. A low value is routinely applied to all remaining areas, with the understanding that the information required to prove the absence of any mineral resource potential will never be available.