Tertiary subsurface solution in the Mississippian Leadville Limestone geothermal aquifer of Colorado
Subsurface solution by geothermal waters during the Tertiary rather than karst formation during the Paleozoic may account for the solution features found at the top of the Mississippian Leadville Limestone. Evidence at Guernsey, Wyoming suggests overlying sediments were lithified long before solution features formed. At Treasure Mountain, Colorado, a 108 ft (33 m) interval above the fill material is also Mississippian, which may indicate nearly continuous Mississippian deposition in the axis of the Mississippian seaway. It is unlikely that a karst surface could have developed in this restricted time period. The chert breccias of Guernsey and Treasure Mountain show no evidence of abrasion. This chert appears to have been precipitated from silica dissolved by geothermal waters in Tertiary time and later fractured by slumping. Earlier workers found much debris from overlying formations in Leadville solution features, but most dismissed the possibility of late-state subsurface dissolution contemporaneous with ore deposition. The authors postulate that subsurface solution took place in Tertiary time during the heating phase associated with orogeny, mineralization, and igneous activity. Dissolution was localized by pressure differences and fluid flow near major faults associated with mineralization. The largest solution areas are associated with deep-seated faults such as the Rio Grande Rift. Moderate to intense local solution is associated with mineralization. Small-scale, local solution and alteration may be associated with topographically controlled hot spring systems.
- OSTI ID:
- 6047171
- Journal Information:
- Mountain Geologist; (USA), Vol. 27:2; ISSN 0027-254X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COLORADO
GEOLOGIC FORMATIONS
MINERALIZATION
LIMESTONE
PRECIPITATION
ABRASION
AQUIFERS
CARBONIFEROUS PERIOD
CHERT
COMPARATIVE EVALUATIONS
DEPOSITION
DISSOLUTION
FLUID FLOW
GEOLOGIC FAULTS
GEOLOGIC HISTORY
GEOTHERMAL FLUIDS
HYDROLOGY
OROGENESIS
PRESSURE DEPENDENCE
RESERVOIR PRESSURE
SOLVENT PROPERTIES
TERTIARY PERIOD
WYOMING
CARBONATE ROCKS
CENOZOIC ERA
FEDERAL REGION VIII
FLUIDS
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
NORTH AMERICA
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
USA
150200* - Geology & Hydrology of Geothermal Systems