Magmatic and tectonic processes related to the formation of hydrothermal mineral deposits in the Rocky Mountains

Conference · Thu Apr 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5098420

Thompson, T B ^[1]

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1. Colorado State Univ., Fort Collins, CO (United States). Dept. of Earth Resources

Hydrothermal mineral deposits along the Rocky Mountain trend from Montana to New Mexico occur along distinct northeasterly linear trends, reflecting first order structural control on localization of the deposits. The Great Falls Tectonic Zone, Colorado Mineral Belt, and Jemez Zones have localized hydrothermal mineral deposits from Late Cretaceous to the late Tertiary. The deposits range from porphyry-related Climax-and Leadville-types of deposits to epithermal vein and breccia system that have some magmatic component. Local skarn development is important in some districts, typically exhibiting retrograde effects. Less common north and northwest trends localized mineral deposits. Notably, the Wyoming Archean terrane was less favorable than the Proterozoic basement terrane elsewhere along the Rocky Mountains. Magmas associated with the hydrothermal mineral deposits range from subduction-related calc-alkaline systems to back-arc alkaline systems. The two magma types are temporally-separated but spatially associated. The alkaline systems developed with the inception of extensional tectonics. Areas with thin (<40 km) continental crust were important in localizing the alkaline magmas and associated mineral deposits. The limited Nd- and Sr-isotopic data indicate that Late Cretaceous to Tertiary intrusive-volcanic systems exhibit increased [epsilon][sub Nd] and initial Sr values with decreasing age, interpreted to reflect increasing crustal contamination. S, O, H, and Pb isotopic- and fluid inclusion-data from many of the Rocky Mountain ore systems exhibit a wide range of sources, but reflect the importance of igneous activity in the ore-forming process.

• OSTI ID: 5098420
• Report Number(s): CONF-9305259-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC DEPOSITS
HYDROTHERMAL SYNTHESIS
ORES
ROCKY MOUNTAINS
HYDROTHERMAL SYSTEMS
CHEMICAL COMPOSITION
CRETACEOUS PERIOD
GEOCHEMISTRY
HYDROTHERMAL ALTERATION
ISOTOPE RATIO
MAGMATISM
MINERALIZATION
PETROCHEMISTRY
CHEMISTRY
ENERGY SYSTEMS
GEOLOGIC AGES
GEOTHERMAL SYSTEMS
MESOZOIC ERA
MOUNTAINS
SYNTHESIS
580000* - Geosciences