Metamorphism and fluid flow related to Mesozoic thrusting in west-central Arizona
- Arizona State Univ., Tempe, AZ (United States). Dept. of Geology
Petrologic, fluid inclusion, and stable isotope investigations are being conducted on rocks from the Granite Wash mountains (GWM) and the Harquahala Mountains (HM), located in west-central Arizona, to constrain fluid flow paths and metamorphism during basement-involved thrusting. Regional south-vergent thrusting in west-central Arizona resulted in widespread greenschist-facies metamorphism. In the GWM, upper greenschist-facies metamorphic conditions are indicated by (1) the presence of kyanite and andalusite in aluminum-rich metavolcanic rocks, (2) the presence of calcic amphibole in metabasites, and (3) the absence of garnet in pelitic units. In the HM, higher P-T conditions are indicated by the assemblage kyanite + staurolite + garnet in metasedimentary lithologies. A complex fluid history is recorded by fluid inclusions from both ranges. Individual microfractures from quartz veins parallel to the thrust-related fabric contain either liquid-rich, vapor-rich, or three phase inclusions, representing several stages of fluid flow. A C-O-H fluid was present during thrusting based on the occurrence of three-phase inclusions in quartz veins, CO[sub 2]-bearing inclusions in kyanite crystals related to the thrusting event, and the formation of chlorite and calcite in upper plate granite of the Hercules thrust in the GWM. Homogenization temperatures of [approximately]270 C, which constrain minimum temperatures of the fluid, are common for the liquid-rich inclusions; vapor-rich and three-phase inclusions homogenize at higher temperatures. Preliminary stable isotope analyses suggest large volumes of isotopically light fluid may have flowed preferentially along thrust surfaces.
- OSTI ID:
- 5099791
- 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
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Related Subjects
ARIZONA
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
INCLUSIONS
PETROLOGY
GEOLOGY
GEOCHEMISTRY
CHEMICAL COMPOSITION
FLUID FLOW
GEOBAROMETRY
GEOTHERMOMETRY
ISOTOPE RATIO
METAMORPHISM
MINERALIZATION
CHEMISTRY
DEVELOPED COUNTRIES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
NORTH AMERICA
USA
580000* - Geosciences