Feldspar-influenced rock rheologies
Journal Article
·
· Geology; (USA)
- Univ. of Utah, Salt Lake City (USA)
- Utah State Univ., Logan (USA)
Progressive fracture, subsequent cataclasis, and syntectonic alteration of feldspar to phyllosilicates transformed a massive granite into a quartz-mica phyllonite during early Tertiary deformation in a 20-30-m-wide shear zone in southeastern Arizona. The ductile deformation proceeded at temperatures and pressures approximating middle to upper crustal levels. Most of the deformation was taken up by the feldspar and its alteration products. Quartz deformed by both brittle fracture and crystal plastic mechanisms. These results show that under certain temperature-pressure-strain rate conditions feldspar are weaker than quartz. The observed deformation mechanisms indicate that the brittle to ductile transition in fault zones is not simply a function of the onset of temperature-activated plastic deformation in quartz nor of the frictional behavior of rocks, as inferred in the familiar strength vs. depth curves. It is more likely that the transition is complex and depends on a variety of parameters. One such factor delineated in this study is the fracture and fracture-facilitated syntectonic alteration of feldspar under hydrated conditions.
- OSTI ID:
- 7242857
- Journal Information:
- Geology; (USA), Journal Name: Geology; (USA) Vol. 16:12; ISSN GLGYB; ISSN 0091-7613
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Conference
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Wed Mar 31 23:00:00 EST 1993
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5019661
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·
Tue Dec 31 23:00:00 EST 1991
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·
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Thu Feb 28 23:00:00 EST 1991
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·
OSTI ID:5731952
Related Subjects
58 GEOSCIENCES
580000* -- Geosciences
ARIZONA
BRITTLE-DUCTILE TRANSITIONS
CHALCOGENIDES
DEFORMATION
DEPTH
DIMENSIONS
FEDERAL REGION IX
FELDSPARS
FRICTION
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GRANITES
IGNEOUS ROCKS
MECHANICAL PROPERTIES
MICA
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLASTICITY
PLUTONIC ROCKS
PRESSURE DEPENDENCE
QUARTZ
ROCKS
SILICON COMPOUNDS
SILICON OXIDES
TEMPERATURE DEPENDENCE
USA
580000* -- Geosciences
ARIZONA
BRITTLE-DUCTILE TRANSITIONS
CHALCOGENIDES
DEFORMATION
DEPTH
DIMENSIONS
FEDERAL REGION IX
FELDSPARS
FRICTION
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GRANITES
IGNEOUS ROCKS
MECHANICAL PROPERTIES
MICA
MINERALS
NORTH AMERICA
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLASTICITY
PLUTONIC ROCKS
PRESSURE DEPENDENCE
QUARTZ
ROCKS
SILICON COMPOUNDS
SILICON OXIDES
TEMPERATURE DEPENDENCE
USA