Brittle and ductile evolution of a thrust zone: thin and thick cataclasites along the Saltville Fault

Conference · Mon Dec 31 23:00:00 EST 1984 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6320895

Paul, J B; Woodward, N B

Deformation along thrust surfaces in external and intermediate sheets occurs by both brittle and ductile processes. A detailed study of the Saltville Fault exposed in Knoxville, Tennessee reveals the occurrence of fault zones ranging in thickness from less than 3 cm to more than 3 m. Thin fault zones consist of a single discreet sliding surface composed of pervasive cataclasite. Thick fault zones are composed of multiple sliding surfaces ranging in thickness from 3 cm to 1.5 m, separated by zones of fractured, non-cataclastic rocks. In all cases, cataclasites occur in dolomites or dolomites interbedded with siltstones. No cataclasites are developed in incompetent, thin bedded sandstones and shales. Cataclasis has occurred by a sequential process of 1) initial brittle fracturing, 2) shearing along fractures with rigid grain rotation and communition, and 3) gouge development and the total disruption of original rock fabric with ductile processes dominating progressive deformation within the zone of cataclasis. Renewed brittle processes after ductile flow signal the onset of late stage extension and thinning of the cataclasite in the direction of transport. This process is cyclic in nature and may cease with the development of a renewed period of cataclasis. The authors propose the process of late stage extension within zones of cataclasis as a mechanism for thinning of the fault zone. This process may provide an explanation for the occurrence of varying thickness of cataclasite along preserved fault exposures in Knoxville and other locations in the Southern Appalachians.

• Research Organization: Univ. of Tennessee, Knoxville (USA)
• OSTI ID: 6320895
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Vol. 17; ISSN GAAPB
• Country of Publication: United States
• Language: English

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DEFORMATION
FEDERAL REGION IV
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
GEOMETRY
MATHEMATICS
MECHANICAL PROPERTIES
MECHANICS
NORTH AMERICA
ROCK MECHANICS
TECTONICS
TENNESSEE
USA