Deformation across the western Mina deflection: field studies in the Huntoon Springs quadrangle, California-Nevada
Document Type
Oral Presentation
Campus where you would like to present
SURC Ballroom A
Start Date
17-5-2012
End Date
17-5-2012
Abstract
The Mina deflection (MD) defines a major right step in the NW-trending eastern California shear zone (ECSZ)-Walker Lane belt (WLB) dextral system, and transfers fault slip from the ECSZ to the WLB along ENE- and NW-trending faults. Three models have been proposed to explain this fault slip transfer: (1) the displacement transfer model suggests that Pliocene slip was transferred along NE-striking normal faults, (2) the transtensional strain model suggests that Pleistocene strain was transferred by extension-dominated transtension in the west and wrench-dominated transtension in the east, and (3) the rotational block model suggests that slip was transferred by clockwise rotating blocks bounded by NE-striking sinistral faults. New geologic mapping and structural studies in the Huntoon Springs quadrangle (HSQ) of the western MD evaluate these hypotheses. Here, Pliocene andesite lavas, basalt lavas, and unconformably underlying Miocene ignimbrite are cut and offset by primarily high-angle ENE-striking sinistral faults and by lesser NW-striking normal faults. Sinistral faults are identified by linear fault traces, alternating scarp-facing directions, sinistral offsets of normal faults, fractures, and volcanic units, and by the presence of extensional basins at releasing steps, or pop-up structures at restraining steps. Normal faults are identified by sinuous fault traces, the lack of lateral offset along strike, or as connecting faults between left-stepping sinistral faults. Major NE-striking sinistral faults documented in the HSQ may be related to block rotation, but further study is required to verify this hypothesis.
Recommended Citation
Hogan, Eliya, "Deformation across the western Mina deflection: field studies in the Huntoon Springs quadrangle, California-Nevada" (2012). Symposium Of University Research and Creative Expression (SOURCE). 64.
https://digitalcommons.cwu.edu/source/2012/posters/64
Poster Number
3
Additional Mentoring Department
Geological Sciences
Deformation across the western Mina deflection: field studies in the Huntoon Springs quadrangle, California-Nevada
SURC Ballroom A
The Mina deflection (MD) defines a major right step in the NW-trending eastern California shear zone (ECSZ)-Walker Lane belt (WLB) dextral system, and transfers fault slip from the ECSZ to the WLB along ENE- and NW-trending faults. Three models have been proposed to explain this fault slip transfer: (1) the displacement transfer model suggests that Pliocene slip was transferred along NE-striking normal faults, (2) the transtensional strain model suggests that Pleistocene strain was transferred by extension-dominated transtension in the west and wrench-dominated transtension in the east, and (3) the rotational block model suggests that slip was transferred by clockwise rotating blocks bounded by NE-striking sinistral faults. New geologic mapping and structural studies in the Huntoon Springs quadrangle (HSQ) of the western MD evaluate these hypotheses. Here, Pliocene andesite lavas, basalt lavas, and unconformably underlying Miocene ignimbrite are cut and offset by primarily high-angle ENE-striking sinistral faults and by lesser NW-striking normal faults. Sinistral faults are identified by linear fault traces, alternating scarp-facing directions, sinistral offsets of normal faults, fractures, and volcanic units, and by the presence of extensional basins at releasing steps, or pop-up structures at restraining steps. Normal faults are identified by sinuous fault traces, the lack of lateral offset along strike, or as connecting faults between left-stepping sinistral faults. Major NE-striking sinistral faults documented in the HSQ may be related to block rotation, but further study is required to verify this hypothesis.
Faculty Mentor(s)
Jeff Lee, Wendy Bohrson, Anne Egger