Conference proceeding
Cretaceous southeast-vergent ductile shear in the lower-plate of the Miocene northwest-vergent Silver Peak - Lone Mountain extensional complex, western Great Basin
American Geophysical Union Fall Meeting, Vol.2016
American Geophysical Union 2016 fall meeting
12/2016
Abstract
From nearly equal 12 to 4 Ma, the Silver Peak - Lone Mountain (SPLM) extensional complex transferred displacement between misaligned northwest-striking dextral transcurrent faults in the southern and central Walker Lane. Top-to-the northwest displacement in the SPLM complex occurred on a shallowly northwest-dipping detachment and exhumed amphibolite to upper greenschist facies tectonites from beneath an upper-plate of Paleozoic strata, Mesozoic plutons, and Neogene sedimentary and volcanic rocks. Upper-plate extension localized the deposition of mid-Miocene to early Pliocene volcanic and sedimentary rocks in fault-bounded basins that were active until displacement on the detachment ceased at nearly equal 4 Ma. The lower-plate assemblage is composed of Proterozoic carbonate and clastic rocks, Jurassic plutons (174 Ma U-Pb) and cross-cutting leuocratic dikes (91 Ma U-Pb), all of which are penetratively deformed (D (sub 1) structures) and cross-cut by ductile shear zones. Ductile deformation formed in top-to-the southeast transport, with shear sense determined from asymmetric porphyroclasts of feldspar and leuocratic intrusive rocks ranging from millimeters to 25 m in diameter. Leucocratic dikes (82 Ma U-Pb) cross-cut ductile structures and ostensibly are related to emplacement of a granitic pluton (83-85 Ma U-Pb) that cross-cuts rocks with ductile structures. A Miocene diorite pluton (23-19 Ma U-Pb), and a cross-cutting granitic pluton (19 Ma U-Pb), intrude the lower-plate rocks. The Miocene plutonic rocks are deformed in three generations of superposed foliations, which correspond to folds with axial-planar cleavage in metasedimentary tectonites and post-ductile foliations in Mesozoic plutonic rocks. Brittle fabrics localized in proximity to the detachment are superposed on all lower-plate fabrics and indicate top-to-the north to northwest movement. Paleomagnetic studies show a 25-30 degree clockwise rotation of the SLPM since 6 Ma, indicating Cretaceous transport was easterly.
Details
- Title: Subtitle
- Cretaceous southeast-vergent ductile shear in the lower-plate of the Miocene northwest-vergent Silver Peak - Lone Mountain extensional complex, western Great Basin
- Creators
- D. T Katopody - University of Texas at Dallas Richardson, TX USA United StatesJ. S OldowW McClelland
- Resource Type
- Conference proceeding
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2016
- Conference
- American Geophysical Union 2016 fall meeting
- Publisher
- American Geophysical Union
- Alternative title
- AGU 2016 fall meeting
- Language
- English
- Date published
- 12/2016
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984240902102771
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