Structural Analysis and a Kink Band Model for the Formation of the Gemini Fault Zone, an Exhumed Left-Lateral Strike Slip Fault Zone in the Central Sierra Nevada, California

• Main Author: Pachell, Matthew A.
• Format: Others
• Published: DigitalCommons@USU 2001
• Subjects: structural analysis; regional tectonic setting; gemini fault zone; left lateral; strike slip fault zone; central sierra nevada; california; Geology
• Online Access: https://digitalcommons.usu.edu/etd/5244; https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=6296&context=etd

The structure and regional tectonic setting of an exhumed, 9.3-km long, left-lateral strike-slip fault zone eludicates processes of growth, linkage, and termination for strike-slip fault zones in granitic rocks. The Gemini fault zone is composed of three steeply dipping, southwest-striking, noncoplanar segments that nucleated and grew along preexisting joints. The fault zone has a maximum slip of 131 m and is an example of a segmented, hard-linked fault zone in which geometrical complexities of the faults and compositional variations of protolith and host rock resulted in nonuniform slip orientations, complex interactions at fault segments, and an asymmetric slip-distance profile. Regional structural analysis shows that joints and left-lateral fault zones have accommodated slip within a 4.8-km wide, right-lateral monoclinical kink band with vertical fold axes and northwest-striking axial surfaces. Geometric modeling of the kink band indicates that as little as 1.1 km of right-lateral displacement across the kink band may have produced the observed slip on kilometer-scale faults within the kink band.