Data for "Serpentinite-rich Gouge in a Creeping Segment of the Bartlett Springs Fault, Northern California: Comparison with SAFOD and Implications for Seismic Hazard"

This report presents the mineral chemistry dataset that was used in a published study of serpentinite-rich gouge from an actively creeping trace of the Bartlett Springs Fault in northern California. The fault gouge consists of porphyroclasts of antigorite serpentinite, talc, chlorite, and tremolite-actinolite in a sheared matrix of the same materials. The compositions of spinels in the serpentinite clasts (Table S1) indicate a forearc-peridotite origin for the serpentinite, consistent with a source in the Coast Range ophiolite. The other major minerals in both the porphyroclasts and matrix were analyzed (Table S2) for comparison with serpentinite-bearing gouge from the creeping section of the San Andreas Fault. Table S3 presents serpentine mineral compositions from outcrops of the Coast Range Ophiolite located away from the fault.