Truckhaven – West Salton Detachment Fault Zone Architecture at Wonderstone Wash, Southern California
Thursday, May 7th, 2015
The Rainbow Rock Quarry has been a gold and silver mining prospect for over one hundred years. It is situated along the north edge of Wonderstone Wash in the northwestern Seventeen Palms USGS 7.5 minute quadrangle, located in the southeastern section of the active San Andreas Fault system. This region is characterized by seismic activity, continental rifting, volcanism, hydrothermal alteration, rapid sedimentation and active precious metal deposition. The Truckhaven Fault zone strikes approximately NE and separates a Jurassic quartz monzonite footwall from a Pleistocene conglomerate hanging wall. This oblique normal fault zone dips southeast and hosts sites of alteration, including gold and silver mineraliziation and argillization. To the southwest of Rainbow Rock is the source of Wonderstone Wash. Our goal was to observe remnants of where the Truckhaven fault possibly soles into the West Salton Detachment. During mapping of the Truckhaven Fault along Wonderstone Wash we observed several exposures of hydrothermal alteration; reverse faulting and metamorphic amphibolite rocks. Thin section analysis attempts to classify observed metamorphic exposures and further illustrate regional tectonics and mineralization of precious metals. By illustrating the architecture of these two faults, we hope to understand the kinematics during their activity, in order to question whether they remain active, or accommodation has been relieve by the San Jacinto fault system.