Comparative Study of Pull-Apart Basins: The Salton Trough and Death Valley, California Regions

To unravel the forces and better understand the processes that drive continental rifting, we integrate new and previously collected data from two Californian pull-apart basins: the Salton Trough and Death Valley. In particular, we compute receiver functions and process gravity and aeromagnetic data to constrain crustal structure, and then compare the results from the two rift areas. South of the Salton Sea, the Moho is 22 km deep and deepens to 30 km in the region west of the Salton Trough. In Death Valley, the Moho is 24 km deep in the central part of the basin, deepens to 32 km out of the basin, and is dome shaped because of magmatic activity in the lower crust and upper mantle. The density of the lower crust for the Salton Trough and for Death Valley is similar (2950 kg/m3 and 2900 kg/m3, respectively), while the density of the upper crust varies from 2650 kg/m3 to 2450 kg/m3 in the Salton Trough and from 2600 kg/m3 to 2250 kg/m3 in Death Valley. Rifting style and magnitude vary significantly between the two areas. The Salton Trough is generally a wide, well developed rift that is moving toward sea floor spreading. A combination of thermal and sedimentation drive rifting processes in the Salton Trough. In contrast Death Valley is smaller in size than the Salton Trough and it is a narrow depression. Death Valley is in the initial stage of rifting and magmatic (thermal) forces appears to drive the rifting process in Death Valley.