Active Deformation along the Southern End of the Tosco-Abreojos Fault System: New Insights from Multibeam Swath Bathymetry

作者：Michaud Francois^*; Calmus Thierry; Ratzov Gueorgui; Royer Jean Yves; Sosson Marc; Bigot Cormier Florence; Bandy William; Mortera Gutierrez Carlos

来源：Pure and Applied Geophysics, 2011, 168(8-9): 1363-1372.

DOI：10.1007/s00024-010-0193-y

• Tosco-Abreojos fault
• seafloor morphology
• submarine canyon
• plate boundary
• Baja California peninsula
• Mexico

The relative motion of the Pacific plate with respect to the North America plate is partitioned between transcurrent faults located along the western margin of Baja California and transform faults and spreading ridges in the Gulf of California. However, the amount of right lateral offset along the Baja California western margin is still debated. We revisited multibeam swath bathymetry data along the southern end of the Tosco-Abreojos fault system. In this area the depths are less than 1,000 m and allow a finer gridding at 60 m cell spacing. This improved resolution unveils several transcurrent right lateral faults offsetting the seafloor and canyons, which can be used as markers to quantify local offsets. The seafloor of the southern end of the Tosco-Abreojos fault system (south of 24A degrees N) displays NW-SE elongated bathymetric highs and lows, suggesting a transtensional tectonic regime associated with the formation of pull-apart basins. In such an active tectonic context, submarine canyon networks are unstable. Using the deformation rate inferred from kinematic predictions and pull-apart geometry, we suggest a minimum age for the reorganization of the canyon network.

• 出版日期2011-8