期刊
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
卷 8, 期 -, 页码 -出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2006GC001429
关键词
Basin and Range; crustal seismology; gravity; transition zone; tectonics; geodesy and gravity : general or miscellaneous; seismology : continental crust; tectonophysics : continental tectonics : extensional
[1] The northwestern margin of the Basin and Range Province is characterized by a transition from low-magnitude ( similar to 20%) extension in northwestern Nevada to relatively unextended volcanic plateaus in northeastern California. Seismic-velocity and potential-field modeling provides new control on the Mesozoic-to-present tectonic evolution of this poorly understood portion of the U. S. Cordillera. We document similar to 20% crustal thinning associated with Basin and Range extension from a crustal thickness of similar to 37 km under northeastern California to similar to 31 km under northwestern Nevada that is consistent with the amount of extension recorded in the upper crust in northwestern Nevada, suggesting the crustal response to extension was relatively homogeneous over the entire crustal column. Our modeling also shows a well-defined, 80-km-wide zone of unusually low upper-crustal velocities ( similar to 5.9 - 6.1 km/s) that coincide with the surface location of sparse Cretaceous granites, locating the elusive northern extension of the Sierra Nevada batholith through northwestern Nevada for the first time in the subsurface. Combining geological and geophysical data, we reconstruct the late Cretaceous-to-present crustal evolution of this region, documenting an interplay between magmatic addition to the crust, erosional exhumation, sedimentation, and extension that has reversed the direction of crustal thinning from a west-facing continental margin to an east-facing interior basin margin over this time interval. Finally, we find no evidence in northwestern Nevada for unusually thick crust (> 40 km) prior to Basin and Range extension.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据