Crustal structure beneath the Blue Mountains terranes and cratonic North America, eastern Oregon, and Idaho, from teleseismic receiver functions
Crustal structure beneath the Blue Mountains terranes and cratonic North America, eastern Oregon, and Idaho, from teleseismic receiver functions
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DOI：
10.1002/2016jb012989
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发表时间：
2016-07
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通讯作者：
A. Christian Stanciu;R. Russo;V. Mocanu;P. M. Bremner;S. Hongsresawat;M. Torpey;J. VanDecar;D. Foster;J. Hole
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作者：
A. Christian Stanciu;R. Russo;V. Mocanu;P. M. Bremner;S. Hongsresawat;M. Torpey;J. VanDecar;D. Foster;J. Hole
我们提出了新的岩石圈结构的图像，从P-to-S转换定义的接收器功能在85个宽带地震台站的EarthScope爱达荷州实验。我们解决了地壳厚度下的蓝山省和前西部边缘的北美东部，西部爱达荷州剪切带（WISZ）的几何形状，和之间的边界松鸡溪和法明顿省。我们使用迭代时域反褶积方法计算P-to-S接收函数，并使用H-k网格搜索方法和公共转换点叠加来成像岩石圈结构。蓝山火山岩下的莫霍面深度为24 - 34 km，而爱达荷州岩基和爱达荷州中东部地壳延伸区域下的地壳厚度为32-40 km。蓝山群奥尔兹费里岩的特点是研究区地壳最薄，厚约24公里。有一个明显的中断，在连续性的莫霍面整个WISZ，深度增加，从28公里以西的剪切带的36公里以东的表面表达。在WISZ以东约20 km处的爱达荷州岩基下方约18 km处存在一个强中地壳转换界面，表明该区域存在构造楔作用。一个向北突出约7公里的偏移莫霍面深度，变薄的东部，是目前的失落河山脉和Pashimeroi山谷下，我们确定这种尖锐的偏移的边界，并列太古代松鸡溪块与古元古代法明顿区。
We present new images of lithospheric structure obtained from P‐to‐S conversions defined by receiver functions at the 85 broadband seismic stations of the EarthScope IDaho‐ORegon experiment. We resolve the crustal thickness beneath the Blue Mountains province and the former western margin of cratonic North America, the geometry of the western Idaho shear zone (WISZ), and the boundary between the Grouse Creek and Farmington provinces. We calculated P‐to‐S receiver functions using the iterative time domain deconvolution method, and we used the H‐k grid search method and common conversion point stacking to image the lithospheric structure. Moho depths beneath the Blue Mountains terranes range from 24 to 34 km, whereas the crust is 32–40 km thick beneath the Idaho batholith and the regions of extended crust of east‐central Idaho. The Blue Mountains group Olds Ferry terrane is characterized by the thinnest crust in the study area, ~24 km thick. There is a clear break in the continuity of the Moho across the WISZ, with depths increasing from 28 km west of the shear zone to 36 km just east of its surface expression. The presence of a strong midcrustal converting interface at ~18 km depth beneath the Idaho batholith extending ~20 km east of the WISZ indicates tectonic wedging in this region. A north striking ~7 km offset in Moho depth, thinning to the east, is present beneath the Lost River Range and Pahsimeroi Valley; we identify this sharp offset as the boundary that juxtaposes the Archean Grouse Creek block with the Paleoproterozoic Farmington zone.