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在大盆地(Great Basin)南部的死谷(Death Valley)地区,已经可以用COCORP(大陆反射剖面联合会)的深部地震反射剖面探测出以前未认识的中地壳岩浆体。在6s处(深15km)的强信号和较宽带的反射,是由于部分熔融物质近水平的侵入引起的。这个“亮点”(bright spot)在死谷中部下方横向延伸至少15km。一个中度倾斜的正断层,可能从这个推测的岩浆房,一直向上延伸到一个690000年前的玄武岩质火山渣锥。推测该断层带在这个火山渣锥形成期间,已成了岩浆的通道。根据地壳反射特性的垂直变化假定,死谷中的岩浆体可能已经沿一条解耦带侵入,这个解耦带把断裂的脆性上地壳与比较可塑的和/或可侵入的下地壳分隔开。死谷亮点类似于1977年在Rio Grande裂谷、由COCORP记录到的反射,后一地区的地球物理和大地测量资料支持这样一种推论:在20km深处存在着一个板状岩浆房。
In the deep Death Valley area to the south of the Great Basin, previously unrecognized mid-crustal magmas have been detected using the deep seismic reflection profiles of the COCORP (Continental Reflective Profile Association). Strong signals and wider band reflections at 6 s (15 km deep) are due to the near horizontal intrusion of some of the molten material. This “bright spot” extends laterally at least 15km below the middle of the valley. A moderately inclined normal fault may extend from this supposed magma chamber all the way up to a basaltic volcanic slag cone of 690,000 years ago. It is presumed that the fault zone has become a magma passage during the formation of this volcanic slag cone. Based on the vertical variations in crustal reflection properties, it is assumed that the magma in the dead valley may have invaded along a decoupling zone that separates the fractured brittle upper crust from the more pliable and / or invaginable lower crust. The Death Valley highlights are similar to the reflections recorded by the COCORP in the Rio Grande rift in 1977, and the geophysical and geodetic data in the latter area support the corollary of the existence of a plate-shaped magma chamber at depths of 20km.