Modeling continental crust: Structural and chemical constraints
Modeling continental crust: Structural and chemical constraints
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模拟大陆地壳：结构和化学约束
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
S. Smithson
中科院分区：
文献类型：
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作者：
S. Smithson
地震反射研究揭示了深部地壳的横向和纵向异质性，与地质观测表明的结果相当。在这种异质的地壳中，“康拉德不连续面”的概念没有什么意义。地壳深处的近水平反射体是由地球重力场内变质岩的水平运动和岩浆结晶形成的。下地壳中的上地壳岩石表明，地壳的大部分是由上地壳堆积而成的。平均地壳成分约为石英闪长岩至花岗闪长岩。这种成分不能通过简单地通过安山岩岛弧的增生添加材料来实现，而是必须考虑更多的长英质材料。
Seismic reflection studies reveal lateral and vertical heterogeneity of the deep crust that is comparable to that indicated by geologic observations. In a crust this heterogeneous, the concept of a “Conrad Discontinuity” has little meaning. Near-horizontal reflectors in the deep crust are formed by horizontal movements in metamorphic rocks and magmatic crystallization within the earth’s gravity field. Supracrustal rocks in the lower crust suggest that much of the crust was built up as a supracrustal pile. Mean crustal composition is approximately quartz dioritic to granodioritic. This composition cannot be achieved by simply adding material through accretion of andesitic island arcs but must account for more felsic material.