Structural Processes at Slow-Spreading Ridges
Structural Processes at Slow-Spreading Ridges
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DOI：
10.1126/science.257.5070.627
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发表时间：
1992-07
期刊：
影响因子：
56.9
通讯作者：
J. Mutter;J. Karson
中科院分区：
文献类型：
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作者：
J. Mutter;J. Karson
缓慢扩张（每年小于35毫米）的洋中脊主要是像大陆裂谷一样的分段、不对称的裂谷洼地。快速扩张的海脊显示出对称的、隆起的火山机构，它们的形状和大小沿着轴变化。深源地震、主要的正断层和下地壳岩石的出露只有在沿着缓慢扩张的海脊上才常见。这些对比鲜明的特征表明，在缓慢扩张的海脊，机械变形对地壳形成的重要性远大于快速扩张的海脊。新的地震图像表明，缓慢扩张的洋脊的分割的性质和规模是不可分割的变形过程，而不是岩浆过程，可能控制分割的快速扩张的洋脊。
Slow-spreading (<35 millimeters per year) mid-ocean ridges are dominated by segmented, asymmetric, rifted depressions like continental rifts. Fast-spreading ridges display symmetric, elevated volcanic edifices that vary in shape and size along axis. Deep earthquakes, major normal faults, and exposures of lower crustal rocks are common only along slow-spreading ridges. These contrasting features suggest that mechanical deformation is far more important in crustal formation at slow-spreading ridges than at fast-spreading ridges. New seismic images suggest that the nature and scale of segmentation of slow-spreading ridges is integral to the deformational process and not to magmatic processes that may control segmentation on fast-spreading ridges.