Gloria survey of the east pacific rise near 3.5°S: Tectonic and volcanic characteristics of a fast spreading mid-ocean rise
Gloria survey of the east pacific rise near 3.5°S: Tectonic and volcanic characteristics of a fast spreading mid-ocean rise
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南纬 3.5° 附近东太平洋隆起的 Gloria 调查：快速扩张的洋中隆起的构造和火山特征
DOI：
10.1016/0040-1951(84)90119-7
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发表时间：
1984
期刊：
影响因子：
2.9
通讯作者：
R. Searle
中科院分区：
文献类型：
--
作者：
R. Searle
对南纬3°和4°之间东太平洋海隆波峰约100平方公里区域的长距离侧扫声纳（格洛丽亚）勘测扩展了Lonsdale（1977）在同一区域使用深拖获得的结果。这座轴向线性火山被发现在75公里的距离上是连续的。确认了主要向内和向外的断层崖的存在，但格洛丽亚数据显示了两个断层集之间的几个明显差异。向内倾斜的断层比向外倾斜的断层数量更多、间距更近、长度更长，而且它们的倾角反向散射声音比向外倾斜的断层更广泛;而且它们中的大多数似乎形成于距轴2 km以内，而大多数向外倾斜的断层开始发育于距轴5 ~ 8 km之间。这些差异表明这两组断层有不同的起源。向内倾斜断层的水平模式与在所有扩张速率下在其他洋中隆起上观察到的相似，尽管陡坎的长度和间距略小于扩张速率较慢的隆起，而且陡坎的落差相当大。这种共同的水平模式表明，无论扩张速率如何，所有隆起上的向内倾斜断层都有一种共同的形成模式。水平张力可能是主导因素，但需要一个额外的机制来解释在距离轴2-8公里的区域发生的断层倾角的极化。东太平洋海隆的主要断层间距与缓慢扩张海隆的相似性表明，断层在空间上是不变的，而不是时间上的，并且这些断层形成的岩石圈（距离扩张轴约2公里）对于所有扩张速率都具有相似的小厚度。这是由于热液循环和板块冷却的调节作用。
A long-range, sidescan sonar (GLORIA) survey of an approximately 100-km square area of the East Pacific Rise crest between 3°S and 4°S extends results obtained in the same area by Lonsdale (1977) using Deep-tow. The axial, linear volcano was found to be continuous over a distance of 75 km. The presence of major inward and outward facing fault scarps was confirmed, but the GLORIA data show several distinct differences between the two fault sets. The inward dipping faults are more numerous, more closely spaced, and longer than the outward dipping ones, and their dip-slopes backscatter sound more extensively than those of the outward dipping faults; moreover most of them appear to be formed within 2 km of the axis, whereas the majority of the outward dipping faults begin to develop between 5 and 8 km from the axis. These differences suggest that the two sets of faults have different origins. The horizontal pattern of inward dipping faults is similar to those observed on other mid-ocean rises at all spreading rates, though the lengths and separations of the scarps are slightly, and their throws considerably, less than on slower spreading rises. This common horizontal pattern suggests that inward dipping faults on all rises have a common mode of formation regardless of spreading rate. Horizontal tension is probably the dominant factor, but an additional mechanism is needed to explain the polarization of fault dips that occurs in the region 2–8 km from the axis. The similarity of major fault spacings on the East Pacific Rise to those on slower spreading rises suggests that faulting is invariant in space, rather than time, and that the lithosphere where these faults are formed (about 2 km from the spreading axis) has a similar, small thickness for all spreading rates. This is attributed to the regulating effect of hydrothermal circulation and plate cooling.