地幔柱与洋脊分段成因探讨

The mantle plume and the cause of segmentation of ocean ridges

地幔柱产生岩浆的核幔交界部位相当于"岩浆洋",下地幔与上地幔、上地幔与软流圈之间的岩浆流通道相当于"岩浆河流",岩浆由软流圈经岩石圈喷出地表的通道相当于"岩浆小溪",在它们之间都会有许多的"岩浆支流",其中有的"支流"将这些"河流"与"河流"或"河流"与"小溪"联系起来。洋脊分段现象是由于地幔柱中存在横向的"岩浆支流",它们的横向流动在岩体底部产生方向相反的剪切应力使洋壳内部之间产生位移错动。洋脊分段是伴随洋壳内部之间的相互位移错动而形成的。1级洋脊分段下伏的"岩浆支流"在深度、规模、对岩层底部产生的剪切牵引力均要大于2,3,4级。洋脊分段的成因动力学在性质上与前人研究的主要受地幔岩浆周期性脉动上涌控制有很大的区别。

Mantle plume generates magma at the junction of the core-mantle,which is equivalent to a ＂magma ocean＂,magma flow passiges between the lower mantle and the upper mantle,and between the upper mantle and the asthenosphere flow are equivalent to ＂magma rivers＂,magma from the asthenosphere through the lithosphere spray out of the ground through passiges which are equivalent to some ＂magma streams＂.Among them,there are many ＂magma tributary streams＂,some ＂magma tributary streames＂link ＂magma rivers＂with＂magma rivers＂ or ＂magma rivers＂with＂magma tributary streams＂,each other.The phenomenon of segmentation of ocean ridges is due to the existence of horizontal ＂magma tributary streams＂ in the mantle plume,which laterally flow,shear stress of the opposite direction generates at the bottom of rock bodies,the dislocation of displacement creats between ocean crusts.The ＂magma tributary streams＂of the first rank of segmentation of the ocean ridges are much larger than second,third and forth rank in depth,scale and shear traction at the bottom of rock stratums.The dynamics of segmentation of the ocean ridges differs from the previous studies which are considered that the segmantation of the ocean ridges is mainly controlled by the periodic pulse upwelling of magma in the mantle.