地幔柱与洋脊分段成因探讨
The mantle plume and the cause of segmentation of ocean ridges
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摘要: 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。Abstract: 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.
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Key words:
- mantle plume /
- segmentation of ocean ridges /
- transform fault
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WILSON J T.A possible origin of the Hawaiian Islands [J].Can J Phys, 1963, 41:863-870. MORGAN M J.Plate motions and deep mantle convection [J].Geol Soc Am Mem, 1972, 132:7-22. 李凯明,汪洋,赵建华,等.地幔柱、大火成岩省及大陆裂解--兼论中国东部中、新生代地幔柱问题[J].地震学报,2003,25(3):314-323. 鄢全树,石学法.洋中脊与地幔柱热点相互作用研究进展[J].海洋地质与第四纪地质,2006,26(5):131-138. 徐义刚,何斌,黄小龙,等.地幔柱大辩论及如何验证地幔柱假说[J].地学前缘,2007,14(2):1-9. 吴树仁,陈庆宣,谭成轩.洋脊分段研究进展[J].地质科技情报,1998,17(2):1-6. MACDONALD K C, FOX P J.Overlapping spreading centers:new accretion geometry on the East Pacific Rise [J].Nature, 1983,302:55-58. 徐义刚.地幔柱构造、大火成岩省及其地质效应[J].地学前缘,2002,4(9):341-353. 周连成,白伟明,赵俐红,等.地幔柱研究评述[J].海洋地质动态,2004,20(8):16-19. HILL R I, CAMPBELL I H, DAVIES G F, et al.Mantle plume and continental tectonic [J].Science,1992,256:186-192. 曾普胜,莫宣学,喻学惠.大火成岩省研究新进展[J].地学前缘,1999,6(4):378. 赵海玲,狄永军,李凯明,等.大火成岩省及地幔柱动力学[J].岩石矿物学杂志,2001,20(3):307-312. KERR R A.2000 leagues under the earth [J].Science,1997,275:614. LASSITER John.Hawaiian plume dynamics [J].Science,1999,285:846-847. MCNUTT M K, CARESS D W, REYNOLODS J, et al.Failure of plume theory to explain midplate volcanism in the southern Austral Islands [J].Nature,1997,389:479-482. 王晓丰,张志诚,郭召杰,等.酒西盆地南缘旱峡白垩世火山岩地球化学特征及其构造意义[J].高校地质学报,2004,10(4):569-577. 隋建立,樊祺诚,刘嘉麒,等.长白山火山地幔不均一性--微量元素及同位素地球化学研究[J].岩石学报,2007,23(6):1512-1520. KELLOGG L H, HAGER B H, VAN DER HILST R D.Compositional stratification in the deep mantle [J].Science,1999,283:1881-1884. VAN DER HILST R D, KARASON K.Compositional heterogeneity in the bottom 1000 km of earth’s mantle: towards a hybrid convection model [J].Science,1999,283:1885-1888. MACDONALD K C, SCHEIDER D S, CARBOTTE S M.Mid-oceanic ridges:discontinuities,segments and giant cracks[J].Science,1991,53:986-994. 李三忠,郭晓玉,侯方辉,等.洋中脊分段性及其拓展和叠接机制[J].海洋地质动态,2004,20(11):19-28. MACDONALD K C, FOX P J.Overlapping spreading centers:new accretion geometry on the East Pacific Rise [J].Nature, 1983, 302:55-58. -
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