摘要
变质岩中的金刚石是在地壳还是在地幔中形成的,是地学中争议很大的问题.分析认为地壳中存在楔块和楔块运动,正楔块运动应有增压效应,能使地壳底部一定区域内的压力成倍增加.正楔底部的增压效应与其厚度成正比,与其下底面积成反比.正软楔的运动则是保持下底面积不变、岩石不断增厚的过程,能导致增压效应不断加强.因此造山带(正软楔运动)地壳的底部是形成高压变质岩和金刚石等高压变质矿物的有利部位.
Whether the formation of the diamond in metamorphic rocks is formed in crust or in mantle still remains a controversial issue.For the fact of crustal movement between the wedges,the author proposes that the pressure enhancement effect of the upright wedge block might be double the pressure in the bottom of crust.However,the enhancement effect of the wedge block is proportional to the depth and is inversely proportional to the basal area.The movement of the upright soft wedge blocks make the basement to remain the same and the rock thickening,inducing the pressure increased.Therefore,it's concluded that bottom of orogenic belt(the movement of the upright wedge block) is suitable for the formation of the metamorphic mineral,such as metamorphic rock,diamond and so on.
出处
《宁夏师范学院学报》
2011年第3期69-72,共4页
Journal of Ningxia Normal University
关键词
正楔
倒楔
硬楔
软楔
楔块运动
增压效应
Upright wedge block
Inverse wedge block
Hard wedge block
Soft wedge block
Pressure enhancement effect