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西藏冈底斯地区是典型的中、新生代造山区。这里侵入岩带和火山岩带在时空上紧密伴生;岩石组合类型相似;造岩元素演变趋势图表明初始岩浆具类似的成分,演变趋势基本一致;两者成分相当的岩石所含某些微量元素丰度趋近;锶同位素比值吻合。表明两者的母岩浆是同源的,可能是由上地幔和下部地壳部分熔融混合而成。也许由于侵入岩岩浆的缓慢侵位方式,使之易于从围岩介质中摄取外来组分,而导致侵入岩比火山岩具有相对较高的大离子亲石元素和水分。
The Gangdise area in Tibet is a typical middle and new Cenozoic orogenic area. The intrusive rock belt and volcanic belt are closely associated with each other in time and space. The types of rock assemblages are similar. The evolution trend of rock elements shows that the initial magma has the similar composition with the same trend of evolution. Some trace elements Degree approaches; Strontium isotope ratios coincide. It indicates that the parent magma of the two are homologous, probably formed by the partial melting and melting of the upper mantle and the lower crust. Perhaps due to the slow emplacement of intrusive magma, it is easy to invade alien components from the surrounding rock medium, leading to intrusive rocks with relatively large ion lithophile and water content than volcanic rocks.