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在东缅密支那缝合带以东 ,滇西盈江岛弧岩体中发现了具正常洋中脊属性的基性麻粒岩包体 .采用40 Ar/3 9Ar微区连续激光质谱方法 ,对其早期变质矿物组合的石榴子石和单斜辉石测定 ,获得等时线年龄为≈ 75Ma .结合研究区新生代岩石圈构造演化、构造热事件、变形 变质年龄 ,给定了新特提斯洋壳俯冲到下地壳深度的时间 .在岛弧地体中寻找高级 (高压 )变质的洋壳残片包体 ,研究其P T t轨迹 ,可以直接追溯洋壳俯冲、裂离、折返年代和过程 ,看来是研究古洋盆的一个重要途径
The basic granulite inclusions with normal mid-ridge property were found in the arc rock mass of Yingjiang Island, eastern Yunnan Province, east of the Myeongdong suture zone in Dongmao. The 40 Ar / 3 9Ar microarray continuous-flow laser mass spectrometry In the early metamorphic mineral assemblages of garnet and clinopyroxene, the isochron age was ≈75Ma. Combined with the Cenozoic lithospheric tectonic evolution, tectonic thermal events and deformation metamorphic age in the study area, the Neo-Tethys Ocean Looking into the high-grade (high-pressure) metamorphic oceanic crust inclusions in the island arc terrane and studying the PT t trajectory, we can directly trace the age and process of oceanic crust subduction, fissure and reentry, To study ancient ocean is an important way