福建将乐盖竹洋绿片岩地质特征及构造环境探讨

On the Geological Characters and Structural Environment of the Gaizhuyang Green Schist in Jiangle County, Fujain Province

通过 1∶ 5万夏茂幅区调 ,在政和—大埔断裂带以西 ,南平—宁化构造带中段 ,首次发现一套中元古代变质基性火山岩组合 ,即盖竹洋绿片岩。通过对这套绿片岩组合地质特征、岩石化学和地球化学、同位素地质学特征等多方面与闽东地区中元古代绿片岩组合的对比和探讨 ,发现二者特征基本一致。据原岩建造等推论 ,这套绿片岩组合是在中元古代地壳拉张减薄的环境下 ,幔源物质沿南平—宁化构造带的海底裂隙侵位喷发 ,同时接受间断性海相钙镁硅质、砂泥质沉积而形成的。

During the regional geological survey (scale 1:50000), a suite of Middle Proterozoic metamorphic basic volcanic rocks was first discovered in the middle segment of Nanping Ninghua tectonic belt and the western part of Zhenghe Dapu Deep Fracture Zone, which is Gaizhuyang green schist. According to the analysis results of the Gaizhuyang green schist association and the Middle Proterozoic green schist association in Eastern Fujian, it is shown that they are consistent with the geological, isotopic, lithochemical and geochemical characters in the main. It is inferred that the emplacement and eruption of the mantle materials in the surveyed area are along the marine fractures of the Nanping Ninghua tectonic belt, that the green schist association was formed after the discontinuous marine calc megnesium sillicate and argillaceous deposition and under the tensional and thinning environment of the crust in Middle Proterozoic Period.