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新桥花岗岩体处在政和一大埔深大断裂的中段。其围岩有麻源组和中下石炭统的区域变质岩系及下侏罗统梨山组地层等。岩体的主要岩石类型有花岗岩、二长花岗岩、花岗闪长岩、斜长花岗岩。自岩体中心往外有交代花岗岩→混合岩→区域交质岩的规律分带性,由地质、岩石、岩石化学、稀土元素地球化学和含矿特征等方面的分析研究,均表明新桥岩体属变质交代成因型的花岗岩。由于西太平洋板块的消减,洋壳物质俯冲到一定深度脱水所产生的气热液和来自地壳深处的岩汁一起沿政和一大埔断裂上升,对处在该断裂带中段的变质岩系进行贯入和渗透交代,使原岩经过化学和矿物的交换而成为花岗质岩石。由于原岩组分的差异而交代生成了不同类型的岩石。
The Xinqiao granite body is located in the middle of the deep rupture of the Zhenghe-Daipu fault. The surrounding rocks include Mayuan Group, Middle-Lower Carboniferous metamorphic rocks and Lower-Jurassic Lishan Formation. The main rock types are granite, monzogranite, granodiorite and plagiogranite. From the center of the granite to explain the granite → migmatite → regional petrology of the regular zonation, from the geological, rock, petrochemical, rare earth element geochemistry and ore-bearing characteristics of the analysis and studies have shown that the new bridge rock Is a metamorphic metamorphic granite. As a result of the depletion of the western Pacific plate, the hydrothermal fluids resulting from the subduction of oceanic crust to a certain depth and the rock juice from deep crusts rise along the Zhenghe-Tai Po fault, and the metamorphic rocks in the middle section of the fault zone Penetration and infiltration account, so that the original rock through chemical and mineral exchange and become a granitic rock. Due to the difference of the original rock components account for the formation of different types of rocks.