二叠纪地幔柱与地表系统演变

发布时间：2018-06-23 03:17

本文选题：大火成岩省 + 地幔柱　；参考：《矿物岩石地球化学通报》2017年03期

【摘要】：本文简要总结了国家重点基础研究发展计划项目《二叠纪地幔柱构造与地表系统演变》的主要研究进展:(1)峨眉山大火成岩省形成于~259 Ma,持续时间小于1 Ma,是地幔柱头熔融的产物;塔里木大火成岩省为多阶段喷发(~300,~290,280 Ma),持续时间超过20 Ma,是孕育地幔柱活动的产物。(2)利用综合地球物理方法发现峨眉山大火成岩省内带上下地壳界面"消失"、下地壳增厚且具高波速特征、岩石圈地幔减薄,是地幔柱熔融产物在地壳不同深度底侵和内侵的结果。(3)完善了大火成岩省岩浆矿床的形成机理,构建了地幔柱成矿系统的基本框架,提出地幔柱结构、岩浆源区特征、结晶分异过程、硫化物饱和、地壳混染和岩浆侵位过程等是地幔柱成矿的关键控制因素。(4)从相对和绝对时间角度确证了西伯利亚和峨眉山大火成岩省分别对应于二叠纪末(PTB)和瓜德鲁普统-乐平统界线(GLB)生物灭绝事件;重建了华南二叠-三叠纪海水温度和p H值的演变历史,使甄别二叠纪末生物大灭绝的直接诱因成为可能。
[Abstract]:This paper briefly summarizes the main research progress of the National key basic Research and Development Program, "Permian mantle plume structure and surface system evolution": (1) the Emeishan great igneous province was formed at 259Maand lasted less than 1 Ma. it is the mantle. The product of columnar melting; The large igneous rock province of Tarim is a multi-stage eruption (290280 Ma) with a duration of more than 20 Ma, which is the product of mantle plume activity. (2) the upper and lower crustal interface of the Emeishan great igneous rock province has been found to be "disappeared" by comprehensive geophysical method, and the lower and lower crust has disappeared. The shell is thickened and characterized by high wave velocity. The lithospheric mantle thinning is the result of mantle plume melting products transgression and internal transgression at different depths of the crust. (3) the formation mechanism of magmatic deposits in great igneous provinces is improved, the basic framework of mantle plume metallogenic system is constructed, and the mantle plume structure is proposed. Characteristics of magma source region, crystallization differentiation process, sulphide saturation, Crustal mixing and magmatic emplacement are the key controlling factors of mantle plume mineralization. (4) it is confirmed that Siberia and Emeishan igneous provinces correspond to the late Permian (PTB) and Guadrop series-Le respectively from the angle of relative and absolute time. GLB extinction event; The evolution history of Permian-Triassic seawater temperature and pH value in South China has been reconstructed, which makes it possible to identify the direct cause of the end Permian biological extinction.
【作者单位】：中国科学院广州地球化学研究所同位素地球化学国家重点实验室;国家海洋局第一海洋研究所海洋沉积与环境地质实验室;中国科学院广州地球化学研究所院边缘海与大洋地质重点实验室;中国科学院广州地球化学研究所院矿物学与成矿学重点实验室;中国科学院地质与地球物理研究所岩石圈演化国家重点实验室;
【基金】：国家重点基础研究发展计划项目(2011CB808900) 中国科学院先导B专项(XDB18000000)
【分类号】：P534.46;P542.5

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