华北大陆地壳─上地幔岩石学结构与演化
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摘要
本文基于出露的前寒武纪变质岩系、中、新生代岩浆活动以及新生代玄武岩中上地幔包体的岩石学与地质压力计研究，结合地球物理测涤资料与高温高压下岩石中地震波传播速度的实验成果，提出了华北大陆三个地区（河北平原、太行－五台、鄂尔多斯）的地壳－上地幔岩石学结构，讨论了界面性质及其演化。在强调ｖ＿ｐ、ｖｂ、σ结构与岩石学结构共同约束的基础上，有效地识别了不同地区硅铝质陆壳在物质组成上的差异和上地幔低速层或矿物相转变等特征。本文提出壳－幔岩石学结构及其演化，密切地与陆壳主要形成时期的太古－早元古构造岩浆事件相关，又与显生宙构造岩浆事件对它的改造程度有关，壳－幔岩石学结构是我们追索大陆的构造性质及其演化的一个重要记录和科学依据。
Thls paper presents theconept of petrological structure in the study of crust-mantie structure。The crust-mantle petrological structure of three regions (Hebei plain,Taihang-Wutai and Eerdnosi )of the North China continent is suggested based on the petrological and geobaIometric data of the Precambrian metamorPhic rock series,the Mesoic and Cenozoic magmatic activity,and the upper mantle xenoliths in the Cenozoic basalts,in combination with the geophy-sical data and the experimental meaurements of Vp values for the rock sam-ples at high temperature and pressure。It is emphasized that,with the combina-tive constraints of Vp,V_s,σand petrological structure,one can effectively recog-nize the difference in composition of the sialic crust among the different regions,and distinguish the upper mantle low-velocity layer from mineral phase transition(spinel or garnet phase)。This paper has reached the conclusion that the crust-mantle petrological structure and its evolution are closely related not only to the Archeozoic-Early Proterozoic tectonic-magmatic events, but also to Phanerozoic tectonic-magmatic evel1ts and the extent of the reformation,and that tne crust-mantle petrorological strucure is the important record and evidence for tracing the nature and evolution of the continent tectonics。Institutc of Geology,State Seismological Bureau
Thls paper presents theconept of petrological structure in the study of crust-mantie structure。The crust-mantle petrological structure of three regions (Hebei plain,Taihang-Wutai and Eerdnosi )of the North China continent is suggested based on the petrological and geobaIometric data of the Precambrian metamorPhic rock series,the Mesoic and Cenozoic magmatic activity,and the upper mantle xenoliths in the Cenozoic basalts,in combination with the geophy-sical data and the experimental meaurements of Vp values for the rock sam-ples at high temperature and pressure。It is emphasized that,with the combina-tive constraints of Vp,V_s,σand petrological structure,one can effectively recog-nize the difference in composition of the sialic crust among the different regions,and distinguish the upper mantle low-velocity layer from mineral phase transition(spinel or garnet phase)。This paper has reached the conclusion that the crust-mantle petrological structure and its evolution are closely related not only to the Archeozoic-Early Proterozoic tectonic-magmatic events, but also to Phanerozoic tectonic-magmatic evel1ts and the extent of the reformation,and that tne crust-mantle petrorological strucure is the important record and evidence for tracing the nature and evolution of the continent tectonics。Institutc of Geology,State Seismological Bureau
引文
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