basaltic crust 中文意思是什麼
basaltic crust
解釋
玄武巖殼-
Secondly, based on the microbeam analytical technique, on the one hand, through investigating the characteristic of major elements in the mantle minerals the author acquired the static information from mantle ; on the other hand, through multi - point analysis of a part of the minerals from mantle, the auther got dynamic information from mantle. finally, generalizating the fruits of this study and predecessors, the autor holds that the constituents of lithospheric mantle possibly includes spinel lherzolites, clinopyroxenites, websterite, dunite, harzburgites, garnet lherzite, phlogopite lherzite, eclogites, clinopyroxene megacrysts ; compared with east china and north china platform, the research field mantle shows the characteristics of higher degree of partial melting processes and more depleted mantle ; the. upper mantle beneath north hetian area is heterogeneous, with a tendency of deficit in a12o3 and lree from kaliyang in west hetian to the river basin of kalakshi river and yulongkashi river ; the subduction of the crust beneath north hetian has ever occurred in geological history and caused the mixing of mantle - crust ; the depth of the origination of basaltic magmas beneath north hetian exceeds 73km ; the thickness of the lithosphere beneath the research area amounts to 204. 9km ; the mantle beneath north hetian has geological condtions for forming diamond deposits
最後，綜合本區幔源礦物和地幔巖石的特徵以及地球物理資料，得出如下結論：本區上地幔的物質組成有尖晶石二輝橄欖巖、二輝巖、單斜輝石巖、純橄欖巖、方輝橄欖巖、石榴石二輝橄欖巖、金雲母二輝橄欖巖、榴輝巖；與中國東部以及華北地臺上地幔相比，研究區上地幔具有富集主元素中相容元素和虧損其中的不相容元素的特徵，局部熔融程度較高；上地幔存在橫向和縱向的不均一性，從西部的克里陽到喀拉喀什河和玉龍喀什河流域， al和lree富集程度呈下降趨勢，不同來源的相同礦物中主元素的含量差異較大；地質歷史時期這里可能發生過地殼俯沖並產生殼幔混合作用；玄武巖漿的起源深度73km ；從幔源重砂礦物的溫壓估算結果，可以推斷出巖石圈厚度可達204 . 9km ；綜合巖石圈物質組成特徵、巖石圈熱狀態、地幔溫壓狀態、氧逸度以及幔源巖石和幔源礦物的化學成分，認為研究區具備了金剛石成礦地幔地質條件。 -
2. early jurassic mafic volcanic rocks in yanshan area were derived from decompression melting of an ancient continental lithospheric mantle, which had been previously metasomatized by subducted slabs during the closure of paleo - asian ocean ; the mantle source of late jurassic mafic volcanic rocks were contributed by dominant emi and insignificant subducted metasomatic components ; early cretaceous mafic volcanic rocks were derived from decompression melting of an ancient continental lithospheric mantle ( emi ). with regard to the basaltic lavas, the felsic rocks resulted from partial melting of continental crust, which closely related to basaltic underplating
2燕山地區早侏羅世中基性火山巖來自於早期俯沖交代的古老巖石圈地幔部分熔融作用，俯沖交代作用可能與早期古亞洲洋閉合事件有關；晚侏羅世中基性火山巖更多來自於類似於emi型地幔源區的部分熔融作用，俯沖交代成分貢獻很弱；早白堊世基性火山巖則來自於emi型地幔源區的部分熔融作用。
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