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  4. 岩石圈演化国家重点实验室
Thermodynamic constraints on the composition of orogenically thickened lower crust

文献类型：期刊论文

作者Li, Yi-Bing2,3,4; Wu, Yu-Wen1; Su, Bin2,4; Chen, Si2,3,4; Zhang, Qing-Hua2,3,4; Chen, Yi2,3,4
刊名JOURNAL OF METAMORPHIC GEOLOGY
出版日期2022-06-23
页码22
关键词density garnet-omphacite granulite rheology thermodynamic modelling thickened lower crust
ISSN号0263-4929
DOI10.1111/jmg.12679
英文摘要Orogenically thickened lower crust is the key site of crustal differentiation, crustal deformation, and Moho modification. However, the composition of thickened lower crust is still highly debated. Here, we calculate a set of pseudosections with mafic lower crust compositions in the Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-O-2 (NCKFMASHTO) system. Our modelling results show that the maximum thickness of the mafic lower crust increases with the Moho temperature (T-Moho). In addition, the lithologies of stable mafic crust are characterized by medium-pressure (MP) to high-pressure (HP) granulites at 40-50 km, HP granulites and garnet-omphacite granulites at 50-60 km, and garnet-omphacite granulites at 60-70 km. Under the Pamir geothermal conditions, mafic rocks with high SiO2 (>50.2 wt%), X-Mg (>0.70), X-Ca (>0.49), or low X-Al (<0.11) could be stable at 70 km; however, only similar to 10% of global mafic granulite xenoliths lie within this compositional range. Further modelling indicates that if T-Moho reaches 900-1000 degrees C, neither the lower crust nor the upper mantle has significant strength relative to the upper crust and that only similar to 5-37% of mafic materials are gravitationally stable at 70 km. This implies that the base of doubly thickened (70 km) crust is dominated by intermediate-felsic rocks, consistent with the low V-p and V-p/V-s values seismically observed in young orogenic crustal roots. Thus, most mafic materials at >70 km could delaminate into the deep mantle. Our results provide insights on the formation of extremely thick crust with a predominantly intermediate-felsic base and the crustal thickness variation in continental collision zones.
WOS关键词HIGH-PRESSURE GRANULITES ; MINERAL EQUILIBRIA CALCULATIONS ; ZIRCON U-PB ; CONTINENTAL-CRUST ; SEISMIC VELOCITY ; METAMORPHIC HISTORY ; PHASE-EQUILIBRIA ; HIGH-TEMPERATURE ; TIBETAN PLATEAU ; BOHEMIAN MASSIF
资助项目National Natural Science Foundation of China[42172064] ; National Natural Science Foundation of China[41822202]
WOS研究方向Geology
语种英语
WOS记录号WOS:000814679400001
出版者WILEY
资助机构National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China
源URL[http://ir.iggcas.ac.cn/handle/132A11/105881]  
专题地质与地球物理研究所_岩石圈演化国家重点实验室
通讯作者Chen, Yi
作者单位1.Beijing Wuzi Univ, Sch Informat, Beijing, Peoples R China
2.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
3.Univ Chinese Acad Sci, Beijing, Peoples R China
4.Chinese Acad Sci, Innovat Acad Earth Sci, Beijing, Peoples R China
推荐引用方式
GB/T 7714		 Li, Yi-Bing,Wu, Yu-Wen,Su, Bin,et al. Thermodynamic constraints on the composition of orogenically thickened lower crust[J]. JOURNAL OF METAMORPHIC GEOLOGY,2022:22.
APA Li, Yi-Bing,Wu, Yu-Wen,Su, Bin,Chen, Si,Zhang, Qing-Hua,&Chen, Yi.(2022).Thermodynamic constraints on the composition of orogenically thickened lower crust.JOURNAL OF METAMORPHIC GEOLOGY,22.
MLA Li, Yi-Bing,et al."Thermodynamic constraints on the composition of orogenically thickened lower crust".JOURNAL OF METAMORPHIC GEOLOGY (2022):22.

入库方式： OAI收割

来源：地质与地球物理研究所

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