Timing of Partial Melting and Cooling across the Greater Himalayan   Crystalline Complex (Nyalam, Central Himalaya): In-sequence Thrusting   and its Implications

doi:10.1093/petrology/egv050

CORC > 北京大学 > 地球与空间科学学院

	Timing of Partial Melting and Cooling across the Greater Himalayan Crystalline Complex (Nyalam, Central Himalaya): In-sequence Thrusting and its Implications
	Wang, Jia-Min ; Rubatto, Daniela ; Zhang, Jin-Jiang
刊名	JOURNAL OF PETROLOGY
	2015
关键词	monazite partial melting trace elements tectonic discontinuity U-Pb geochronology EAST-CENTRAL NEPAL CHANNEL FLOW MODELS MAIN CENTRAL THRUST LA-ICP-MS TIBETAN DETACHMENT SYSTEM LOW-PRESSURE ANATEXIS MOUNT EVEREST REGION LIKHU KHOLA REGION SHRIMP U-PB SOUTHERN TIBET
DOI	10.1093/petrology/egv050
英文摘要	The timing of crustal melting and cooling has been investigated across the migmatites of the Greater Himalayan Crystalline Complex (GHC) in the Nyalam region, central Himalaya. Monazite U-Pb ages vary from 32 to 14Ma and are linked to metamorphic conditions on the basis of monazite internal zoning, mineral inclusions, and changes in heavy rare earth element and Y composition. Metamorphic temperatures were estimated by Zr-in-rutile thermometry and cooling rates were further constrained by rutile U-Pb ages. The results reveal two distinct blocks within the GHC of the Nyalam region. The upper GHC experienced higher peak metamorphic temperatures (730-750 degrees C) and a higher degree of melting (15-25%). Partial melting was dominated by muscovite dehydration melting, which lasted from similar to 32 to 25 Ma, possibly until similar to 20 Ma. The lower GHC experienced lower peak metamorphic temperatures (640-675 degrees C) and a lower degree of melting (0-10%) mainly via H2O-saturated melting from 19 to 16 Ma. At different times, both upper and lower blocks experienced initial slow cooling (rates 35 +/- 8 and 10 +/- 5 degrees C Ma(-1), respectively) followed by rapid cooling (100 +/- 20 degrees C Ma(-1)). The documented diachronous metamorphism implies the presence of the 'High Himalayan Thrust' that was active at similar to 25-16 Ma within the GHC of the central Himalaya. Different degrees and durations of partial melting in the investigated section suggest that a channel flow process dominated the exhumation of the upper GHC migmatites at 25-16 Ma, whereas a critical taper process dominated the exhumation of the relatively lower-grade lower GHC rocks and cooled upper GHC migmatites at 16-10 Ma. We suggest that propagating thrusts along large tectonic boundaries together with low-viscosity lateral crustal flow could contribute to exhumation of high-grade metamorphic rocks in the Himalaya and other similar collisional orogens.; National Natural Science Foundation of China [41172176, 41121062]; China Geological Survey; China Scholarship Council [201306010046]; SCI(E); ARTICLE; zhjj@pku.edu.cn; 9; 1677-1702; 56
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/439467]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Wang, Jia-Min,Rubatto, Daniela,Zhang, Jin-Jiang. Timing of Partial Melting and Cooling across the Greater Himalayan Crystalline Complex (Nyalam, Central Himalaya): In-sequence Thrusting and its Implications[J]. JOURNAL OF PETROLOGY,2015.
APA	Wang, Jia-Min,Rubatto, Daniela,&Zhang, Jin-Jiang.(2015).Timing of Partial Melting and Cooling across the Greater Himalayan Crystalline Complex (Nyalam, Central Himalaya): In-sequence Thrusting and its Implications.JOURNAL OF PETROLOGY.
MLA	Wang, Jia-Min,et al."Timing of Partial Melting and Cooling across the Greater Himalayan Crystalline Complex (Nyalam, Central Himalaya): In-sequence Thrusting and its Implications".JOURNAL OF PETROLOGY (2015).