کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6440590 | 1638650 | 2016 | 37 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Syn-collisional granitoids in the Qilian Block on the Northern Tibetan Plateau: A long-lasting magmatism since continental collision through slab steepening
ترجمه فارسی عنوان
گرانیتویدهای سقفی منفی در بلوک کیلیان در فلات تبت شمالی شمالی: یک ماگماتیسم طولانی مدت از زمان برخورد قاره ای از طریق فرو ریختن تخته
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
In this paper we present a new model that can explain the large zircon age spectrum of ~ 510 - 420 Ma within a single sample from the Gangcha (Gcha) biotite granodiorite and the Huangyuan (HY) two-mica monzogranite on the northern Tibetan Plateau. The large age spread recorded in zircons is characteristic of granitoid samples from the studied region, which is best explained by the long-lasting magmatism since the onset of continental collision at ~ 500 Ma, followed by slab steepening and the ultimate slab break-off at ~ 450 Ma. These granitoids have a large major and trace element compositional variation, but limited initial Sr (ISr[450] = 0.709 to 0.715), Nd (ÔNd[450] = â 6.5 to â 3.7), Hf (ÔHf[450] = â 4.3 to 1.5) and Pb (206Pb/204Pb[450] = 17.70 to 17.17; 207Pb/204Pb[450] = 15.60 to 15.69; 208Pb/204Pb[450] = 38.04 to 38.73) isotopic variation. The small negative whole rock ÔNd[450] and ÔHf[450] values are most consistent with the granitoid source being dominated by subducted seafloor materials. The inherited zircons with large negative ÔHf[450] values (e.g. â 50) are indicative of input from the lower continental crust and subducted sediments. The correlated variations among major elements, trace elements and radiogenic isotopes are best interpreted as reflecting melting-induced mixing of a compositionally heterogeneous source with superimposed effect of varying extent of fractional crystallization and crustal assimilation. The inherited zircons of Palaeo-Proterozoic age and the Archean crustal model ages signify the involvement of ancient basement rocks.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Lithos - Volumes 246â247, March 2016, Pages 99-109
Journal: Lithos - Volumes 246â247, March 2016, Pages 99-109
نویسندگان
Hui Huang, Yaoling Niu, Xuanxue Mo,