Petrologic, chronological and geochemistry characteristics and formation mechanism of alkaline porphyries in the Beiya gold district, western Yunnan

	Petrologic, chronological and geochemistry characteristics and formation mechanism of alkaline porphyries in the Beiya gold district, western Yunnan
	Xu, XW; Cai, XP; Song, BC; Zhang, BL; Ying, HL; Xiao, QB; Wang, J
刊名	ACTA PETROLOGICA SINICA
	2006-03-01
卷号	22 期号:3 页码:631-642
关键词	alkaline porphyry magmatism in cave peperite Ar-39/Ar-40 age geochemistry formation mechanism
ISSN号	1000-0569
文献子类	Article
英文摘要	We report the new discoveries of ore-hearing quartz albite porphyry and of some peculiar geological phenomenon, including intrusions of quartz K-feldspar porphyries into karst caves and biotite K-feldspar porphyries into poorly consolidated lacustrine sedimentary rocks and formation of some rare structures and textures, such as coexistence of microcrystalline and vitreous-cryptocrystalline groundmass and formation of new type peperites, in the Beiya gold mineral district, western Yunnan. We also show Ar-39/Ar-40 ages of the porphyries in Beiya which indicate that the quartz albite porphyry intruded in early Tertiary with an age of 65.56Ma, while the quartz K-feldspar porphyries formed between 25 and 33Ma, and the biotite K-feldspar porphyries have intrusive ages of 3.78 Ma to 3.65 Ma. All the quartz albite porphyry, quartz K-feldspar porphyries and biotite K-feldspar porphyries in the Beiya gold mineral district are alkaline and have some similar geochemistry features, including (K2O + Na2O) > 10%, SiO2 > 67%, Sr >400 x 10(-6), Sr-87/Sr-86 >0.707, LREE rich, REI. distribution pattern similar to that of OIB. Features of REE composition and Nd-Sr-Pb isotope of these alkaline porphyries suggest. that they are most likely to be origin form a mixed source containing compositions of OIB, MORB, normal sedimentary rocks and upper mantle (EMII + PREMA), and we further propose that the alkaline porphyries in the Beiya gold mineral district, similar to other Tertiary alkaline porphyries in western Yunnan, are related to partial melting lie within a shear zone between buried paleo-Tethyan oceanic lithosphere and upper mantle lithosphere, caused by the subduction and collision of India to Asia.
WOS关键词	TIBET ; CHINA
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000237332500012
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/66284]
专题	中国科学院地质与地球物理研究所
通讯作者	Xu, XW
作者单位	Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Xu, XW,Cai, XP,Song, BC,et al. Petrologic, chronological and geochemistry characteristics and formation mechanism of alkaline porphyries in the Beiya gold district, western Yunnan[J]. ACTA PETROLOGICA SINICA,2006,22(3):631-642.
APA	Xu, XW.,Cai, XP.,Song, BC.,Zhang, BL.,Ying, HL.,...&Wang, J.(2006).Petrologic, chronological and geochemistry characteristics and formation mechanism of alkaline porphyries in the Beiya gold district, western Yunnan.ACTA PETROLOGICA SINICA,22(3),631-642.
MLA	Xu, XW,et al."Petrologic, chronological and geochemistry characteristics and formation mechanism of alkaline porphyries in the Beiya gold district, western Yunnan".ACTA PETROLOGICA SINICA 22.3(2006):631-642.