Origin of lamprophyres by the mixing of basic and alkaline melts in magma chamber in Beiya area, western Yunnan, China

doi:10.1016/j.lithos.2007.06.011

	Origin of lamprophyres by the mixing of basic and alkaline melts in magma chamber in Beiya area, western Yunnan, China
	Xu, Xing-Wang; Zhang, Bao-Lin; Qin, Ke-Zhang; Mao, Qian; Cai, Xin-Ping
刊名	LITHOS
	2007-12-01
卷号	99 期号:3-4 页码:339-362
关键词	lamprophyre quartz megacrysts intragranular inclusion multiple reaction zones melt mixing mafic melt alkaline melt
ISSN号	0024-4937
DOI	10.1016/j.lithos.2007.06.011
文献子类	Article
英文摘要	Lamprophyres consisting mainly of diopside, phlogopite and K-feldspar formed in the early Tertiary around 60 Main the Beiya area and are characterized by low SiO2 +/- 46-50 wt.%), Rb (31-45 ppm) and Sr (225-262 ppm), high Al2O3, (11.2-13.1 wt.%), CaO (8.0-8.7 wt.%), MgO (11.5-12.1 wt.%), K2O(4.9-5.5 wt.%), TiO2 (2.9-3.3 wt.%) and REE (174-177 ppm), and compatible elements (e.g. Sc, Cr and Ni) and HSF elements (e.g. Th, U, Zr, Nb, Ta, Ti and Y), and low Nd-143/Nd-144 0.512372-0.512536, middle Sr-87/Sr-86 0.707322-0.707395, middle Pb-206/Pb-204 18.50-18.59, Pb-207/Pb-204 15.60-15.65 and Pb-208/Ph-204 38.75-38.8. These rocks developed peculiar quartz megacrysts with poly-layer reaction zones, melt inclusions, and partial melted K-feldspar and plagioclase inclusions, and plastic shapes. Important features of these rocks include: (1) hybrid composition of elements, (2) abrupt increase of SiO2 content of the melt, recorded by zoned diopside, (3) development of sanidine and aegirine-augite reaction zones, (4) alkaline melt and partial melted K-feldspar and plagioclase inclusions, (5) deformed quartz inclusions associated with quartz megacrysts, (6) the presence of quartz megacrysts in plastic shape with their parent melts, (7) the occurrence of olivine, high-MgO ilmenite and spinel inclusions within earlier formed diopside, phlogopite and magnetite. Median Sr-87/Sr-86 values between Tertiary alkaline porphyries in the Beiya area and the western Yunnan and Tertiary basalt in the western Yunnan indicate that the Beiya lamprophyre melts were derivative and resulted from the mixing between basic melts that were related to the partial melting of phenocrysts of spinel iherzolite from a mantle source. The alkaline melts originated from partial melting along the Jinshajiang subduction ductile shear zone at the contact between the buried Palaeo-Tethyan oceanic lithosphere and the upper mantle lithosphere. The alkaline melts are composed of 65% sanidine (Or(70)Ab(28)An(2)) and 35% SiO2. The melt mixing occurred in magma chambers in the middle-shallow crust at 8-10 km before the derivative lamprophyre melts intruded into the shallow cover in Beiya area. This mixing of basic and alkaline melts might represent a general process for the formation of lamprophyre in the western Yunnan. (C) 2007 Elsevier B.V. All rights reserved.
WOS关键词	TRACE-ELEMENT ; SHOSHONITIC LAMPROPHYRES ; CRUSTAL CONTAMINATION ; LITHOSPHERIC MANTLE ; VOLCANIC FIELD ; GOLD DEPOSITS ; YILGARN BLOCK ; GEOCHEMISTRY ; ND ; MINETTES
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000251966000009
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/67606]
专题	中国科学院地质与地球物理研究所
通讯作者	Xu, Xing-Wang
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, Xing-Wang,Zhang, Bao-Lin,Qin, Ke-Zhang,et al. Origin of lamprophyres by the mixing of basic and alkaline melts in magma chamber in Beiya area, western Yunnan, China[J]. LITHOS,2007,99(3-4):339-362.
APA	Xu, Xing-Wang,Zhang, Bao-Lin,Qin, Ke-Zhang,Mao, Qian,&Cai, Xin-Ping.(2007).Origin of lamprophyres by the mixing of basic and alkaline melts in magma chamber in Beiya area, western Yunnan, China.LITHOS,99(3-4),339-362.
MLA	Xu, Xing-Wang,et al."Origin of lamprophyres by the mixing of basic and alkaline melts in magma chamber in Beiya area, western Yunnan, China".LITHOS 99.3-4(2007):339-362.