The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal;Deposit in Western Sichuan Province: Evidence from Isotope Dating

doi:10.1111/1755-6724.12033

CORC > 中国地质调查局 > 中国地质调查局 > 中国地质科学院矿产资源研究所

	The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal;Deposit in Western Sichuan Province: Evidence from Isotope Dating
	Li Jiankang 1; Wang Denghong ; Chen Yuchuan
刊名	ACTA GEOLOGICA SINICA-ENGLISH EDITION
	2013
卷号	87 期号:1 页码:91-101
关键词	isotope dating liquid immiscibility in granitic magmas pegmatite Jiajika rare metal deposit
ISSN号	1000-9515
DOI	10.1111/1755-6724.12033
英文摘要	Granitic pegmatites are commonly thought to form by fractional crystallization or by liquid immiscibility of granitic magma; however, these proposals are based mainly on analyses of fluid and melt inclusions. Here, we use the Jiajika pegmatite deposit, the largest spodumene deposit in Asia, as a case study to investigate ore forming processes using isotope dating. Daring of a single granite sample from the Jiajika deposit using multiple methods gave a zircon U-Pb SHRIMP age of 208.4 +/- 3.9 Ma, an Ar-40/Ar-39 age for muscovite of 182.9 +/- 1.7 Ma, and an Ar-40/Ar-39 age for biotite of 169.9 +/- 1.6 Ma. Based on these dating results and the Ar-40/Ar-39 age of muscovite from the Jiajika pegmatite, a temperature-time cooling track for the Jiajika granite was constructed using closure temperatures of the different isotope systems. This track indicates that the granite cooled over similar to 40 m. y., with segregation of the pegmatite fluid from the granitic magma at a temperature of similar to 700 degrees C. This result suggests that the Jiajika pegmatite formed not by fractional crystallization, but by segregation of an immiscible liquid from the granitic magma. When compared with fractional crystallization, the relatively early timing of segregation of an immiscible liquid from a granitic magma can prevent the precipitation of ore-forming elements during crystallization, and suggests that liquid immiscibility could be an important ore-forming process for rare metal pegmatities. We also conclude that isotope dating is a method that can potentially be used to determine the dominant ore-forming processes that occurred during the formation of granite-related ore deposits, and suggest that this method can be employed to determine the formation history of the W-Sn ore deposits found elsewhere within the Nanling Metallogenic Belt.
学科主题	矿床地质
WOS关键词	U-PB GEOCHRONOLOGY ; GRANITIC PEGMATITES ; SOUTH-DAKOTA ; BLACK-HILLS ; LIQUID IMMISCIBILITY ; MELT INCLUSIONS ; SILICATE MELTS ; TEMPERATURE ; PRESSURE ; SYSTEM
WOS研究方向	Geology
语种	英语
出版者	WILEY-BLACKWELL
WOS记录号	WOS:000315340000024
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/40033]
专题	中国地质科学院矿产资源研究所
作者单位	1.CAGS, Inst Mineral Resources, MLR Key Lab Metallogeny & Mineral Assessment, Beijing 100037, Peoples R China. 2.Changan Univ, Coll Earth Sci & Resources, Xian 710054, Peoples R China.
推荐引用方式 GB/T 7714	Li Jiankang,Wang Denghong,Chen Yuchuan. The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal;Deposit in Western Sichuan Province: Evidence from Isotope Dating[J]. ACTA GEOLOGICA SINICA-ENGLISH EDITION,2013,87(1):91-101.
APA	Li Jiankang,Wang Denghong,&Chen Yuchuan.(2013).The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal;Deposit in Western Sichuan Province: Evidence from Isotope Dating.ACTA GEOLOGICA SINICA-ENGLISH EDITION,87(1),91-101.
MLA	Li Jiankang,et al."The Ore-forming Mechanism of the Jiajika Pegmatite-Type Rare Metal;Deposit in Western Sichuan Province: Evidence from Isotope Dating".ACTA GEOLOGICA SINICA-ENGLISH EDITION 87.1(2013):91-101.