Fractional crystallization and the formation of thick Fe-Ti-V oxide layers in the Baima layered intrusion, SW China

	Fractional crystallization and the formation of thick Fe-Ti-V oxide layers in the Baima layered intrusion, SW China
	Xiao-Qi Zhang; Xie-Yan Song; Lie-Meng Chen; Wei Xie; Song-Yue Yu; Wen-Qin Zheng; Yu-Feng Deng; Jia-Fei Zhang; Shu-Guang Gui
	2012
发表期刊	Ore Geology Reviews
卷号	49 期号:1 页码:96-108
摘要	The Baima layered intrusion is located in the central part of the Emeishan Large Igneous Province (ELIP). The N-S striking intrusion is similar to 24 km long and similar to 2 km thick and dips to the west. Based on variations in modal proportions and cumulus mineral assemblages, the intrusion from the base to the top is simply subdivided into a lower zone (12) with most of the economic magnetite layers, and an upper zone (UZ) with apatite-bearing troctolite and gabbro. The rock textures suggest crystallization of the Fe-Ti oxide slightly later than plagioclase (An(67-54)) but relatively earlier than olivine (Fo(74-55)), followed by clinopyroxene and finally apatite. Relatively low olivine forsterite content and abundant ilmenite exsolution lamellae in clinopyroxene indicate that the Baima parental magma is a highly evolved Fe-Ti-rich magma. Via MELTS model, it demonstrates that under a closed oxygen system, extensive silicate mineral fractionation of a picritic magma might lead to Fe and Ti enrichment and oxygen fugacity elevation in the residual magma. When such Fe-Ti-rich magma ascends to the shallower Baima intrusion, the Fe-Ti oxides may become an early liquidus phase. Well-matched olivine and plagioclase microprobe data with the results of MELTS calculation, combined with relatively low CaO content in olivine (0.02-0.08 wt.%) indicate that wall-rock contamination probably plays a weak role on oxygen fugacity elevation and the early crystallization of Fe-Ti oxides. Several reversals in whole-rock chromium and plagioclase anorthite contents illustrate that multiple recharges of such Fe-Ti-rich magma mainly occurred along the lower part of the Baima magma chamber. Frequent Fe-Ti-rich magma replenishment and gravitational sorting and settling are crucial for the development of thick Fe-Ti oxide layers at the base of the Baima layered intrusion.
关键词	Emeishan Large Igneous Province Baima Layered Intrusion Fe–ti Oxide Closed To Oxygen System Magma Replenishment Melts
收录类别	SCI
语种	英语
文献类型	期刊论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/5133
专题	矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文矿床地球化学国家重点实验室
推荐引用方式 GB/T 7714	Xiao-Qi Zhang,Xie-Yan Song,Lie-Meng Chen,et al. Fractional crystallization and the formation of thick Fe-Ti-V oxide layers in the Baima layered intrusion, SW China[J]. Ore Geology Reviews,2012,49(1):96-108.
APA	Xiao-Qi Zhang.,Xie-Yan Song.,Lie-Meng Chen.,Wei Xie.,Song-Yue Yu.,...&Shu-Guang Gui.(2012).Fractional crystallization and the formation of thick Fe-Ti-V oxide layers in the Baima layered intrusion, SW China.Ore Geology Reviews,49(1),96-108.
MLA	Xiao-Qi Zhang,et al."Fractional crystallization and the formation of thick Fe-Ti-V oxide layers in the Baima layered intrusion, SW China".Ore Geology Reviews 49.1(2012):96-108.

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