The eruption trigger of the dacitic magma in Tengchong during the Middle Pleistocene

	The eruption trigger of the dacitic magma in Tengchong during the Middle Pleistocene
	Ding LeiLei 1,2; Liu JiaQi 1,2; Guo ZhengFu 1,2; Zhang Lei 1,2
刊名	ACTA PETROLOGICA SINICA
	2018
卷号	34 期号:1 页码:113-125
关键词	Tengchong Dacite Magma chamber Magma mixing Eruption trigger
ISSN号	1000-0569
文献子类	Article
英文摘要	Temporal-spatial and physical-chemical conditions of pre-eruption magma chamber are vital factors to unravel the eruption mechanism. In this study, we carry out high-resolution geochronological dating for volcanic rocks collected from Mazhan Drilling Core, Tengchong, China. Zircons of dacites are euhedral to semi-euhedral with clear oscillatory zoning which may imply a magmatic origin. Dating of zircons gets a result of similar to 0.7Ma, with a Middle Pleistocene overlying layer, which means the eruption happened at the Middle Pleistocene. Geochemistry of dacites shows high potassic calc-alkaline affinity. Dacites in Drilling Core could be divided into an upper part and the lower part based on the existence of amphibole. Amphibole bearing dacites in the upper part with mineral assemblages: Cpx + Opx + Pl + Il + Mag. Some augite crystals are rimmed by enstatite and pigeonite, and lower An plagioclase are rimmed by higher An value, which are all suggest that mafic magma injected into the magma chamber before the eruption; Pyroxene bearing dacites from lower part with mineral assemblages: Cpx + Opx + Pl + Kf + Bi + Il + Mag + Q. The increased temperature and pressure of plagioclase with lower An value show that silicic magma injected into the magma chamber before the eruption. Furthermore, the dacites from two layers have the similarity of bulk compositional and mineral core composition indicate these two different dacites initially from one mamga chamber, but experience two separate composition mamga injection event. The mamga injection induced the instability of the magma chamber, which is the direct cause of this eruption.
WOS关键词	PLAGIOCLASE PHENOCRYSTS ; VOLCANIC-ERUPTIONS ; DYNAMICS ; SYSTEM ; FE ; VESICULATION ; CONSTRAINTS ; BAROMETER ; PROFILES ; PRODUCTS
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000424882800011
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/82679]
专题	中国科学院地质与地球物理研究所
通讯作者	Liu JiaQi
作者单位	1.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China
推荐引用方式 GB/T 7714	Ding LeiLei,Liu JiaQi,Guo ZhengFu,et al. The eruption trigger of the dacitic magma in Tengchong during the Middle Pleistocene[J]. ACTA PETROLOGICA SINICA,2018,34(1):113-125.
APA	Ding LeiLei,Liu JiaQi,Guo ZhengFu,&Zhang Lei.(2018).The eruption trigger of the dacitic magma in Tengchong during the Middle Pleistocene.ACTA PETROLOGICA SINICA,34(1),113-125.
MLA	Ding LeiLei,et al."The eruption trigger of the dacitic magma in Tengchong during the Middle Pleistocene".ACTA PETROLOGICA SINICA 34.1(2018):113-125.