Hornblendites as a record of differentiation, metasomatism and magma fertility in arc crust

doi:10.1016/j.chemgeo.2024.121974

	Hornblendites as a record of differentiation, metasomatism and magma fertility in arc crust
	Zhu, Ren-Zhi 1; Smith, Daniel J.2; Wang, Fangyue 3; Qin, Jiang-Feng 1; Zhang, Chao 1; Zhao, Shaowei 4; Liu, Min 1; Zhang, Fangyi 5; Zhu, Yu 1; Lai, Shao-Cong 1
	2024-04-05
发表期刊	CHEMICAL GEOLOGY
ISSN	0009-2541
卷号	650 页码:15
通讯作者	Zhu, Ren-Zhi([email protected]) ; Lai, Shao-Cong([email protected])
摘要	The fractionation of hornblende is a common phenomenon in arc magmas, and gives rise to a number of notable geochemical characteristics. However, it is often cryptic, with limited direct petrographic evidence for the fractionation, or even presence of amphibole in volcanic suites. Newly identified hornblendites in the SE Tibet represent direct evidence for hornblende fractionation in the Gangdese arc. The hornblendites have age ranges from 95.3 +/- 0.2 to 92.6 +/- 0.2 Ma, recording magmatic activities over a ca. 2 Myr interval. Textural relationships indicate that hornblendites form by peritectic reactions between an evolving melt and earlier-formed clinopyroxenites. Relict clinopyroxenes and primitive pargasite record melt evolution from high Sr/Y basaltic andesite to dacite, during cooling from similar to 1050 degrees C to similar to 850 degrees C in the mid to lower crust. The clinopyroxene precursors interacted with water-rich high SiO2 fluids/melts at ca. 800 degrees C. Zircons have high delta O-18 values (up to 7.62 parts per thousand) and positive epsilon Hf(t) values (up to +13.0), but bulk rock data show high Sr-87/Sr-86 ratios (up to 0.7093) and negative epsilon(Nd)(t) values (ca. -3.2). This decoupled signature implies the primary magmatic source was metasomatized by 5-10% recycled subducted sediments. Magmas have a high oxygen fugacity (Delta NNO can up to +2.40) through a combination of metasomatism during subduction, and subsequent melt-mush interaction that is recorded by zoned hornblendes. Metasomatism, widespread and long-term fractionation of amphibole +/- garnet +/- clinopyroxene, and high oxygen fugacity, are all positive indicators for the fertility of arc magmas with respect to porphyry copper formation. This study demonstrates that late-stage melt-mush interaction can contribute to peritectic hornblendite formation and facilitate magma fertility.
关键词	Fractionation of hornblende Arc magmas Metasomatism Melt-mush interaction Porphyry copper fertility
DOI	10.1016/j.chemgeo.2024.121974
收录类别	SCI
语种	英语
资助项目	National Natural Science Foundation of China[41802054]; Sino-British Fellowship Trust[IES\R3\213093]; NSFC[42172056]
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:001200707100001
出版者	ELSEVIER
WOS关键词	SOUTHERN TIBET EVIDENCE ; U-PB ; CONTINENTAL COLLISION ; TRACE-ELEMENTS ; AMPHIBOLE FRACTIONATION ; ISOTOPIC CONSTRAINTS ; EASTERN GANGDESE ; ISLAND ARCS ; HF ISOTOPES ; LU-HF
引用统计	被引频次：3[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/185565
专题	深海极端环境与生命过程研究中心
通讯作者	Zhu, Ren-Zhi; Lai, Shao-Cong
作者单位	1.Northwest Univ, Dept Geol, State Key Lab Continental Dynam, Xian 710069, Peoples R China 2.Univ Leicester, Sch Geog Geol & Environm, Leicester, England 3.Hefei Univ Technol, Ore Deposit & Explorat Ctr ODEC, Sch Resources & Environm Engn, Hefei 230009, Peoples R China 4.Changan Univ, Sch Earth Sci & Resources, Key Lab Western Chinas Mineral Resources & Geol En, Minist Educ, Xian 710054, Peoples R China 5.Chinese Acad Sci, Inst Oceanog, Ctr Deep Sea Res, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Zhu, Ren-Zhi,Smith, Daniel J.,Wang, Fangyue,et al. Hornblendites as a record of differentiation, metasomatism and magma fertility in arc crust[J]. CHEMICAL GEOLOGY,2024,650:15.
APA	Zhu, Ren-Zhi.,Smith, Daniel J..,Wang, Fangyue.,Qin, Jiang-Feng.,Zhang, Chao.,...&Lai, Shao-Cong.(2024).Hornblendites as a record of differentiation, metasomatism and magma fertility in arc crust.CHEMICAL GEOLOGY,650,15.
MLA	Zhu, Ren-Zhi,et al."Hornblendites as a record of differentiation, metasomatism and magma fertility in arc crust".CHEMICAL GEOLOGY 650(2024):15.