Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation

doi:10.1007/s00126-023-01203-w

	Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation
	Tornos, Fernando 1,2; Hanchar, John M.2; Steele-MacInnis, Matthew 3; Crespo, Elena 4; Kamenetsky, Vadim S.5; Casquet, Cesar 1,4
	2023-09-02
发表期刊	MINERALIUM DEPOSITA
ISSN	0026-4598
页码	37
通讯作者	Tornos, Fernando([email protected])
摘要	Magnetite-(apatite) ore deposits are interpreted as being formed by the crystallization of iron-rich ultrabasic melts, dominantly generated by the interaction of silicate melts with oxidized P-F-SO4-bearing sedimentary rocks. This hypothesis is supported by geologic evidence, experimental studies, numerical modeling, stable and radiogenic isotope geochemistry, mineralogy, and melt-and mineral-inclusion data. Assimilation of crustal rocks during ascent promotes separation from a silicate magma of Fe-rich, Si-Al-poor melts with low solidus temperatures and viscosities, allowing coalescence, migration, and emplacement at deep to subaerial crustal environments. When the iron-rich melt attains neutral buoyancy, fractional crystallization leads to melt immiscibility similar to that observed in industrial blast furnaces, which promotes separation of massive magnetite ore overlain by different types of "slag" containing actinolite or diopside +/- phosphates +/- magnetite +/- feldspar +/- anhydrite +/- scapolite, commonly enriched in high field strength elements. The mineralogy and morphology of this iron-depleted cap strongly depend on the depth of emplacement and composition of the iron-rich magma. Most of these systems exhibit high oxygen fugacity, which inhibits the precipitation of significant sulfide mineralization. The initially high fO(2) of these systems also promotes the formation of low-Ti (< 1 wt%) magnetite: Ti acts as an incompatible component and is enriched in the iron-poor caps and in the hydrothermal aureole. High fluid-phase pressures produced during massive crystallization of magnetite from the melt further facilitate the exsolution of magmatic-hydrothermal fluids responsible for the formation of aureoles of alkali-calcic-iron alteration with hydrothermal replacement-style iron mineralization. On the whole, these systems are dramatically different from the magmatic-hydrothermal systems related to intermediate to felsic igneous rocks; they are more akin to carbonatite and other ultramafic rocks.
关键词	Magnetite-(apatite) deposits Mineral chemistry Isotope geochemistry Melt inclusions Cordillera Andes Chile
DOI	10.1007/s00126-023-01203-w
收录类别	SCI
语种	英语
资助项目	CRUE-CSIC agreement; Springer Nature; project NANOMET[PID2022-138768OB-I00]; project Exploration Information Systems (EIS) of Horizon Europe[101057357]; NSERC Discovery Grants (Canada); MCIN/AEI[PID2020-117332GB-C2 1]; MCIN/AEI[PID2020-117332GB-C2 2]; Chinese Academy of Sciences
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
WOS类目	Geochemistry & Geophysics ; Mineralogy
WOS记录号	WOS:001060174600002
出版者	SPRINGER
WOS关键词	OXIDE-COPPER-GOLD ; LOWER YANGTZE-RIVER ; MAGNETITE-APATITE DEPOSITS ; RARE-EARTH-ELEMENT ; FRANCOIS MOUNTAINS TERRANE ; CARAJAS MINERAL PROVINCE ; EASTERN CHINA IMPLICATIONS ; HIGH-TEMPERATURE GASES ; BEAR MAGMATIC ZONE ; EL LACO VOLCANO
引用统计	被引频次：10[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/337002/181815
专题	深海极端环境与生命过程研究中心
通讯作者	Tornos, Fernando
作者单位	1.Inst Geociencias CSIC UCM, Dr Severo Ochoa 7, Madrid 28040, Spain 2.Mem Univ Newfoundland, Dept Earth Sci, St John, NF A1B 3X5, Canada 3.Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G2E3, Canada 4.Univ Complutense Madrid, Dept Petrol & Mineral, Madrid 28040, Spain 5.Chinese Acad Sci, Inst Oceanol, Ctr Deep Sea Res, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Tornos, Fernando,Hanchar, John M.,Steele-MacInnis, Matthew,et al. Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation[J]. MINERALIUM DEPOSITA,2023:37.
APA	Tornos, Fernando,Hanchar, John M.,Steele-MacInnis, Matthew,Crespo, Elena,Kamenetsky, Vadim S.,&Casquet, Cesar.(2023).Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation.MINERALIUM DEPOSITA,37.
MLA	Tornos, Fernando,et al."Formation of magnetite-(apatite) systems by crystallizing ultrabasic iron-rich melts and slag separation".MINERALIUM DEPOSITA (2023):37.