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Geochemical characteristics of magnetite in Longqiao skarn iron deposit in the Middle-Lower Yangtze Metallogenic Belt, Eastern China

Citation

Liu, Y and Fan, Y and Xiao, X and White, N and Thompson, Jay and Hong, H and Zhang, LJ, Geochemical characteristics of magnetite in Longqiao skarn iron deposit in the Middle-Lower Yangtze Metallogenic Belt, Eastern China, Mineralium Deposita, 24 pp. 1229-1242. ISSN 0026-4598 (2019) [Refereed Article]

Copyright Statement

Copyright 2019 Springer-Verlag GmbH Germany, part of Springer Nature

DOI: doi:10.1007/s00126-019-00871-x

Abstract

The Longqiao Fe deposit is the only large stratabound Fe skarn in Eastern China. This extensive ore body is suitable for investigating the spatial variations in trace elements in magnetite from the intrusion to the wall rocks and tracing the evolution of the mineralizing fluid in a skarn deposit. Magnetite samples were collected every 200 m from the ore-forming gabbro-diorite to the edge of the ore body, including the diopside-magnetite and epidote-chlorite-magnetite stages. Our results show that magnetite proximal to the gabbro-diorite displays lower Mg, Al, and Si and higher contents of Ti and V than those found further from the gabbro-diorite. The hydrothermal fluids in both diopside-magnetite and epidote-chlorite-magnetite stages were influenced by reaction with marine sedimentary rocks. Magnetites from different parts of the ore body display a wide range of trace element contents and fall into the porphyry and skarn fields on a (Mn + Al) vs. (Ti + V) discrimination diagram. Based on our results and published data, we propose that the early-stage magnetite from skarn and iron oxide-apatite (IOA) Fe deposits is compositionally similar, and fluid compositional variations are largely dependent on differences in the composition of the wall rock and the intensity of fluid-rock interactions. This results in a large variation in (Ti + V) in magnetite compositions from skarn deposits in the (Mn + Al) vs. (Ti + V) discrimination diagram, which is different from IOA deposits. This study shows that magnetite trace element evolution trends can provide a reliable indication to recognize skarn and IOA deposit types.

Item Details

Item Type:Refereed Article
Keywords:Eastern China, Longqiao Fe deposit, LA-ICP-MS, Magnetite, Skarn
Research Division:Earth Sciences
Research Group:Geology
Research Field:Resource geoscience
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Mineral exploration
Objective Field:Iron ore exploration
UTAS Author:White, N (Professor Noel White)
UTAS Author:Thompson, Jay (Mr Jay Thompson)
UTAS Author:Zhang, LJ (Dr Lejun Zhang)
ID Code:137498
Year Published:2019
Web of Science® Times Cited:8
Deposited By:CODES ARC
Deposited On:2020-02-17
Last Modified:2020-06-23
Downloads:0

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