University of Tasmania
Browse

File(s) under permanent embargo

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

journal contribution
posted on 2023-05-20, 11:01 authored by Liu, Y, Fan, Y, Xiao, X, Noel WhiteNoel White, Thompson, Jay, Hong, H, Lejun ZhangLejun Zhang
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.

Funding

Hefei University of Technology

History

Publication title

Mineralium Deposita

Volume

24

Pagination

1229-1242

ISSN

0026-4598

Department/School

School of Natural Sciences

Publisher

Springer

Place of publication

United States

Rights statement

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

Repository Status

  • Restricted

Socio-economic Objectives

Iron ore exploration

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC