ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Geochemistry
Volume 13 - 2025 | doi: 10.3389/feart.2025.1576709
Geochemical characteristics of the Shuanghu crystalline graphite deposit in East China: Implications for original rocks, sedimentary environments and carbon sources
Provisionally accepted
- 1Geological Exploration Technology Institute of Jiangsu Province, Nanjing, Liaoning Province, China
- 2School of Earth Sciences and Engineering, Hohai University, Nanjing, Liaoning Province, China
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The Shuanghu crystalline graphite deposit, situated in the Sulu ultra-high pressure metamorphic belt, has received limited research attention. In this study, geochemical characteristics of this deposit were investigated to determine original rocks, sedimentary environments, carbon sources, and metallogenic processes. SiO2 (56.94% to 72.84%) and Al2O3 (9.7% to 13.29%) are enriched in graphite quartzite and granulite while CaO (21.89% to 42.56%) and MgO (5.56% to 18.4%) are enriched in (graphite-bearing) marbles. Ba and Nb are depleted to varying degrees in all rocks. In graphite quartzite and granulite, the Rb/Sr ratios are higher than the Sr/Ba ratios. All rocks are characterized by LREE enrichment and HREE depletion with negative Eu and Ce anomalies. The δ 13 C value of graphite in graphite quartzite (-31.2‰ to -30.2‰) is more negative than in graphite-bearing marble (-24.4‰ to -23.2‰) while the δ 13 C values of carbonates in (graphite-bearing) marbles approximate 0‰. The integrated geochemical data indicate initial deposition of this deposit occurred in coastal-neritic environments under oxygen-deficient conditions, with original rocks comprising argillaceous-sandy clastic rocks and carbonates. Carbon isotopic signatures suggest quartzite graphite originated solely from organic matter, whereas marble graphite resulted from a mixture of organic and minor carbonate-derived carbon. A three-stage metallogenic model for the Shuanghu crystalline graphite deposit was proposed: (1) late Proterozoic organic deposition, (2) Triassic metamorphic mineralization, (3) post-200 Ma tectonic activation. These findings enhance understanding of graphite genesis in the Sulu orogen and provides guidance for regional exploration strategies.
Keywords: Sulu orogenic zone, Graphite-bearing rocks, Geochemical characteristics, Original rocks, Ore genesis
Received: 14 Feb 2025; Accepted: 12 Jun 2025.
Copyright: © 2025 Liu, Rao, Zhang, Yao, Xu, Ren, Li and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Wenbo Rao, School of Earth Sciences and Engineering, Hohai University, Nanjing, 211100, Liaoning Province, China
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