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Article: Syn-tectonic fluids decoding effects of tectono-metamorphic cycles on regional metallogenic evolution of the Chinese Altai, central Asia

TitleSyn-tectonic fluids decoding effects of tectono-metamorphic cycles on regional metallogenic evolution of the Chinese Altai, central Asia
Authors
Issue Date10-Aug-2023
PublisherGeological Society of America
Citation
GSA Bulletin, 2023 How to Cite?
Abstract

Despite their close temporal and spatial relationships, the effects of tectono-thermal events on ore formation remain obscure. To better understand this process, a comprehensive geochemical investigation on paleofluids from syn-tectonic felsic and quartz veins associated with the Devonian subduction and Permian collision of the Chinese Altai was conducted. We found that the Devonian fluids were organic alkanes-CO2-S-Ca-Mg-rich saline fluids with variable CO2/CH4 (0.09−5.03) and lower F/SO42− (0.02−0.14) and Al3+/Mg2+ (0−0.11) ratios, whereas the Permian fluids were immiscible fluids including CO2-C4H10-CO-rich oxidized gas bubbles and CH4-C3H8-C2H6-Ca-Na-K-Al-S-Cl-F-rich reduced saline fluids with lower CO2/CH4 (0−1.31, mostly <1) and higher F/SO42− (0.21−0.76) and Al3+/Mg2+ (0.10−2.56) ratios. The Devonian and Permian fluids also have similar δ13C-CO2 values of −23.8‰ to −3.5‰ and −16.5‰ to −3.7‰, respectively. These data suggest that both fluids derived mainly from devolatilization and dehydration melting of metasediments; the Permian fluids likely involve more biotite melting in the deeper crust and more mantle-derived components, whereas the Devonian fluids contain more meteoric components. Base metal-dominated Devonian mineralization occurred as deep-sourced organic matter- and S-rich fluids promoted base metal migration, whereas the relatively oxidized fluid conditions inhibited the mineralization of many other metals. By contrast, the more reduced and F-rich Permian fluids with more mantle contributions facilitated the extraction of Au and uptakes of rare metals from reworked metasediments and promoted their mineralization. These findings provide a more complete picture of how tectono-thermal events fertilize the crust and demonstrate that syn-tectonic fluids can serve as proxies for metallogenic processes during orogenic cycles in general.


Persistent Identifierhttp://hdl.handle.net/10722/331754
ISSN
2023 Impact Factor: 3.9
2023 SCImago Journal Rankings: 1.770

 

DC FieldValueLanguage
dc.contributor.authorXiao, Ming-
dc.contributor.authorJiang, Yingde-
dc.contributor.authorZhao, Guochun-
dc.contributor.authorYuan, Chao-
dc.contributor.authorCai, Yue-
dc.contributor.authorQiu, Huaning-
dc.contributor.authorHao, Lulu-
dc.contributor.authorZhang, Wanfeng-
dc.contributor.authorKong, Lingzhu-
dc.date.accessioned2023-09-21T06:58:38Z-
dc.date.available2023-09-21T06:58:38Z-
dc.date.issued2023-08-10-
dc.identifier.citationGSA Bulletin, 2023-
dc.identifier.issn0016-7606-
dc.identifier.urihttp://hdl.handle.net/10722/331754-
dc.description.abstract<p>Despite their close temporal and spatial relationships, the effects of tectono-thermal events on ore formation remain obscure. To better understand this process, a comprehensive geochemical investigation on paleofluids from syn-tectonic felsic and quartz veins associated with the Devonian subduction and Permian collision of the Chinese Altai was conducted. We found that the Devonian fluids were organic alkanes-CO<sub>2</sub>-S-Ca-Mg-rich saline fluids with variable CO<sub>2</sub>/CH<sub>4</sub> (0.09−5.03) and lower F<sup>−</sup>/SO<sub>4</sub><sup>2−</sup> (0.02−0.14) and Al<sup>3+</sup>/Mg<sup>2+</sup> (0−0.11) ratios, whereas the Permian fluids were immiscible fluids including CO<sub>2</sub>-C<sub>4</sub>H<sub>10</sub>-CO-rich oxidized gas bubbles and CH<sub>4</sub>-C<sub>3</sub>H<sub>8</sub>-C<sub>2</sub>H<sub>6</sub>-Ca-Na-K-Al-S-Cl-F-rich reduced saline fluids with lower CO<sub>2</sub>/CH<sub>4</sub> (0−1.31, mostly <1) and higher F<sup>−</sup>/SO<sub>4</sub><sup>2−</sup> (0.21−0.76) and Al<sup>3+</sup>/Mg<sup>2+</sup> (0.10−2.56) ratios. The Devonian and Permian fluids also have similar δ<sup>13</sup>C-CO<sub>2</sub> values of −23.8‰ to −3.5‰ and −16.5‰ to −3.7‰, respectively. These data suggest that both fluids derived mainly from devolatilization and dehydration melting of metasediments; the Permian fluids likely involve more biotite melting in the deeper crust and more mantle-derived components, whereas the Devonian fluids contain more meteoric components. Base metal-dominated Devonian mineralization occurred as deep-sourced organic matter- and S-rich fluids promoted base metal migration, whereas the relatively oxidized fluid conditions inhibited the mineralization of many other metals. By contrast, the more reduced and F-rich Permian fluids with more mantle contributions facilitated the extraction of Au and uptakes of rare metals from reworked metasediments and promoted their mineralization. These findings provide a more complete picture of how tectono-thermal events fertilize the crust and demonstrate that syn-tectonic fluids can serve as proxies for metallogenic processes during orogenic cycles in general.<br></p>-
dc.languageeng-
dc.publisherGeological Society of America-
dc.relation.ispartofGSA Bulletin-
dc.titleSyn-tectonic fluids decoding effects of tectono-metamorphic cycles on regional metallogenic evolution of the Chinese Altai, central Asia-
dc.typeArticle-
dc.identifier.doi10.1130/B36903.1-
dc.identifier.eissn1943-2674-
dc.identifier.issnl0016-7606-

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