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Article: Nature of parent rocks, mineralization styles and ore genesis of regolith-hosted REE deposits in South China: An integrated genetic model

TitleNature of parent rocks, mineralization styles and ore genesis of regolith-hosted REE deposits in South China: An integrated genetic model
Authors
KeywordsRegolith-hosted deposits
Ion-adsorption
Rare earth elements
South China
Granite
Weathering
Issue Date2017
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/jseaes
Citation
Journal of Asian Earth Sciences, 2017, v. 148, p. 65-95 How to Cite?
AbstractRegolith-hosted rare earth element (REE) deposits, also called ion-adsorption or weathered crust elution-deposited REE deposits are distributed over Jiangxi, Guangdong, Fujian, Hunan, Guangxi and Yunnan provinces in South China. In general, these deposits can be categorized into the HREE-dominated type, for example the famous Zudong deposit in southern Jiangxi province and the LREE-dominated type, such as the Heling and Dingnan deposits in southern Jiangxi province. Most of these deposits form from weathering of biotite and muscovite granites, syenites, monzogranites, granodiorites, granite porphyries, and rhyolitic tuffs. The parent rocks are generally peraluminous, siliceous, alkaline and contain a variety of REE-bearing minerals. Mostly, REE patterns of regolith are inherited from the parent rocks, and therefore, characteristics of the parent rocks impose a significant control on the ore formation. Data compilation shows that autometasomatism during the latest stage of granite crystallization is likely essential in forming the HREE-enriched granites, whereas LREE-enriched granites could form through magmatic differentiation. These deposits are normally two- to three-fold, but could be up to ten-fold enrichment in REE compared to the parent granites, where the maximum enrichment usually occurs from the lower B to the upper C horizon. Ce shows different behavior with the other REEs. Strongly positive Ce anomalies commonly occur at the upper part of weathering profiles, likely due to oxidation of Ce3+ to Ce4+ and removal of Ce from soil solutions through precipitation of cerianite. Vertical pH and redox gradients in weathering crusts facilitate dissolution of REE-bearing minerals at shallow level and fixation of REE at depth through either adsorption on clay minerals or precipitation of secondary minerals. At the same time, mass removal of major elements plays an important role in concentrating REE in regolith. Combination of mass removal and eluviation-illuviation dynamics is the main mechanism for REE accumulation in weathering crusts. Favorable exogenetic factors facilitate the accumulation of REE in regolith and preservation of the ore bodies. These include quasi-equilibrium between denudation and exhumation at regional scales, local geomorphology dominated by low-lying gentle slopes, adequate rainfall, and favorable groundwater conditions. Continuous operation of such a dynamic weathering system is essential in the formation of regolith-hosted REE deposits.
Persistent Identifierhttp://hdl.handle.net/10722/262321
ISSN
2017 Impact Factor: 2.866
2015 SCImago Journal Rankings: 1.393
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorLi, YH-
dc.contributor.authorZhao, W-
dc.contributor.authorZhou, MF-
dc.date.accessioned2018-09-28T04:57:19Z-
dc.date.available2018-09-28T04:57:19Z-
dc.date.issued2017-
dc.identifier.citationJournal of Asian Earth Sciences, 2017, v. 148, p. 65-95-
dc.identifier.issn1367-9120-
dc.identifier.urihttp://hdl.handle.net/10722/262321-
dc.description.abstractRegolith-hosted rare earth element (REE) deposits, also called ion-adsorption or weathered crust elution-deposited REE deposits are distributed over Jiangxi, Guangdong, Fujian, Hunan, Guangxi and Yunnan provinces in South China. In general, these deposits can be categorized into the HREE-dominated type, for example the famous Zudong deposit in southern Jiangxi province and the LREE-dominated type, such as the Heling and Dingnan deposits in southern Jiangxi province. Most of these deposits form from weathering of biotite and muscovite granites, syenites, monzogranites, granodiorites, granite porphyries, and rhyolitic tuffs. The parent rocks are generally peraluminous, siliceous, alkaline and contain a variety of REE-bearing minerals. Mostly, REE patterns of regolith are inherited from the parent rocks, and therefore, characteristics of the parent rocks impose a significant control on the ore formation. Data compilation shows that autometasomatism during the latest stage of granite crystallization is likely essential in forming the HREE-enriched granites, whereas LREE-enriched granites could form through magmatic differentiation. These deposits are normally two- to three-fold, but could be up to ten-fold enrichment in REE compared to the parent granites, where the maximum enrichment usually occurs from the lower B to the upper C horizon. Ce shows different behavior with the other REEs. Strongly positive Ce anomalies commonly occur at the upper part of weathering profiles, likely due to oxidation of Ce3+ to Ce4+ and removal of Ce from soil solutions through precipitation of cerianite. Vertical pH and redox gradients in weathering crusts facilitate dissolution of REE-bearing minerals at shallow level and fixation of REE at depth through either adsorption on clay minerals or precipitation of secondary minerals. At the same time, mass removal of major elements plays an important role in concentrating REE in regolith. Combination of mass removal and eluviation-illuviation dynamics is the main mechanism for REE accumulation in weathering crusts. Favorable exogenetic factors facilitate the accumulation of REE in regolith and preservation of the ore bodies. These include quasi-equilibrium between denudation and exhumation at regional scales, local geomorphology dominated by low-lying gentle slopes, adequate rainfall, and favorable groundwater conditions. Continuous operation of such a dynamic weathering system is essential in the formation of regolith-hosted REE deposits.-
dc.languageeng-
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/jseaes-
dc.relation.ispartofJournal of Asian Earth Sciences-
dc.subjectRegolith-hosted deposits-
dc.subjectIon-adsorption-
dc.subjectRare earth elements-
dc.subjectSouth China-
dc.subjectGranite-
dc.subjectWeathering-
dc.titleNature of parent rocks, mineralization styles and ore genesis of regolith-hosted REE deposits in South China: An integrated genetic model-
dc.typeArticle-
dc.identifier.emailZhao, W: zhaowen2@hku.hk-
dc.identifier.emailZhou, MF: mfzhou@hku.hk-
dc.identifier.authorityZhou, MF=rp00844-
dc.identifier.doi10.1016/j.jseaes.2017.08.004-
dc.identifier.hkuros293455-
dc.identifier.volume148-
dc.identifier.spage65-
dc.identifier.epage95-
dc.identifier.isiWOS:000413384800005-
dc.publisher.placeUnited Kingdom-

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