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Article: Late Paleoproterozoic to early Mesoproterozoic Dongchuan Group in Yunnan, SW China: Implications for tectonic evolution of the Yangtze Block

TitleLate Paleoproterozoic to early Mesoproterozoic Dongchuan Group in Yunnan, SW China: Implications for tectonic evolution of the Yangtze Block
Authors
KeywordsColumbia supercontinent
Continental rift
Dongchuan Group
Paleoproterozoic
Yangtze Block
Zircon
Issue Date2010
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/precamres
Citation
Precambrian Research, 2010, v. 182 n. 1-2, p. 57-69 How to Cite?
AbstractThe Dongchuan Group including the Yinmin, Luoxue, Etouchang, and Luzhijiang Formations from the base upward has extensive outcrops in the western Yangtze Block. It was previously thought to be the lower part of the late Mesoproterozoic to early Neoproterozoic Kunyang Group, but there was a lack of precise age determination. The whole sequence is more than 4. km in thickness and consists of conglomerate, sandstone, slate, dolostone, carbonaceous slate, and minor tuffaceous volcanic rocks. The basal unit, the Yinmin Formation, is a continental red-bed deposit thought to have been formed in an intra-continental rift basin.Zircons from the sandstone and volcanic rocks of the Yinmin Formation are analyzed for U-Pb and Lu-Hf isotopes in this study. Detrital zircons from the sandstone have U-Pb age populations at 1.8-1.9Ga, 2.25-2.35Ga, ~2.5Ga, and 2.7-2.9Ga with the oldest age of ~3.7Ga. Most zircons have high Th/U ratios (>0.1) and were probably derived from igneous rocks, whereas a few 2.05-1.95Ga grains with low Th/U ratios (<0.1) may have a metamorphic origin. The age groups are roughly consistent with those of known tectonothermal events in the northern Yangtze Block. The youngest detrital zircons of the Yinmin Formation have 207Pb/ 206Pb ages of ~1780Ma and dolerite dykes intruding the formation have a zircon 207Pb/ 206Pb age of 1690±32Ma (2σ). A zircon 207Pb/ 206Pb age of 1742±13Ma (2σ) was obtained from a tuff sample of the Yinmin Formation and is considered to represent the deposition age. In combination with other age data of the Dongchuan Group, the newly obtained U-Pb age data thus constrain the deposition of the Dongchuan Group to the period between ~1.7Ga and 1.5Ga, significantly older than previously thought. Presence of late Paleoproterozoic continental rift in the western Yangtze Block is contemporaneous with the break-up of the Columbia supercontinent, and provide further evidence to support the idea that the Yangtze Block was likely part of the supercontinent.Detrital zircons of the Yinmin Formation mostly have Hf continental modal ages (T DM C) between 3.5Ga and 2.6Ga with the oldest T DM C of 3.9Ga, indicating that the western Yangtze Block experienced significant continental crustal growth during the Paleo- to Neo-archean and contains Eoarchean crustal rocks. In combination with data from others, our results suggest that the Yangtze Block have a widespread Archean basement. The Archean zircons have both positive and negative e{open} Hf(t) values (-10.1 to +6.5) suggesting both juvenile crustal growth and reworking of older materials. In contrast, the Paleoproterozoic zircons have highly variable but mostly negative e{open} Hf(t) values implying episodic crustal reworking of Archean crustal rocks. Unlike the Paleoproterozoic detrital zircons, igneous zircons from the tuff and dolerite dyke samples mostly have positive e{open} Hf(t) values (-0.8 to +10.1), indicating contributions of juvenile materials from a depleted mantle source due to continental rifting. © 2010 Elsevier B.V.
Persistent Identifierhttp://hdl.handle.net/10722/124651
ISSN
2015 Impact Factor: 4.037
2015 SCImago Journal Rankings: 3.214
ISI Accession Number ID
Funding AgencyGrant Number
Council of Hong KongHKU7072/10P
CAS/SAFEAKZCX2-YVV-t004
State Key Lab of Geological Processes and Mineral ResourcesGPMR200710
Funding Information:

This study was supported by the Research Grant Council of Hong Kong (HKU7072/10P), CAS/SAFEA International Partnership Program for Creative Research Teams (KZCX2-YVV-t004), and an opening fund of the State Key Lab of Geological Processes and Mineral Resources (GPMR200710). We thank Mr. Zhanke Li, Xiaodong Deng and Shijian Bi for their assistance in the field and with the zircon U-Pb dating. We thank Prof. Paul Robinson and Prof. Jin-Hai Yu for reading an early draft of this paper and two anonymous reviewers and the editor, Prof. P.A. Cawood, for their insightful comments.

References

 

DC FieldValueLanguage
dc.contributor.authorZhao, XFen_HK
dc.contributor.authorZhou, MFen_HK
dc.contributor.authorLi, JWen_HK
dc.contributor.authorSun, Men_HK
dc.contributor.authorGao, JFen_HK
dc.contributor.authorSun, WHen_HK
dc.contributor.authorYang, JHen_HK
dc.date.accessioned2010-10-31T10:46:29Z-
dc.date.available2010-10-31T10:46:29Z-
dc.date.issued2010en_HK
dc.identifier.citationPrecambrian Research, 2010, v. 182 n. 1-2, p. 57-69en_HK
dc.identifier.issn0301-9268en_HK
dc.identifier.urihttp://hdl.handle.net/10722/124651-
dc.description.abstractThe Dongchuan Group including the Yinmin, Luoxue, Etouchang, and Luzhijiang Formations from the base upward has extensive outcrops in the western Yangtze Block. It was previously thought to be the lower part of the late Mesoproterozoic to early Neoproterozoic Kunyang Group, but there was a lack of precise age determination. The whole sequence is more than 4. km in thickness and consists of conglomerate, sandstone, slate, dolostone, carbonaceous slate, and minor tuffaceous volcanic rocks. The basal unit, the Yinmin Formation, is a continental red-bed deposit thought to have been formed in an intra-continental rift basin.Zircons from the sandstone and volcanic rocks of the Yinmin Formation are analyzed for U-Pb and Lu-Hf isotopes in this study. Detrital zircons from the sandstone have U-Pb age populations at 1.8-1.9Ga, 2.25-2.35Ga, ~2.5Ga, and 2.7-2.9Ga with the oldest age of ~3.7Ga. Most zircons have high Th/U ratios (>0.1) and were probably derived from igneous rocks, whereas a few 2.05-1.95Ga grains with low Th/U ratios (<0.1) may have a metamorphic origin. The age groups are roughly consistent with those of known tectonothermal events in the northern Yangtze Block. The youngest detrital zircons of the Yinmin Formation have 207Pb/ 206Pb ages of ~1780Ma and dolerite dykes intruding the formation have a zircon 207Pb/ 206Pb age of 1690±32Ma (2σ). A zircon 207Pb/ 206Pb age of 1742±13Ma (2σ) was obtained from a tuff sample of the Yinmin Formation and is considered to represent the deposition age. In combination with other age data of the Dongchuan Group, the newly obtained U-Pb age data thus constrain the deposition of the Dongchuan Group to the period between ~1.7Ga and 1.5Ga, significantly older than previously thought. Presence of late Paleoproterozoic continental rift in the western Yangtze Block is contemporaneous with the break-up of the Columbia supercontinent, and provide further evidence to support the idea that the Yangtze Block was likely part of the supercontinent.Detrital zircons of the Yinmin Formation mostly have Hf continental modal ages (T DM C) between 3.5Ga and 2.6Ga with the oldest T DM C of 3.9Ga, indicating that the western Yangtze Block experienced significant continental crustal growth during the Paleo- to Neo-archean and contains Eoarchean crustal rocks. In combination with data from others, our results suggest that the Yangtze Block have a widespread Archean basement. The Archean zircons have both positive and negative e{open} Hf(t) values (-10.1 to +6.5) suggesting both juvenile crustal growth and reworking of older materials. In contrast, the Paleoproterozoic zircons have highly variable but mostly negative e{open} Hf(t) values implying episodic crustal reworking of Archean crustal rocks. Unlike the Paleoproterozoic detrital zircons, igneous zircons from the tuff and dolerite dyke samples mostly have positive e{open} Hf(t) values (-0.8 to +10.1), indicating contributions of juvenile materials from a depleted mantle source due to continental rifting. © 2010 Elsevier B.V.en_HK
dc.languageengen_HK
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/precamresen_HK
dc.relation.ispartofPrecambrian Researchen_HK
dc.subjectColumbia supercontinenten_HK
dc.subjectContinental riften_HK
dc.subjectDongchuan Groupen_HK
dc.subjectPaleoproterozoicen_HK
dc.subjectYangtze Blocken_HK
dc.subjectZirconen_HK
dc.titleLate Paleoproterozoic to early Mesoproterozoic Dongchuan Group in Yunnan, SW China: Implications for tectonic evolution of the Yangtze Blocken_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0301-9268&volume=182&issue=1-2&spage=57&epage=69&date=2010&atitle=Late+Paleoproterozoic+to+early+Mesoproterozoic+Dongchuan+Group+in+Yunnan,+SW+China:+Implications+for+tectonic+evolution+of+the+Yangtze+Blocken_HK
dc.identifier.emailZhou, MF:mfzhou@hkucc.hku.hken_HK
dc.identifier.emailSun, M:minsun@hku.hken_HK
dc.identifier.authorityZhou, MF=rp00844en_HK
dc.identifier.authoritySun, M=rp00780en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.precamres.2010.06.021en_HK
dc.identifier.scopuseid_2-s2.0-77956186274en_HK
dc.identifier.hkuros181430en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77956186274&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume182en_HK
dc.identifier.issue1-2en_HK
dc.identifier.spage57en_HK
dc.identifier.epage69en_HK
dc.identifier.isiWOS:000282388100005-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridZhao, XF=49061648300en_HK
dc.identifier.scopusauthoridZhou, MF=7403506005en_HK
dc.identifier.scopusauthoridLi, JW=36067183300en_HK
dc.identifier.scopusauthoridSun, M=25932315800en_HK
dc.identifier.scopusauthoridGao, JF=25638167000en_HK
dc.identifier.scopusauthoridSun, WH=7404011340en_HK
dc.identifier.scopusauthoridYang, JH=35280993000en_HK
dc.identifier.citeulike7479895-

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