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Article: Late Cryogenian magmatic activity in the North Lhasa terrane, Tibet: Implication of slab break-off process
Title | Late Cryogenian magmatic activity in the North Lhasa terrane, Tibet: Implication of slab break-off process |
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Authors | |
Keywords | East African Orogen Geochemistry and isotope North Lhasa terrane Tibet Zircon U–Pb dating |
Issue Date | 2019 |
Publisher | Elsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/jcr |
Citation | Gondwana Research, 2019, v. 71, p. 129-149 How to Cite? |
Abstract | The North Lhasa terrane in Tibet is generally interpreted to be paleotectonically unrelated to the East African Orogen (EAO) and is instead thought to have derived from northeastern India or northwestern Australia. In this study, we present petrogenetic and geochronological results pertaining to the analysis of gabbros (ca. 652 Ma), diorites (ca. 658 and 646 Ma), and tonalites (ca. 652 Ma) from the North Lhasa terrane. The gabbros are calc-alkaline and exhibit arc-like geochemical features. Low positive zircon ε Hf (t) values (+1.0 to +3.8), high zircon δ 18 O (6.25‰ to 7.94‰), and low negative whole-rock ε Nd (t) values (−3.5 to −1.4) indicate that the gabbros were derived from the lithospheric mantle, with geochemical modification by a subduction component. The diorite suite is characterized by a wide range of whole-rock chemistries (e.g., SiO 2 = 51.33–61.98 wt%) and Hf–O–Sr isotopic compositions (ε Hf (t) = −10.8 to −0.1; δ 18 O = 5.17‰ to 7.11‰; I Sr = 0.706 to 0.710), and negative whole-rock ε Nd (t) values (−7.0 to −4.7). These diorites are geochemically similar to OIB and are interpreted to be products of the partial melting of a relatively deep mantle source (>85 km) prior to extensive modification by continental crustal material. The tonalites are adakitic and have moderate Mg # values (47–54), low compatible element abundances, positive zircon ε Hf (t) values (+3.4 to +6.2), high I Sr values (0.714 to 0.715), and small negative whole-rock ε Nd (t) values (−1.6 to −0.4). These tonalites most likely formed by the melting of thickened Mesoproterozoic continental crust. The generation of these ca. 650 Ma magmatic rocks was related to slab break-off in a collision zone. By integrating the findings of previous studies with the data of the present study, we suggest that the North Lhasa terrane was most likely located in the northern segment of the EAO in paleotectonic reconstructions of the Gondwana supercontinent. © 2019 International Association for Gondwana Research |
Persistent Identifier | http://hdl.handle.net/10722/274961 |
ISSN | 2023 Impact Factor: 7.2 2023 SCImago Journal Rankings: 1.742 |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Hu, P.Y. | - |
dc.contributor.author | Zhai, G | - |
dc.contributor.author | Zhao, G | - |
dc.contributor.author | Wang, J | - |
dc.contributor.author | Tang, Y | - |
dc.contributor.author | Wang, H | - |
dc.contributor.author | Zhu, Z | - |
dc.contributor.author | Wu, H | - |
dc.contributor.author | Wang, W | - |
dc.contributor.author | Huang, Z | - |
dc.date.accessioned | 2019-09-10T02:32:29Z | - |
dc.date.available | 2019-09-10T02:32:29Z | - |
dc.date.issued | 2019 | - |
dc.identifier.citation | Gondwana Research, 2019, v. 71, p. 129-149 | - |
dc.identifier.issn | 1342-937X | - |
dc.identifier.uri | http://hdl.handle.net/10722/274961 | - |
dc.description.abstract | The North Lhasa terrane in Tibet is generally interpreted to be paleotectonically unrelated to the East African Orogen (EAO) and is instead thought to have derived from northeastern India or northwestern Australia. In this study, we present petrogenetic and geochronological results pertaining to the analysis of gabbros (ca. 652 Ma), diorites (ca. 658 and 646 Ma), and tonalites (ca. 652 Ma) from the North Lhasa terrane. The gabbros are calc-alkaline and exhibit arc-like geochemical features. Low positive zircon ε Hf (t) values (+1.0 to +3.8), high zircon δ 18 O (6.25‰ to 7.94‰), and low negative whole-rock ε Nd (t) values (−3.5 to −1.4) indicate that the gabbros were derived from the lithospheric mantle, with geochemical modification by a subduction component. The diorite suite is characterized by a wide range of whole-rock chemistries (e.g., SiO 2 = 51.33–61.98 wt%) and Hf–O–Sr isotopic compositions (ε Hf (t) = −10.8 to −0.1; δ 18 O = 5.17‰ to 7.11‰; I Sr = 0.706 to 0.710), and negative whole-rock ε Nd (t) values (−7.0 to −4.7). These diorites are geochemically similar to OIB and are interpreted to be products of the partial melting of a relatively deep mantle source (>85 km) prior to extensive modification by continental crustal material. The tonalites are adakitic and have moderate Mg # values (47–54), low compatible element abundances, positive zircon ε Hf (t) values (+3.4 to +6.2), high I Sr values (0.714 to 0.715), and small negative whole-rock ε Nd (t) values (−1.6 to −0.4). These tonalites most likely formed by the melting of thickened Mesoproterozoic continental crust. The generation of these ca. 650 Ma magmatic rocks was related to slab break-off in a collision zone. By integrating the findings of previous studies with the data of the present study, we suggest that the North Lhasa terrane was most likely located in the northern segment of the EAO in paleotectonic reconstructions of the Gondwana supercontinent. © 2019 International Association for Gondwana Research | - |
dc.language | eng | - |
dc.publisher | Elsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/jcr | - |
dc.relation.ispartof | Gondwana Research | - |
dc.subject | East African Orogen | - |
dc.subject | Geochemistry and isotope | - |
dc.subject | North Lhasa terrane | - |
dc.subject | Tibet | - |
dc.subject | Zircon U–Pb dating | - |
dc.title | Late Cryogenian magmatic activity in the North Lhasa terrane, Tibet: Implication of slab break-off process | - |
dc.type | Article | - |
dc.identifier.email | Zhao, G: gzhao@hku.hk | - |
dc.identifier.authority | Zhao, G=rp00842 | - |
dc.description.nature | link_to_subscribed_fulltext | - |
dc.identifier.doi | 10.1016/j.gr.2019.02.005 | - |
dc.identifier.scopus | eid_2-s2.0-85063099665 | - |
dc.identifier.hkuros | 302987 | - |
dc.identifier.volume | 71 | - |
dc.identifier.spage | 129 | - |
dc.identifier.epage | 149 | - |
dc.identifier.isi | WOS:000486980900008 | - |
dc.publisher.place | Netherlands | - |
dc.identifier.issnl | 1342-937X | - |