New Lu–Hf geochronology constrains the onset of continental subduction in the Dabie orogen

Hao, Changchun; Zhang, Chao; Vervoort, Jeffrey D.; Wu, Yuan–Bao; Zheng, Yong‐Fei; Zheng, Shao-Hui; Zhou, Zhengchao

doi:10.1016/j.lithos.2010.10.004

Cited by 58 publications

(48 citation statements)

References 69 publications

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“…256 Ma (cf. Liu et al 2008a;Cheng et al 2011) by dating the UHP/HP eclogites with continental affinity with various geochronological methods, such as Sm-Nd, Lu-Hf, Ar-Ar, and U-Pb. However, the time of the oceanic subduction prior to the onset of continental subduction remains controversial because geochronology of the oceanic-type metamorphic rocks within this belt yielded Carboniferous U-Pb zircon ages Liu et al 2010;Cheng et al 2009) as well as Permian Lu-Hf and Sm-Nd ages (Cheng et al 2009(Cheng et al , 2013Brouwer et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Combined geochemistry and geochronology constrains coupled subduction of oceanic and continental crust in the Huwan shear zone, central China

Hao

Vervoort

2014

American Mineralogist

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Subduction of rocks into the mantle results in high-pressure metamorphism and the formation of eclogites from basaltic precursor rocks. In general, many kilometers of oceanic lithosphere are ultimately consumed prior to the subsequent continental slab subduction and collision. The exposure of the eclogites derived from oceanic subduction and continental subduction at the surface of Earth today record provide different P-T-t records of the subduction process. The Huwan shear zone in the Hong'an orogenic belt, marking a former ocean-continent transition zone, has been the focus of many studies on subduction-related high-pressure metamorphism. In this study, Lu-Hf garnet, U-Pb zircon, and ArAr mica ages are combined with geochemical data to understand the origin of two coexisting eclogite bodies exposed along the Xuehe River in the Huwan Shear zone. In total, the results indicate that the two eclogites have different protoliths but experienced a similar metamorphic history. This observation requires new tectonic model for the coupled subduction of oceanic and continental crust in subduction zones. Combined geochemistry and zircon U-Pb geochronology suggest distinct oceanic and continental affinities for the eclogite protoliths. The Lu-Hf dates of 261.5 ± 2.4 Ma of the continental-type eclogite and 262.7 ± 1.7 Ma of the oceanic-type eclogite reflect garnet growth and are interpreted to closely approximate the age of eclogite-facies metamorphism. Therefore, both the geochemically oceanic-and continental-type eclogites underwent the same episode of Permian eclogite-facies metamorphism. The Permian Lu-Hf ages of ca. 262 Ma and the obtained Triassic Ar-Ar ages (~240 Ma) of the oceanic-type and continental-type eclogites imply coupled subduction and exhumation of oceanic and continental crustal materials in the Hong'an orogenic belt during the Permian and the Triassic. Though limited, the geochemical and geochronological results of this study, together with the discrepant Carboniferous dates for the nearby eclogites of previous studies, apparently suggest that the Huwan shear zone was not always a single coherent unit but instead comprises different tectonic slices that were metamorphosed at different times before final assembly. Some slices of the oceanic and continental crust underwent two subduction cycles during the Carboniferous and the Permian, whereas some eclogites registered only a single subduction-exhumation loop during the convergence between the South China Block and the North China Block in the Huwan shear zone. The consistent ages of the oceanic-and continental-type eclogites disfavor the traditional mélange model that high-pressure rocks are dismembered fragments that have been assembled and intercalated with rocks devoid of any high-pressure history at shallow crustal levels, forming a tectonic mélange.

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Section: Introductionmentioning

confidence: 99%

Combined geochemistry and geochronology constrains coupled subduction of oceanic and continental crust in the Huwan shear zone, central China

Hao

Vervoort

2014

American Mineralogist

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“…The supporting evidence is summarized as follows. (1) Zircon U-Pb and mineral-whole-rock Rb-Sr isochron ages of continental-type eclogites in the Tongbai orogen are determined to be ~255 Ma , which has been confirmed by garnet-whole-rock Lu-Hf dating (Cheng et al, 2011). (2) As mentioned previously, although the metamorphism of the oceanic-type eclogites from Xiongdian eclogite belt in the Hong'an orogen was dated at ~310 Ma using zircon U-Pb method, the garnet-whole-rock Lu-Hf and Sm-Nd isochron or garnet-omphacite tie-line ages obtained for the same eclogites are concentrated to 270-250 Ma Cheng et al, 2009Cheng et al, , 2010bCheng et al, , 2013Cheng and Vervoort, 2015;Brouwer et al, 2011), suggesting that these oceanictype eclogites may have been reworked by later continental subduction.…”

Section: Latest Paleozoic-early Mesozoic Continental Subduction and Cmentioning

confidence: 84%

“…The peak P-T conditions of different eclogite zones are slight different, 530-560C and 2.0-2.2 GPa for the Qiliping eclogite zone, 490-510C and 1.9-2.0 GPa for the Qijiaoshan eclogite zone, and 460-560C and 1.3-1.9 GPa for the Shuanghezhen eclogite zone (Liu et al, 2004a. Similar to the case of the Hongyihe-Huwan HP eclogite zone, the metamorphic ages of eclogites from different localities are also different, ~255 Ma for those from Shuanghezhen Cheng et al, 2011) and ~240 Ma for those from Hong'an (Cheng et al, 2010a).…”

Section: Latest Paleozoic-mesozoic Collisional Orogenic Systemmentioning

confidence: 86%

“…Using conventional geothermobarometers, the peak metamorphic conditions were estimated to be 530-610°C and 1.7-2.0 GPa for the Hongyihe eclogite zone in the Tongbai area and 550-570C and 2.1 GPa for the Huwan eclogite zone in the Hong'an area (Liu et al, 2004a). Metamorphic ages are slightly different, ~255 Ma for the former Cheng et al, 2011) and ~240 Ma for the latter . In addition, oceanic-type eclogites were also found at Xiongdian, Hujiawan and Sujiahe in the northwestern corner of the Hong'an orogen.…”

Section: Latest Paleozoic-mesozoic Collisional Orogenic Systemmentioning

confidence: 99%

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Tectonic evolution of the Tongbai-Hong’an orogen in central China: From oceanic subduction/accretion to continent-continent collision

Liu

Jahn

2015

Sci. China Earth Sci.

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The Tongbai-Hong'an orogen is located in a key tectonic position linking the Qinling orogen to the west and the Dabie-Sulu orogen to the east. Because the orogen preserves a Paleozoic accretionary orogenic system in the north and a latest PaleozoicMesozoic collisional orogenic system in the south, it may serve as an ideal place to study the tectonic evolution between the North and South China Blocks. The available literature data in the past 20 years indicate that the tectonic processes of the Tongbai-Hong'an orogen involved four stages during the Phanerozoic: (1) Early Paleozoic (490-420 Ma) oceanic subduction, arc magmatism and arc-continent collision created a new Andean-type active continental margin on the North China Block; (2) Late Paleozoic (340-310 Ma) oceanic subduction and accretion generated separated paired metamorphic belts: a medium P/T Wuguan-Guishan complex belt in the south of the Shandan-Songpa fault and a high P/T Xiongdian eclogite belt in the northern edge of the Mesozoic HP metamorphic terrane; (3) Latest Paleozoic-Early Mesozoic (255-200 Ma) continental subduction and collision formed the Tongbai HP terrane in the west and the Hong'an HP/UHP terrane in the east as a consequence of deep subduction towards the east and syn-subduction detachment/exhumation of the down-going slab; (4) Late Mesozoic (140-120 Ma) extension, voluminous magma intrusion and tectonic extrusion led to the final exhumation of the Tongbai-Hong'an-Dabie HP/UHP terrane and the wedge-shaped architecture of the terrane narrowing towards the west. However, many open questions still remain about the details of each evolutionary stage and earlier history of the orogen. Besides an extensive study directly on the Tongbai-Hong'an orogen in the future, integrated investigation on the "soft-collisional" Qinling orogen in the west and the "hard-collisional" Dabie-Sulu orogen in the east is required to establish a general tectonic model for the whole Qinling-TongbaiHong'an-Dabie-Sulu orogenic belt. oceanic subduction, accretion, continental subduction, collision, Tongbai-Hong'an orogen Citation: Liu X C, Li S Z, Jahn B M. 2015. Tectonic evolution of the Tongbai-Hong'an orogen in central China: From oceanic subduction/accretion to continent-continent collision. Science China: Earth Sciences,Orogens lying at convergent plate margins can be divided into accretionary orogens and collisional orogens (Cawood et al., 2009). Accretionary orogens form through the continuing subduction of oceanic lithosphere and can be further grouped into retreating and advancing types. The former is represented by the trench-arc-basin system of the West Pacific, and the latter by the Andean orogenic belt of the East Pacific. Collisional orogens form through continent-continent collision at the termination of oceanic subduction. The most typical example is the Alpine-Himalayan orogenic belt.

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“…The garnet Sm–Nd ages in the east Dabie orogen (224–218 Ma; Cheng et al., ) are broadly consistent to those in the Sulu terrane, within analytical uncertainties. Several older garnet Lu–Hf dates from eclogites have also been reported in the west Dabie orogen (243–238 Ma; Cheng et al., ), and much older dates of 256–247 Ma (Cheng et al., ) in the Tongbai Mountains, farther west, have been interpreted to date the timing of onset of the continental collision. Based on available data from both Sulu and Dabie orogens, the garnet Lu–Hf dates become progressively older from the Sulu terrane towards the Dabie orogen in the west.…”

Section: Discussionmentioning

confidence: 99%

Integrated garnet and zircon–titanite geochronology constrains the evolution of ultra‐high–pressure terranes: An example from the Sulu orogen

Vervoort

Fisher

et al. 2019

Journal Metamorphic Geology

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Dating ultra‐high–pressure (UHP) metamorphic rocks provides important timing constraints on deep subduction zone processes. Eclogites, deeply subducted rocks now exposed at the surface, undergo a wide range of metamorphic conditions (i.e. deep subduction and exhumation) and their mineralogy can preserve a detailed record of chronologic information of these dynamic processes. Here, we present an approach that integrates multiple radiogenic isotope systems in the same sample to provide a more complete timeline for the subduction–collision–exhumation processes, based on eclogites from the Dabie–Sulu orogenic belt in eastern China, one of the largest UHP terranes on Earth. In this study, we integrate garnet Lu–Hf and Sm–Nd ages with zircon and titanite U–Pb ages for three eclogite samples from the Sulu UHP terrane. We combine this age information with Zr‐in‐rutile temperature estimates, and relate these multiple chronometers to different P–T conditions. Two types of rutile, one present as inclusions in garnet and the other in the matrix, record the temperatures of UHP conditions and a hotter stage, subsequent to the peak pressure (‘hot exhumation') respectively. Garnet Lu–Hf ages (c. 238–235 Ma) record the initial prograde growth of garnet, while coupled Sm–Nd ages (c. 219–213 Ma) reflect cooling following hot exhumation. The maximum duration of UHP conditions is constrained by the age difference of these two systems in garnet (c. 235–220 Ma). Complementary zircon and titanite U–Pb ages of c. 235–230 Ma and c. 216–206 Ma provide further constraints on the timing of prograde metamorphism and the ‘cold exhumation' respectively. We demonstrate that timing of various metamorphic stages can thus be determined by employing complementary chronometers from the same samples. These age results, combined with published data from adjacent areas, show lateral diachroneity in the Dabie–Sulu orogeny. Three sub‐blocks are thus defined by progressively younger garnet ages: western Dabie (243–238 Ma), eastern Dabie–northern Sulu (238–235 Ma) and southern Sulu terranes (225–220 Ma), which possibly correlate to different crustal slices in the recently proposed subduction channel model. These observed lateral chronologic variations in a large UHP terrane can possibly be extended to other suture zones.

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New Lu–Hf geochronology constrains the onset of continental subduction in the Dabie orogen

Cited by 58 publications

References 69 publications

Combined geochemistry and geochronology constrains coupled subduction of oceanic and continental crust in the Huwan shear zone, central China

Combined geochemistry and geochronology constrains coupled subduction of oceanic and continental crust in the Huwan shear zone, central China

Tectonic evolution of the Tongbai-Hong’an orogen in central China: From oceanic subduction/accretion to continent-continent collision

Integrated garnet and zircon–titanite geochronology constrains the evolution of ultra‐high–pressure terranes: An example from the Sulu orogen

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