Transitional time of oceanic to continental subduction in the Dabie orogen: Constraints from U–Pb, Lu–Hf, Sm–Nd and Ar–Ar multichronometric dating

Hao, Changchun; King, Robert L.; Nakamura, Eizo; Vervoort, Jeffrey D.; Zheng, Yong‐Fei; Ota, Tsutomu; Wu, Ya‐Pan; Kobayashi, Katsura; Zhou, Zhiqiang

doi:10.1016/j.lithos.2009.01.013

Cited by 86 publications

(92 citation statements)

References 90 publications

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“…The conclusion is supported by the following two facts. (1) The garnet-whole rock Lu-Hf and Sm-Nd isochron ages of the oceanic-type eclogites from Xiongdian and adjacent area in the Hong'an orogen are concentrated to 271-252 Ma [26][27][28][29], which are later than the metamorphic zircon U-Pb ages of ~315 Ma obtained for the same eclogites [27,[30][31][32]. This suggests that these Carboniferous oceanic-type eclogites may have been reworked by continental subduction during the Late Permian.…”

Section: Interpretation Of Diachroneity Across the Direction Of The Omentioning

confidence: 94%

Diachroneity of continental subduction and exhumation: Constraints from the Permian-Triassic HP metamorphic terrane in the Tongbai orogen, central China

Liu

Jahn

2013

Chin. Sci. Bull.

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High-pressure (HP) metamorphic terrane in the Tongbai orogen comprises two HP slices (I and II) and a tectonic mélange zone in the northeast and a blueschist-greenschist zone in the southwest. HP slice I is represented by the northern and southern eclogite zones on the two sides of the Tongbaishan antiform. HP slice II is represented by retrograded eclogite-bearing metamorphic enclaves in Cretaceous gneissic granites in the Tongbai Complex. U-Pb, Lu-Hf, Rb-Sr and 40 Ar/ 39 Ar multichronometric data indicate that the peak metamorphism of HP slice I took place at ~255 Ma, whereas the metamorphic ages of HP slice II are as young as 232-220 Ma. By contrast, the tectonic mélange zone near the suture was metamorphosed at ~256 Ma. Such a diachroneity of different slices across the direction of the orogen in the Hong'an-Dabie-Sulu HP/UHP terrane is ubiquitous, and it can be interpreted by a syn-subduction detachment/exhumation model. Furthermore, the metamorphic age of HP slice I in the Tongbai orogen is older than that of the equivalent HP slice in the Hong'an orogen by ~15 Ma, suggesting that the diachroneity may have also existed along the direction of the orogen. A seesaw-type subduction/exhumation model is proposed to explain this age disparity and the subduction of the South China Block becomimg shallower towards the west. The processes and mechanism of exhumation of ultrahighpressure (UHP) metamorphic rocks to the Earth's surface from mantle depths exceeding ~100 km remain as one of the most difficult problems in earth science. It appears that a simple mechanism involving buoyancy and erosion is unable to explain the rapid exhumation required for the preservation of coesite. Much attention should be paid to the deepseated tectonic processes of continental slab. Based on the nature of structural contacts and existence of metamorphic gaps between different HP/UHP metamorphic units in the Dora Maira Massif of the western Alps, Chopin [1] andSchreyer [2] inferred that the end of the downgoing slab might have successively broken to several slices during its subduction along very low geothermal gradients (~7C/km). The earlier subducted slices could be uplifted as the overlying hanging-walls during the subduction of the later underlying slices. Liu and Hu [3] have formerly noticed the similarity of HP/UHP terrane from the Dabie Mountains and the Dora Maira Massif. Lately Liu et al. [4,5] distinguished UHP, HP and low-temperature (LT) HP slices and a tectonic mélange zone with the time difference of exhumation of ~30 Ma in the Hong'an orogen on the basis of thermobaric structure and geochronological data, and proposed a diachronous subduction/exhumation model for the formation of

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Section: Interpretation Of Diachroneity Across the Direction Of The Omentioning

confidence: 94%

Diachroneity of continental subduction and exhumation: Constraints from the Permian-Triassic HP metamorphic terrane in the Tongbai orogen, central China

Liu

Jahn

2013

Chin. Sci. Bull.

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“…Their results show that the protolith ages of the eclogites from Sujiahe and Hujiawan are about 406 ± 5 Ma-420 ± 7 Ma ( Figure 2), indicating their protoliths intruded in the late Silurian or early Devonian [21] . Cheng et al [67] reported similar LA-ICPMS zircon U-Pb ages for eclogite from the Xiongdian outcrop. The same results have also been obtained by others, but they were interpreted as eclogite-facies metamorphic ages [34,35,65] or detrital zircon ages [17] due to a lack of detailed studies of the genesis of the zircons.…”

Section: Age and Nature Of The Protoliths Of Eclogites In The Westernmentioning

confidence: 84%

“…2.0 GPa, and retrograde metamorphism of 530 -685℃ and 0.6 GPa [60,66,67] . They have quite different geochemical characteristics from those of the most exposed eclogites in the Dabie-Sulu orogen [64][65][66] .…”

Section: Age and Nature Of The Protoliths Of Eclogites In The Westernmentioning

confidence: 95%

“…Coesite has also been identified in zircon from regional granitic gneiss, indicating that they have experienced the same UHP metamorphism. In recent years, integrated studies of tectonic, petrology, isotope geochronology, and geochemistry reveal that the Qinling-Dabie-Sulu orogen has experienced a multistage amalgamation process, and is a typical multiple collision orogen [11][12][13]17,21,34,35,53,57,[62][63][64][65][66][67] .…”

Section: Geological Settingsmentioning

confidence: 99%

“…They have quite different geochemical characteristics from those of the most exposed eclogites in the Dabie-Sulu orogen [64][65][66] . Eclogites from Xiongdian, Hujiawan and Yangchong are characterized by MORB-like trace element, high ε Nd (t) (up to 6.6) and high δ 18 O values, implying that their protoliths might have been derived from the Paleotethyan ocean crust [64][65][66][67] . Li et al [64] have reported that some eclogites from the Hujiawan outcrop show variable enrichment in large-ion-lithophile (LIL) elements, depletion in highfield-strength (HFS) elements, and low ε Nd (t) values, with relatively old zircon U-Pb ages, and thus their protoliths were assumed as Late Proterozoic island arc basalt.…”

Section: Age and Nature Of The Protoliths Of Eclogites In The Westernmentioning

confidence: 99%

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Multistage evolution of continental collision orogen: A case study for western Dabie orogen

2009

Sci. Bull.

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Constraints on Lu‐Hf and Nb‐Ta systematics in globally subducted oceanic crust from a survey of orogenic eclogites and amphibolites

Zirakparvar

2016

Geochem Geophys Geosyst

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To further understand Lu‐Hf and Nb‐Ta systematics in globally subducted oceanic crust, this paper evaluates all available Lu‐Hf garnet isochron ages and initial ɛHf values in conjunction with present‐day bulk‐rock Lu‐Hf isotope and trace element (K, Nb, Ta, Zr, and Ti in addition to Lu‐Hf) data from the world's orogenic eclogites and amphibolites (OEAs). Approximately half of OEAs exhibit Lu‐Hf and Nb‐Ta systematics mimicking those of unsubducted oceanic crust whereas the rest exhibit variability in one or both systems. For the Lu‐Hf system, mixing calculations demonstrate that subduction‐related phase transformations, in conjunction with open system behavior, can shift subducted oceanic crust toward higher Lu/Hf, or toward lower Lu/Hf that can also be associated with unradiogenic ɛHf values. However, evaluation of potential mechanisms for fractionating Nb from Ta is more complicated because many of the OEAs have Nb‐Ta systematics that are decoupled from Lu‐Hf and the behavior of K, Zr, and Ti. Nonetheless, the global data set demonstrates that the association between unradiogenic ɛHf and elevated Nb/Ta observed in some kimberlitic eclogite xenoliths can be inherited from processes that occurred during subduction of their oceanic crustal protoliths. This allows for a geologically based estimate of the Nb concentration in a reservoir composed of deeply subducted oceanic crust. However, mass balance calculations confirm that such a reservoir, when considered as a whole, likely has a Nb concentration similar to unsubducted oceanic crust and is therefore not the solution to the problem of the Earth's “missing” Nb.

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Transitional time of oceanic to continental subduction in the Dabie orogen: Constraints from U–Pb, Lu–Hf, Sm–Nd and Ar–Ar multichronometric dating

Cited by 86 publications

References 90 publications

Diachroneity of continental subduction and exhumation: Constraints from the Permian-Triassic HP metamorphic terrane in the Tongbai orogen, central China

Diachroneity of continental subduction and exhumation: Constraints from the Permian-Triassic HP metamorphic terrane in the Tongbai orogen, central China

Multistage evolution of continental collision orogen: A case study for western Dabie orogen

Constraints on Lu‐Hf and Nb‐Ta systematics in globally subducted oceanic crust from a survey of orogenic eclogites and amphibolites

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