Zircon SHRIMP U–Pb dating for gneisses in northern Dabie high T/P metamorphic zone, central China: Implications for decoupling within subducted continental crust

Liu, Yi-Can; Li, Shuguang; Xu, Suo-Ping

doi:10.1016/j.lithos.2006.09.010

Cited by 113 publications

(101 citation statements)

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“…Both Triassic and early Cretaceous metamorphic zircon U-Pb ages from the retro-eclogites and granitic gneisses in the NDC (Xie et al, 2004a;Liu et al, 2007b;Zhao et al, 2007Zhao et al, , 2008, suggest that the NDC was importantly reworked in the early Cretaceous (Zhao et al, 2008). The P-T paths of the NDC also indicate that the overprinted UHT stage reflects the formation of the granulite symplectite assemblages in the early Cretaceous.…”

Section: Distinct P-t Conditions and P-t Paths Of The Ndc And Its Rewmentioning

confidence: 93%

“…In addition, a zircon U-Pb age of 191 ± 5 Ma for a tonalitic gneiss reported by Liu et al (2007b) may reflect a post-peak initial HP metamorphic event, whereas many inherited zircon cores of the Neoproterozoic ages of 700-800 Ma obtained from retroeclogites and various gneisses in the NDC (Xie et al, 2001(Xie et al, , 2004bLiu et al, 2007a,b;Wu et al, 2007;Zhao et al, 2007Zhao et al, , 2008, show protolith ages consistent with those of the UHP eclogites and gneisses in the CBD. They are mainly inherited magmatic zircon cores with ages mostly around 750 Ma, implying that their protolith formation was associated with the breakup of Rodinia supercontinent (Zhao et al, 2008;Zheng, 2008).…”

Section: Timing Of the Multiple Metamorphic Events Of The Ndcmentioning

confidence: 99%

“…Whereas an Sm-Nd isochron age of 136 ± 18 Ma for a mafic granulite from Huilanshan (Hou et al, 2005), a zircon U-Pb age of 128 ± 2 Ma for a gneiss (Xie et al, 2006), and zircon U-Pb ages of 130 Ma for a tonalitic gneiss (Liu et al, 2007b) and 126 ± 4 Ma to 131 ± 36 Ma for granitic gneisses (Zhao et al, 2008), together with zircon U-Pb ages of 145 ± 2 Ma to 120 ± 2 Ma for the migmatites , suggest that the NDC underwent an intense overprinting HT/UHT granulite facies metamorphism and migmatitization in the early Cretaceous ( 130 Ma).…”

Section: Timing Of the Multiple Metamorphic Events Of The Ndcmentioning

confidence: 99%

See 2 more Smart Citations

Diverse P–T paths of the northern Dabie complex in central China and its reworking in the early Cretaceous

Tong

Jahn

Zheng

2011

Journal of Asian Earth Sciences

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Section: Distinct P-t Conditions and P-t Paths Of The Ndc And Its Rewmentioning

confidence: 93%

Section: Timing Of the Multiple Metamorphic Events Of The Ndcmentioning

confidence: 99%

Section: Timing Of the Multiple Metamorphic Events Of The Ndcmentioning

confidence: 99%

See 1 more Smart Citation

Diverse P–T paths of the northern Dabie complex in central China and its reworking in the early Cretaceous

Tong

Jahn

Zheng

2011

Journal of Asian Earth Sciences

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“…The peak UHP metamorphism in the diamond stability field may have took place at 238-235 Ma [12]. In contrast, UHP metamorphism in the northern Dabie orogen occurred at ages as young as 226-214 Ma [7,51]. The Northern Dabie Complex shows typical structural characteristics of metamorphic core complexes [52], which could be comparable with the Tongbai Complex.…”

Section: Interpretation Of Diachroneity Along the Direction Of The Ormentioning

confidence: 99%

“…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 different HP/UHP slices. Similarly, three HP/UHP slices with different peak metamorphic ages were also recognized in the Dabie-Sulu orogen in the light of precise isotopic dating, and multi-slice or differential subduction/exhumation model was established accordingly [6][7][8][9][10][11][12]. It seems that the idea of differential subduction and exhumation of continental slab has been generally accepted for the formation and evolution of the UHP terranes in China [12].…”

mentioning

confidence: 99%

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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Chromium isotope signature during continental crust subduction recorded in metamorphic rocks

Shen

Liu

Qin

et al. 2015

Geochem Geophys Geosyst

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The chromium isotope compositions of 27 metamorphic mafic rocks with varying metamorphic degrees from eastern China were systematically measured to investigate the Cr isotope behavior during continental crust subduction. The Cr isotope compositions of all samples studied were Bulk Silicate Earth (BSE) like, with d 53 Cr NIST979 of greenschists, amphibolites, and eclogites ranging from 20.06& to 20.17&, 20.05& to 20.27&, and 20.01& to 20.24&, respectively. The lack of resolvable isotopic variability among the metamorphic rocks from different metamorphic zones indicated that no systematic Cr isotope fractionation was associated with the degree of metamorphism. However, the Cr isotopic variability among homologous samples may have reflected effects induced by metamorphic dehydration with a change of redox state, rather than protolith heterogeneity (i.e., magma differentiation). In addition, the differences in d 53 Cr (D 53 Cr Cpx-Gt ) between coexisting clinopyroxene (Cpx) and garnet (Gt) from two garnet pyroxenites were 0.06& and 0.34&, respectively, indicating that significant inter-mineral Cr isotope disequilibria could occur during metamorphism. To provide a basis for comparison with metamorphic rocks and to provide further constraints on the potential Cr isotope heterogeneity in the mantle and in the protolith of some metamorphic rocks, we analyzed mantle-derived chromites and the associated peridotites from Luobusa, and we obtained the following general order: chromite-free peridotites (20.21& to 20.11&) < chromite-bearing peridotite (20.07&) < chromite (20.06&). These findings imply potential mantle heterogeneity as a result of partial melting or fractional crystallization associated with chromite. Key Points:It is the first time to investigate Cr isotopic behaviors during subduction We obtain the limited Cr isotopic fractionation during metamorphic dehydration There are potential Cr isotopic fractionations between hightemperature minerals (2015), Chromium isotope signature during continental crust subduction recorded in metamorphic rocks, Geochem. PUBLICATIONSDue to the high compatibility of chromium during magma activity, ultramafic and mafic rocks are the major reservoirs of Cr in Bulk Silicate Earth (BSE) [Faure, 1991]. Schoenberg et al. [2008] first studied the Cr isotope compositions of a variety of mantle-derived rocks, including mantle xenoliths, ultramafic rocks, cumulates, and oceanic and continental basalts. The Cr isotope composition (d 53 Cr NIST979 ) of the investigated samples was in a limited range of 20.21& to 20.02& with an average value of 20.12 6 0.10& (2SD), implying that mantle-derived rocks have relatively homogenous Cr isotope compositions. Farka s et al. [2013] observed that the global igneous chromites have slightly heavier Cr isotope compositions with an average d 53 Cr NIST 979 value of 20.08 6 0.13& (2SD) compared with the BSE reported by Schoenberg et al. [2008] and then inferred that chromite-bearing mantle might be isotopically heavier than mantle without chromites. This phe...

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Zircon SHRIMP U–Pb dating for gneisses in northern Dabie high T/P metamorphic zone, central China: Implications for decoupling within subducted continental crust

Cited by 113 publications

References 71 publications

Diverse P–T paths of the northern Dabie complex in central China and its reworking in the early Cretaceous

Diverse P–T paths of the northern Dabie complex in central China and its reworking in the early Cretaceous

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

Chromium isotope signature during continental crust subduction recorded in metamorphic rocks

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