Regional metamorphism at extreme conditions: Implications for orogeny at convergent plate margins

Zheng, Yong‐Fei; Chen, Ren‐Xu

doi:10.1016/j.jseaes.2017.03.009

Cited by 153 publications

(133 citation statements)

References 244 publications

Supporting

Mentioning

128

Contrasting

Order By: Relevance

“…In the second cycle, heating dominates the P–T evolution of the Tongbai granulites and UHT metamorphic conditions were even achieved locally. This indicates metamorphism at high thermal gradients in crustal levels shallower than the lower crust, which is common in extensional settings subsequent to delamination of orogenic roots (Zheng & Chen, ). UHT metamorphism can be produced by lithospheric extension in response to asthenospheric upwelling subsequent to lithospheric thinning (Currie & Hyndman, ; Gibson & Ireland, ; Zheng & Chen, ).…”

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

“…This indicates metamorphism at high thermal gradients in crustal levels shallower than the lower crust, which is common in extensional settings subsequent to delamination of orogenic roots (Zheng & Chen, ). UHT metamorphism can be produced by lithospheric extension in response to asthenospheric upwelling subsequent to lithospheric thinning (Currie & Hyndman, ; Gibson & Ireland, ; Zheng & Chen, ). In fact, foundering of orogenic roots through gravitational delamination of the lower continental crust or convective erosion of the asthenospheric mantle can lead to upwelling of the asthenospheric mantle for active rifting, supplying the high heat flow for UHT metamorphism (Zheng & Chen, , ).…”

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

“…UHT metamorphism can be produced by lithospheric extension in response to asthenospheric upwelling subsequent to lithospheric thinning (Currie & Hyndman, ; Gibson & Ireland, ; Zheng & Chen, ). In fact, foundering of orogenic roots through gravitational delamination of the lower continental crust or convective erosion of the asthenospheric mantle can lead to upwelling of the asthenospheric mantle for active rifting, supplying the high heat flow for UHT metamorphism (Zheng & Chen, , ). The HP metamorphism in the Tongbai granulites and UHP eclogite facies metamorphism in the Qinling eclogites suggests the existence of collision‐thickened orogens in both Tongbai and Qinling regions.…”

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

“…In particular, the delamination of orogenic roots exerts a profound influence on lithospheric thinning and its subsequent regional metamorphism and bimodal magmatism (e.g. Dewey, Ryan, & Andersen, ; Doblas & Oyarzun, ; Zheng & Chen, ). The later high‐/ultrahigh‐temperature (HT/UHT) metamorphism associated with this thinning in most cases has obscured or even obliterated records of the collisional orogeny.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Granulites record the tectonic evolution from collisional thickening to extensional thinning of the Tongbai orogen in central China

Zhang

Gao

Chen

et al. 2020

Journal Metamorphic Geology

View full text Add to dashboard Cite

A combined study of petrology and geochemistry was carried out for granulites from the Tongbai orogen in central China. The results reveal the tectonic evolution from collisional thickening to extensional thinning of the lithosphere at the convergent plate boundary. Petrographic observations, zircon U–Pb dating, and pseudosection calculations indicate that the granulites underwent four metamorphic stages, which are categorized into two cycles. The first cycle occurred at 490–450 Ma and involves high‐P (HP) metamorphism (M1) at 785–815°C and 10–14 kbar followed by decompressional heating to 840–880°C and 8–9 kbar for medium‐pressure granulite facies metamorphism (M2), defining a clockwise P–T path. The high pressure is indicated by the occurrence of inclusions of rutile+kyanite+K‐feldspar in the garnet mantle. The second cycle occurred at c. 440 Ma and shows an anticlockwise P–T path with continuous heating to ultrahigh‐temperature (UHT) metamorphism (M3) at 890–980°C and 9–11 kbar, followed by decompressional cooling to 740–880°C and 7–9 kbar (M4) till 405 Ma. The HP metamorphism is synchronous with the ultrahigh‐pressure eclogite facies metamorphism in the Qinling orogen, indicating its relevance to the continental collision in the Cambrian. The UHT metamorphism took place at reduced pressures, indicating thinning of the collision‐thickened orogenic lithosphere. Therefore, the Tongbai orogen was initially thickened by the collisional orogeny and then thinned, possibly as a result of foundering of the orogenic root. Such tectonic evolution may be common in collisional orogens where compression during continental collision switched to extension during continental rifting.

show abstract

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

Section: Implications For the Tectonic Evolution Of The Tongbai Orogenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Granulites record the tectonic evolution from collisional thickening to extensional thinning of the Tongbai orogen in central China

Zhang

Gao

Chen

et al. 2020

Journal Metamorphic Geology

View full text Add to dashboard Cite

show abstract

“…The first two episodes were most likely associated with the breakdown of phengite during decompressional exhumation (Chen et al, , ; Li et al, ; Zhao, Zheng, Chen, Xia, & Wu, ). In comparison, the second two episodes are likely to be associated with lithospheric extension (Liu, Robinson, et al, ; Liu, Robinson, & Liu, ), most likely as a thermal response to the thinning of a collision‐thickened region of the orogenic lithosphere (Zheng & Chen, ). The northeastern Sulu orogen contains widespread Jurassic granitoids that yield ages of 141–174 Ma (Jiang et al, ; Zhang et al, ; Zhao, Liu, et al, ; Zhao & Zheng, ), providing further evidence of a tectonothermal anomaly during this period.…”

Section: Implications For the Tectonic Evolution Of The Dabie–sulu Ormentioning

confidence: 99%

Migmatites record multiple episodes of crustal anatexis and geochemical differentiation in the Sulu ultrahigh‐pressure metamorphic zone, eastern China

Zhou

Chen

Zheng

et al. 2019

Journal Metamorphic Geology

View full text Add to dashboard Cite

Partial melting of ultrahigh‐pressure (UHP) metamorphic rocks is common during collisional orogenesis and post‐collisional reworking, indicating that determining the timing and processes involved in this partial melting can provide insights into the tectonic evolution of collisional orogens. This study presents the results of a combined whole‐rock geochemical and zirconological study of migmatites from the Sulu orogen in eastern China. These data provide evidence of multiple episodes of crustal anatexis and geochemical differentiation within the UHP metamorphic rocks. The leucosomes contain higher concentrations of Ba and K and lower concentrations of the rare earth elements (REE), Th and Y, than associated melanosomes and granitic gneisses. The leucosomes also have homogenous Sr–Nd–O isotopic compositions that are similar to proximal (i.e. within the same outcrop) melanosomes, suggesting that the anatectic melts were generated by the partial melting of source rocks that are located within individual outcrops. The migmatites contain zircons with six different types of domains that can be categorized using differences in structures, trace element compositions, and U–Pb ages. Group I domains are relict magmatic zircons that yield middle Neoproterozoic U–Pb ages and contain high REE concentrations. Group II domains represent newly grown metamorphic zircons that formed at 230 ± 1 Ma during the collisional orogenesis. Groups III, IV, V, and VI zircons are newly grown anatectic zircons that formed at 222 ± 2 Ma, 215 ± 1 Ma, 177 ± 2 Ma, and 152 ± 2 Ma, respectively. The metamorphic zircons have higher Th/U and lower (Yb/Gd)N values, flat heavy REE (HREE) patterns with no significantly negative Eu anomalies relative to the anatectic zircons, which are characterized by low Th/U ratios, steep HREE patterns, and negative Eu anomalies. The first two episodes of crustal anatexis occurred during the Late Triassic at c. 222 Ma and c. 215 Ma as a result of phengite breakdown. The other two episodes of anatexis occurred during the Jurassic period at c. 177 Ma and c. 152 Ma and were associated with extensional collapse of the collision‐thickened orogen. The majority of Triassic anatectic zircons and all of the Jurassic zircons are located within the leucosomes, whereas the melanosomes are dominated by Triassic metamorphic zircons, suggesting that the leucosomes within the migmatites record more episodes of crustal anatexis. Both metamorphic and anatectic zircons have elevated εHf(t) values compared with relict magmatic zircon cores, suggesting that these zircons contain non‐zircon Hf derived from material with more radiogenic Hf isotope compositions. Therefore, the Sulu and Dabie orogens experienced different episodes of reworking during the exhumation and post‐collisional stages.

show abstract

An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks

Lei

Chen

Wang

et al. 2023

Contrib Mineral Petrol

View full text Add to dashboard Cite

Regional metamorphism at extreme conditions: Implications for orogeny at convergent plate margins

Cited by 153 publications

References 244 publications

Granulites record the tectonic evolution from collisional thickening to extensional thinning of the Tongbai orogen in central China

Granulites record the tectonic evolution from collisional thickening to extensional thinning of the Tongbai orogen in central China

Migmatites record multiple episodes of crustal anatexis and geochemical differentiation in the Sulu ultrahigh‐pressure metamorphic zone, eastern China

An early Eocene magmatic event in southern Tibet triggered by oceanic slab break-off: evidence from ocean island basalt-like mafic rocks

Contact Info

Product

Resources

About