Syn-exhumation partial melting and melt segregation in the Sulu UHP terrane: Evidences from leucosome and pegmatitic vein of migmatite

Song, Yanru; Xu, Haijin; Zhang, Junfeng; Wang, Deyuan; Liu, Endong

doi:10.1016/j.lithos.2014.05.017

Cited by 37 publications

(28 citation statements)

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“…Summary of different partial melting events recorded in zircons from migmatite, leucosome, and pegmatite within the Sulu orogen. Reference data are from Liu, Robinson, et al (), Liu Robinson and Liu (), Li et al (), Li et al (), Xu et al (), and Song et al (). The UHP eclogite facies metamorphic ages of 225–240 Ma are after Zheng et al ()…”

Section: Discussionmentioning

confidence: 99%

“…Previous research on leucosomes within migmatites in the Sulu orogen suggests that plagioclase‐rich leucosomes were derived from the fractional crystallization of primary melts, whereas K‐feldspar‐rich leucosomes were produced by the later crystallization of residual hydrous melts (Song, Xu, Zhang, Wang, & Liu, ; Xu et al, ). The U–Pb dating of newly grown zircons from both types of leucosome yielded a significant age difference ( c. 10 Ma; Song et al, ; Xu et al, ). However, zircons from both types of leucosome of this study are near identical in terms of age and geochemical composition.…”

Section: Discussionmentioning

confidence: 99%

“…Liu, Robinson, & Liu, F I G U R E 1 1 The U-Pb ages for migmatites from the Weihai region of the Sulu orogen; grey bar denotes the weighted average value for each group of zircon in individual samples F I G U R E 1 2 Summary of different partial melting events recorded in zircons from migmatite, leucosome, and pegmatite within the Sulu orogen. Reference data are from Liu, Robinson, et al (2010), Liu Robinson andLiu (2012), Li et al (2013), Li et al (2016), Xu et al (2013), and Song et al (2014). The UHP eclogite facies metamorphic ages of 225-240 Ma are after Zheng et al (2009) 2012; Liu, Gao, et al, 2010).…”

Section: Frizsimonsmentioning

confidence: 99%

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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

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Frizsimonsmentioning

confidence: 99%

See 1 more Smart Citation

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

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“…8,9 and 15). Such fea tures are thought to de velop by recrystallisation in the pres ence of aque ous flu ids in deep-seated set tings, for instance dur ing late to post-mag matic cool ing (Pidgeon and Compston, 1992;Nemchin and Pidgeon, 1997;Schaltegger et al, 1999), due to meta mor phic recrystallisation in the solid state (Hoskin and Black, 2000;Corfu et al, 2003) or dur ing the par tial melt ing (Song et al, 2014). Youn ger ages in the range ~488-463 Ma for cores in such dou ble struc tured grains were likely due to alter ation caused by later Zr-car ry ing and sig nif i cantly U-en riched flu ids.…”

Section: Carboniferous Eventmentioning

confidence: 99%

An insight into a gneiss core of the Orlica-Śnieżnik Dome, NE Bohemian Massif: new structural and U–Pb zircon data

Redlińska-Marczyńska

Żelaźniewicz

Fanning

2016

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The Orlica-OEnie¿nik Dome in the Sudetes, the NE Bo he mian Mas sif, em braces two for ma tions of fel sic gneiss es of con trover sial or i gin and evo lu tion. Our study shows that de spite sim i lar geo chem i cal sig na tures, they carry sys tem atic mi nor dif ferences in min eral, iso tope, zir con and geothermobarometric char ac ter is tics. Four vari ants of the Giera³tów gneiss es in clude migmatites and have a lon ger struc tural his tory than the OEnie¿nik augen orthogneisses. U-Pb SHRIMP anal y ses yielded U-Pb ages of ~500 Ma for cores and ~498 Ma for wide outer parts of zir con grains in the twice-folded Giera³tów gneiss es, and an age of ~500 Ma for a dis cor dant neosome vein. Neoproterozoic meta sedi ments were among pre cur sors of the lithologically di ver si fied Giera³tów Gneiss For ma tion. First de for ma tion, meta mor phism, and migmatisation of these rocks oc curred at 515-475 Ma and over lapped with the de vel op ment and em place ment of a por phy ritic S-type gran ite pre cur sor to the OEnie¿nik Gneiss For ma tion. The metagranite (= OEnie¿nik augen orthogneiss) em braced migmatitic xe no liths. Zir con grains from such xe no liths re vealed dis torted and re placed cores which yielded U-Pb ages that dis persed around 507-487 Ma, whilst wide darker poorly zoned out growths yielded ages from ~343 Ma to ~325 Ma (mean ~340 Ma). These out growths were in ter preted as a re cord of Car bon if er ous meta mor phism as sisted by rich Zr-and U-car ry ing flu ids. The Variscan meta mor phic over print was het er o ge neous, and var i ously af fected rocks of the two gneiss for ma tions.

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“…One complicating factor in attempting to use an OEA's geochemistry to understand the chemical consequences of subduction is that it can be difficult to understand when a sample acquired its geochemical characteristics. Fluid circulation and partial melting are well known to occur during the exhumation of formerly subducted terranes (Song et al, 2014;Little et al, 2011) as well as during a sample's residence in the middle to upper crust of mountain belts (e.g., Miller et al, 1994), which can readily shift a sample's chemical and/or isotopic composition away from that acquired during subduction metamorphism.…”

Section: ■ Introductionmentioning

confidence: 99%

Lu-Hf and Sm-Nd geochronological constraints on the influence of subduction metamorphism in controlling the Hf-Nd terrestrial array: Evidence from the world’s orogenic belts

Zirakparvar

2019

Geosphere

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To create a better understanding of the influence of subduction metamorphism on the Hf-Nd terrestrial array, this study examines all of the available Lu-Hf and Sm-Nd garnet isochron ages from the world's orogenic eclogites and amphi bolites. The garnet isochron y-intercept values provide a record of each sample's epsilon Hf (ε Hf) and Nd (ε Nd) at the age recorded by the isochron, which in the case of most orogenic eclogites and amphibolites is the time of prograde metamorphism during subduction. It is further possible to assess the extent to which each sample's Lu-Hf and Sm-Nd isotope systematics have remained undisturbed since the date recorded by the isochron by comparison of the bulk-rock isotope systematics with the isochron initial value. This approach provides a means of understanding the Lu-Hf and Sm-Nd systematics of post-subduction metamorphic oceanic crust. On a global scale, the coupled Lu-Hf and Sm-Nd isotope systematics of this crust closely align with the Hf-Nd terrestrial array and have average 176 Lu/ 177 Hf and 147 Sm/ 144 Nd ratios within error of the chondritic uniform reservoir values. This is an important finding because it suggests that a reservoir of deeply subducted oceanic crust, possibly residing at the core-mantle boundary, is unlikely to be significantly fractionated from the Hf-Nd terrestrial array. In contrast to the samples of subduction-metamorphosed oceanic crust, metamorphic rocks with a continental crustal protolith demonstrate garnet isochron initial values and bulkrock Lu-Hf and Sm-Nd isotope systematics indicating significant decoupling from the Hf-Nd terrestrial array. However, because this material is not readily subducted, this strongly decoupled signature is unlikely to be transferred into deep Earth. Mixing calculations aimed at developing a clearer understanding of what factors control decoupling of a sample's Lu-Hf and Sm-Nd systematics from the Hf-Nd terrestrial array highlight the complexity of mass-transfer regimes operating in the subduction environment.

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Syn-exhumation partial melting and melt segregation in the Sulu UHP terrane: Evidences from leucosome and pegmatitic vein of migmatite

Cited by 37 publications

References 86 publications

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

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

An insight into a gneiss core of the Orlica-Śnieżnik Dome, NE Bohemian Massif: new structural and U–Pb zircon data

Lu-Hf and Sm-Nd geochronological constraints on the influence of subduction metamorphism in controlling the Hf-Nd terrestrial array: Evidence from the world’s orogenic belts

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