Reduction of buried oxidized oceanic crust during subduction

Liu, Yan; Santosh, M.; Yuan, Tingyuan; Li, Huaqi; Li, Tianfu

doi:10.1016/j.gr.2015.02.014

Cited by 20 publications

(9 citation statements)

References 67 publications

(12 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on our analysis of eastern SAB, this research considers that S-type granitoids with fractionated REE in the Early Devonian were emplaced mainly within the process of oceanic subduction (Figure 10e). Liu et al (2016) reported that a decrease of FeO T /MgO can verify a subduction setting, which could be further evidence of geotectonics in our study region (Table 2). In association with the subduction of Palaeo-Tethys Ocean since the Devonian (Dong et al, 2013;Li, 2018), the Early Devonian oceanic subduction in the eastern segment of the SAB might be related to the subduction of Palaeo-Tethys Ocean, and the granitoids emplaced during the Devonian were from the crustal collision occurred under the setting of oceanic subduction.…”

Section: Palaeozoic Tectonic Settingsupporting

confidence: 73%

“…Specifically, the new granitoid samples from eastern segment of SAB provide more in‐depth implications on the timing and tectonic setting for these magmatic suites in SAB. At the beginning of the Cambrian, the SACB subducted northward beneath the CACB and formed UHP eclogites and granites at about 500 Ma (Liu, Santosh, Yuan, Li, & Li, 2016); the South Altyn Ocean (SAO) underwent spreading and sinking (Figure 10a, b), forming granites with ages from 503 ± 2 to 497 ± 2 Ma at the SACB (Kang et al, 2013; Sun et al, 2012). During this time, the eclogites of SAB, with metamorphic ages of 493 and 499 Ma, imply the continental collision resulted from the northward subduction of SAB (Liu, Wang, Chen, Zhang, & Liou, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The reactivation of this orogenic belt led to the decompression melting of SAB and formed a minor amount of granitic plutons during the Middle Permian as well (Wu et al, 2008). According to the low ratios of FeO T /MgO (Berndt, 2004; Koepke et al, 2007; Liu et al, 2016), the S‐type granitoids of the east of SAB were derived from the melting of crust during the process of oceanic subduction (Figure 10e). The high‐Kcalc–alkaline series indicate a subduction and island arc origin (Defant & Drummond, 1990; Kay, 1978; Müller, Rock, & Groves, 1992).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Origin and tectonic implications of granitoids from the eastern segment of the South Altyn Block, North‐western China: Constraints from petrogeochemistry, zircon U–Pb dating, and Lu–Hf isotope geochemistry

et al. 2020

View full text Add to dashboard Cite

The South Altyn Block (SAB), located along the southern margin of the Altyn Tagh in Qaidam Basin, has a significant relationship with the tectonics of the Qaidam Basin basement. This study presents the petrological features, geochemical compositions, and zircon U-Pb and Hf isotope data of four granitic plutons from the eastern segment of the SAB to constrain the petrogenesis and tectonic setting of this region during the Palaeozoic. Basing on previous U-Pb dating results, the zircon U-Pb analysis in this study suggests that Palaeozoic magmatic events can be subdivided into four episodes: Late Cambrian (approximately 502 Ma), Late Ordovician (approximately 444 Ma), Early Devonian, and Middle Permian (approximately 271 Ma). The Palaeozoic granitoids were derived mainly from Neoproterozoic juvenile crustal components, with minor palaeoproterozoic ancient materials. The Sand I-type granitoids in Late Cambrian indicate a compressional tectonic environment with respect to subduction, and A-type granitoids suggest post-collision regime. The Late Ordovician granodiorites of A-type imply typical magmatism within a post-collision extensional setting. Ascribing to the subduction of Palaeo-Tethys Ocean during the Devonian, S-type granites were emplaced in the Early Devonian accompanied with the crust thickening. The Middle Permian magmatic events include a series of S-type granitoids, demonstrating the setting of oceanic subduction along with the closure of the Palaeo-Tethys Ocean.

show abstract

Section: Palaeozoic Tectonic Settingsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Origin and tectonic implications of granitoids from the eastern segment of the South Altyn Block, North‐western China: Constraints from petrogeochemistry, zircon U–Pb dating, and Lu–Hf isotope geochemistry

et al. 2020

View full text Add to dashboard Cite

show abstract

“…For example, the genesis of major Au and Au-rich Cu deposits in supra-subduction zone type environments requires oxidation of the mantle wedge (e.g. Mungall, 2002;Kerrich, Goldfarb & Richards, 2005;Liu et al 2016). The presence of two periods of Carlin-like Au Yan et al 2003;Faure et al 2014Faure et al , 2016bQiu, L. et al 2014.…”

Section: Introductionmentioning

confidence: 99%

Geochronology of early Mesozoic diabase units in southwestern China: metallogenic and tectonic implications

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Ferric iron is important to stabilize Fe 3+ ‐bearing minerals, such as epidote and amphibole, during pseudosection calculations. The Fe 3+ that is obtained by conventional methods, such as the wet chemistry method and point counting, may not be appropriate for intensive retrograde metamorphic rocks because late redox reactions and possible fluid circulation may significantly modify the oxidation state of the rock (Groppo & Castelli, ; Liu, Santosh, Yuan, Li, & Li, ). The possible redox reaction of the Pangna amphibole schists is ep (M1) +amp (M1) ±garnet−ep (M2) +amp (M2) +O 2 + H 2 O, along with decreasing oxygen fugacity (Figure ).…”

Section: Discussionmentioning

confidence: 99%

Pseudosection modelling and garnet Lu–Hf geochronology of HP amphibole schists constrain the closure of an ocean basin between the northern and southern Lhasa blocks, central Tibet

Cao

Hao

Zhang

2017

Journal Metamorphic Geology

View full text Add to dashboard Cite

The P-T-t path of high-P metamorphic rocks in subduction zones may reveal valuable information regarding the tectonic processes along convergent plate boundaries. Herein, we present a detailed petrological, pseudosection modelling and radiometric dating study of several amphibole schists of oceanic affinity from the Lhasa Block, Tibet. The amphibole schists experienced an overall clockwise P-T path that was marked by post-P max heating-decompression and subsequent isothermal decompression following the attainment of peak high-P and low-T conditions (~490°C and 1.6 GPa). Pseudosection modelling shows that the amphibole schists underwent water-unsaturated conditions during prograde metamorphism, and the stability field of the assemblage extends to lower temperatures and higher pressures within the water-unsaturated condition relative to water-saturated model along the prograde path. The high-P amphibole schists were highly reduced during retrograde metamorphism. Precise evaluation of the ferric iron conditions determined from the different compositions of epidote inclusions in garnet and matrix epidote is crucial for a true P-T estimate by garnet isopleth thermobarometry. Lu-Hf isotope analyses on garnet size separates from a garnet-bearing amphibole schist yield four two-point garnet-whole-rock isochron ages from 228.2 AE 1.2 Ma to 224.3 AE 1.2 Ma. These Lu-Hf dates are interpreted to constrain the period of garnet growth and approximate the timing of prograde metamorphism because of the low peak metamorphic temperature of the rock and the well-preserved Mn/Lu growth zoning in garnet. The majority of zircon U-Pb dates provide no constraints on the timing of metamorphism; however, two concordant U-Pb dates of 222.4 AE 3.9 Ma and 223.3 AE 4.2 Ma were obtained from narrow and uncommon metamorphic rims. Coexistence of zircon and sphene in the samples implies that the metamorphic zircon growth was likely assisted by retrogression of rutile to sphene during exhumation. The near coincident radiometric dates of zircon U-Pb and garnet Lu-Hf indicate rapid burial and exhumation of the amphibole schists, suggesting a closure time of c. 224-223 Ma for the fossil ocean basin between the northern and southern Lhasa blocks.

show abstract

Reduction of buried oxidized oceanic crust during subduction

Cited by 20 publications

References 67 publications

Origin and tectonic implications of granitoids from the eastern segment of the South Altyn Block, North‐western China: Constraints from petrogeochemistry, zircon U–Pb dating, and Lu–Hf isotope geochemistry

Origin and tectonic implications of granitoids from the eastern segment of the South Altyn Block, North‐western China: Constraints from petrogeochemistry, zircon U–Pb dating, and Lu–Hf isotope geochemistry

Geochronology of early Mesozoic diabase units in southwestern China: metallogenic and tectonic implications

Pseudosection modelling and garnet Lu–Hf geochronology of HP amphibole schists constrain the closure of an ocean basin between the northern and southern Lhasa blocks, central Tibet

Contact Info

Product

Resources

About