Insights into OIB-like magmatism contemporaneous with oceanic subduction: Petrogenetic constraints on the Kendelong metagabbro in the North Qaidam

Gao, Xinyu; Yu, Shengyao; Peng, Yanjun; Lv, Pei; Wang, Meng; Liu, Yongjiang; Li, Sanzhong; Jiang, Xingzhou; Ji, Wentao; Li, Chuanzhi

doi:10.1016/j.lithos.2021.106130

Cited by 13 publications

(6 citation statements)

References 108 publications

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“…The protoliths of Pianshishan retrograded eclogite-type rocks were classified as alkaline basalt series (Figure 5) and show enrichment in LREE and LILE without any negative Ta, Ti or Nb anomalies (Figure 6a, b), consistent with OIB geochemical signatures (X. Y. Gao et al, 2021).…”

Section: Magmatic Sourcementioning

confidence: 66%

Middle Triassic remnant of the Palaeo‐Tethys Ocean, central Tibet: Constraints from the Pianshishan retrograded eclogite‐type rocks

Sun

et al. 2022

Geological Journal

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The high‐pressure and low‐temperature metamorphic rocks constitute the important parts of the Longmu Co‐Shuanghu suture zone (LSS) in Tibet, providing a natural window for unveiling the tectonic evolution of the Palaeo‐Tethys Ocean. In this contribution, geochemical studies, including the whole‐rock geochemistry, Sr‐Nd isotopes and zircon U–Pb geochronology, were performed on the Pianshishan garnet amphibolites and retrograded eclogites, to reconstruct the genesis of the protoliths and to reveal tectonic evolution of the Longmu Co‐Shuanghu Palaeo‐Tethys Ocean (LSPTO). The garnet amphibolites show characteristics similar to the retrograded eclogites, representing different degrees of retrograde metamorphism of the Pianshishan eclogites. The protoliths of garnet amphibolites and retrograded eclogites are alkaline basalts, with geochemical characteristics similar to ocean island basalts (OIB) without Nb, Ta or Ti negative anomalies. Furthermore, geochemical data imply that the protoliths were formed by fractional crystallization of the magma derived from partial melting of garnet lherzolites without crustal contamination. The parental magma was probably generated in a relatively depleted but heterogeneous asthenosphere mantle source. Their protoliths erupted as a seamount within the LSPTO. Garnet amphibolites and retrograded eclogites yielded zircon U–Pb weighted mean ages of 240.2 ± 1.7 Ma and 239.1 ± 2.7 Ma, respectively. Combining with previous studies, we suggest that the LSPTO remained open in the Pianshishan area during the Middle Triassic, and the whole ocean might be gradually closed during the Early to Late Triassic. The small remnant ocean basin during the Middle Triassic can well explain a rapid evolution of the Pianshishan eclogite‐type rocks, that is, from generation to eclogite‐facies metamorphism and then to exhumation‐related retrograde metamorphism within ~19 Myr.

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Section: Magmatic Sourcementioning

confidence: 66%

Middle Triassic remnant of the Palaeo‐Tethys Ocean, central Tibet: Constraints from the Pianshishan retrograded eclogite‐type rocks

Sun

et al. 2022

Geological Journal

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“…(2018b, 2022) and Gao et al. (2021). AC–accretionary complex; FB–forearc basin; IA–intra‐oceanic arc.…”

Section: Geological Backgroundmentioning

confidence: 97%

“…This study mainly focuses on unit B within the Tanjianshan Group in the Tuomoerrite area. It is further subdivided, based on the rock assemblage and geochemical data, into three belts separated by thrust faults, namely 2015) and Fu et al (2022aFu et al ( , 2023; continental arc intrusive rocks are from Li et al (2018bLi et al ( , 2022 and Gao et al (2021). AC-accretionary complex; FB-forearc basin; IA-intra-oceanic arc.…”

Section: Field Geology and Petrographymentioning

confidence: 99%

Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau

Fu,

Yan,

Aitchison

et al. 2024

Earth and Space Science

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The possibility that the Proto‐Tethys Ocean may have undergone intra‐oceanic subduction during ocean closure remains poorly constrained due to a lack of geological evidence for a mature intra‐oceanic arc. Here we present new geochemical and geochronological data for potential arc‐related volcanic rocks adjacent to the accretionary complex and forearc basin in the North Qaidam collisional belt, northern Tibetan Plateau. The volcanic rocks are dominated by foliated basalt, andesite, tuff, and minor dacite with zircon U‐Pb ages ranging from 517 to 497 Ma. They show distinctive geochemical characteristics and can be subdivided into three groups: island‐arc intermediate‐basic volcanic rocks, back‐arc basin basalts (BABB), and dacites with intra‐oceanic arc affinity. The island‐arc volcanic rocks have variable εNd(t) values (+1.6 to +7.5) that decrease northward and were generated by partial melting of depleted mantle wedge modified by hydrous fluid and sediment melt. The BABBs have high εNd(t) values (+5.3 to +6.6) and formed through the melting of MORB‐like mantle, whereas the nearby dacites have positive εNd(t) values (+1.9 to +3.6) similar to the surrounding island‐arc volcanic rocks and were derived from partial melting of intra‐oceanic arc crust as a result of BABB underplating. Integrated analysis of the spatial‐temporal distribution of these volcanic rocks and the reconstructed intra‐oceanic arc‐trench system confirms the existence of the earliest Phanerozoic intra‐oceanic arc formed in response to north‐directed intra‐oceanic subduction. This unrecognized subduction of the Proto‐Tethys Ocean in the North Qaidam belt initiated at ca. 530 Ma, matured ca. 520 Ma, and terminated by ca. 480 Ma.

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“…Como demonstrado, a variação de elementos traço pode fornecer informações importantes sobre as características da fonte magmática, além de ser uma ferramenta de modelamento petrológico de corpos ígneos (e.g. Aldanmaz et al, 2006;Gao et al, 2021). Considerando a natureza relativamente primitiva desses magmas, estimar as condições de fusão parcial com base nesses elementos é uma alternativa para explicar a gênese das amostras mais primitivas (SiO 2 < 40%; MgO > 15%; Ni > 200 ppm).…”

Section: Gênese De Magma Por Fusão Parcial Em Equilíbriounclassified

Geologia e geoquímica do vulcanismo miocênico da região de Serra Preta, Pedro Avelino/RN, NE do Brasil

Oliveira

Souza

Vilalva

2022

Geol. USP. Sér. Cient.

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No nordeste brasileiro, sistemas vulcânicos de pequena escala constituem uma ampla província cenozoica tectono-magmática, o Alinhamento Macau-Queimadas, composto de rochas vulcânicas máficas alcalinas. O objetivo desta pesquisa foi caracterizar a petrogênese e o mecanismo de colocação de uma dessas ocorrências, localizada na borda sul da Bacia Potiguar. Para isso, são apresentados dados de mapeamento geológico, petrográficos e geoquímicos de rocha total. Na área estudada, três corpos vulcânicos ocorrem com diferentes geometrias. O mais expressivo tem alojamento magmático controlado tectonicamente, gerando um sistema de diques nas direções NNW-SSE e NE-SW. Petrograficamente, o conjunto mostra feições vulcânicas e intrusivas rasas, constituídas de olivina basaltos e nefelina microgabros. As fácies texturais observadas indicam resfriamento final em nível crustal raso de magmas alcalinos insaturados em sílica, gerando basanitos, melanefelinitos e olivina basaltos. Em termos litoquímicos, são rochas relativamente primitivas (#mg = 65–79), com baixo SiO2 (39–43%) e elevados MgO (12–19%) e Ni (> 200 ppm). Apresentam enriquecimento em terras raras leves (LaN/YbN ~ 35–17) e em elementos incompatíveis, destacando-se anomalias negativas de Rb, K e Hf. Modelamento geoquímico de óxidos com base em equações de balanço de massa e simulações com MELTS mostra taxa de cristalização de ~64% e cumulato composto de olivina, melilita, nefelina, magnetita, apatita e perovskita. Modelamento geoquímico de elementos traço para fusão parcial em equilíbrio sugere taxa de fusão menor que 5% de fonte do tipo granada-lherzolito enriquecido em elementos incompatíveis e contendo anfibólio e/ou flogopita. O mecanismo de colocação é associado à instabilidade do campo de tensões local no Mioceno, que reativou estruturas das unidades encaixantes favorecendo abertura de canais para escoamento de magmas de origem mantélica...

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Insights into OIB-like magmatism contemporaneous with oceanic subduction: Petrogenetic constraints on the Kendelong metagabbro in the North Qaidam

Cited by 13 publications

References 108 publications

Middle Triassic remnant of the Palaeo‐Tethys Ocean, central Tibet: Constraints from the Pianshishan retrograded eclogite‐type rocks

Middle Triassic remnant of the Palaeo‐Tethys Ocean, central Tibet: Constraints from the Pianshishan retrograded eclogite‐type rocks

Subduction Within the Proto‐Tethys Ocean Revealed by Recognition of the Earliest Phanerozoic Intra‐Oceanic Arc, Northern Tibetan Plateau

Geologia e geoquímica do vulcanismo miocênico da região de Serra Preta, Pedro Avelino/RN, NE do Brasil

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