Mantle transition zone-derived EM1 component beneath NE China: Geochemical evidence from Cenozoic potassic basalts

Xiao-jun, Wang; Chen, Li‐Hui; Hofmann, Albrecht W.; Mao, Fu-Gen; Liu, Jianqiang; Zhong, Yuan; Xie, Lie‐Wen; Yang, Yue‐Heng

doi:10.1016/j.epsl.2017.02.028

Cited by 149 publications

(110 citation statements)

References 85 publications

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“…Variation in the Sr, Nd, Pb, and Hf isotopic composition of the Huihe nephelinites. Data for Cenozoic basalts in Eastern China are shown for comparison (NE China: Basu et al, ; Chu et al, ; Kuritani et al, ; Liu, Chen, et al, ; Rasskazov et al, ; Sun, Teng, et al, ; Sun et al, ; Wang et al, ; Yan & Zhao, ; Yan et al, ; Zhang et al, ; Zhang et al, ; Zhao et al, ; Zou et al, ; Zou et al, . North China: Basu et al, ; Chen et al, ; Choi et al, ; Guo et al, ; Han et al, ; Ho et al, ; Li, Ma, et al, ; Wang et al, ; Xu et al, ; Yu et al, ; Zeng et al, ; Zhang et al, ; Zhang et al, ; Zou et al, .…”

Section: Whole‐rock Compositions Of the Huihe Nephelinitesmentioning

confidence: 99%

“…Sedimentary carbonates have extremely light Mg isotopic compositions (δ 26 Mg = −5.57‰ to −0.38‰; Huang, Ke, et al, ; Wombacher et al, ; Young & Galy, ). Light Mg isotopic signatures of basalts have therefore been widely interpreted to reflect contributions from this isotopically light component in the form of recycled carbonates in their mantle sources (e.g., Huang, Li, et al, ; Li et al, ; Wang et al, ; Yang et al, ). Melts with light Mg isotopic signature, but low or moderately low CaO contents, however, cannot be produced by direct partial melting of carbonate‐bearing source rocks (Wang et al, ).…”

Section: Nature Of the Light Mg Isotope Mantle Componentmentioning

confidence: 99%

“…Heavy δ 66 Zn signatures (δ 66 Zn = 0.30‰ to 0.63‰; Liu et al, ) of the basalts, compared to peridotite mantle values (δ 66 Zn = 0.16 ± 0.06‰; Sossi et al, ), reflect contributions from isotopically heavy subducted carbonated material (average δ 66 Zn = 0.91 ± 0.47‰; Pichat et al, ). Highly variable but consistently light Mg isotopic compositions of these rocks (δ 26 Mg = −0.60‰ to −0.25‰; Huang, Li, et al, ; Tian et al, ; Wang et al, ; Yang et al, ; Li et al, ; Yu et al, ) are also usually attributed to recycled sedimentary carbonates (with extremely light Mg isotopic compositions; δ 26 Mg = −5.57‰ to −0.38‰; Huang, Ke, et al, ; Wombacher et al, ; Young & Galy, ) in the mantle sources.…”

Section: Introductionmentioning

confidence: 99%

“…The region above this stagnant slab has been termed the “Big Mantle Wedge” (BMW; Zhao et al, ), which extends to over 1,000 km from the trench, where the BMW and the crustal section above are considered as an intraplate setting (Xu et al, ). Cenozoic basalts occurring to the east of the DTGL in eastern China have consistently light Mg isotopic compositions and define a large low δ 26 Mg anomaly within the BMW (δ 26 Mg = −0.60‰ to −0.34‰; Huang, Li, et al, ; Tian et al, ; Wang et al, ; Yang et al, ; Sun, Teng, et al, ; Su et al, ; Li et al, ). Basalts erupted at Chaihe in the nearby DTGL area (Figure a), in contrast, show terrestrial, mantle‐like Mg isotopic composition (δ 26 Mg = −0.34‰ to −0.19‰; Li et al, ; Sun, Teng, et al, ), which may suggest a spatial relationship between the large‐scale Mg isotopic anomaly and the stagnant Pacific slab or the BMW beneath eastern Asia (Li et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Light Mg Isotopic Composition in the Mantle Beyond the Big Mantle Wedge Beneath eastern Asia

Chen

Shi

et al. 2019

JGR Solid Earth

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Low‐δ26Mg basalts are commonly interpreted to represent melts derived from carbonated mantle sources. The mantle domain feeding low‐δ26Mg Cenozoic basalts in eastern China overlaps the so‐called Big Mantle Wedge (BMW) above the stagnant Pacific slab in the mantle transition zone, which indicates that the BMW is an important carbon reservoir generated by the slab. However, Mg isotopic composition in the nearby mantle beyond the BMW and, thus, the spatial extent of carbonated components in the mantle beneath eastern Asia have not yet been extensively characterized. Therefore, it remains largely unconstrained if additional or alternative carbon reservoirs exist. Here we carried out a geochemical study on Cenozoic Huihe nephelinites, which crop out ~500 km west of the present‐day BMW. These rocks are characterized by negative K, Zr, Hf, and Ti anomalies, high Zr/Hf, Ca/Al ratios, and low δ26Mg values, which suggest that they are derived from a carbonated mantle source. The composition of the nephelinites demonstrates that low δ26Mg mantle components exist at significant distances from the present‐day BMW, which highlights that in addition to the stagnant Pacific slab, other oceanic slab(s) also contribute(s) carbonate‐bearing crustal materials to the mantle sources of Cenozoic volcanism in eastern Asia.

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Section: Whole‐rock Compositions Of the Huihe Nephelinitesmentioning

confidence: 99%

Section: Nature Of the Light Mg Isotope Mantle Componentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Light Mg Isotopic Composition in the Mantle Beyond the Big Mantle Wedge Beneath eastern Asia

Chen

Shi

et al. 2019

JGR Solid Earth

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“…Low S and P wave velocity anomalies extend from the top of the mantle transition zone, and possibly from the deep mantle, to several of the Cenozoic volcanic centers (e.g., at Changbaishan, Wudalianchi, Halaha; Figure a), suggesting a close relation between the mantle transition zone and the wide‐spread volcanism (Chen et al, ; Huang & Zhao, ; Kimura et al, ; Tang et al, ; Wei et al, ; Zhao, ). Many geochemical studies have further shown that enriched mantle components play an important role in the formation of the magmas, which are thought to derive from the stagnant Pacific slab and/or from ancient subducted slabs (Kimura et al, ; Kuritani et al, , ; Tang et al, ; Wang et al, ; Xu et al, ).…”

Section: Introductionmentioning

confidence: 99%

Hot, volatile‐poor, and oxidized magmatism above the stagnant Pacific plate in Eastern China in the Cenozoic

Erdmann

Chen

Liu

et al. 2019

Geochem Geophys Geosyst

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Eastern China has experienced widespread and voluminous, basaltic to andesitic intraplate magmatism in the Cenozoic. Seismic tomography and kinematic reconstructions show that magmas have erupted above the stagnant Pacific plate, which currently extends within the mantle transition zone for >1500 km beyond the active arc. Seismic studies also show in intriguing detail that low‐velocity wave anomalies reach from the mantle transition zone or below to major volcanic centers, suggesting an intimate relation between the magmatism and components derived from the mantle‐transition zone and possibly from deeper levels. Here, we provide new petrological, mineral chemical, and whole‐rock geochemical data showing that Cenozoic basaltic andesitic and andesitic magmas that have erupted above the present‐day edge of the subducted Pacific plate are largely unfractionated, ≥1130‐1160±15‐50 °C hot, mantle‐derived melts that were volatile‐poor (undegassed melt CO2 and H2O of ~2400‐3100±500 ppm and ~0.5‐0.6±0.4‐1.1 wt%), and relatively oxidized (~FMQ to ~FMQ+1.3±1.0). We further infer that the magmas were derived by partial melting of oxidized, H2O‐ and CO2‐poor eclogite‐rich sources (~FMQ‐1.0 to ~FMQ). We use this to suggest that the low‐velocity seismic anomalies below Eastern China largely reflect the presence of oxidized and enriched, hot and not necessarily particularly hydrous mantle domains as common interpretation has suggested. This is crucial information for quantifying material flow above and around the subducted Pacific plate and for constraining residence times of subducted components in Eastern Asia and globally.

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Magnesium Isotopic Evidence for Ancient Subducted Oceanic Crust in LOMU‐Like Potassium‐Rich Volcanic Rocks

et al. 2017

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To evaluate the role of subducted oceanic crust in the genesis of potassium‐rich magmas, we report high‐precision Mg isotopic data for a set of Cenozoic volcanic rocks from Northeast China. These rocks overall are lighter in Mg isotopic composition than the normal mantle and display considerable Mg isotopic variations, with δ26Mg ranging from −0.61 to −0.23. The covariation of δ26Mg with TiO2 in these rocks suggests that their light Mg isotopic compositions were derived from recycled oceanic crust in the form of carbonated eclogite in the source region. The strong correlations between δ26Mg and (Gd/Yb)N ratio as well as Sr‐Pb isotopes further indicate a multicomponent and multistage origin of these rocks. Magnesium isotopes may thus be used as a novel tracer of recycled oceanic crust in the source region of mantle‐derived magmas.

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Mantle transition zone-derived EM1 component beneath NE China: Geochemical evidence from Cenozoic potassic basalts

Cited by 149 publications

References 85 publications

Light Mg Isotopic Composition in the Mantle Beyond the Big Mantle Wedge Beneath eastern Asia

Light Mg Isotopic Composition in the Mantle Beyond the Big Mantle Wedge Beneath eastern Asia

Hot, volatile‐poor, and oxidized magmatism above the stagnant Pacific plate in Eastern China in the Cenozoic

Magnesium Isotopic Evidence for Ancient Subducted Oceanic Crust in LOMU‐Like Potassium‐Rich Volcanic Rocks

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