Discovery of the Early Mesozoic granulite xenoliths in North China Craton

Shao, Jing; Han, Qingjun; Li, Huimin

doi:10.1007/bf02911949

Cited by 22 publications

(17 citation statements)

References 8 publications

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“…As shown in Figure 3, the mafic melt and heat provided by ascending mantle could result in the thermal/chemical erosion and change the nature of the lithospheric mantle. This process might influence the formation of the crust‐mantle transition zone with a thick mafic basal layer beneath the eastern NCC as displayed in the seismic imaging of the TSR, and revealed by the Mesozoic mafic xenoliths of the YSTB and the TSR [ Shao et al , 2000; Chen et al , 2001]. However, in local region such as the YSTB, the foundering of orogenic thickened and/or magmatic underplating crust might disturb/overthrow the stable mantle convection, and form a sharp crust‐mantle boundary.…”

Section: Discussionmentioning

confidence: 99%

Insight into the geodynamics of cratonic reactivation from seismic analysis of the crust‐mantle boundary

Zheng

Zhao

Zhu

2008

Geophysical Research Letters

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The reactivation of craton is a crucial issue for the understanding of continent lithosphere. Although the partial loss of the thick lithospheric root of the North China Craton (NCC) was documented, its mechanism remains a contentious topic in the study of cratonic evolution. In this paper, we imaged the crust‐mantle structures by using the data from 36 permanent stations with fine spatial coverage in the Yanshan tectonic belt (YSTB) and the Taihangshan region (TSR) in the northern NCC. Two tectonic units with distinct crust‐mantle structures were recognized and their junction zone was identified. The results reveal distinct features of the crust‐mantle boundaries of the YSTB and the TSR which are characterized by a sharp interface and a thick transition zone, respectively. Based on the analysis of the seismic structures of the crust‐mantle boundary and the upper mantle, we propose that the NCC reactivation was possibly derived by a slow secular ascension of hydrated asthenospheric material atop the stagnant Pacific slab, which influenced the formation of crust‐mantle transition zone in the eastern NCC. On the other hand, regional delamination of the deep crust after orogenic thickened and/or magmatic underplating beneath the YSTB caused the spatial variation of the crust‐mantle boundary. Both of the mantle processes possibly changed the nature of the lithospheric mantle.

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Section: Discussionmentioning

confidence: 99%

Insight into the geodynamics of cratonic reactivation from seismic analysis of the crust‐mantle boundary

Zheng

Zhao

Zhu

2008

Geophysical Research Letters

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“…It was such a favourable scenario that led to the formation of the middle Triassic Xiaofangshen gabbros, the early Triassic adakitic rocks (Jiang et al 2007) and A-type granites (Zhang et al 2008b) from the northern Hebei area, the Triassic Fanshan ultramafic complex dating from 218 to 243 Ma (Mu et al 2001;Jiang et al 2004) and the Triassic cumulate and granulite xenoliths dating from 220 to 251 Ma from Chifeng of the southern Inner Mongolia (Shao et al 1999;Shao, Han & Li, 2000). Dehydration of the thinning lithosphere resulted ultimately in the shift in a few million years from calc-alkaline to alkaline magmatic suites, as indicated by the Triassic alkaline intrusions dating from 205 to 250 Ma within the continental interior of the newly amalgamated North China-Mongolian Plate (Shao, Mu & Zhang, 2000;Yan et al 2000).…”

Section: B Tectonic Implicationsmentioning

confidence: 97%

Geochemistry of Middle Triassic gabbros from northern Liaoning, North China: origin and tectonic implications

Zhang

Zhai

et al. 2008

Geol. Mag.

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The Xiaofangshen mafic stock is a hornblende gabbroic body emplaced in the Faku dome of northern Liaoning within the continental interior of the North China-Mongolian plate. Zircon U-Pb SHRIMP dating yields an emplacement age of 241 ± 6 Ma. These gabbroic rocks exhibit strong enrichment in large ion lithophile elements (e.g. Th, U) and light REE, slightly negative Eu anomalies, and pronounced depletion in high field strength elements (e.g. Nb, Ta, Zr, Ti). They show a relatively narrow range of isotopic compositions with initial 87 Sr/ 86 Sr ratios of 0.7053 to 0.7055, ε Nd (t) values of +0.40 to +0.68 and zircon ε Hf (T) values from +5.0 to +7.4. These geochemical features suggest that they might have been derived from partial melting of a subduction-related metasomatized lithospheric mantle source, which is tectonically affiliated to the Xing-Meng orogenic belt. Combined with our previous geochronological dating on the predominantly granitic intrusions from the Faku dome, it is inferred that the northern Liaoning block has a tectonic affinity with the Phanerozoic accretionary orogenic belt. This revelation further leads to the proposition that the Chifeng-Kaiyuan fault likely represents the Mesozoic lithospheric boundary between the North China craton and the Xing-Meng orogenic belt in northern Liaoning. The Xiaofangshen gabbros, together with the Triassic mafic-ultramafic cumulates and granulite xenoliths and the Triassic alkaline intrusions within the continental interior of the newly amalgamated North China-Mongolian Plate, constitute an important post-orogenic to within-plate anorogenic magmatic province, in response to the continued magmatic underplating caused by lithospheric delamination and hot asthenosphere upwelling.

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“…Fractionation in the underplating basaltic magma would form cumulate complexes in the lower crust (e.g., Shao et al, 1999). This process would produce two effects within the pre-existing lower crust, one being contemporary granulite-facies metamorphism (e.g., the formation of the granulite xenoliths described by Shao et al (2000) and She et al (2006)), and the other being partial melting of the lower crust (to produce e.g., the diorites of the Chifeng area , see Fig. 1a).…”

Section: Magma Sources: a Partial Melting Modelmentioning

confidence: 99%

Triassic “adakitic” rocks in an extensional setting (North China): Melts from the cratonic lower crust

Zheng

Griffin

et al. 2012

Lithos

206

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Discovery of the Early Mesozoic granulite xenoliths in North China Craton

Cited by 22 publications

References 8 publications

Insight into the geodynamics of cratonic reactivation from seismic analysis of the crust‐mantle boundary

Insight into the geodynamics of cratonic reactivation from seismic analysis of the crust‐mantle boundary

Geochemistry of Middle Triassic gabbros from northern Liaoning, North China: origin and tectonic implications

Triassic “adakitic” rocks in an extensional setting (North China): Melts from the cratonic lower crust

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