P wave radial anisotropy tomography of the upper mantle beneath the North China Craton

Jian Wang, Huohua Wu, Dapeng Zhao

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

We present the first P wave radial anisotropy tomography of the crust and upper mantle beneath the North China Craton (NCC), determined using a large number of high-quality arrival-time data of local earthquakes and teleseismic events. Our results show a prominent high-velocity (high-V) anomaly down to ∼250 km depth beneath the Ordos block, a high-V anomaly in the mantle transition zone beneath the eastern NCC, and a low-velocity (low-V) anomaly down to ∼300 km depth beneath the Trans-North China Orogen (TNCO). The Ordos block exhibits significant negative radial anisotropy (i.e., vertical Vp > horizontal Vp), suggesting that its cratonic lithosphere has kept the frozen-in anisotropy formed by vertical growth via high-degree melting mantle plume in the early Earth. Prominent low-V anomalies with positive radial anisotropy (i.e., horizontal Vp > vertical Vp) exist beneath the Qilian and Qaidam blocks down to ∼400 km depth, suggesting that the horizontal material flow resulting from the Tibetan Plateau is blocked by the Ordos thick lithosphere. Beneath the eastern NCC, high-V anomalies with negative radial anisotropy exist in the upper mantle, possibly reflecting sinking remains of the Archean cratonic lithosphere. A high-V anomaly with positive radial anisotropy is revealed in the mantle transition zone under the eastern NCC, which reflects the stagnant Pacific slab. Key Points We present 3-D P wave radial anisotropy in the upper mantle under the NCC Ordos block lithosphere shows high-V anomaly with negative radial anisotropy High-V Pacific slab shows positive radial anisotropy under eastern NCC

Original languageEnglish
Pages (from-to)2195-2210
Number of pages16
JournalGeochemistry, Geophysics, Geosystems
Volume15
Issue number6
DOIs
Publication statusPublished - 2014 Jun

Keywords

  • North China Craton
  • Ordos block
  • P wave tomography
  • Pacific slab
  • radial anisotropy

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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