Cretaceous Pacific plate movement beneath SE China

evidence from episodic volcanism and related intrusions

Lei Liu, Xisheng Xu*, Yan Xia

*Corresponding author for this work

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

Extensive Late Mesozoic igneous rocks in SE China have been widely considered to be generated under the paleo-Pacific tectonic regime, the plate subduction model, however, remains controversial. This study focuses on the Cretaceous volcanic rocks in northwestern Zhejiang Province. Zircon U-Pb age determination indicates that Cretaceous volcanism in northwestern Zhejiang took place at three episodes of 140-130, 130-127 and 123-118Ma, in good agreement with the coeval lower volcanic series in southeastern Zhejiang, but lacking the episode at 110-88Ma corresponding to the upper volcanic series. The Cretaceous volcanic rocks in Zhejiang therefore show an oceanward younging trend. In situ zircon Hf isotope analyses of three episodes of volcanics yield εHf(t) values of -11.2 to -8.7, -4.8 to -2.4 and -4.4 to +2.2, respectively. The entire sequences display typical isotopic features of magma mixing, implying progressive involvement of juvenile component. Based on systematical researches on the Cretaceous volcanic rocks and a series of granitoid plutons in Zhejiang, it is also identified that the juvenile component involvement gradually occurred from the inland to the coast under an enhanced lithospheric extensional tectonic setting. All the observations in this study indicate the northwestward paleo-Pacific plate subduction with episodic slab rollback which triggered the arc system to retreat towards the Pacific Ocean, rather than the southwestward subduction related to the ridge subduction along the Lower Yangtze River belt.

Original languageEnglish
Pages (from-to)170-184
Number of pages15
JournalTectonophysics
Volume614
DOIs
Publication statusPublished - 18 Feb 2014
Externally publishedYes

Keywords

  • Cretaceous
  • Crust-mantle interaction
  • Episodic volcanism
  • Paleo-Pacific subduction
  • SE China
  • Zircon U-Pb-Hf isotopes

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