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Science in China Series D: Earth Sciences

, Volume 43, Issue 5, pp 458–463 | Cite as

Sr, Nd isotope geochemistry of volcanic rock series and its geological significance in the middle Okinawa Trough

  • Xianwei Meng
  • Zhihua Chen
  • Dewen Du
  • Jinlong Wu
Article

Abstract

There exists extensive basic-acidic volcanic rock series in the middle section of the Okinawa Trough. Different types of these volcanic rocks have their own average strontium ratios of 0.704 749, 0.705 062, 0.708 771, 0.704 840 and 0.720 301 with average143Nd/144Nd ratios of 0.512 820, 0.512 673, 0.512 413, 0.512 729 and 0.512 034. These ratios of Sr and Nd isotopes all fall on a theoretic hyperbolic curve of mixing between two end-members of MORB and rhyolitic magma. So we infer that these different kinds of volcanic rocks in the middle Okinawa Trough are the erupted product in different stages of formation and evolution of the trough crust. MORB magma, which had suffered assimilation, mixed with the early-formed crust-derived rhyolitic partial melt mass at different ratios; then, these mixed magma erupted and formed volcanic rock types of the trough. This study indicates that the Okinawa Trough is coming into a stage of submarine spreading from the stage of continental rift.

Keywords

Okinawa Trough volcanic rocks Sr and Nd isotopes 

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Copyright information

© Science in China Press 2000

Authors and Affiliations

  • Xianwei Meng
    • 1
    • 2
  • Zhihua Chen
    • 1
  • Dewen Du
    • 1
    • 2
  • Jinlong Wu
    • 1
  1. 1.First Institute of OceanographyState Oceanic AdministrationQingdaoChina
  2. 2.Key Laboratory of Marine Science and Numerical ModelingState Oceanic AdministrationQingdaoChina

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