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Geoscience ›› 2011, Vol. 25 ›› Issue (4): 682-691.

• igneous petrology • Previous Articles     Next Articles

The Mashan Indosinian Oceanic Island Basalt Outcropping along the Lingshan Fracture in Southeast Guangxi and Its Tectonic Implications

WU Genyao, LI Yuejun   

  1. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing100029, China
  • Received:2011-03-24 Revised:2011-05-06 Online:2011-08-29 Published:2011-08-31

Abstract:

The Mashan Indosinian basalt outcropped along the Lingshan fracture in southeast Guangxi The discriminant diagrams of major elements showed the tectonic setting of the alkali basalt being oceanic island The trace element contents indicated the characteristics of oceanic withinplate basalt The REE patterns of the Mashan Indosinian basalt were a group of subparalled and gently rightinclined curves, with(La/Yb)N= 1169,(Ce/Yb)N=864,(Ce/Sm)N=241, and a tendency of total REE contents increased with increasing of the total alkali contents, which comprehended the Mashan oceanic island should belong to the Azorestype one This provided, firstly, an evidence of geological records from the oceanic basin for that the area of southeast Guangxi and neighbouring southwest Guangdong should be a part of the Paleotethysides, and the Lingshan fracture should be a suture resulted from closure of the Paleotethyan branch oceanic basin Furthermore, the paper represented a work model for evolution of the Lingshan oceanic basin based on the recent fruits of the Paleotethyan study in the border areas of Guangxi and Guangdong

Key words: Azorestype oceanic island, Indosinian basalt, petrochemistry, Paleotethysides, Lingshan fracture, southeast Guangxi

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