关键词: 亚速尔型洋岛, 印支期玄武岩, 岩石地球化学, 古特提斯造山带, 灵山断裂, 桂东南

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