关键词: 早石炭世, 珊瑚, 昌都地块, 特提斯, 青海

Abstract:

Abundant coral fossils were collected from the Zadoi Group(Lower Carboniferous)in southern Qinghai. In the study area, the Zadoi Group is composed of three formations, which are the Lower Carbonate Formation(C1z1), the Clastic Formation(C1z2), and the Upper Carbonate Formation(C1z3) in ascending order. Based on the characteristics of the coral fauna, two assemblages may be established, which are the Siphonodendron scitulus-Lithostrotionella zadoensis assembalge(Visean)occurred in the Lower Carbonate Formation and Clastic Formation, and the Lithostrotion decipiens-Kueichouphyllum sinense-Siphonodendron irregulare asiaticum assembalge(ViseanSerpukhovian)occurred in the Upper Carbonate Formation. The Siphonodendron scitulus-Lithostrotionella zadoensis assembalge is characterized by endemic genera, and dominated by genera Siphonodendron and Lithostrotionella compound in form. In the Lithostrotion decipiens-Kueichouphyllum sinense-Siphonodendron irregulare asiaticum assembalge, genus Kueichouphyllum solitary in form, which is one of warmwater genera of South China, first occurred. As an important element of the Northtype of Eurasia Province, genus Gangamophyllum also occurred, but in a small amount. And the diversity of this assemblage is significantly higher than that of the underlying assemblage. This coral fauna correlated well with those faunas from East Tibet, South China, and adjacent areas of the same period. The Otsuka similarity coefficient and Qcluster analysis of these coral faunas shows that the Early Carboniferous coral fauna from southern Qinghai is warmwater Tethystype, and belongs to the BayankalaSanjiang subprovince, Tethys Realm. And this fauna differs significantly from those faunas in south of Longmu CoShuanghuLancang River Suture Zone.

Key words: Early Carboniferous, coral, Qamdo Block, Tethys, Qinghai