海南岛早志留世晚期腕足类Xinanospirifer的发现--兼论南好组

海南岛保亭县毛感乡南兵至南好公路边南好组以往被确认为下石炭统岩关阶 ,并认为与其下的上志留统足赛岭组呈角度不整合接触。著者最近在该剖面南好组中发现兰多维列世特里奇期晚期 (LateTelychian)Xi nanospirifer腕足动物群和三叶虫Latiproetuscf.latilimbatus,证明久归于下石炭统岩关阶南好组的地质时代应改归于早志留世 (Llandoverian) ;海南岛地区在早志留世明显属于扬子地台区的范畴 ;从地质时间上还暗示南好组与其下伏的足赛岭组不可能存在角度不整合接触 ;

DISCOVERY OF LATE LLANDOVERIAN BRACHIOPOD XINANOSPIRIFER FROM HAINAN ISLAND AREA, CHINA WITH COMMENTS ON THE NANHAO FORMATION

The Nanhao Formation of the lectostratotype section (usually assigned to the Yanguanian of Early Carboniferous age) contains brachiopods Xinanospirifer flabellum Rong, Xu et Yang, X. cf. sanduensis (Jiang), Plectatrypa ? sp., Cyrtiidae gen. et sp. indet., and trilobite Latiproetus cf. latilimbatus (Grabau) in Maogan Region, Baoting County, Southwest of Hainan Province, China. Among them, Xinanospirifer is a typical element of the Salopinella Xinanospirifer Assemblage Zone of Late Telychian of Late Llandoverian in Yangtze Region, China, its horizon is general equivalent to the upper parts of the graptolite griestoniensis Biozone to graptolite spiralis grandis Biozone (Rong Jia yu and M. G. Bassett, 1996); trilobite Latiproetus ( Astroproetus ) latilimbatus (Grabau) is also a significant element of the Coronocephalus Assemblage Zone of the Upper Member of Xiushan Formation of the Telychian Stage in Yangtze Region, China (Wu Hong ji and P. D. Lane, 1996). The present indisputable fact indicates that the Nanhao Formation of the lectostratotype section belongs to the Late Telychian of Llandoverian, rather than the Yanguanian of Early Carboniferous. The Nanhao Formation must be abandoned.