河南内乡晚奥陶世石燕河组牙形石及其地质意义

将河南内乡晚奥陶世石燕河组牙形石自下而上建立了Ｏｕｌｏｄｕｓｕｉｒｉｃｈｉ－Ａｐｈｅｌｏｇｎａｔｈｕｓｓｈｏｓｈｏｎｅｎｓｉｓ带，Ｏｎｏｄｕｓｒｏｂｕｓｔｕｓ带，Ａｐｈｅｌｏｇｎａｔｈｕｓｇｒａｎｄｉｓ带，Ａｐｈｅｌｏｇｎａｔｈｕｓｄｉｖｅｒｇｅｎｓ带和Ａｐｈｅｌｏｇｎａｔｈｕｓｚｕｏｑｕｅｎｓｉｓ带。这个序列与北美中大陆的很相似，两者可详细对比。充分证实了北美中大陆型牙形石动物群以及中国合此类型牙形石的最高奥陶纪地层在华北地台以南的武当地块北缘的存在，并指明了其古生物地理分区和构造意义。

BIOSTRATIGRAPHY AND TECTONIC IMPLICATIONS OF LATE ORDOVICIAN CONODONTS FROM SHIYANHE FORMATION, NEIXIANG, HENAN

Conodonts from the Upper Ordovician Shiyanhe Formation in the Shigang Section,abc+ut 10 km southwest of Neixiang County and tectonically located in the northern marginof the Wudang Massif, are re-examined in order to establish a more precise and detailedspecific sequence. Under identification were over 2 200 specimens from 33 trough-samplesrepresenting a section of 320 meters in total. The conodonts represent biozones of theAshgillian, with 5 zones similar to those from the Upper Ordovician rocks of North American Midcontinent Province distinguished in descending order as follows