新疆西准噶尔晚泥盆世法门晚期菊石动物群的发现及其意义

Discovery and significance of Late Famennian ammonoid faunas in western Junggar,Xinjiang

首次在新疆准噶尔盆地西北缘和什托洛盖以北地区的晚泥盆世法门晚期地层中发现板海神石及大型弓海神石菊石动物。板海神石动物群由Platyclymenia(Pl.)subnautilina(Sandberger)、Sporadoceras sp.和Prionocerasfrechi(Wedekind)等分子组成;可能与Annulata事件有关。弓海神石动物群中Protactoclymenia sp.和Cyrtoclymenia?sp.以壳体硕大为显著特征,直径可达20cm。这些菊石可与西欧晚泥盆世标准菊石带第Ⅳ带的菊石组合进行对比(相当于牙形石Upper trachytera至Lower expansa带),而且在区域上的分布具有一定的稳定性,尤其是弓海神石动物群,其产出层位可作为和什托洛盖以北地区地层对比的标志层。

A number of ammonoids are discovered for the first time from the Late Devonian （late Famennian） in the north of Hoxtol-gay of western Junggar, Xinjiang. The Platyclymenia fauna includes Platyclymenia （Pl.） subnautilina （Sandberger）, Sporadoceras sp., Prionoceras frechi （Wedekind）, and others, which was probably related to the Annulata Event. The cyrtoclymeniid fanua is character-ized by spectacularly large-sized Protactoclymenia sp. and Cyrtoclymenia？ sp. with a diameter up to ca. 20 cm. These ammonoids can be correlated with the assemblage of the standard Devonian ammonoidⅣZone of West Europe （conodont Upper trachytera Zone to Lower expansa Zone）. The occurrences of the late Famennian cyrtoclymeniid fauna in different sections in the area north of Hoxtolgay can be well correlated. The horizons bearing these fossils can be regarded as a marker layer for stratigraphic correlation in this area.