摘要
许杰(1934)在研究安徽宁国县胡乐一带的地层时，建立了两个地层单位：宁国页岩和胡乐页岩。宁国页岩厚约141m,为“各种颜色之泥质页岩”上部31m为“淡黄色。
The Xiakengwu stratigraphic section of the Middle Ordovician Hulo Formation isdescribed, and the graptolite fauna from this section and others in the Hulo area is discussedin detail. Three graptolite zones can be recognized: (1) the Glyptograptus teretiusculuszone. which is characterized by the diplograptids, the early dicellograptids with smallrhabdosomes and the early dicranograptids with short biserial .portions; (2) the Nemagra-ptus gracilis zone, the base of which coincides with the first appearance of its name-giver,In this zone, the dicellograptids diversify into the forms with large or twisted rhabdoso-mes, and the dicranograptids into the forms with long biserial portions. The appearanceand abundance of calcaratus--type orthograptids in the uppermost part of the zone are significant in worldwide stratigraphic correlations (3)the Dicranoggraius sinensis zong in which its name-giver and c,bicornis begin to appear and dicellograptid fauna is still abundant hulo area is the type locality for the hulo formation and the xiakengwu stratigraphic section may be the completest of the known sections in this area thus we suggest that this section be used as the type section if the hulo stage is officially establi-shed in future
出处
《地层学杂志》
CSCD
北大核心
1989年第4期269-278,共10页
Journal of Stratigraphy
基金
国家自然科学基金 4860151
