摘要
本文首次详细描记了扬子区五峰组中已发现的胞石,计有7属12种。文中提出了二个胞石带,并与国外其它地区作了对比。根据本文所研究的胞石,认为苏北地区五峰早期为陆架深水环境。因此推断东台以北应面对或毗邻大陆坡而不是华北古陆。扬子板块与华北板块的碰撞对接,不可能发生在晚奥陶世。
The first report on ehitinozoans from the Wufeng Formation of the Yangzi Region was put forth by Hou Jinpeng and Wang Xiaofeng (1982), in which they mentioned the finding of Conochitina sp. and Cyathochitina sp. from the formation in Qijiaag, Sichuan associated with the graptolites Tangyagraptus typicus Mu Climacograptus superlus Elles et Wood, C. hastatus T. S. Hall and others, while Conochitina sp.A Achab was also described and illustrated by Geng Liaagyu et el. (1984) from the Kuanyinehiao Bed of the formation at Zhongshu of Renhuai,Guizhou. From this it is clear that the study of Ashgillian chitinozoans in the region is still in an early stage with a tremendous amount of basic taxonomic and descriptive work left to be done.Two ehitinozoan zones have been recognized in the Wufeng Formation(Table 1 in the Chinese text), which are discussed below in ascending order.1. Ancyrochilina merga merga ZoneThis zone occuoies the lower and middle parts of the formation, with its lower and upper limits defined by the appearance and disappearance of Ancyrochitina m. merga subsp. nov. respectively. Its characteristic species include Lagenochitina baltica Eis., Conochitina baculata Achab, C. sp. A Achab, C. aff. lepida Jenk., C. elegans Eis., Rhabdochitina magna Eis., and R. allantoides sp. nov. From the underlying horizons there have been identified the graptolitie genera referred to Zones W_1—W_2, namely, Glyptograptus sp., Climacograptus sp., Orthograptus sp., Pseudoclimacograptus sp., Dicellograptus sp., and Leptograptus sp. (Ge Mei-yu, 1979, unpublished).2. Tanuchitina fusiformis ZoneThis zone is present in the upper part of the formation, with its lower and upper limits marked by the first and last occurrences of Tanuchitina fusiformis Bouche respectively. Typical of this zone are such species as Rhabdochitina gallica Taug., Belonechitina micracantha Eis. and Spinachitina rugosa sp. nov. in associa- tion with some other species of the preceding zone, namely, Conochitina baculata Achab, C. sp. A Achab and Rhabdochitina
出处
《微体古生物学报》
CSCD
北大核心
1989年第1期45-64,121-124,共20页
Acta Micropalaeontologica Sinica
基金
国家自然科学基金
