| 上扬子区晚奥陶世海退的生态地层证据与冰川活动影响 |
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| 引用本文： | 戎嘉余.上扬子区晚奥陶世海退的生态地层证据与冰川活动影响[J].地层学杂志,1984(1). |
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| 作者姓名： | 戎嘉余 |
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| 摘 要： | <正> 根据海域范围的不断窄缩,上扬子区晚奥陶世的海退现象,从古地理的变迁角度,早已证实(刘鸿允,1955;卢衍豪,1959;张文堂,1962;穆恩之等,1981等)。除了古地理方面外,是否还存在着其它的,例如生态地层(Ecostratigraphy)方面的证据呢?此外,引起上扬子区晚奥陶世海退的主要原因是什么?广布于上扬子区的赫南特贝动物群(Hir-
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Ecostratigraphic evidence of the Upper Ordovician regressive sequences and the effect of glaciation |
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| Abstract: | An Early Ashgillian brachiopod Foliomena fauna consisting of Foliomena folium (Barran-de), Christiania nilssoni Sheehan, Trimurellina incerta (Xu and Bong) and others is found in the Linxiang Formation (s. 1.) of Guizhou and Sichuan Provinces, Southern China. It has previously been recorded in. Europe and N. America where it occurs in relatively deep shelf communities. Interestingly, the occurrences of the widely documented terminal Ordovician shelly fauna in the same area indicates progressively shallower environments accompanied by the shallower Hirnantia brachiopod communities. Eeostratigraphic evidences may be taken, to suggest a gradual regression of the Ashgillian sea in this area. It is more likely that sea-level changes during Ashgillian time were glacially controlled; and, thus, the extinction of the Hirnantia fauna as a whole is important for determining the Ordovician and Silurian boundary. |
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