摘要:
生物作为一种举足轻重的判别沉积环境的标志,已为广大沉积学者所公认。然而,这种标志是通过古生物与其有亲缘关系的现代生物的生活环境的对比及可靠的相标志互为验证而得到的。对于那些早已绝种而无法与现代生物生活环境参照对比的生物来说,研究形态群与环境的关系显得格外重要而有意义。
Abstract:
The bioherms are widespread during deposition of the Lower Cambrian Qingxudong Formation in the Huayuan district, western Hunan. They comprise nineteen genera and species of calcareous algae and may be subdivided into four groups and seven subgroups according to their morphologies: (1) botryoidal group; (2) dendritic group including: (a) fine and short subgroup, (b) clustered and ball-shaped subgroup, and (c) dendritic subgroup; (3) tubular group including: (a) fan-shaped tubular subgroup, (b) isolated and scattered tubular subgroup, (c) clustered tubular subgroup, (d) coiled-massive and spiral subgroup, and (4) blanket hair-like group.
One or several algal morphological groups and/or subgroups can be assigned to either of four algal environmental zones of the bioherms, where the distribution of energy differs from that in the organic reefs. For example, the low-energy zone occurs at the bottom and periphery of the bioherms, whereas relatively high-energy in the central part of the bioherms, and very high-energy zone on the top of the bioherms. No differences in energy have been identified in the environments around the bioherms; all the algal environmentsl are confined to the deeper-water low-energy environments in the study area.
下载:
