摘要
自1980年第26届国际地质大会在巴黎召开以来,国际古生物协会(IPA)就开始组织“地球历史上几次重大生物变化”(即全球事件和生物演化)课题的研究。早在35亿年前,地球上就开始出现兰藻和细菌。距今10亿年左右,开始出现软躯体动物所形成的遗迹化石。9亿年有蠕形动物的实体化石——淮南生物群。7亿年软躯体后生动物——埃迪卡拉动物群(西陵峡生物群、高家山生物群)大量繁殖,使晚前寒武纪生物演化进入一个新阶段。6亿年左右出现的骨骼化动物——梅树村动物群(或托莫特动物群),开始有更多的生物能够以化石保存下来,提供对生物演化史研究的材料。5.
The algal flora (Huailai Biota) represented by Longfengshania began to appear in about 900--850 Ma (B. P.). Which is the earliest biota discovered in the Qingbaikou System in China. The Liulaobei Formation and Jiuliqiao Formation of the Huainan Group in Huainan district of Anhui province have collected the Huainan Biota predominated by chuarid, vermes and vendotaenides which are the earliest horizons containinganimal remains in our country, corres onding to the early period of Sinian (840--650 Ma B. P.). The Xilinxia and Gaojiashan Biotas discovered in the districts of Hubei and southern Shamxi, etc., mainly consisting of vermes, tubular fossils, pennatulids and trace fossils are of the Middle, Upper Sinian age (650--600 Ma B. P.), approximately corresponding to the Ediacara Fauna in Australia. During the uppermost Sinian to early Lower Cambrian (596.9--570.7 Ma B. P.), the oldest skeletogenous biota (Meishucun Fauna) occurred, such a small ahelly fauna can be used as the reliable evidence to divide the Precmbrian--Cambrian boundary. The boundary stratotype point of Precambrian--Cambrian is placed between the zones of Anabarites--Protohertzina and Paragloborilus--Siphogonuchites (i. e., the boundary locality between the bed 6 and bed 7 in Meishucun section). At the early Lower Cambrian (the Qiongzhusian period) the oldest shelly fauna of trilobite began to emerge and the occurrence of arthropoda of trilobite and bradorids represented by Parabadiella marks a new beginning for biological evolution on earth. After that the Chengjiang fauna and Malong fauna successively flourished. The former consists mainly of soft-body medusae and vermes of metazoan as well as arthropod preserved soft-body appendages, and the latter, of anomalous trilobites.
出处
《云南地质》
1989年第3期222-228,共7页
Yunnan Geology
