中文摘要：

云南寒武纪澄江生物群是布尔吉斯页岩型化石宝库之一，以精美的软躯体化石保存为典型特征，展示了寒武纪早期后生动物多样性面貌，为建立动物谱系演化关系和探讨早期生态结构提供了难得的研究材料。文中以澄江生物群中常见的4类不同生活方式的物种（底栖潜穴型以Cricocosmia jinningensis，Mafangscolex sinensis为例；表栖固着型以Heliomedusa orienta为例；表栖运动型以Naraoia spinosa为例；浮游生活型以Stellostomites eumorphus为例）为研究材料，通过对化石在事件沉积（远基风暴沉积）泥岩中的保存状态、位置和化石大小等的统计分析，探讨化石保存特征和生物体逃逸行为对化石组合的影响。结果表明不同生活方式的物种在沉积物里具有不同的保存特点，如底栖潜穴型蠕虫化石多聚集保存在事件沉积层的下部，向上呈离散式分布；浮游生活型水母状化石保存在事件沉积层上部且在同一水平微层面上平铺密集分布等。这些特征反映了生物体在快速沉积埋藏过程中，由于种间生活方式和种内个体差异而引起生物体逃逸能力的不同，从而体现在化石保存在泥岩中位置和状态的变化。也就是说，生物体在快速埋藏过程中最终保存以及在沉积物中的形态和位置除与沉积物自身特性有关外，还与生物体本身运动反应能力有关。依据沉积事件的强度和软躯体化石在沉积泥岩中的位置、状态和大小关系，推测该研究地区多数底栖生物化石为原地埋藏，并在快速埋藏过程中发生逃逸行为，但并不能做出有效反应和成功逃离，因而其保存下来的化石组合记录了底栖群落的基本特征。那么，是什么因素抑制了澄江生物的逃逸能力、从而使大量的精美软躯体化石保存？是寒武纪生物自身原因（运动能力弱处于演化的初级阶段），还是寒武纪沉积物本身特有的物理化

英文摘要：

Because of its exquisite soft-bodied fossil preservation the famous Cambrian Chengjiang Lagerstfitte of eastern Yunnan presents a unique window in time, revealing a fascinating glimpse on the diversification and palaeoecology of early metazoans. Based on statistical analysis of preservational body orientations, stratigraphic horizon, and of size distribution of four ecological kinds of Chengiiang fossils in the event mudstone layers, we demonstrate here how different organisms responded to sedimentary events. This enables an evaluation of whether taphonomic ‘escape biases＇ may have significantly altered the composition of the original living community compared with that of the death assemblages found actually preserved as fossils. The four ecological kinds of organism studied include： 1） infaunal vagrant forms of Cricocosmia jinningensis and Ma fangscolex sinensis;2） an epifaunal sessile form, Heliomedusa orienta 3） the epifaunal vagrant form Naraoia spinosa;and 4） the pelagic Stellostomites eumorphus. Our results demonstrate that these different ecological forms left different preservational signatures in the event mudstone layer, which may reflect differences in responsiveness and ability to escape from sudden sediment input amongst the different animals. The thickness （several millimetres to centimetre thick） of the event mudstone layers which include the preservation of many such kinds of soft-bodied fossils, and the relationship between stratigraphic position and size distribution of these organisms, indicate that most benthic animals could not make a sufficiently rapid response to escape burial as a result of the rapid sediment deposition. So the fossil assemblage in the Chengjiang Lagerstatte appears to reflect the original biodiversity. However, exactly which factors restrained Lagerstatte appears to reflect the original biodiversity. However, exactly which factors restrained the escape capacity of some of the living organisms to escape burial is not yet clear. They may relate to the un