灵台任家坡动物群年龄组成以老年、幼年个体为主，显示动物正常死亡条件下的骨骼富集积累过程。由于动物死亡与掩埋之间时限的长短不同导致个体间风化痕迹、关节分解、破损程度不同。化石具有明显的定向性及分选性，经过季节性水流短距离搬运和较弱的分选作用。化石的埋藏特点与泛滥平原骨骼富集有较多的相似性，但沉积物组成差别很大，暗示中国红粘土物源的特殊性。

Abundant mammalian fossils of Neogene fauna are widely spread in eolian dust accumulation in northern China. In field buried skeletons are overlapped, fossils saved in a panticular state. Taphonomic process and deposition environment of fossiliferous layers are problems that paleontologists hope to solve. The discovery of new mammalian fossils in Renjiapo, Lingtai, Gansu throws some light on those doubts. Most skeletons of Renjiapo Pliocene mammalian fauna are saved organically isolated,a few connected materials are skulls and Alta vertebrae,and the ends of limb bones, etc. Weathering traces on the skeleton surface are diverse. A lot of gnaw marks of rodents are on bones. The damages of fossil materials are about 30 percent of whole ones. Rupture of the bones is stepping one. Orientation of long axes of elongate bones in the fossiliferous layer has obvious direction. There are some similarities in taphonomic features between the Renjiapo Pliocene mammalian fauna and the flood plain fauna. The general features are: fossils are abundant and concentratedly distributed. They include parts of individual bodies and different taxa. Joint and scattered bones, complete and broken bones exist in same area. Acting marks of other animals are general, age distribution of population indicate attrition mortality. The actions of water transportation and sorting existed. However, there are also different features. For example, the grain size of flood plain deposits is relatively coarse. They usually contain some sands. Fossils are distributed successively. These general and specific characters may be considered as the similarity of taphonomic process and variance of taphonomic environment. The taphonomic character of Renjiapo Pliocene mammalian fauna is similar to that in North China. Distinguishable features may be caused by different transportation course, transportation distance and transporting agent. Therefore, taphonomic knowledge of Renjiapo Hipparion fauna affords some references to understand the taphonomic processes of Hipparion fauna in China.

Q915.87 Q915.2

国家自然科学基金 (No .49972 0 0 4)，教育部骨干教师资助课题