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[摘要]
近年来对位于莱阳棘鼻青岛龙发现地点(1号化石地点)以东新发现的2号化石地点进行大规模发掘,已发现5个化石富集层,赋存的化石均以鸭嘴龙科为主,一部分个体可能代表栉龙亚科的成员,而另一部分个体归于赖氏龙亚科的棘鼻青岛龙。这些鸭嘴龙化石从个体大小上分别代表成年、亚成年和幼年晚期个体。化石富集层以灰绿色和褐红色含砂砾泥岩沉积为主,具有典型的泥石流沉积特征和骨骼埋藏特征,并具有两种主要的死亡和埋藏模式,即恐龙群体活着时遭遇泥石流被吞没集群死亡后,肢体在短距离搬运中被撕裂并迅速沉积掩埋,骨骼分散但完整,同一个体的骨骼相距不远;恐龙正常或经泥石流导致其非正常死亡后,部分遗体未被掩埋,经暴露软组织腐烂,被后续发生的泥石流卷入并二次搬运,最终埋藏,表现为分散但较完整的骨骼与破碎呈砾石磨圆状的骨骼共生保存。这些富集层的化石及其埋藏特征反映了生活在河湖边的鸭嘴龙动物群,在鸭嘴龙幼年晚期刚刚加入成年鸭嘴龙动物群后,被卷入突发的洪水泥石流导致其集群死亡并快速埋藏的事件。
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[Abstract]
In recent years,five fossil-bearing layers,which mainly contain abundant dinosaur fossils,are found in the massive excavations at Locality 2 of Laiyang,Shandong Province.It is east of theLocality 1(Young’s Tsintaosaurus quarry).The main fossils are hadrosaurids,some of which would be referred to Saurolophinae,with some bones of Tsintaosaurus spinorhinus(Lambeosaurinae).The hadrosaurid elements can be assigned to an assu-med adult,subadult,and late juvenile individuals according to their size.These fossil-bearing layers are mainly grey-green or red-brown mudstones.The fossil in these layers are interpreted as having been carried by debris flows and deposited.This indicates two different taphonomic modes.Alive hadrosaurids were swallowed and torn by a sudden debris flow,and the carcasses were carried a short distance and quickly buried.The fossils in this layer are complete but disarticulated,and the ones belonged to a same individual are sited in a small area.The carcasses,natural death or killed by flood or debris flows,which were exposed on the floodplain,were rotted,and broken as fragments by the debris flows during the final burial.The fossils in this layer are mixed by the complete and fractured bones.The taphonomic feature of these fossil-bearing layers indicates that there was a fauna,which was dominated by various hadro- saurids,that lived nearby the lake or river.After the late juvenile individuals joined into the adult groups,the mass mortality,which were caused by the debris flows,killed and quickly buried the fauna.
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