Paleoecology and taphonomy of fossil rocky-shore assemblages

岩岸生境通常保存在地质记录中，并有很高的潜力与古地理和古环境变化的重建对接。2003年，我注意到北海道第四纪岩岸软体动物组合的产状模式，并研究了古生态和化石特征。此外，我还分析了软体动物死亡组合的区系组成和攻击学属性，并研究了高能环境下的石化过程。2004年，我对冲绳第四纪岩岸软体动物进行了初步研究，分析了珊瑚礁海滩软体动物的死亡组合。日本北部北海道西南部的Setana组沉积于冰川海平面变化时期。我研究了这个地层的Soebetsu段，在那里，保存完好的软体贝壳的嵌入密度大约在1.0到0.8 Ma之间。根据…对软体动物的组合进行了定量分析更多形成为三个生态属性，包括水深、底质和生活方式。每个样品中岩石基质物种的出现频率约为30%至40%。该地层中软体动物组合的古生态特征反映了海平面上升过程中沉积环境的变化。北海道西南部的岩石潮汐台地根据其海底动物群被划分为5个带。对软体动物死亡组合的5个攻击学属性进行了岩相分析。这五个岩岸带可以通过这些贝壳的攻丝特征来表征。在这个隐蔽的岩岸栖息地，软体动物死亡群落之间的分流梯度反映了基于水深(=淹没时间)和波浪作用的环境梯度。这些化石属性通常保存在化石组合中，因此对隐蔽的岩岸生境的古环境重建是有用的。较少

Rocky-shore habitats have often been preserved in the geological record, and have a high potential for interfacing with reconstructions of paleogeography and paleoenvironmental change. I paid attention to mode of occurrences of rocky-shore molluscan assembleges from the Quaternary of Hokkaido and examined paleoecologic and taphonomic features in 2003. In addition, I analyzed faunal composition and taphonomic attributes of the molluscan death assemblages and examined a fossilization process in a high energy environments. I preliminary examined rocky-shore molluscs from the Quaternary of Okinawa and analyzed molluscan death assembleges on the beach of coral reef in 2004.The Setana Formation of southwestern Hokkaido, northern Japan, was deposited at a time of glacial sea-level change. I studied the Soebetsu section of this formation, in which intercalated concentrations of well-preserved mollusc shells date to about 1.0 to 0.8 Ma. Quantitative analysis of the molluscan assemblages was per … More formed for three ecological attributes, including water depth, substrate and life style. The frequency of rocky-substrate species in each sample is approximately 30 to 40%. The paleoecological characteristics of the molluscan assemblages in this stratigraphic section reflect changes in the sedimentary environment during a sea-level transgression.The rocky tidal platform in southwestern Hokkaido is divided into five zones, based on its benthic fauna. Taphofacies analysis of the molluscan death assemblages was performed for five taphonomic attributes. The five rocky-shore zones can be characterized by the taphonomic attributes of these shells. Taphonomic gradients among the molluscan death assemblages in this sheltered, rocky-shore habitat reflect environmental gradients based on water depth (=submergence time) and wave action. These taphonomic attributes are commonly preserved in fossil assemblages and therefore are useful for paleoenvironmental reconstruction of sheltered, rocky-shore habitats. Less