【摘要】 通过显微镜、扫描电镜以及微量化学成分分析,对现代瓣鳃类粗饰蚶、花蛤和腹足类纺锤螺,第三纪美壳螺,三叠纪克氏蛤,石炭—二叠纪燕海扇,泥盆纪云南贝、颠石燕,奥陶纪震旦角石、赫南特贝等贝壳生长纹层进行了综合研究。结果表明,奥陶纪以来贝壳生长纹层具有年、半年、双周、日、半日生长周期的变化,年中所含双周生长纹层数、双周所含日生长纹数均呈递减的趋势。通过观测计算得出:奥陶纪每年的日数为415.69 d,泥盆纪为407.1 d,石炭—二叠纪为400.51 d,三叠纪为393.98 d,第三纪为374.13 d,第四纪为367.4 d,表明自奥陶纪以来有地球自转速度变慢、地月距离增大、月球后退速率减小等变化趋势。更多还原

【Abstract】 This thesis studies the growth laminates of biological shell by microscope,scanning electron microscope and chemical composition analyze,which includes the modern Bivalve Anadara,Astartella and Gastropoda Fusus,Tertiary Cochliop,Triassic Claraia,Carboniferous-Permian Aviculopenten,Devonian Yunnanella and Acrospirifer,Ordovician Sinoceras and Hirnantia and so on.The result of annual,semi-annual,fortnightly,daily and sub-daily growth laminates of the biological shell have been identified.Fortnightly and daily growth laminates have the decreasing tendency.It has been found that there were 415.69 d for an annual period in Ordovician,407.1 d in Devonian,400.51 d in Carboniferous-Permian,393.98 d in Tertiary,374.13 d in Triassic,367.4 d in Qua-ternary.The result shows that the velocity of the Earth rotation had been slowed down from Ordovician to Quaternary and that the Earth-Moon distance had been increasing while the rate of lunar retreat had been decreasing.更多还原