华北下奥陶统旋回地层学和锶同位素地层学对比研究

On the basis of detailed study on cyclostratigraphy of the Lower and Middle Ordovician in North China, we distinguished the stacking pattern of sedimentary cycles on five scales. High-frequency sea-level changes have been reconstructed. The correlatability of sedimentary cycles suggests that high-frequency sea-level fluctuations controlled the origin of the sedimentary cycles in the Lower and Middle Ordovician of North China. We sampled the micritic matrix in the lime mudstone and wackestone by microdrilling methods, and analyzed their strontium isotopic element. The fluctuation of 87Sr/86Sr in the Ordovician of North China can be correlated with the global 87Sr/86Sr curves, and might have been controlled by third-order sea-level rises and falls. This study provided important evidence for the establishment of high-resolution stratigraphy of the Ordovician in North China.

通过对华北下奥陶统旋回地层学和锶同位素地层学的对比研究，探讨各级沉积旋回的叠加方式；恢复早奥陶世海平面和锶同位素变化曲线，确定高频率旋回的成因；综合古生物学、沉积学和地球化学数据，建立理想复合剖面，大幅度提高地层划分和对比的精度。进而探讨地质事件和古环境的详细演化过程及天文因素对古气候变化的影响等重要问题。