Pelagic sediment contains tiny grain of material .
它的变化特征虽然可以忠实地记录原生沉积环境的变迁，但不能简单套用远洋沉积物中所总结出的模式。
Although the characteristic of oxygen isotope can not be illustrated by an extant model designed for pelagic sediment , it can reflect the change of original environment faithfully .
远洋沉积物