摘要
生物演化的特性使生物地层单位具有不完备性、重叠性和时间性,且无明确的级别.不能形成独立完整的地层分类系统.地层中的生物遗体和遗迹是岩层总体特征的具体表现,故生物地层划分本质上属于岩性地层划分.
Biostratigraphic units are those classified according to the speciality and uniformity of paleontologic characteristics of fossiliferous strata. The evolution of organisms makes biostratigraphic units incomplete, irreversible and overlap in time and space, and have no unambiguous hierarchy of subdivision. Therefore, they can not become an independent and complete stratigraphic classification system. Fossils make a part of strata and traces of organisms are specific manifestations of stratigraphic entity, and biostratigraphic subdivision belongs to the lithostratigraphic subdivision in nature.There are only two kinds of criterion for stratigraphic classification, one is concrete(lithologic) and the other is abstract (timely). Biostratigraphic units are merely a useful method in stratigraphic correlation and the establishment of the geologic time scale.
关键词
地层划分
生物地层单位
不完备性
incompleteness
overlapping
sfratigraphic subdivision
lithostratigraphic units
chronostratigraphic units
