海平面变化的原因及结果

20世纪80年代初期以来,科学大洋钻探已累计完成了DSDP80、93、95和ODP133、143、 144、150、150X、166、174A、174AX、182、194等10多个与海平面变化有关的科学航次,在美国新泽西被动大陆边缘、澳大利亚东北部及南部被动大陆边缘、巴哈马台地、太平洋中西部平顶海山等地获得了大量的钻探资料。根据这些资料,建立了过去42 Ma来的海平面变化年表,确立了大陆边缘层序界面与全球海平面下降之间的成因联系,在估计全球海平面变化幅度方面取得进展。尽管如此,对全球海平面变化的幅度、机制及地层响应等基本问题的了解,还存在很大的不确定性。在综合有关文献基础上,对科学大洋钻探在海平面变化研究方面所取得的成就、存在的问题及发展方向进行简要介绍。

CAUSES AND EFFECTS OF SEA-LEVEL CHANGE

Since the early 1980s, more than ten legs have been drilled on the Irish (DSDP Leg 80), New Jersey (DSDP Legs 93 and 95, ODP Legs 150, 150X, 174A, and 174AX), Bahamas (ODP 166), and Australian (ODP Legs 133, 182, and 194) margins, as well as on the northwest Pacific guyots (ODP Legs 143, 144). These drillings have provided a chronology of eustatic lowering for the past 42 million years, established a causal link between sequence boundaries on continental margins and eustatic lowerings. Better estimating of amplitudes of eustatic sea level changes has been consequently made. There are fundamental uncertainties, however, in the rates, amplitudes, and mechanisms for the eustatic change and its stratigraphic response.This paper gives a brief summary on the accomplishments, problems and the prospects of scientific ocean drilling.