【摘 要】
：
Fifty-six samples of nannofossil ooze were collected from Core PC5794 in the northern equatorial Pacific at 5 cm intervals. With the methods of mass spectromete
【机 构】
：
Institute of Oceanology,Key Lab of Marine Sedimentology and Environmental Geology,Graduate School,Mo
论文部分内容阅读
Fifty-six samples of nannofossil ooze were collected from Core PC5794 in the northern equatorial Pacific at 5 cm intervals. With the methods of mass spectrometer (VG354) and ICP, the Nd isotopic compositions εNd(t ), Mn contents and Mg/Sr ratios of carbonate phase have been analyzed. CaCO3 contents of bulk sediments were obtained by dissolution of 0.5 mol/L HCl. Based on these data, the high-resolution εNd(t) profile of seawater in early Miocene with core depth(or time) have been established. The values of εNd(t) range from -6.2 to -2.97 and 4 fluctuation cycles existed during 24.06-22.02 Ma. 4 low εNd(t) values (about -6.4) correspond to high CaCO3 contents, which implicates that there were 4 cold epochs or 4 times of Antarctic Bottom Water activity. They occurred at the time of 24.06 Ma, 23.85 Ma, 22.88 Ma and 22.26 Ma, respectively. High εNd(t ) values correspond to the high Mn contents and high values of Mg/Sr ratio, which indicates the existence of 4 intense hydrothermal activity periods during 24.06-22 Ma, the durations of them are 4.05-23.98 Ma, 23.69-23.15 Ma, 22.74-22.37 Ma and 22.06-22.02 Ma, respectively.
其他文献
The relative Euler vectors of the Pacific, Philippine, Amurian, Okhotsk, N. Honshu and South China plates or blocks are deduced from earthquake slip vectors, tr
本文通过分析半刚性基层裂缝产生的原因,提出裂缝防治的措施.
当前,福建省农民工职业教育培训的形势十分严峻,"总量过剩、结构短缺"的矛盾十分突出.开展农民工职业教育培训问题与对策研究,提高农民工的就业与再就业能力的问题已迫切地摆
Starting with the change of the land cover and the landscape patterns as well as the cold-island effect of the oasis, the temporal and spatial variation and the stability of the oasis of the alluvial-
A CAD/CMM workpiece modeling system based on IGES file is proposed. The modeling system is implemented by using a new method for labelling the tolerance items o
Debris flow is a common disaster in mountain regions. The valley slope, storm rainfall and amassed sand-rock materials in a watershed may influence the types of
The IAP numerical annual climate prediction system has been presented in this paper. In order to evaluate this annual prediction system, annual ensemble hindcas
Based on the analysis of the field observation data off the Changjiang mouth in August 2000 and satellite image of sea surface temperature (SST) in summer of 19
从编辑管理的现代化建设、稿件质量控制、开拓期刊发行与巩固办刊经费、编辑素质培养四个方面,对办好科技期刊进行了论述。
From the four aspects of the modernization of
The sediment core DGKS9603 collected from the Okinawa Trough was used as research target. By use of unsaturated index of long-chain alkenone, δ13C of POC and o