黄河口海域沉积速率的研究

本文根据黄河口海域的特点,提出了一个新的模式描述沉积过程。将岩芯分成几个较大的部份,每一部份都代表一种沉积环境。在一种沉积环境中,输沙量虽有波动,但这种波动是有周期性的。在不同的周期中,可以认为。~(210)Pb的沉积通量是恒定的。计算不同层段之间的沉积时间可以采用公式: 由于输沙量的周期性变化,沉积物的含水量也往往呈现有规律的周期性变化。文中求出了各岩芯含水量W与。~(210)Pb含量之间的回归方程式,发现相关系数普遍较高。

SEDIMENT RATE IN AND NEAR THE HUANGHE RIVER DELTA BASIN

The average load of Huanghe River is 12 hundred million tons a year, varying a factor of 9 between the flood and dry years. Maximum load occurs in July-October (more than 83% of the annual load), especially in August. Because of the very large load, the river bed is silted up so severely that Huanghe River Mouth often changes, bringing about also a change of sedimental environment of the basin, thus complicating the sedimentation process. The general approach to the sedimentation process problem will not fit. A new model to compute accurately the sediment rates of the basin is presented here. The rock core is cut into several parts. Each part of the core represents a sort of sedimental environment. In one sort of sedimental environment the fluctuation of load is periodic irrespective of fluctuation load. The precipitating fluxes of ₂₁₀Pb are the same in different Periods. Therefore, the part of the core in one sort of sedimental environment is subdivided into several layers. Each layer represents a period. To compute the precipitating duration between the different layers the following formula is used:Because of periodic change of the load, water content in sediment has also a periodic change. The regress equations between contents of water and ₂₁₀Pb of different cores are obtained. The correlation coefficients are quite big, indicating, remarkable correlationship between them. Both water contents and ₂₁₀Pb are necessary and effective in the analysis of sedimental process.The contents of ₁₃₇Cs and species of the sediments are also studied in this article. They justify the results of the computions of various points of view.