Study on Sediment Transport in the Qianjiang Bay of Guang' ao, Shantou City by Using the Element Geochemistry Method

Nine samples of suspended matter at the surface or bottom and 34 elements in 20 samples of substrate sediment have been used in the neutron activation analyses. Authors study sediment and suspended matter movement by using the method of element geochemistry, and conclude through synthetic analysis and processing that the movement direction of suspended matter and substrate sediment tends to converge on the central area.

Dispersal and Fate of Dredged Materials Disposed of in the Changjiang Estuary Determined by Use of An in Situ Rare Earth Element Tracer

To investigate the dispersal pattern and the fate of dredged materials disposed at a pre-selected disposal site, a field tracer experiment was conducted in the North Passage of the Changjiang Estuary during the 2005 flood season. Three tons of dredged materials were mixed with 2.792 kg of sodium hexachloroiridate （IV） hexahydrate （SHH）, which contained the rare earth element tracer iridum （Ir）. Sampling was conducted at pre-selected sections of the estuary on the second, third and fourth day after the release of dredged materials. All samples were evaluated by use of neutron activation analysis. The majority of the dredged material was dispersed nearly parallel to the navigation channel and deposited between the channel and the south dike. Only a small quantity of dredged materials entered or crossed the navigation channel, and the back silting ratio in the navigation channel was about 5%. The dredged materials also dispersed southeasterly beyond two dike heads.

用元素地球化学方法研究汕头广澳前江湾的泥沙运移

应用中子活化方法分析9个表、底悬移质和20个底质沉积物样品里的34个元素,并应用元素地球化学方法,研究广澳前江湾泥沙和悬移质运移情况,通过对数据综合分析处理后,提出该海域的悬移质及底质泥沙运动的方向有向中心地带汇聚的趋势。

中子活化法测定地球化学样品中32种元素

采用中子活化法测定地球化学样品中32种元素。通过对谱线干扰、铀裂变干扰、(n,p)和(n,α)反应干扰进行校正,利用超热中子活化部分待测元素来提高方法的准确度和改善方法的检出限。32种元素的检出限在2×10-8~4.48×10-4之间。方法用于测定标准物质,测定值与标准值一致,测定值的相对标准偏差在0.7%~10%之间。

长江口北槽泥沙运动现场示踪分析研究

研究利用铱(Ir)作为信号元素制备示踪沙,在长江口北槽深水航道维护困难区段开展示踪沙的现场投放及回收试验。利用火试金法对回收的泥沙样品进行痕量铱金属的提炼,并将其富集在微小铅珠中;再将铅珠压成薄片,并作为原子反应堆照射靶样进行中子活化分析,检测铱的含量。实验结果表明,在位于北槽深水航道北侧的3#坑投放示踪沙,北槽试验区所有泥沙样品中均检测出铱含量,其中位于深水航道南侧滩地上泥样中铱含量最高。因此,北侧3#贮泥坑流失的泥沙存在着跨越航道进入南侧边滩的情况,这对北槽中段航道回淤的影响较大,为改善北槽深水航道困难段的维护条件需要改进该处的抛吹泥工艺或限制抛泥活动。

中国东部断陷盆地岩盐样品的仪器中子活化分析

地质上蒸发岩是天然卤水在蒸发、浓缩过程中通过化学沉淀而形成的,随着浓缩作用的进行,盐度不断增加。而盐水湖和淡水湖的物理、化学过程很不相同,盐水湖沉淀有机物不易分解且很好地保存下来,沉积物中有机质含量主要取决于这种保存过程。根据报道,蒸发岩与油气之间存在着密切关系,含油极富的中东、苏联、北美、欧洲等地的油气都是贮存在蒸发岩之下或分布于蒸发岩近侧。与此情况相似,中国东部许多新生代含油盆地都发育着巨厚的蒸发岩系。对于规模如此巨大的蒸发岩及其与油气的密切关系,目前引起了人们的极大关注。对于我国东部新生代盆地的地质复杂性。