【摘要】 <正>本文以南海沉积物为对象、进行若干条件实验、拟出适合海洋沉积物中微量铀、钍分离的化学流程。用加入铀、钍同位素示踪剂²⁸²U-²²⁸Th的方法,测定了南海陆坡水深1,600米的沉积岩芯的铀、钍含量及其同位素的比值。更多还原

【Abstract】 10 grams of sediment samples are used to some conditional experiments, including removal of organic matter from the samples at high temperature, coprecipitation of U and Th with iron hydroxide, determination of pH of the solution while U and Th are coprecipitated, static time of the copreci-pitation, affecting the recovery of U and Th, etc.A chemical procedure for separating trace U and Th and their isotopes from sediments was worked out. A method of adding standard U and Th into the sample was used. In the procedure the recovery rates of U and Th were 85.9% and 97.6%, respectively.In the procedure, U and Th were separated from the samples, and then their radioactive sources were prepared by electro-deposition. These sources satisfied the requirements of the radioactivity determination.In analyzing the cores of sediments from the continental slope of the South China Sea, isotopes282U-223 Th were added into the sediment samples as a tracer. Data of the contents of U and Th and their isotopes 284U, 288U and 280Th, 282Th which are distributed along the cores, and the ratios of these isotopes284 U/238U and280 Th/282Th were obtained.更多还原