黄土高原中部全新世沉积物辐射剂量率研究

摘要

Twenty Holocene sediment samples were collected from the middle part of the loess tableland. The mass concentrations of the radioactive elements U, Th, K were determined by neutron activation analysis ( NAA). And the natural dose-rate was calculated. The analytical results indicated that dose-rate was influenced by the grain-size composition of sediment and climate change. The natural dose-rate is maximum in the layers of paleoflood slack water deposit, and the loess layers is minimum, the soil layer is in the middle.%通过野外考察,在黄土高原中部采得20个沉积层剖面样品.使用中子活化法测得样品放射性元素U、Th、K质量分数,计算得出样品所在环境的辐射剂量率,发现在黄土土壤剖面中,古土壤层中辐射剂量率大于黄土层；古洪水滞流沉积剖面中的辐射剂量率最大.沉积物剖面中辐射剂量率变化与沉积时期气候环境和沉积物粒度相关.