石灰土剖面Th富集的地球化学研究

选择黔中岩溶地区的4条石灰3：-44面作为研究对象，通过精细采样分析，讨论了石灰土形成过程中Th富集的地球化学特征及行为．结果表明：1）岩一土界面是Th发生显著富集的重要地球化学作用场所，主要表现为岩一土界面反应中伴随碳酸盐快速溶蚀导致体积巨大缩小变化后的残余富集．在此过程中，Th表现出明显的惰性．2）在石灰土剖面形成和演化过程中，Th的地球化学行为可能因剖面间存在的微环境差异而有所不同．对于发育浅薄的剖面，Th受铁氧／氢氧化物和粘土矿物的吸附而表现出惰性；对于发育相对深厚的剖面，Th表现出明显的活性，其行为不受铁氧／氢氧化物和粘土矿物的明显影响．

Geochemical Research on Enrichment Behavior of Thorium in Limestone Soil Profiles

Selecting four limestone soil profiles as the subject investigated from karst area of central Guizhou Province, and based on careful sampling and analysis, this work discusses geochemical characteristics and behavior of Th enrichment during the formation of limestone soils. The results show that ： 1 ） the rock-soil interface is an important geochemical reaction place for significant enrichment of Th, and this mainly stems from residual enrichment of Th through huge changes in volume reduction of weathered residua accompanied by rapid disso- lution of carbonates in the interaction of rock-soil interface. In this process ,Th appears obviously inert. 2） During the formation and evolution of limestone soil profiles, different geo- chemical behavior of Th exists between profiles possibly owing to micro-environmental diver- sities. For shallowly developed profiles,Th shows evident inertia by adsorption of iron oxide/ hydroxide and clay minerals;for relatively profoundly developed profiles, Th exhibits some activity ,and its behavior is not susceptible to iron oxide/hydroxide and clay minerals.