元素活动态测量法在鄂尔多斯盆地砂岩型铀矿勘查中的应用

Application of the method of determination of element mobile forms in exploration for sandstone-type uranium deposits in the Ordos basin,China.

常规化探方法勘查砂岩型铀矿难以奏效。应用深穿透地球化学方法系列中的元素活动态测量法在鄂尔多斯盆地砂岩型铀矿上的试验结果表明,几种U元素活动态在矿体上方都有异常出现,特别是其中的粘土吸附态U含量级别高、异常衬度大。因此,土壤粘土吸附态U测量法是本区化探找铀矿的有效方法;取样深度和取样粒级分别以60～90cm和-120目为宜;采用400m的取样点距基本不影响本区砂岩型铀矿的找矿效果。在盆地东北部应用土壤粘土吸附态U测量法预测了3个有利地段,并在其中1个地段的深部发现了较好的铀矿化。

Conventional geochemical methods are difficult to yield effects in exploration for sandstone-type uranium deposits. Tests for the application of the determination of element mobile forms, which is one of the deep-penetrative geochemical exploration methods, to a sandstone-type uranium deposit in the Ordos basin show that anomalies of uranium of several mobile forms appear above the deposit, and especially that the uranium of clay-adsorbed form has a high content and a large anomaly contrast. Therefore the method of determination of uranium of clay-adsorbed form in soils is an effective geochernical exploration method for uranium deposits in this area. The test results also show that the suitable sampling parameters are depth 60-90 cm and grain size-120 mesh, and the 400 m sampling site distance in the main does not affect the results of exploration for the sandstone-type uranium deposit in this area. Three favorable areas in the northeastern Ordos basin have been evaluated using this method, and good uranium mineralization is found at depth in one of these areas.