自然α杯法壤中氡气测量在化探异常评价中的应用

应用自然α杯法壤中氡气测量来评价金和多金属矿床所形成的化探异常的工作做得还不多。为了开拓氡气测量应用的新领域和为可靠评价化探异常增加一个新指标,我们在位于半干旱草原景观的新疆某Au异常区和黄土沟壑景观的甘肃蛟龙掌多金属黄铁矿区进行了初步尝试。结果表明:(1)Rn气异常令人满意地圈定了已知Au矿化体的赋存部位(包括隐伏部分),并圈出了几处找Au远景区段(其中一处已经验证,结果表明推测基本正确)。说明自然α杯法氡气测量可以作为圈定构造破碎带控制的隐伏Au矿化体的有效手段之一。与其他化探方法配合,可为找寻含Au构造破碎带提供可靠的信息。(2)在黄土和第三系红色粘土埋深20m左右的多金属矿化带及构造破碎带上方具有Rn气弱异常。说明自然α杯法氡气测量在黄士覆盖区用于找寻隐伏多金属矿化是有效的。

THE APPLICATION OF SOIL RADON VAPOR SURVEYWITH NATURAL α-CUP METHOD TO THE APPRAISALOF GEOCHEMICAL ANOMALIES

Only a small amount of work has been done concerning the application ofsoil radon vapor survey with natural α-cup method to the appraisal of geo-chemical anomalies formed by gold and polymetallic ore deposits. In order toopen a new field for radon vapor survey and add a new reliable criterion tothe appraisal of geochemical anomalies, we made some preliminary tests in acertain gold anomalous area in Xinjiang belonging to semiarid steppe landscapeand the Jiaolongzhang polymetallic pyrite ore district in Gansu belonging toloessial ravine landscape. The results show that the radon vapor anomaliespinpoint satisfactorily the localities (including the concealed parts) of theknown gold mineralized bodies, and delineate several promising sectors for goldprospecting(one of them have already been verified). This demonstrates thatthe soil radon vapor with natural α-cup method can be used as one of theeffective means for delineating concealed gold mineralizations controlled bystructural fracture zones and, together with other geochemical prospecting me-thods, it may provide reliable information for finding gold-bearing structuralfracture zones. Faint radon vapor anomalies exist over the polymetallic mine-ralized zones and structural fracture zones covered with loess and Tertiary redclay some 20 m in thickness, and this suggests that the soil radon vapor sur-vey with natural α-cup method is effective in search for concealed polyme-tallic mineralizations in the loess region.