Magnetic and gravity data are used in the early stages of exploration for uranium deposits in the Athabasca Basin of Canada, just as for many other mineral exploration scenarios. Uranium mineralization in the Athabasca Basin is located where faults in the basement intersect the unconformity between the basement and the overlying sandstones. The gravity and magnetic data are dominated by signatures from the basement and an overburden of glacial sediments. The gravity and magnetic data are effective at mapping the basement geology. Any subtle gravity signal from the mineralization related to the formation of the uranium deposits is masked by the signal from the variable-thickness overburden. Three-dimensional joint inversion of gravity and magnetic data, first without and then with constraints, is evaluated as a means of better determining the structure of the three main lithologies (overburden, sandstones, and basement) in the Athabasca Basin. A significant amount of physical property information is available for the main rock units (and overburden), which makes the use of the compositional approach to joint inversion appropriate. For the joint inversion, the fuzzy c-means clustering method is used. Results from representative synthetic examples indicate that the joint inversions can construct the overburden and basement structures better than the independent inversions of gravity and magnetic data. Furthermore, constrained joint inversion allows delineation of all three major layers in the area. The same inversion strategies then are applied to real airborne gravity and magnetic data from the McArthur River area in the eastern Athabasca Basin. The results we obtain demonstrate the capabilities of joint inversion for real-life situations.

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磁和重力数据的联合和约束反演：以加拿大麦克阿瑟河地区为例

像许多其他矿产勘探方案一样，在加拿大阿萨巴斯卡盆地铀矿勘探的早期阶段就使用了磁和重力数据。阿萨巴斯卡盆地的铀矿化位于基底断层与基底和上覆砂岩之间的不整合面相交的地方。重力和磁数据主要来自地下室的标志和冰川沉积物的覆盖层。重力和磁数据可有效绘制地下室地质图。来自与铀矿床形成有关的矿化作用的任何微妙的重力信号都被厚度可变的覆盖层的信号掩盖了。重力和磁数据的三维联合反演，首先没有约束，然后有约束，为了更好地确定阿萨巴斯卡盆地的三种主要岩性（上覆岩层，砂岩和地下室）的结构，对该岩层进行了评估。对于主要岩石单元（和上覆岩层）可获得大量的物理性质信息，这使得采用组合方法进行联合反演是合适的。对于联合反演，使用模糊c均值聚类方法。有代表性的综合实例的结果表明，与重力和磁数据的独立反演相比，联合反演可以更好地构造覆盖层和基底结构。此外，受约束的联合反演可以描述该地区所有三个主要层。然后，将相同的反演策略应用于来自阿萨巴斯卡盆地东部麦克阿瑟河地区的真实空中重力和磁数据。我们获得的结果证明了联合反演在现实生活中的功能。