A mineralogical and geochemical study of minerals on seven types of fracture fillings from near and above the McArthur River unconformity-related uranium deposit has been carried out to determine if fracture filling materials and wall rocks record evidence of primary and secondary dispersion of elements from the deposit. This study shows that Pb extracted by weak acid leaching (2% HNO₃) provides Pb-Pb model ages near 1100 Ma for fractures with any of the three REE patterns: 1) LREE-enriched patterns, 2) REE patterns that are concave and similar to uraninite in the deposit, and 3) fractures with flat REE patterns. The REE patterns and ages indicate the fractures are an open system to post-mineralization dispersion of radiogenic Pb from a U-rich source, with a major mobilization of Pb from the uranium deposit at ca. 1100 Ma.

Brown (Type 1) fractures, which host Mn-Fe oxides and clay minerals, provide the best evidence of U mineralization through post-mineralization dispersion, containing elevated concentrations of pathfinder elements Co, Ba, Tl, Mn and radiogenic Pb near the surface and at depth. Post-mineralization dispersion is also observed within brown (Type 1) and pink (Type 7; clay minerals + hematite) fractures and wall rock, showing low ²⁰⁷Pb/²⁰⁶Pb values of 0.29–0.50 that were subsequently overprinted by fluids with more common Pb, as recorded in fractures with higher ²⁰⁷Pb/²⁰⁶Pb values of 0.51–0.84.

Fracture fillings were analyzed by continuous leach inductively coupled plasma mass spectrometry (CL-ICP-MS) to determine the relationship between trace elements and elemental release from specific mineral phases. CL-ICP-MS results indicate that common Pb (with ²⁰⁷Pb/²⁰⁶Pb values > 0.7) and anomalous Co (360 ppm) and V (220 ppm) contents are resident in organic phases that are dissolved during the 10% H₂O₂ leach phase. CL-ICP-MS also indicates that radiogenic Pb, as well as Ni and V, are resident in clay minerals and Fe-Mn oxy-hydroxides that break down during leaching with 30% HNO₃. Uranium contents are low in the leachate during release of Fe, Al, Mn, and Pb using the 10% and 30% HNO₃ leaches, reflecting post-mineralization dispersion of radiogenic Pb, but not U. Thus, secondary dispersion of elements into fractures enhances the size of the deposit footprint, particularly in deep fractures near the P2 fault, but also in some fractures near the surface. The results of this study strongly suggest that fractures did indeed act as conduits for dispersion of elements from the deposit, reaching all the way from deposit to the surface, providing viable exploration targets for U mineralization in sedimentary basins.

进行了麦克阿瑟河附近和不整合相关铀矿床上七种类型的裂缝充填物中矿物的矿物学和地球化学研究，以确定裂缝充填材料和围岩是否记录了该矿床中元素的一次和二次扩散的证据。这项研究表明，通过弱酸浸提（2％HNO ₃）提供三种REE模式中任何一种的裂缝的1100 Ma附近的Pb-Pb模型年龄：1）富LREE模式，2）凹陷且与矿床中的尿素岩相似的REE模式，以及3）扁平REE模式的裂缝。REE模式和年龄表明，该裂缝是矿化后来自富铀来源的放射性Pb分散的开放系统，并且主要从铀矿床附近的Pb中动员了Pb 。1100毫安。

布朗裂缝（类型1）含有Mn-Fe氧化物和黏土矿物，通过矿化后的弥散提供了U矿化的最佳证据，矿化后的Co，Ba，Tl，Mn和地表附近的放射性Pb含量较高。在深处。矿化后的弥散也出现在棕色（1型）和粉红色（7型；粘土矿物+赤铁矿）裂缝和围岩中，显示出较低的²⁰⁷ Pb / ²⁰⁶ Pb值为0.29–0.50，随后被更常见的流体套印记录在²⁰⁷ Pb / ²⁰⁶ Pb值为0.51-0.84较高的裂缝中的Pb。

通过连续浸出电感耦合等离子体质谱法（CL-ICP-MS）分析裂缝填充物，以确定痕量元素与元素从特定矿物相中释放之间的关系。CL-ICP-MS结果表明，常见的Pb（²⁰⁷ Pb / ²⁰⁶ Pb值> 0.7）和异常的Co（360 ppm）和V（220 ppm）含量存在于有机相中，该有机相在10％H ₂ O时溶解。₂浸出阶段。CL-ICP-MS还表明，放射性矿物中的Pb以及Ni和V都存在于粘土矿物质和Fe-Mn羟基氧化物中，在用30％HNO ₃浸出时会分解。使用10％和30％的HNO ₃释放Fe，Al，Mn和Pb时，渗滤液中的铀含量低矿化后的浸出，反映了成矿后的放射性Pb而不是U的分散。因此，元素在裂缝中的二次分散会增加沉积足迹的大小，特别是在P2断层附近的深部裂缝中，在地表附近的某些裂缝中也是如此。这项研究的结果有力地表明，裂缝确实确实充当了元素从矿床中散布的管道，从矿床一直延伸到地表，为沉积盆地中的U矿化提供了可行的勘探目标。