The Teena Zn-Pb deposit is located in the Carpentaria Zn Province (Australia), which contains some of the largest clastic dominant (CD-type) massive sulfide Zn-Pb deposits in the world. The timing of the main stage of hydrothermal sulfide mineralization in the Teena subbasin is constrained to the midstage of burial diagenesis, during a period of short-lived regional extension. To distinguish hydrothermal alteration from spatially and temporally overlapping burial diagenetic alteration, and to establish the primary controls on hydrothermal mass transfer, it is necessary to evaluate the various foot- and hanging-wall alteration assemblages that formed between early- (eogenesis) and late- (mesogenesis) stage diagenesis. To achieve this, we have statistically evaluated a large lithogeochemistry dataset (n >2,500) and selected a subset (n = 65) of representative samples for detailed mineralogical (X-ray diffraction, illite crystallinity) and petrographic (scanning electron microscopy) analyses; hyperspectral core imaging data were then used to upscale key paragenetic observations.We show that sulfide mineralization was predated by multiple diagenetic alteration assemblages, including stratiform pyrite, dolomite nodules and cement, disseminated hematite and authigenic K-feldspar. These assemblages formed during eogenesis in multiple subbasins across the broader McArthur Basin and are not part of the synmineralization alteration footprint. Whereas pyrite and dolomite formed primarily from the in situ degradation of organic matter, feldspar authigenesis was the product of K metasomatism that was focused along permeable coarse-grained volcaniclastic sandstone beds within the host-rock sequence. The immature volcaniclastic input is broadly representative of the siliciclastic compositional end member in the subbasin, which formed the protolith for phyllosilicate (illite, phengite, chlorite) formation during burial diagenesis. There is no evidence of extensive phyllosilicate alteration in any of the geochemical, mineralogical (illite crystallinity), or petrographic datasets, despite some evidence of K-feldspar replacement by sphalerite in the Lower and Main mineralized lenses. Rather, the high Zn grades formed via dolomite replacement, which is resolvable from a chemical mass balance analysis and consistent with petrographic observations.There are significant exploration implications associated with carbonate-replacement sulfide mineralization during mesogenesis: (1) the capacity for secondary porosity generation in the host rock is as important as its sulfate-reducing capacity; (2) hydrothermal mineralization has a short-range cryptic lateral and vertical synmineralization alteration footprint due to acid neutralization by a carbonate-rich protolith; and (3) the distribution and chemistry of premineralization phases (e.g., pyrite, dolomite nodules) cannot be directly related to the mineralization footprint, which is localized to the 4^th-order subbasin scale. Future exploration for this deposit style should therefore be focused on identifying units that contain a mixture of organic carbon and carbonate in the protolith, at favorable stratigraphic redox boundaries, and proximal to feeder growth faults.

中文翻译：

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Teena Zn-Pb 矿床（澳大利亚麦克阿瑟盆地）。第二部分：埋藏成岩过程中碳酸盐替代硫化物成矿——对矿产勘探的启示

Teena Zn-Pb 矿床位于 Carpentaria Zn 省（澳大利亚），其中包含一些世界上最大的碎屑优势（CD 型）块状硫化物 Zn-Pb 矿床。蒂纳亚盆地热液硫化物成矿主阶段时间被限制在埋藏成岩中期，处于短暂的区域延伸时期。为了将热液蚀变与时空重叠的埋藏成岩蚀变区分开来，并建立对热液传质的主要控制，有必要评估形成于早（始生）和晚(mesogenesis) 阶段成岩作用。为了实现这一目标，我们对一个大型岩石地球化学数据集进行了统计评估（n > 2，500) 并选择了代表性样品的子集 (n = 65) 进行详细的矿物学（X 射线衍射、伊利石结晶度）和岩相学（扫描电子显微镜）分析；然后使用高光谱岩心成像数据来放大关键的共生观察。我们表明硫化物矿化早于多种成岩蚀变组合，包括层状黄铁矿、白云岩结核和胶结物、浸染赤铁矿和自生钾长石。这些组合在更广泛的麦克阿瑟盆地的多个子盆地的演化过程中形成，并且不是同矿化改变足迹的一部分。而黄铁矿和白云石主要由有机物的原位降解形成，长石自生是 K 交代作用的产物，K 交代作用集中在主岩层序内可渗透的粗粒火山碎屑砂岩层。未成熟火山碎屑输入广泛代表了盆地中的硅质碎屑成分端部成员，其在埋藏成岩作用期间形成了页硅酸盐（伊利石、苯镁石、绿泥石）形成的原岩。在任何地球化学、矿物学（伊利石结晶度）或岩相数据集中都没有证据表明存在广泛的页硅酸盐蚀变，尽管有一些证据表明在下矿化透镜体和主矿化透镜体中钾长石被闪锌矿替代。相反，高锌品位是通过白云石置换形成的，这可以通过化学质量平衡分析解决，并与岩相观察一致。中生期碳酸盐替代硫化物成矿具有重要的勘探意义：(1) 母岩中次生孔隙生成能力与其硫酸盐还原能力同等重要；(2) 由于富含碳酸盐的原岩的酸中和作用，热液成矿具有短程隐蔽的横向和纵向同矿化蚀变足迹；(3) 矿化前期（如黄铁矿、白云石结核）的分布和化学性质与矿化足迹不能直接相关，矿化足迹位于 4 (2) 由于富含碳酸盐的原岩的酸中和作用，热液成矿具有短程隐蔽的横向和纵向同矿化蚀变足迹；(3) 矿化前期（如黄铁矿、白云石结核）的分布和化学性质与矿化足迹不能直接相关，矿化足迹位于 4 (2) 由于富含碳酸盐的原岩的酸中和作用，热液成矿具有短程隐蔽的横向和纵向同矿化蚀变足迹；(3) 矿化前期（如黄铁矿、白云石结核）的分布和化学性质与矿化足迹不能直接相关，矿化足迹位于 4^次阶子流域的规模。因此，这种矿床类型的未来勘探应侧重于识别在原岩中含有有机碳和碳酸盐混合物的单元，在有利的地层氧化还原边界处，并靠近馈线生长断层。