The western North American Great Basin's Carlin-type deposits represent the largest accumulation of gold in the Northern Hemisphere. The controversy over their origins echoes the debate between Neptunists and Plutonists at the birth of modern geology: were the causative processes meteoric or magmatic? Sulfur isotopes have long been considered key to decoding metal cycling in the Earth's crust, but previous studies of Carlin-type pyrite lacked the spatial resolution to quantify differences among the numerous generations of sulfide mineralization. We developed a new dual-method, nanoscale approach to examine the fine-grained ore pyrite. The δ34S of the ore pyrite varies systematically with Au concentration at the nanoscale, indicating that both magmatic and meteoric fluids contributed during mineralization, but the magmas brought the gold. Repeated oscillations in fluid ratios upgraded the metal content, resulting in high gold endowment. Our results demonstrate that high-spatial-resolution studies are key to elucidate the spatiotemporal evolution of complex hydrothermal systems.The Carlin-type gold deposits in the Great Basin (western North America; Fig. 1) are the largest accumulations of gold and the least understood gold deposit type in the Northern Hemisphere, inspiring questions about the processes governing metal cycling and mineralization in the Earth's crust. More gold is produced annually from these deposits than from any other site in the world (Harper, 2020). Carlin-type deposits also represent potential resources of “critical minerals”, including arsenic and antimony (Goldfarb et al., 2016). Carlin-type ore occurs as disseminated hydrothermal replacement bodies, primarily hosted in structures crosscutting decarbonated silty limestones. The gold exists in solid solution or as nanoparticles within micron- to nanometer-thick rims of hydrothermal arsenian pyrite overgrowing older sedimentary and magmatic-hydrothermal pyrite grains that were present in the host rocks prior to gold mineralization. Although deposits with similar characteristics occur elsewhere on the planet, it has been suggested that the enormous gold endowment in the Great Basin represents a nonreplicable combination of geologic processes (Cline et al., 2005). The source of Carlin-type gold has eluded definition, echoing the debate waged between neptunists and plutonists at the birth of modern geology: Did meteoric fluids scavenge and then redeposit gold as they circulated through the sedimentary rocks (Ilchik and Barton, 1997; Emsbo et al., 2003; Large et al., 2011), or was the gold introduced by magmas (Sillitoe and Bonham, 1990; Ressel and Henry, 2006; Muntean et al., 2011)?Carlin-type deposits are notoriously difficult to study because their mineralogy is not amenable to the traditional tools used to fingerprint the origins of metal enrichment (Richards, 2011). Fine-scale zonation in sulfide mineral geochemistry is common in many deposit styles, and the spatial resolution of traditional analytical techniques has been insufficient to differentiate among Carlin-type pyrite generations. Hydrogen and oxygen isotopes of the clays and fluid inclusions at Carlin-type deposits represent mixtures between syn-ore and pre-ore phases, consistent with precipitation from a meteoric fluid or mixing between meteoric and magmatic fluids (Hofstra and Cline, 2000; Cline et al., 2005, and references therein). Carlin-type mineralization ages are imperfectly constrained due to the paucity of dateable syn-ore minerals, but the timing of mineralization appears to track the late Eocene southwestern sweep of calc-alkaline magmatism through the region (Cline et al., 2005). Several Carlin-type gold districts in the Great Basin show no evidence of Eocene magmatism (Fig. 1), and the sedimentary host rocks are unusually enriched in metals including Au and As (Emsbo et al., 2003; Large et al., 2009). Similar smaller deposits elsewhere in the world lack evidence for syn-mineralization magmatism (Cline, 2018; Pinet et al., 2020).Because reduced sulfur served as the principal ligand during gold transport (Cline et al., 2005), sulfur isotopes have long been considered the unattainable key to determine the origins of Carlin-type gold (gold itself has only one stable isotope). The term “δ34S” refers to the isotope ratio 34S/32S (‰) relative to Vienna Cañon Diablo troilite. The δ34S values of ore pyrite can be compared to the δ34S of potential sulfur reservoirs. Elemental analyzer–isotope ratio mass spectrometry (EA-IRMS) of whole grains gives δ34S values that average the older pyrite and hydrothermal pyrite overgrowths; results are permissive of either magmatic or sedimentary origins (Cline et al., 2005; Christiansen et al., 2011). Traditional secondary ion mass spectrometry (SIMS) studies reached varying conclusions based on only a few data points from spot sizes of 10–30 μm encompassing multiple compositional zones in the pyrite. Data are suggestive of a magmatic origin at Getchell and Betze-Post (Nevada, USA; Cline et al., 2003; Kesler et al., 2003; Henkelman, 2004; Kesler et al., 2005). Relative differences in 34S/32S between cores and rims were determined for three grains from Turquoise Ridge and West Banshee using qualitative nanoscale SIMS (NanoSIMS) mapping (Barker et al., 2009) and atom probe tomography (Gopon et al., 2019), but the data were not standardized so the origins of the gold-bearing fluid remained elusive. We paired NanoSIMS depth profiles and laser ablation–multicollector–inductively coupled plasma mass spectrometry (LA-MC-ICPMS) to resolve the insufficient spatial resolution and the potential for matrix effects inherent in previous methods.We examined ore pyrites in 40 samples from five well-studied Carlin-type deposits in Nevada—Carlin, Deep Star, Beast, Turquoise Ridge, and Getchell—as well as northern Carlin-trend Eocene dikes (Fig. 1; see the Supplemental Material1). From petrography and scanning electron microscopy of thousands of pyrite grains, we selected 64 locations in representative grains for in situ sulfur isotopic and trace element study. We made NanoSIMS maps of the grains by collecting 63Cu, 75As, 107Ag, 117Sb, and 197Au data on electron multipliers and calibrated the data with relative sensitivity factors using an electron microprobe. Figure 2 shows representative examples of the target locations and NanoSIMS maps.Standardized, quantitative analyses of sulfur isotopes in sulfide minerals were previously only possible at a spatial resolution of 1–15 μm (Zhang et al., 2014, 2017; Hauri et al., 2016). The methods ignored compositional heterogeneity in the Z-direction, averaging NanoSIMS data over the length of an entire analytical run. We improved the method to record nanoscale compositional variation by producing a depth profile at each of our 64 spots, gathering 2400 individual data points per analytical run as the beam penetrated through successive heterogeneous geochemical zones (see the Supplemental Material). Each depth-profile data point represents a depth interval of <1 nm. Figure 3 shows six representative depth profiles. To quantify trends in a manageably reduced number of data points, we calculated plateau averages from zones of consistent composition within each depth profile (see the Supplemental Material). In Figures 4A–4D and in Table S1 (in the Supplemental Material), we present data for 89 NanoSIMS plateaus. The average δ34S ratio error for plateaus was ±0.86 (one standard deviation) (Table S1). We validated our NanoSIMS results from coarse areas using 5 μm LA-MC-ICPMS spots in 23 locations. The δ34S data are consistent between the two methods (Table S2), indicating that our observed core-rim fractionations are not due to matrix effects.The pre-mineralization sedimentary pyrite at Carlin, Getchell, and Turquoise Ridge contains little Au or As (Figs. 2 and 3A–3E). Sedimentary pyrite δ34S varies widely between locations and stratigraphic horizons, and most of our samples are isotopically heavy (Figs. 3A–3C and 3E versus Fig. 3D; Table S1). Many of our depth profiles through sedimentary pyrite grain cores generated smooth plateaus (representative depth profiles in Figures 3A–3C, resulting in plateau data points shown in Figure 4). Several showed heterogeneity in δ34S (Figs. 3D and 3E), perhaps due to fluctuations in microbial activity during sedimentary pyrite formation.The unmineralized Jurassic magmatic-hydrothermal pyrite grain cores from Deep Star contain minor Au and δ34S values of 6.5‰–6.9‰ (Fig. 4D), close to the mean δ34S of Jurassic magmatic sulfur in the Great Basin (Arehart et al., 2013). The Eocene magmatic pyrites at Betze-Post, Deep Star, and Beast contain minor Au with δ34S values (Fig. 4D) within the range of Tertiary magmatic sulfur in the Great Basin, which is itself isotopically variable due to variable host-rock interaction (Fig. 4F).The NanoSIMS maps and depth profiles show a sharp contact between the precursor pyrite cores and the Au-As–rich hydrothermal rims (Figs. 2 and 3). The Au concentrations vary within the rims at a finer scale than previously surmised (Cline et al., 2005; Barker et al., 2009; Muntean et al., 2011; Large and Maslennikov, 2020) and also vary widely between samples (Figs. 3 and 4). In most samples, the depth profiles also show a dramatic change in δ34S at the contact between precursor cores and hydrothermal rims (Fig. 3). Within the rims, the δ34S values commonly vary inversely with Au (Figs. 3 and 4A–4C) but lack correlation with As. The lowest plateau values from the rims come from Au-rich zones: 1.7‰ δ34S at Getchell, 2.5‰ at Carlin, 1.2‰ at Turquoise Ridge, 4.2‰ at Deep Star, and 2.1‰ at Beast (Figs. 4A–4D).At each deposit, the δ34S plateau values from the rims plot on a mixing line between two end members (Figs. 4A–4E): (1) an Au-poor sulfur source isotopically similar to local host pyrite cores, and (2) an Au-rich sulfur source with δ34S values similar to those of mineralizing Eocene magmatic-hydrothermal fluids in the nearby Battle Mountain district (−1.8‰ to 7‰; Fig. 4F) and similar to the mean δ34S of Great Basin Tertiary granitoid magmas (7.1‰; Arehart et al., 2013). Our microanalytical evidence for two-component mixing is supported by whole-rock geochemical data from Betze-Post's Screamer ore body (Fig. 4D; Christiansen et al., 2011): isotopically variable host pyrite in the Popovich Formation controls the δ34S values in samples without detectable gold, and a sulfur source near 0‰ contributes substantially at high ore grades. The depth profiles show nanoscale zonation resulting from variation in relative contributions of the two sources over time (Fig. 3).The Au-poor sulfur source may represent dissolution of sulfur-bearing minerals and organosulfur complexes during meteoric fluid circulation through the sedimentary host-rock package. The Au-rich sulfur requires an alternate source to explain the strong correlations between δ34S and Au. A meteoric fluid convecting deeply through sedimentary rock would achieve δ34S compositions representing regional or local averages of the stratigraphy. Although such a fluid could become Au rich by interacting with large volumes of rock containing trace metals or during passage through metalliferous sedimentary horizons (e.g., Large et al., 2011), initial correlations between δ34S and metal content at a mutual point of origin would be lost during fluid circulation due to interaction with isotopically varied sulfur elsewhere in the rock package.The Au-rich sulfur in Carlin-type ore was most likely derived from Eocene magmas. Magmatic-hydrothermal sulfide minerals from the nearest Eocene porphyry and other pluton-proximal deposits in the Battle Mountain district have δ34S values ranging from −1.0‰ to 6.6‰ (this study; Theodore et al., 1986; King, 2017; Holley et al., 2019). Using a range of realistic precipitation temperatures, the δ34S of the causative Eocene magmatic fluids can be constrained to −1.8‰ to 7.0‰ (Table S3). Temperature-induced fractionation would cause those fluids to precipitate Carlin-type pyrite with a δ34S of 0.0‰–8.8‰ at 200 °C (a reasonable temperature estimate for Carlin-type mineralization; Cline et al., 2005). Because the Au-rich zones of our pyrites gave δ34S values in this range (Figs. 4A–4D), we attribute their origins to the Eocene magmatic fluid.The causative magmas were isotopically similar to those that generated the Beast dike (δ34S depth profile values of 2.1‰–8.5‰). Eocene magmas of similar compositions either stalled out at depth beneath the Getchell trend or remain unrecognized. During magma cooling, Au and As would have become enriched in the exsolving fluids. Circulation of these fluids in the magmatic-hydrothermal environment led to variable interaction with Au-poor meteoric fluids and other sulfur sources, including isotopically heavy and light sedimentary sulfur minerals, as well as older magmatic and magmatic-hydrothermal sulfur and metals. Upon reaching favorable lithologic horizons and hydrologic or structural traps, these mixing fluids encountered preexisting pyrite. Sulfidation led to hydrothermal pyrite precipitation, and temporal fluctuations in the relative contribution of Au-rich magmatic and Au-poor meteoric fluids led to sequential nanoscale zones with covarying Au and δ34S.Carlin-type pyrite provides insights into the processes driving the formation of giant ore deposits. Fluid mixing led to fluctuations in metal precipitation, although the time scales over which the relative fluid contributions varied are unknown. These repeated oscillations were essential in upgrading metal concentrations at the mineral scale, ultimately leading to the formation of world-class ore bodies. In the absence of nanoscale data, previously developed models for metal enrichment in these deposits were overly simplistic, and such models require reevaluation (e.g., Sillitoe and Bonham, 1990; Ilchik and Barton, 1997; Emsbo et al., 2003; Ressel and Henry, 2006; Large et al., 2011; Muntean et al., 2011; Kusebauch et al., 2019; Xing et al., 2019). Low-spatial-resolution analytical methods have been applied to ore deposits for decades, even where micron- to submicron-scale trace element zonation or mineral intergrowths are visible in reflected light microscopy or scanning electron backscatter imaging. Such textures give intriguing hints that fluid mixing played a key role during mineralization in numerous geological settings, and our study highlights how high-spatial-resolution observations can elucidate the underlying geological processes.This study was funded by U.S. National Science Foundation (NSF) Career Award EAR-1752756 (E.A. Holley). The Stanford Nano Shared Facilities are supported by NSF award ECCS-2026822. We thank Jean Cline, Phillip Gopon, Al Hofstra, Mike Ressel, and Patrick Sack for samples and discussion; Aaron Bell, Nigel Kelly, and Katharina Pfaff for analyses; Jae Erickson, Kelsey Livingston, Sage Langston-Stewart, and Heather Lowers for sample preparation; and Chris Henry, Celestine Mercer, Adam Simon, and an anonymous reviewer for comments. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

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纳米级同位素证据解决了巨型卡林型矿床的起源

北美大盆地西部的卡林型矿床是北半球最大的金矿聚集地。关于它们起源的争论呼应了现代地质学诞生时海王星和冥王星之间的争论：成因过程是流星的还是岩浆的？硫同位素长期以来一直被认为是解码地壳中金属循环的关键，但之前对卡林型黄铁矿的研究缺乏空间分辨率来量化数代硫化物矿化之间的差异。我们开发了一种新的双方法纳米级方法来检查细粒矿石黄铁矿。矿石黄铁矿的δ34S随Au浓度在纳米尺度上系统地变化，表明成矿过程中岩浆流体和陨石流体都有贡献，但岩浆带来了金。流体比率的反复波动提高了金属含量，导致黄金禀赋高。我们的研究结果表明，高空间分辨率研究是阐明复杂热液系统时空演化的关键。大盆地（北美西部；图 1）的 Carlin 型金矿床是金的最大聚集地，也是最少的了解北半球的金矿类型，激发了关于控制地壳中金属循环和矿化过程的问题。这些矿床每年生产的黄金比世界上任何其他地方都多（Harper，2020 年）。卡林型矿床也代表了“关键矿物”的潜在资源，包括砷和锑（Goldfarb 等，2016）。卡林型矿石以浸染性热液置换体的形式出现，主要存在于横切脱碳粉质石灰岩的结构中。金存在于固溶体中或作为纳米颗粒存在于热液砷黄铁矿的微米至纳米厚的边缘中，这些边缘在金矿化之前存在于宿主岩中的较老的沉积和岩浆热液黄铁矿颗粒过度生长。尽管地球上其他地方也有类似特征的矿床，但有人认为，大盆地的巨大黄金禀赋是地质过程不可复制的组合（Cline et al., 2005）。卡林型金的来源尚未得到定义，这与现代地质学诞生时海王星和冥王星之间的争论相呼应：流星流体在沉积岩中循环时是否会清除并重新沉积黄金（Ilchik 和 Barton，1997；Emsbo 等）等，2003；Large 等人，2011 年），还是岩浆引入的金（Sillitoe 和 Bonham，1990 年；Ressel 和 Henry，2006 年；Muntean 等人，2011 年）？众所周知，卡林型矿床很难研究，因为它们的矿物学不适用于用于识别金属富集来源的传统工具（Richards，2011 年）。硫化物矿物地球化学的精细分带在许多矿床类型中很常见，传统分析技术的空间分辨率不足以区分卡林型黄铁矿世代。Carlin 型矿床的粘土和流体包裹体的氢和氧同位素代表同矿相和前成矿相之间的混合物，这与来自大气流体的沉淀或大气流体和岩浆流体之间的混合一致（Hofstra 和 Cline，2000；Cline 等）等人，2005 年，以及其中的参考资料）。由于缺乏可确定年代的同矿石矿物，卡林型矿化年龄不受完全限制，但矿化时间似乎与晚始新世西南地区钙碱性岩浆作用相一致（Cline 等，2005）。大盆地的几个卡林型金矿区没有发现始新世岩浆作用的迹象（图 1），沉积母岩异常富集金、砷等金属（Emsbo 等，2003；Large 等，2009） ）。世界其他地方类似的小型矿床缺乏同矿化岩浆作用的证据（Cline，2018 年；Pinet 等人，2020 年）。因为还原硫是黄金运输过程中的主要配体（Cline 等人，2005 年），硫同位素长期以来一直被认为是确定卡林型金起源的高不可攀的关键（金本身只有一种稳定同位素）。术语“δ34S”是指同位素比 34S/32S (‰) 相对于 Vienna Cañon Diablo 陨石。黄铁矿的 δ34S 值可以与潜在硫储层的 δ34S 进行比较。全谷物的元素分析仪-同位素比质谱法 (EA-IRMS) 给出了 δ34S 值，该值是较老的黄铁矿和热液黄铁矿过度生长的平均值；结果允许岩浆成因或沉积成因（Cline 等人，2005；Christiansen 等人，2011）。传统的二次离子质谱 (SIMS) 研究仅基于来自 10-30 μm 光斑大小的几个数据点得出了不同的结论，涵盖了黄铁矿中的多个成分区。数据表明 Getchell 和 Betze-Post 的岩浆成因（美国内华达州；Cline 等人，2003；Kesler 等人，2003；Henkelman，2004；Kesler 等人，2005）。使用定性纳米级 SIMS (NanoSIMS) 映射 (Barker et al., 2009) 和原子探针断层扫描 (Gopon et al., 2019) 确定了来自 Turquoise Ridge 和 West Banshee 的三种晶粒的核心和边缘之间 34S/32S 的相对差异，但数据没有标准化，因此含金液体的来源仍然难以捉摸。我们将 NanoSIMS 深度剖面和激光烧蚀-多收集器-电感耦合等离子体质谱 (LA-MC-ICPMS) 配对，以解决先前方法中空间分辨率不足和潜在的基质效应问题。我们检查了来自 5 个井的 40 个样品中的黄铁矿-研究了内华达州的卡林型矿床——卡林、深星、Beast、Turquoise Ridge 和 Getchell——以及北卡林趋势始新世岩脉（图 1；见补充材料 1）。从数千个黄铁矿晶粒的岩相学和扫描电子显微镜中，我们选择了代表性晶粒中的 64 个位置进行原位硫同位素和微量元素研究。我们通过在电子倍增器上收集 63Cu、75As、107Ag、117Sb 和 197Au 数据来制作晶粒的 NanoSIMS 图，并使用电子微探针使用相对灵敏度因子校准数据。图 2 显示了目标位置和 NanoSIMS 图的代表性示例。以前只能在 1-15 μm 的空间分辨率下对硫化物矿物中的硫同位素进行标准化定量分析（Zhang 等人，2014 年，2017 年；Hauri 等人。 , 2016)。这些方法忽略了 Z 方向的成分异质性，在整个分析运行期间平均 NanoSIMS 数据。我们改进了记录纳米级成分变化的方法，方法是在我们的 64 个点中的每一个点生成深度剖面，当光束穿透连续的异质地球化学区时，每次分析运行收集 2400 个单独的数据点（参见补充材料）。每个深度剖面数据点代表 <1 nm 的深度间隔。图 3 显示了六个具有代表性的深度剖面。为了量化可管理地减少的数据点数量的趋势，我们计算了每个深度剖面内组成一致的区域的高原平均值（参见补充材料）。在图 4A-4D 和表 S1（在补充材料中）中，我们提供了 89 个 NanoSIMS 平台的数据。平台期的平均 δ34S 比率误差为 ±0。86（一个标准偏差）（表S1）。我们在 23 个位置使用 5 μm LA-MC-ICPMS 点验证了粗糙区域的 NanoSIMS 结果。两种方法的 δ34S 数据是一致的（表 S2），表明我们观察到的岩心-边缘分馏不是由于基质效应。Carlin、Getchell 和 Turquoise Ridge 的矿化前沉积黄铁矿含有很少的 Au 或 As（图. 2 和 3A-3E)。沉积黄铁矿 δ34S 在位置和地层层位之间变化很大，我们的大多数样品都是同位素重的（图 3A-3C 和 3E 与图 3D；表 S1）。我们通过沉积黄铁矿颗粒岩心的许多深度剖面产生了平滑的高原（图 3A-3C 中的代表性深度剖面，导致图 4 所示的高原数据点）。有几个显示出 δ34S 的异质性（图 3D 和 3E），可能是由于沉积黄铁矿形成过程中微生物活动的波动。来自Deep Star的未成矿的侏罗纪岩浆-热液黄铁矿颗粒核心含有少量的Au和δ34S值为6.5‰-6.9‰（图4D），接近侏罗纪岩浆的平均δ34S大盆地中的硫（Arehart 等人，2013 年）。Betze-Post、Deep Star 和 Beast 的始新世岩浆黄铁矿在大盆地的第三纪岩浆硫范围内含有具有 δ34S 值的少量金（图 4D），由于主岩相互作用的变化，其本身是同位素变化的（图 4F). NanoSIMS 图和深度剖面显示前体黄铁矿核心和富含 Au-As 的热液边缘之间的强烈接触（图 2 和 3）。Au 浓度在轮辋内的变化比之前推测的更精细（Cline et al., 2005; Barker et al., 2009; 蒙泰恩等人，2011；Large 和 Maslennikov，2020 年），并且样本之间的差异也很大（图 3 和图 4）。在大多数样品中，深度剖面还显示前体岩心和热液边缘之间接触处的 δ34S 发生显着变化（图 3）。在轮缘内，δ34S 值通常与 Au 成反比变化（图 3 和 4A-4C），但与 As 缺乏相关性。边缘的最低高原值来自富金区：Getchell 为 1.7‰ δ34S，Carlin 为 2.5‰，Turquoise Ridge 为 1.2‰，Deep Star 为 4.2‰，Beast 为 2.1‰（图 4A-4D）。在每个矿床中，来自边缘的 δ34S 平台值绘制在两个端部成员之间的混合线上（图 4A-4E）：（1）与当地黄铁矿核心同位素相似的贫金硫源，(2) 富金硫源，其 δ34S 值与附近巴特尔山区成矿始新世岩浆热液相似（-1.8‰ 至 7‰；图 4F），与大盆地平均 δ34S 值相似第三纪花岗岩浆（7.1‰；Arehart 等，2013）。Betze-Post 的 Screamer 矿体的全岩地球化学数据支持我们对双组分混合的微分析证据（图 4D；Christiansen 等，2011）：Popovich 组中同位素可变的宿主黄铁矿控制样品中的 δ34S 值没有可检测到的金，接近 0‰ 的硫源对高矿石品位的贡献很大。深度剖面显示了随着时间的推移两个源的相对贡献的变化导致的纳米级分区（图 3）。贫金硫源可能代表在大气流体循环通过沉积主岩包过程中含硫矿物和有机硫复合物的溶解。富含 Au 的硫需要另一个来源来解释 δ34S 和 Au 之间的强相关性。通过沉积岩对流的流星流体将获得代表地层的区域或局部平均值的 δ34S 成分。虽然这种流体可以通过与大量含有微量金属的岩石相互作用或在穿过含金属沉积层的过程中变得富金（例如，Large 等人，2011 年），但 δ34S 与金属含量在相互起源点之间的初始相关性将在流体循环过程中由于与岩石包裹中其他位置的同位素变化硫相互作用而损失。卡林型矿石中的富金硫很可能来自始新世岩浆。来自巴特尔山区最近的始新世斑岩和其他近岩体矿床的岩浆热液硫化物矿物的 δ34S 值范围为 -1.0‰ 至 6.6‰（本研究；Theodore 等人，1986 年；King，2017 年；Holley 等人., 2019)。使用一系列实际降水温度，始新世成因岩浆流体的 δ34S 可以限制在 -1.8‰ 到 7.0‰ （表 S3）。温度引起的分馏会导致这些流体在 200°C 时沉淀出 δ34S 为 0.0‰–8.8‰ 的卡林型黄铁矿（卡林型矿化的合理温度估计；Cline 等，2005）。因为我们黄铁矿的富金带在这个范围内给出了 δ34S 值（图 4A-4D），我们将它们的起源归因于始新世岩浆流体。成因岩浆在同位素上与产生野兽岩脉的岩浆相似（δ34S 深度剖面值为 2.1‰–8.5‰）。类似成分的始新世岩浆要么在格切尔趋势之下的深处停滞不前，要么仍未被识别。在岩浆冷却期间，Au 和 As 会在溶出流体中变得富集。这些流体在岩浆热液环境中的循环导致与贫金大气流体和其他硫源的相互作用，包括同位素重质和轻质沉积硫矿物，以及更古老的岩浆和岩浆热液硫和金属。在达到有利的岩性层位和水文或构造圈闭时，这些混合流体遇到了预先存在的黄铁矿。硫化导致热液黄铁矿沉淀，富金岩浆和贫金陨石的相对贡献的时间波动和时间波动导致具有共变金和 δ34S 的连续纳米级区域。卡林型黄铁矿提供了对推动巨型矿床形成过程的见解。流体混合导致金属沉淀的波动，尽管相对流体贡献变化的时间尺度尚不清楚。这些反复的振荡对于提高矿物规模的金属浓度至关重要，最终导致世界级矿体的形成。在缺乏纳米级数据的情况下，以前开发的这些沉积物中金属富集的模型过于简单，需要重新评估这些模型（例如，Sillitoe 和 Bonham，1990；Ilchik 和 Barton，1997；Emsbo 等，2003；Ressel 和 Henry , 2006 年；Large 等人，2011 年；蒙泰恩等人，2011；Kusebauch 等人，2019；邢等人，2019）。几十年来，低空间分辨率分析方法已应用于矿床，即使在反射光显微镜或扫描电子反向散射成像中可以看到微米至亚微米尺度的微量元素环带或矿物共生。这种纹理提供了有趣的暗示，即流体混合在许多地质环境中的矿化过程中发挥了关键作用，我们的研究强调了高空间分辨率观测如何阐明潜在的地质过程。这项研究由美国国家科学基金会 (NSF) 资助授予 EAR-1752756（EA Holley）。斯坦福纳米共享设施得到 NSF 奖 ECCS-2026822 的支持。我们感谢 Jean Cline、Phillip Gopon、Al Hofstra、Mike Ressel 和 Patrick Sack 提供样本和讨论；Aaron Bell、Nigel Kelly 和 Katharina Pfaff 进行分析；Jae Erickson、Kelsey Livingston、Sage Langston-Stewart 和 Heather Lowers 用于样品制备；和 Chris Henry、Celestine Mercer、Adam Simon 和一位匿名审稿人征求意见。对贸易、公司或产品名称的任何使用仅用于描述目的，并不意味着得到美国政府的认可。