Petrographic, SEM, and EPMA analyses are used to study the micro-textures and mineralogical composition of samples collected by a TV-grab from the 26°S SMAR (southern Mid-Atlantic Ridge) hydrothermal field. The investigated samples include the outermost chimney walls and sulfide debris. Isocubanite-chalcopyrite intergrowths are the major Cu-Fe sulfide phase in the chimney wall samples. These intergrowths include normal chalcopyrite, anomalous chalcopyrite (Cu-poor, Zn- and Fe-rich), normal isocubanite with Cu/Fe < 0.50, and Cu-rich isocubanite with Cu/Fe > 0.50. Anomalous chalcopyrite and Cu-rich isocubanite represent the intermediate phases between stoichiometric chalcopyrite and isocubanite in the Cu-Fe-S system. Anomalous chalcopyrite occurs as cores or thin rims bordering isocubanite, which associated with sphalerite. While Cu-rich isocubanite commonly associates pyrite. Based on textural relationships and microanalytical data of both phases, we interpret the abundant anomalous chalcopyrite and Cu-rich isocubanite as metastable or as high-temperature (~300 °C) rapidly precipitated hydrothermal sulfides. This interpretation advocates the SMAR 26°S hydrothermal field as an immature and short-living system.

岩相学、SEM 和 EPMA 分析用于研究通过 TV-grab 从 26°S SMAR（南大西洋中脊）热液场收集的样品的微观结构和矿物组成。调查的样品包括最外面的烟囱壁和硫化物碎片。异方石英-黄铜矿共生体是烟囱壁样品中主要的 Cu-Fe 硫化物相。这些共生体包括正常黄铜矿、异常黄铜矿（贫铜、富锌和铁）、铜/铁 < 0.50 的正常异立方岩和铜/铁 > 0.50 的富铜异立方岩。异常黄铜矿和富含铜的异立方岩代表了 Cu-Fe-S 系统中化学计量黄铜矿和异立方岩之间的中间相。异常黄铜矿以与闪锌矿相关的异立方岩的核或薄边缘的形式出现。而富含铜的异方石英通常与黄铁矿相关联。基于两相的结构关系和微观分析数据，我们将丰富的异常黄铜矿和富含铜的异立方岩解释为亚稳态或高温（~300°C）快速沉淀的热液硫化物。这种解释主张 SMAR 26°S 热液场是一个不成熟和短命的系统。