The Paleoproterozoic Mârmorilik Formation in the Karrat basin of West Greenland hosts the Black Angel Zn–Pb deposit. Chlorine-rich scapolite, zones with vuggy porosity and quartz nodules in the ore-bearing marble are herein interpreted to represent metamorphosed, vanished, and replaced evaporites, respectively. Mineralization is closely associated with anhydrite with δ³⁴S values (5.2–12.6‰) broadly comparable to published values for Paleoproterozoic seawater sulfate. Considering the fundamental attributes of the mineralization and host sequence, a Mississippi Valley-type (MVT) model is the most obvious explanation for mineralization. Overlying the ore-bearing sequence are organic-rich semipelites and massive calcitic marbles, which may have served as seals for hydrocarbon or reduced sulfur and acted as chemical traps for deposition of the sulfidic ore. The Mârmorilik Formation contained an interlayered sulfate-rich evaporite-carbonate sequence, a common setting for MVT deposits in the late Neoproterozoic and Phanerozoic, but unique among the few known MVT deposits in the Paleoproterozoic. This ca. 1915 Ma evaporite-carbonate platform is younger than sulfate evaporites deposited during and immediately after the ca. 2220–2060 Ma Lomagundi carbon isotope excursion and records a significant seawater sulfate level during a time interval when it was assumed that it had been too low to form extensive evaporite deposits. Therefore, MVT and clastic-dominated (CD) Zn–Pb deposits in the geological record might progressively fill the apparent gap in marine sulfate evaporites and provide unique insights into Proterozoic seawater sulfate level. Considering the sequence of tectonic events that affected the Karrat basin, the mineralization took place between Nagssugtoqidian collision (< 1860 Ma) and Rinkian metamorphism (ca. 1830 Ma).

西格陵兰 Karrat 盆地的古元古代 Mârmorilik 组拥有 Black Angel Zn-Pb 矿床。含矿大理岩中富含氯的方柱石、具有孔洞孔隙的区域和石英结核在本文中被解释为分别代表变质、消失和置换的蒸发岩。矿化与 δ ^{34的硬石膏密切相关}S 值（5.2-12.6‰）与已发表的古元古代海水硫酸盐值大致相当。考虑到矿化和宿主序列的基本属性，密西西比河谷类型（MVT）模型是矿化最明显的解释。上覆含矿层序的是富含有机物的半泥质岩和块状方解石大理岩，它们可能作为碳氢化合物或还原硫的封印物，并作为硫化矿沉积的化学圈闭。Mârmorilik 组包含层间富含硫酸盐的蒸发岩-碳酸盐序列，这是晚新元古代和显生宙 MVT 矿床的常见环境，但在古元古代为数不多的已知 MVT 矿床中是独一无二的。这个约。1915 Ma 蒸发岩 - 碳酸盐台地比 ca 期间和之后立即沉积的硫酸盐蒸发岩年轻。2220-2060 Ma Lomagundi 碳同位素偏移，并在假设它太低而无法形成广泛的蒸发岩沉积物的时间间隔内记录了显着的海水硫酸盐水平。因此，地质记录中的 MVT 和以碎屑为主（CD）的 Zn-Pb 矿床可能会逐渐填补海相硫酸盐蒸发岩中的明显空白，并为元古代海水硫酸盐水平提供独特的见解。考虑到影响 Karrat 盆地的构造事件序列，矿化发生在 Nagssugtoqidian 碰撞（< 1860 Ma）和 Rinkian 变质作用（约 1830 Ma）之间。地质记录中的 MVT 和以碎屑为主 (CD) 的 Zn-Pb 沉积物可能会逐渐填补海相硫酸盐蒸发岩中的明显空白，并为元古代海水硫酸盐水平提供独特的见解。考虑到影响 Karrat 盆地的构造事件序列，矿化发生在 Nagssugtoqidian 碰撞（< 1860 Ma）和 Rinkian 变质作用（约 1830 Ma）之间。地质记录中的 MVT 和以碎屑为主 (CD) 的 Zn-Pb 沉积物可能会逐渐填补海相硫酸盐蒸发岩中的明显空白，并为元古代海水硫酸盐水平提供独特的见解。考虑到影响 Karrat 盆地的构造事件序列，矿化发生在 Nagssugtoqidian 碰撞（< 1860 Ma）和 Rinkian 变质作用（约 1830 Ma）之间。