Unravelling the genesis of metamorphosed mineral deposits can be complicated due to difficulties in separating between primary features and features that formed during the metamorphic overprint. Such uncertainty exists for stratabound and dolomite- and skarn-hosted Zn-Pb-Ag sulfide deposits in 1.89 Ga rocks in the Bergslagen lithotectonic unit (BLU) of Sweden, where a metasomatic vs. regional metamorphic origin for skarns has long been discussed. By integrating geological mapping with new lithogeochemical, mineralogical, and stable isotope data (C, O, S), we show that complexly zoned garnet and clinopyroxene skarns in the Sala area of the central BLU predate mineralization. Sphalerite-galena mineralization formed after the deposition of a younger, more Mn-rich ferroan diopside and andradite-grossular garnet, and is associated with phlogopite, tremolite-actinolite, chlorite, serpentine, and calcite. Mineralization in conjunction with a transition from high-T metasomatism to hydrolytic alteration is inferred. An average δ³⁴S_V-CDT of 1.6 ± 1.9‰ in sulfides is consistent with a primordial sulfur source. Trends defined by negative shifts in δ¹⁸O_V-SMOW and δ¹³C_V-PDB in dolomite and calcite are consistent with fluid infiltration at 300–500 °C. The alteration system is sharply truncated by unaltered, c. 1.89 Ga calc-alkaline granite and porphyritic intrusions, which along with F₁ folding of the alteration zones and mineralization suggest that mineralization predate regional metamorphism. The Sala deposits are interpreted as Zn skarn deposits formed in conjunction with the emplacement of intrusions into penecontemporaneous marine volcanic and dolomitized limestone strata. The unusually Mg-rich mineralogy in relation to Zn skarns worldwide most likely reflects the dolomitic precursor.

由于难以区分主要特征和变质叠印期间形成的特征，因此解开变质矿床的成因可能很复杂。瑞典 Bergslagen 岩石构造单元 (BLU) 的 1.89 Ga 岩石中的层状和白云岩和矽卡岩含有的 Zn-Pb-Ag 硫化物矿床存在这种不确定性，长期以来一直在讨论矽卡岩的交代与区域变质成因。通过将地质填图与新的岩石地球化学、矿物学和稳定同位素数据（C、O、S）相结合，我们表明中央 BLU 的 Sala 地区复杂分区的石榴石和单斜辉石矽卡岩早于矿化。闪锌矿-方铅矿矿化形成于更年轻、更富锰的透辉石和菱镁矿石榴石沉积后，并与金云母有关，透闪石-阳起石、绿泥石、蛇纹石和方解石。推断矿化与从高 T 交代到水解改变的转变相结合。平均δ硫化物中 1.6 ± 1.9‰的³⁴ S _V-CDT与原始硫源一致。由白云石和方解石中 δ ¹⁸ O _V-SMOW和 δ ¹³ C _V-PDB负移定义的趋势与 300–500 °C 的流体渗透一致。改变系统被未改变的 c. 1.89 Ga 钙碱性花岗岩和斑状侵入体，连同 F ₁蚀变带的折叠和矿化表明矿化早于区域变质作用。Sala 矿床被解释为与侵入体侵入准同期海相火山岩和白云石化石灰岩地层相结合形成的锌矽卡岩矿床。世界范围内与锌矽卡岩有关的异常富镁矿物很可能反映了白云岩前驱体。