Difficulties in dating Mississippi Valley–type (MVT) mineral deposits and the often closely associated dolomitization have led to controversy regarding their origin. We report the first radiometric ages for the Gorno mining district in northern Italy, an example of the Alpine subclass of MVT deposits. U-Pb ages of hydrothermal carbonates pre- and postdating the ore-forming event show that base-metal mineralization occurred shortly after the deposition of the Carnian host rocks. This implies that the Gorno ore deposits formed at shallow burial depth prior to the Early Jurassic western Tethys rifting phase. Contemporaneous Triassic magmatism and extensional tectonics likely contributed to the high geothermal heat fluxes required to drive the mineralizing system. Our study reinforces the need for reliable geochronological data for metallogenic models and warns against a general application of classic North American MVT models to similar deposits worldwide.

中文翻译：

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硫化物伴生的热液白云石和方解石揭示了高山型 Zn-(Pb) 矿床的浅埋深

密西西比河谷型 (MVT) 矿床的年代测定困难和经常密切相关的白云石化导致了对其起源的争议。我们报告了意大利北部 Gorno 矿区的第一个辐射年龄，这是 MVT 矿床高山亚类的一个例子。成矿前后热液碳酸盐的 U-Pb 年龄表明，贱金属矿化发生在卡尼期主岩沉积后不久。这意味着 Gorno 矿床在早侏罗世特提斯西部裂谷阶段之前的浅埋深处形成。同时代的三叠纪岩浆作用和伸展构造可能促成了驱动矿化系统所需的高地热热通量。