The mid-Tournaisian Event, or Lower Alum Shale Event (LASE), is linked to severe facies changes including pelagic carbonates and widespread black siliceous shales and radiolarites in many parts of the world. For the first time, high-resolution inorganic geochemistry and framboidal pyrite analyses were applied to decipher depositional condition changes during the mid-Tournaisian event in the Carnic Alps. The predominance of tiny pyrite framboids, high C_org/P, U/Th, and V/Cr ratios, generally higher enrichments of redox-sensitive metals such as Mo, U, V, and depletion in Mn suggest anoxic/euxinic conditions at the sea bottom. Moreover, we found very large anomalous Hg spikes (with maximum values reaching 3650 ppb) for the first time in the mid-Tournaisian deep-water marine succession of the Carnic Alps. Our results suggest intense volcanism during the LASE, which triggered the mid-Tournaisian anoxic event. The most likely candidate for the observed Hg anomalous contents is submarine arc volcanism and hydrothermal activity connected with the collision of the peri-Gondwanan terranes Paleo-Adria and probably Armorican Terrane Assemblage (ATA) and/or Noric terrane during the first phase of the Variscan orogeny.

Tournaisian 中期事件或下明矾页岩事件 (LASE) 与严重的相变有关，包括世界许多地区的中上层碳酸盐和广泛分布的黑色硅质页岩和放射虫。高分辨率无机地球化学和 fmboidal 黄铁矿分析首次应用于破译卡尼克阿尔卑斯山图尔奈期中期事件期间的沉积条件变化。微小黄铁矿framboids的优势，高C _org/P、U/Th 和 V/Cr 比率，通常较高的氧化还原敏感金属如 Mo、U、V 的富集和 Mn 的消耗表明海底的缺氧/常氧状态。此外，我们在卡尼克阿尔卑斯山的图尔奈中期深水海洋演替中首次发现了非常大的异常汞峰值（最大值达到 3650 ppb）。我们的结果表明 LASE 期间的强烈火山活动引发了图尔奈期中期的缺氧事件。观测到的 Hg 异常含量最有可能的候选者是与冈瓦南周围古阿德里亚地体和可能的阿莫里坎地体组合 (ATA) 和/或诺里克地体在 Variscan 第一阶段的碰撞有关的海底弧火山活动和热液活动造山运动。