Quaternary sediments along a belt that extends from inland to bottom sediments of the Tyrrhenian Sea in southern Tuscany, Italy, are characterized by high concentrations of As (up to >1000 mg/kg). Earlier studies ascribed this anomaly to anthropogenic activities, e.g., past metallurgical processes of materials mined from pyrite and polymetallic deposits. Such activities, however, can only explain local anomalies. Alternatively, the extensive distribution of these high As contents in the Quaternary sediments is referred to a natural dispersion of eroded materials from ore deposits present in the area. This study provides fluid inclusion data in detrital quartz, as well as mineralogical and geochemical data of Quaternary sediments, from two contiguous catchments draining their waters toward the Tyrrhenian Sea. Results constrain the nature of the mineralized crust eroded and deposited in the coastal continental valleys and at the bottom of the Tyrrhenian Sea. Fluid inclusion data suggest that the As anomaly is related to the erosion of pyrite and polymetallic ore deposits, and that the original depth of the ore deposits ranged between about 500 and 2000 m. This shows that the erosion of such ores left an extensive legacy in southern Tuscany coastal valleys and in the Tyrrhenian sea.

意大利南部托斯卡纳南部第勒尼安海从内陆延伸至底部沉积物的一条带上的第四纪沉积物的特征是高浓度的砷（高达> 1000 mg / kg）。早期的研究将这种异常归因于人为活动，例如，过去从黄铁矿和多金属矿床开采的材料的冶金过程。但是，此类活动只能解释局部异常。另外，这些高砷含量在第四纪沉积物中的广泛分布是指侵蚀物质从该地区存在的矿床中自然分散。这项研究提供了碎屑石英中的流体包裹体数据，以及两个连续流域的水向第勒尼安海排放的第四纪沉积物的矿物学和地球化学数据。结果限制了在沿海大陆谷和第勒尼安海底侵蚀和沉积的矿化壳的性质。流体包裹体数据表明，As异常与黄铁矿和多金属矿床的侵蚀有关，矿床的原始深度在500到2000 m之间。这表明此类矿石的侵蚀在托斯卡纳南部沿海山谷和第勒尼安海留下了广泛的遗产。