Abstract The compilation of water, sediment, rock, and condensed gas data of arsenic (As) in the Altiplano-Puna of Chile reveals a link between its natural enrichment and volcanic activity, high crustal thicknesses, and regional structures. Two zones were studied which encompass the Altiplano-Puna and western lowlands of Chile: the Northern Zone (including Los Pintados, Surire, and Huasco) and Southern Zone (including Pedernales, Grande, and Laguna Verde). A positive correlation was found between average As concentrations in saline and brackish water of salt flats and crustal thicknesses of the two studied zones with heightened values to the east (up to 25 mg･L−1 of dissolved As in water and a 64 km depth to the Mohorovicic discontinuity). Furthermore, in the studied Altiplano-Puna salt flats, surrounding Mio-Pliocene to Quaternary felsic and intermediate volcanic outcrops are abundant and As is well correlated with other dissolved components (e.g. Li and B). Sediments show extreme As values at punctual locations within the Altiplano-Puna, where the crust is thick, recent volcanic and hydrothermal activity is present, and regional faults are found. Volcanic rocks and condensed gas in the Altiplano-Puna are also enriched with As (up to 221 and 1234 mg･kg−1 respectively). In this tectonic environment, it is hypothesized that volcanism represents an important source of As and the thick continental crust can provide a large reservoir of As that can be leached by rising thermal fluids. Regional scale fault systems also can allow for preferential upwelling and the heightened concentration of As in fractures. Hydrological processes at the surface transport dissolved As to lower elevation regions through groundwater in aquifers and surface water in perennial rivers, creeks, and gorges, diluting element concentrations where significant evapoconcentration is not present.

中文翻译：

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智利高原-普纳自然升高的砷以及与近期（中新世至第四纪）火山活动、高地壳厚度和地质结构的联系

摘要 智利 Altiplano-Puna 中砷 (As) 的水、沉积物、岩石和冷凝气体数据的汇编揭示了其自然富集与火山活动、高地壳厚度和区域结构之间的联系。研究了包括 Altiplano-Puna 和智利西部低地的两个区域：北部区域（包括 Los Pintados、Surire 和 Huasco）和南部区域（包括 Pedernales、Grande 和 Laguna Verde）。发现盐滩的咸水和微咸水中的平均砷浓度与两个研究区的地壳厚度之间呈正相关，东部值升高（水中溶解的砷高达 25 mg·L-1，深度为 64 公里）到 Mohorovicic 不连续性）。此外，在研究的 Altiplano-Puna 盐滩中，中上新世至第四纪长英质和中间火山露头丰富，并且 As 与其他溶解成分（例如 Li 和 B）密切相关。沉积物在 Altiplano-Puna 内的准点位置显示出极端的 As 值，那里的地壳很厚，存在最近的火山和热液活动，并且发现了区域断层。Altiplano-Puna 的火山岩和凝析气也富含 As（分别高达 221 和 1234 mg·kg-1）。在这种构造环境中，假设火山活动是砷的重要来源，厚厚的大陆地壳可以提供大量的砷，可以通过上升的热流体浸出。区域尺度断层系统也可以允许优先上升流和裂缝中砷的浓度升高。