Abstract Since the 1970s, temporal variations of hydrothermal discharge and thermal output from the numerous hydrothermal features in the Yellowstone Plateau Volcanic Field (YPVF) have been studied by measuring the chloride flux in the major rivers. In this study, the sources, fate, and flux of solutes in the Fall River and its major tributaries, in southwest Yellowstone National Park, were determined. The considerable precipitation in southwest YPVF and high groundwater flow through Quaternary rhyolites results in river solute fluxes that originate from shallow non-thermal groundwater and deep-thermal water. Specific conductance serves as a surrogate measure for thirteen riverine solute concentrations. Combining continuous 15-minute specific conductance and discharge data, the annual chloride, arsenic, fluoride, and silica fluxes from the Fall River were determined to be 11%, 5%, 25%, and 19% of the total flux exiting YPVF. Approximately 11% of the Fall River chloride flux is from non-thermal waters, which is larger than the previous estimate of 4 to 6%. Furthermore, a large proportion of fluoride and silica in the Fall River are derived from water-rock interaction in the shallow non-thermal groundwater system and the non-thermal weathering rate (30 ± 2 t/yr·km2) is higher than other rivers draining the Yellowstone caldera. Consequently, 73 ± 3% of the annual total dissolved solid flux in the Fall River is from thermal sources. Synoptic sampling of river water and discharge measurements was performed during low-flow conditions that allowed for the determination of solute sources and their downstream fate. It was determined that chloride, sodium, arsenic, rubidium, lithium, and boron are primarily (>89%) associated with thermal waters and the Bechler River is the primary source of most hydrothermal solutes in the Fall River, but the major source of arsenic is Boundary Creek. Using the chloride inventory method, the thermal water discharge from several thermal areas was also determined.

中文翻译：

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美国西南黄石高原火山区河流溶质的来源、归宿和通量

摘要 自 1970 年代以来，通过测量主要河流中的氯离子通量，研究了黄石高原火山场 (YPVF) 众多热液特征的热液排放和热输出的时间变化。在这项研究中，确定了黄石国家公园西南部福尔河及其主要支流中溶质的来源、归宿和通量。YPVF 西南部的大量降水和流经第四纪流纹岩的大量地下水导致河流溶质通量源自浅层非热地下水和深层热水。比电导可作为十三种河流溶质浓度的替代指标。结合连续 1​​5 分钟的比电导率和排放数据，每年的氯化物、砷、氟化物、和来自 Fall River 的二氧化硅通量被确定为离开 YPVF 的总通量的 11%、5%、25% 和 19%。Fall River 氯化物通量的大约 11% 来自非热水，这比之前估计的 4% 到 6% 大。此外，福尔河中很大比例的氟化物和二氧化硅来源于浅层非热力地下水系统中的水岩相互作用，非热风化率（30±2 t/yr·km2）高于其他河流排干黄石火山口。因此，福尔河中每年溶解固体总通量的 73 ± 3% 来自热源。在允许确定溶质来源及其下游归宿的低流量条件下对河水进行天气采样和排放测量。经测定，氯、钠、砷、铷、锂和硼主要 (>89%) 与温泉水有关，而 Bechler 河是 Fall River 中大多数热液溶质的主要来源，但砷的主要来源是 Boundary Creek。使用氯化物清单方法，还确定了几个热区的热水排放。