Climate-driven mid- to late Holocene hydrologic evolution of arid wetlands documented by strontium, uranium, and oxygen isotopes from Lower Pahranagat Lake, southern Nevada, USA.

This article focuses on reconstructing the mid- to late Holocene hydrologic evolution of Lower Pahranagat Lake (LPAH), an arid wetland in southern Nevada, using radiogenic isotopes of strontium (⁸⁷Sr/⁸⁶Sr) and uranium ([²³⁴U/²³⁸U]) measured in lacustrine carbonates. The study demonstrates that these isotopic compositions reliably trace varying mixtures of groundwater sources—primarily a regional carbonate aquifer and local volcanic aquifers—feeding the lake over the past ~6,000 years. Results indicate that around 5.78 ka, LPAH was fed almost exclusively by local volcanic aquifer water, followed by a sharp increase in regional carbonate aquifer contributions by ~5.3–5.2 ka. During the Late Holocene Dry Period (~3.15–1.7 ka), reduced regional aquifer input and increased local volcanic aquifer influence correspond with drier, more evaporative conditions, while wetter intervals favored greater regional aquifer contributions. These findings highlight climate-driven shifts in groundwater source contributions controlling wetland hydrology in an arid Great Basin setting.