Weathering dataset collected from climate-threatened glacial river headwaters on the eastern slopes of the Canadian Rocky Mountains (2019-2021)

Here we provide a biogeochemical dataset containing weathering-specific parameters that we collected between 2019-2021 from the headwaters of three rivers (Sunwapta-Athabasca, North Saskatchewan, and Bow) which originate from the glacierized eastern slopes of the Canadian Rocky Mountains. Geochemical weathering can be extremely pronounced in glacierized watersheds due to large quantities of fresh glacial flour, which in turn can impact both local and global carbon budgets depending on the type of weathering that occurs. However, despite glaciers serving as hotspots of geochemical weathering globally, we still know little about how the type and magnitude of various geochemical weathering reactions change downriver of glaciers, and how this effect may change seasonally or interannually. Our dataset begins to address this. River sampling sites were visited monthly in 2019 and 2020 during the open water season (OWS), beginning during snowmelt in late May/early June, through peak glacial melt in July/August, then during the receding flow period in September/October. Additional samples were collected twice in winter (December 2019, January 2021) during base flow, but only at sites where it was safe to do so. In general, at each river sampling site and time, atmospheric CO2(g) and dissolved in situ riverine CO2(aq) concentrations were directly measured with a Vaisala CARBOCAP® GM70 Hand-Held CO2 Meter fitted with a 0 - 2000 ppm GMP222 CO2 probe sealed in a tight Teflon sleeve. Using clean field sampling protocols, we also collected samples for the analyses of δ13C-dissolved inorganic carbon (DIC) and Δ14C-DIC; δ13C-particulate inorganic carbon (PIC); sulfate isotopes (δ34S-SO4, δ18O-SO4), and radiogenic strontium (87Sr/86Sr).