δO18-δD relationship of Marañón surface waters. Data are grouped into three elevation zones (Figure 2c), and compared to the Global Meteoric Water Line (GMWL, (Craig, 1961)) and the Local Meteoric Water Lines (LMWL) derived from GNIP records at high and low-elevation stations. The lower slope of the δO18-δD alpine tributaries as compared to the alpine LMWL indicate evaporative processes may be affecting the water signature in the upper basin, whereas this is not the case for jungle and transitional tributaries. That the LMWLs and GMWL are parallel indicate higher D excess in the LMWL, likely from moisture recycling of air masses moving across the Amazon basin. DOI: https://doi.org/10.1525/elementa.290.f8