Extended Data Fig. 1: Map of study area showing the locations of the groundwater wells (n = 17) within the Palouse Basin Aquifer.
From: Passive degassing of lithospheric volatiles recorded in shallow young groundwater
The colour of the symbol relates to the excess 40Ar (Δ40Ar) and symbol size represents the 3He/4He of the sample relative to air (R/RA). Samples with the highest Δ40Ar correlate with the highest measured 3He/4He. The “crustal” samples (Main text) are shown with a square symbol. Red dashed lines are the Moscow and South Fork fault, and the black dashed line represents a plunging anticline. The inset in the bottom right shows the location of the study area (red rectangle) within the Columbia River Basalts with the main urban areas labelled. Basemap is from ESSRI ArcGIS (https://www.arcgis.com/apps/mapviewer/index.html).
