Figure 6 | Scientific Reports

Figure 6

From: Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium

Figure 6

(a) A combined mixing plot for the irrigation bores. The regression lines represent either the bores with detectable [DOC] (intercept: −55.9‰ (90% CI, −58.3‰ to −53.4‰)) or the bores with no detectable [DOC] (intercept: −69.1‰ (90% CI, −73.2‰ to −65.0‰)). Tritium activity is indicated by the marker color. All boreholes with no 3H activity and detectable [DOC] sit on the regression line with intercept of −55.9‰, indicating gas from the WCM. (b) The cluster of bores around 0.55 ppm−1 highlights a mixing of parameters at the intercept of the regression lines. This indicates that the absence of 3H activity can be used to attribute source but it must be used in tandem with detectable [DOC] values. Mixing model lines of best fit are shown in blue and the 90% confidence interval bands in orange.

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