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Isochron diagrams calculated using in situ white mica 87Rb/87Sr geochronology from samples EV20‐14 and EV20‐20. The two isochron dates are indistinguishable, despite the samples yielding contrasting ages via the in situ 40Ar/39Ar method (see Figure 10). Ellipses are 2σ error. Empty ellipses are analyses that were excluded from the isochron regression.
