Fig. 2: Correlations between the observed and expected subsidence history of the Bidahochi Basin and εHf isotope geochemistry of the detrital zircon record.
From: Basin record of a Miocene lithosphere drip beneath the Colorado Plateau
a Expected progression of the stress component normal to the base of an elastic plate (σyy) at the locus of a developing drip, illustrating the period of prolonged subsidence prior to drip detachment and maximum mantle melting, scaled in the time domain to match the start and end of subsidence. b Subsidence inferred from strata thickness between dated tuffs in stratigraphic sections near the center of the basin27,37 (See text for discussion of labeled numbers in parentheses). c εHf isotopic evolution of detrital zircon from the lower to middle Bidahochi Formation (triangles) and volcaniclastic rocks of the Hopi Buttes volcanic field (circles). Curve at bottom of figure shows the compiled kernel density estimate function of relative probability of detrital zircon U-Pb dates. Dashed purple bar highlights timing of initial melt, which corresponds with the highest Ti concentration, highest Hf/Lu, most mantle-like fO2, and most depleted Hf isotopic signature, as annotated in Fig. 3a–d. HBVF/MB—Hopi Buttes Volcanic Field/Mt. Baldy Volcanics. Error bars are standard error (1σ). Dashed and solid envelopes (1σ, standard deviation) are constructed from running means with ±1 and ±2 Ma windows, respectively, excluding data gaps.
