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Figure 16


Figure 16. Photographs showing the northeastern margin of the Caetano caldera. (A) Large block of Devonian Slaven Chert (Dsc) in white Caetano Tuff (Tcl) near northeastern caldera margin in northern Toiyabe Range. Low rocky ridge is Slaven Chert in caldera margin at A (Fig. 15); caldera boundary fault is developed in the chert. View looking north. (B) Steep caldera structural margin at B (Fig. 15). View looking west-northwest. (C) Close-up view of steep caldera structural margin at B (Figs. 15 and 16B). Densely welded, highly stretched Caetano Tuff is in sharp, approximately vertical contact with brecciated and recemented Devonian Slaven Chert outside caldera. (D) Caldera topographic wall at C (Fig. 15), showing megabreccia consisting of multiple blocks of Devonian Slaven Chert up to at least 50 m in diameter, locally with thin lenses of Caetano Tuff. Light-colored middle ground is lithic-rich Caetano Tuff containing clasts of chert and 35 Ma rhyolite, which crops out just to the right of the photo as megabreccia. View looking west-northwest.