Geology of mid-Tertiary volcanic rocks of the east-central Black Range, Sierra County, New Mexico–Implications for a double-cauldron complex in the Emory cauldron

The Emory cauldron is a north—south elongated, complex eruptive center that may consist of two distinct cauldrons. Despite petrographic similarity and continuous nature of the Kneeling Nun Tuff throughout the complex, associated moat sequences contain andesitic intrusives in the north and rhyolitic intrusives in the south. An arcuate intrusion, associated with the moat deposits in the northern ring-fracture zone, is hypothesized to be the septum region between the two cauldrons.

A megabreccia zone parallels the eastern section of a 180° sinuous fault trace that is interpreted as the structural cauldron margin. Resurgence produced a north-trending apical horst block that is west-stepped in relation to the southern resurgent block of the Emory cauldron. Basin and Range faulting also trends north, implying fundamental control of the regional fabric by basement structures. The reverse motion along structuralcauldron- margin faults is thought to have developed during resurgence and continued to the present.