Some Results from Continental Scientific Drilling Program Core Hole VC-2A Valles Caldera, New Mexico, USA

Abstract

VC-2A is the second in a series of scientific bores that are designed to investigate the magma-hydrothermal system of Valles caldera, a resurgent cauldron in northern New Mexico (Fig. 1) (Goff and Nielson, 1986). The primary objective of VC-2A was to penetrate the vapor cap above, the "interface" between, and the top of a liquid-dom:l.nated hydrothermal system. Secondary obj ectives were to study possible mechanisms of resurgence near the structural intersection of the western ring-fracture zone and the resurgent dome and to study possible mechanisms of ore deposit formation in a large silicic caldera. Technical objectives were to obtain continuous core while reaching a depth of at least 500 m and a temperature of at least 200°C.