MODAL MINERALOGY, TEXTURAL DATA AND GEOCHEMICAL DATA FOR CALDERA-FACIES HELLS MESA TUFF AND A COMAGMATIC LAVA DOME, WITH SELECTED DATA PLOTS AND SUPPORTING MAP DATA:
SUMMARY --This report presents phenocrystic mineral modes, textural data and geochemical data for caldera-facies Hells Mesa Tuff, a slightly younger comagmatic lava dome, and dome-derived tuff breccias that are exposed in the eastern and southwestern sectors of the Socorro caldera (Fig1). This data is presented in support of an article entitled Waning-stage Eruptions of the Oligocene Socorro Caldera, Central New Mexico, which has been submitted for publication by the New Mexico Natural History Museum in their Bulletin 18, Volcanology in New Mexico (Chamberlin, 2001). This new data set supplements detailed geologic mapping of the Luis Lopez quadrangle (Chamberlin and Eggleston, 1996) and a recent 40Ar/39Ar geochronology study of the eastern sector of the Socorro caldera (Chamberlin, McIntosh and Eggleston, in press). Additional Note: Recent mapping (12/01), has shown approximately 30m of upper Hells Mesa lag breccias are present north of the Esperanza mine (thus, Fig.5 of this report supersedes fig. 2 of Chamberlin, 2001).[From the Introduction]