PETROLOGIC AND GEOCHEMICAL ANALYSIS OF DIKES INTRUDING VOLCANIC DEPOSITS AT KNIGHT PEAK AND WALKING X PEAK, GRANT COUNTY, NEW MEXICO

Dikes of varying compositions, including some magnetite-rich rocks, intrude the Tertiary volcanic rock flows and deposits located south of the Burro Mountains, near Knight Peak and Walking X Peak, in southern Grant County, New Mexico. The study area is located in the Basin and Range province, just south of the Mogollon-Datil Volcanic Field, which coincides with the transition zone between the Basin and Range and the Colorado Plateau. The Big Burro Mountains expose deformed and metamorphosed Proterozoic rocks overlain by Cretaceous strata and Tertiary volcanic and volcaniclastic rocks, primarily tuffs and andesites. The goal of this study is to characterize the dikes and their intrusive relationships with the volcanic units in the context of broader regional geologic history. Field work will focus on locating dikes, determining relative age relationships between the dikes and volcanic units, sampling dikes and volcanic rocks, and structural measurements. Thin sections and powdered samples will be prepared for detailed petrography and geochemical analysis using a handheld X-ray fluorescence analyzer (hXRF) and scanning electron microscope (SEM). This data will be interpreted to improve the understanding of relationships between these rocks and the regional history of the Laramide orogeny, ignimbrite flare-up and related mineralization, and Basin and Range extension.