A morphologic analysis of quaternary cinder cones, Potrillo volcanic field, New Mexico

Over one hundred cinder cones reside within the Potrillo volcanic field in southern New Mexico. 3He surface exposure dating and 40Ar/39Ar dating reveal the age of the volcanic field to be from 1 Ma to 20 ka years old. 3He surface exposure dating of lava flows associated with cinder cones and current morphologic dating methods show a relationship between cinder cone slope degradation and relative age. Previous studies investigating the morphology of Quaternary basaltic cinder cones in Hawaii, Nevada and Mexico concluded that the degradation of cinder cone slope angle over time is a reliable age indicator. A morphometric method using digital topographic maps (DRGs) and digital elevation models (DEMs) was used to calculate cinder cone slope angles. Exponential trend analysis of radiometric dates from specific lava flows were used to correlate relative ages with cinder cone slope angles. The spatial distribution of cinder cone slope angles within the Potrillo volcanic field categorized the cinder cones into three age groups. The oldest group of cinder cones had measured slope angles ranging from 4° to 9°. The second and intermediate group of cinder cone slope angles ranged from 10° to 16°. The youngest group measured slope angles ranging from 17° to 21°. Analysis of cinder cone slope distribution in the Potrillo volcanic field suggests that volcanism occurred at different time intervals. In addition, trendline analysis provides a powerful and useful tool for predicting cinder cone ages in the Potrillo volcanic field.