MAPPING FAULTS IN THE LIGHTNING DOCK KNOWN GEOTHERMAL AREA, ANIMAS VALLEY, NEW MEXICO USING SOIL CO_2 FLUX MEASUREMENTS

摘要

Soil carbon dioxide flux measurements were taken over the Lightning Dock Known Geothermal Resource Area (LDKGRA) in the Animas Valley of southwestern New Mexico to determine if they could aid in locating hidden geothermal faults. The LDKGRA is located in an arid, sediment-filled basin, and the geothermal system has no known surface expression. There is a plume of degassed water at temperatures greater than 100 deg C in the valley fill sediments, however the structures that control the geothermal fluids are poorly understood. Our working hypothesis is that CO_2 released by boiling fluid will rise vertically from buried faults and can be detected by measuring soil CO_2 flux over the area. Over four hundred fifty soil CO_2 flux measurements at 50 to 100 meter East-West spacing were made near the main surface heat anomaly over a period of more than a year. One measurement site was monitored at least once each field day to determine day to day and seasonal flux variations.