Magnetic susceptibility measurements on hydrothermally altered rocks in the Silverton caldera, southwest Colorado

The U.S. Geological Survey (USGS) collected magnetic susceptibility measurements on rock outcrops to help understand causative sources of magnetic survey anomalies in the Silverton caldera region, southwest Colorado. A total of 1,400 measurements of magnetic susceptibility from 87 locations have been conducted on Paleogene volcanic and plutonic rocks that have been hydrothermally altered. Magnetic susceptibility measurements were taken using an SM30 handheld instrument manufactured by ZH Instruments. The measurements aid in understanding the geology and potential mineral resources in the Silverton caldera. Previously mapped lithologies and alteration assemblages were used to guide measurement locations. Multiple measurements were made [...]