Magnetic susceptibility measurements on rocks in Alaska to aid geophysical interpretation

The U.S. Geological Survey (USGS) collects magnetic susceptibility measurements on in-situ and laboratory rock samples to help identify the sources of anomalies in aeromagnetic surveys in Alaska. Magnetic susceptibility is a measure of how much a material will become magnetized in an applied magnetic field and is the ratio of magnetization, M (magnetic moment per unit volume), to the applied magnetic field intensity, H. This information can aid in interpretation of aeromagnetic data that are used to understand regional geologic framework and mineral resource potential. This data release is intended to be updated each year with new measurements obtained during the previous field season. In version 1.0, there are 286 measurements. For 19 of these rock samples, magnetic susceptibilities were measured in the lab, whereas the rest were measured in-situ. The location of each was acquired using a handheld Global Positioning System (GPS) unit, and an associated simple rock description is included. We used a ZH Instruments SM-30, a Terraplus KT-10, or a Terraplus KT-20 handheld magnetic susceptibility meter to record measurements for each sample. The median magnetic susceptibility is shown and is considered to be a better representation of the entire unit. The instrument used for each measurement is shown in the .csv file because measurements from separate instruments should not be used to compare separate samples to one another.