Airborne geophysical survey: Helena 1° x 2° Quadrangle

Aeromagnetic and aeroradiometric data were collected along flight lines by instruments in an aircraft that recorded magnetic-field and radiometric values and locations. The magnetic data set presents latitude, longitude, altitude, and magnetic-field values. Geologic symbols or codes are also included. The geologic symbols were picked from surficial geologic maps. The radiometric data set presents latitude, longitude, altitude, geologic symbols or codes, apparent Uranium (Bismuth 214), Thorium (Thallium 208), and Potassium (K 40), the element ratios, and ancillary information.本数据集包含航空磁测与航空放射性测量两类数据：数据由航空器搭载的专用仪器沿飞行航线采集，同步记录磁场参数、放射性测量值及采集位置信息。其中航空磁测数据集涵盖纬度、经度、海拔高度及磁场强度数值，同时附带地质符号或编码，此类地质符号源自地表地质图。航空放射性测量数据集则包含纬度、经度、海拔高度、地质符号或编码、表观铀（铋214）、钍（铊208）、钾（K-40）、元素比值及辅助信息。