Airborne geophysical survey: Cheboygan and Alpena 1° x 2° Quadrangles

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.

航空磁测与航空放射性测量数据由航空器搭载的仪器沿飞行航线采集，同步记录磁场参数、放射性测量参数与定位信息。其中，磁测数据集包含纬度、经度、海拔高度及磁场强度数值，同时附带地质符号或编码，此类地质符号均取自地表地质图。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（钾40）含量、元素比值及辅助信息。