Airborne geophysical survey: McAllen and Brownsville 1° x 2° Quadrangles

Special Note: Only digital radiometric data are available for this
quadrangle. The digital magnetic data are missing. All efforts made to
find these data were unsuccessful.
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.