Aeromagnetic map of the Tanacross Quadrangle, Alaska

The aeromagnetic map (sheet 1) of the Tanacross quadrangle was prepared in 1971 and subsequently released by the State of Alaska as an open-file map (Alaska Div. Geology and Geophysics, 1973). The data were collected along north-south traverses spaced at 1.6-km intervals and from an altitude of 300 m above the ground. Compilation was originally in the form of 30 by 15-minute quadrangles at a scale of 1:63,500; these quadrangles have been combined and reduced to form the present map at a scale of 1:250,000. Contour interval is 10, 20, 100, or 500 gammas, depending upon the steepness of local gradients in the Earth's magnetic field.