Andrew Griscom 1975 <p>The aeromagnetic map (sheet 1) of the Nabesna quadrangle was prepared in 1971 and subsequently released by the State of Alaska as an open-file map (Alaska Div. Geol. and Geophysics, 1973). The data were collected along north-south traverses spaced at 1.6 km intervals at an altitude of 330 m (1000 ft) above the ground. Compilation was originally in the form of 30' x 15' quadrangles at a scale of 1:63,360; 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 on the local range in the earth's magnetic field.&nbsp;</p> application/pdf 10.3133/mf655H en U.S. Geological Survey Aeromagnetic map of the Nabesna Quadrangle, Alaska reports