Gravity Study of the Exeter Pluton, Southeastern New Hampshire
The Exeter diorite pluton of southeastern New Hampshire is a small mesozonal batholith emplaced into asymmetrically folded Silurian metasedimentary rocks. The body produces a positive Bouguer gravity anomaly in excess of 16 mgals. The gravity maximum is located northwest of the northeast-trending axis of the pluton and the Exeter anticline, indicating that the mass concentration is offset in the same direction. Using a density contrast of 0.15 gm/cm 3 , two- and three-dimensional gravity models show a range in body thickness from 1 to 3 km and a roughly tabular subsurface shape. The shape and mass distribution are consistent with the enclosing structure. The three-dimensional geometry of the Exeter pluton suggests emplacement during or after the Middle Devonian Acadian deformation of central New England.