Bouguer gravity of Arkansas

Abstract

The Bouguer gravity anomaly patterns in Arkansas correspond very well with the physiographic provinces and sections of the State. These provinces and sections are, in turn, defined by the limits of separate tectonic events that span the range in time from late Precambrian to Tertiary. Bouguer gravity values range from +37 to -107 mGal within the State. The highest values are associated with ultrabasic alkalic igneous intrusions and the lowest values correspond to the Ouachita Mountains and Arkansas Valley, which were formed during the Ouachita orogeny. Variation in seismically determined crustal thickness from north to south is also reflected in the gravity anomaly; that is, the higher gravity values in the southern part of the State reflect a thinner crust than that in the northern part.