New gravity data in south-central Utah reveal anomalies over major structural and volcanic features in the northern Marysvale volcanic field. Gravity lows are associated with the Mount Belknap and Big John calderas in the Tushar Mountains, and with the Red Hills caldera in the Antelope Range. Steep gravity gradients mark the locations of the Sevier, Elsinore, Dry Wash, and Tushar faults; gravity lows are observed over the grabens dropped down between these major normal faults. The steep gravity gradient across the Basin and Range–Colorado Plateau transition zone is not necessarily the result of deepening of the Moho, but may simply reflect the thick low-density volcanics in the Marysvale field as well as changes in the density of sedimentary rocks across the Cordilleran hingeline. East-northeast–trending gravity contours follow closely the northern edge of a series of Tertiary intrusive bodies and are generally aligned with the trend of the Wah Wah–Tushar mineral belt of southwestern Utah.

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