An area of ∼500 km2 on the central Chukchi shelf contains diapirs and related structural features, including withdrawal synclines, pillow structures, and radial faults. These features were formed during Cretaceous and Tertiary time. The diapirs rise to the sea floor from a large north-trending graben of Tertiary age and pierce more than 5500m of overlying Mesozoic and Cenozoic strata. The diapirs exhibit a columnar cross section and a circular plan view in their upper part, but are continuous or ridgelike near their base. Mobile material appears to emanate from strata of the upper Paleozoic lower Ellesmerian sequence which floor the graben. On the basis of seismic stratigraphy, structural associations, and morphology, we propose that these diapirs are composed of mobilized upper Paleozoic evaporites.