View into the crater from the rim of Upheaval Dome in Canyonlands National Park, Utah
Scientists propose at least two ideas about how Upheaval Dome formed. Some believe that the dome is a sign of a sub-surface salt dome—a rising plug of relatively low-density salt that caused overlying rock layers to dome up in a circular pattern like a basketball underneath a blanket. The overlying rock layers were uplifted and then eroded, leaving the bull’s-eye surface pattern.
Another hypothesis identifies Upheaval Dome as an impact structure, caused by a meteor striking the Earth approximately 60 million years ago. In this interpretation, the erosion-resistant Navajo and Wingate Sandstones define multiple crater rings, while the Chinle, Moenkopi, and older rocks exposed in the middle of the dome are the central peak of the impact structure. Debate about the origin of Upheaval Dome continues; recent evidence—such as microscale deformations of the rocks and minerals that are consistent with a high-energy impact event—lends support to the impact-structure hypothesis.