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Moab, Utah

Upheaval Dome

This raised bulls-eye visible from space was the subject of an intense geologic controversy. 

For decades, two theories about the formation of Utah’s Upheaval Dome jostled for supremacy.

The geological formation in question is three miles across and roughly circular in shape. Although the land around it is flat, the layers that make up Upheaval Dome are layered in a raised circle, surrounded by a ring-like depression.The effect is that of a crater inside a series of concentric rings - something like a crop circle of solid stone. It doesn’t quite look like anything else on earth.

The two theories on the table regarding the dome were that it was either the result of a meteorite impact or the remnants of an ancient salt dome. Confusingly for proponents of both hypotheses, the kind of debris usually found at the site of a meteorite strike was missing and salt domes are usually much shallower in terms of erosion.

Salt domes are common in southeastern Utah, as there’s a thick layer of salt left over from the Pennsylvanian Age simmering under the desert surface. Over millions of years, pressure from overlying sediment can cause the salt to rise upwards, pushing the surrounding rock up in waves. Although the patterning at Upheaval Dome is consistent with an eroded salt dome, in recent years, the meteorite hypothesis has taken the lead. The theory is that the current Upheaval Dome is an impact crater that has been modified considerably from its original form.  Around 60 million years ago, scientists argue, a meteorite hit the site and created only a partially-collapsed crater. Over time, the crater crumbled and underground rocks rose to fill in the gaps, exposing the impact crater’s deep core.

In 2008, the discovery of shocked quartz seemed to settle the matter, as quartz can only exist in such a form after undergoing incredible pressure - exactly like the pressure generated by a massive rock from space hurtling into the ground.