The McCauley Sinks, in the Holbrook basin of northeastern Arizona, are comprised of some 50 individual sinkholes within a 3-km-wide depression.
The sinks are grouped in a semi-concentric pattern of three nested rings. The outer ring is an apparent tension zone containing ring fractures. The two inner rings are semi-circular chains of large sinkholes, ranging up to 100 m across and 50 m deep.
The McCauley Sinks lie south of Winslow along the western edge of Permian salt in the Holbrook basin.
Such large evaporite rock formations are all good if everything stays stable. But as shown by the U.S. Geological Survey, several sub-basins within the larger depression show local downwarping and possible incipient sinkholes.
This is actually no wonder when you learn that the main surface lithology is a limestone – Permian Kaibab Formation limestone – a passive rock unit that collapses into solution cavities developed in underlying salt beds.
The Richards Lake depression, 5 km southeast of McCauley Sinks, is similar in form and size but contains only a single, central sinkhole. Meteor Crater (photo below) is also in the region, 20 miles west of Winslow, AZ.