The largest crater in the field is Quemado crater, which is 1,170 meters (3,840 ft) across and 33 meters (108 ft) below the surrounding terrain, with a slightly elevated rim. This crater shows evidence of cycles of collapse and explosive eruption. It is surrounded by olivine basalt flows.[7]
The field is part of the Jemez Lineament, a zone of young volcanic fields stretching from central Arizona to northeastern New Mexico. Ar-Ar dating of rock from the Red Hill volcanic field reveals that it was erupted in two pulses, from 7.9-5.2 million years ago (Mya) and from 2.5 to 0.071 Mya. The older activity was along a narrow zone roughly aligned with the lineament, while later activity was across a broad north-south zone, with the focus of activity tending to move south to north. Future activity is most likely in the northern part of the field.[5]