[4] High-silica eruptions of the Tewa Group began about 1.85 million years ago and continued almost to the present day.

[5] The Keres Group is a sequence of basalt, andesite, dacite, and rhyolite flows that underlie the southern Jemez Mountains.

The Paliza Canyon Formation is a sequence of mostly andesite flows that is widely exposed in the southern Jemez Mountains.

The formation was erupted by numerous coalesced composite volcanoes centered on an axis from the northern Valles Caldera wall south through Paliza and Peralta Canyons to Ruiz Peak (35°43′01″N 106°32′38″W / 35.717°N 106.544°W / 35.717; -106.544).

The base of the formation is not exposed along this axis, so its total thickness is unknown, but it is estimated from exposures to the west to be about 900 meters (3,000 feet).

[8] The Canovas Canyon Formation is a sequence of rhyolite flows, tuffs, domes, and associated shallow intrusions exposed primarily around Bear Springs Peak (35°40′08″N 106°33′32″W / 35.669°N 106.559°W / 35.669; -106.559).

This has been attributed to rapid crustal extension associated with the Rio Grande rift, whose faulting opened numerous paths to the surface for the magma before it could build up to a catastrophic caldera eruption.

Gold has been mined from the Bland district,[14] from beds identified as the exhumed interior of a Keres Group volcano.

[8] The group was first defined by Bailey, Smith, and Ross in 1969 as part of their work establishing the stratigraphy of the Jemez Mountains.

[8] The division of the precaldera formations of the Jemez Mountains into the Keres and Polvadera Groups, based largely on geography, has been criticized as artificial.