Central Colorado volcanic field
Encyclopedia
The central Colorado volcanic field is a volcanic field
in Colorado
, USA. It is located in the southern Rocky Mountains
and covered a roughly triangular area centered on the Thirtynine Mile volcanic area and extending from the Sawatch Range southeast to the northern Sangre de Christo Range and the Wet Mountains
and northeast to the southern Front Range
south of Denver. The area covered by the volcanic products of the eruptions included some 22,000 km2 produced by at least ten volcanic centers or caldera
s. The field overlaps the San Juan volcanic field
to the west. The volcanic products date from late Eocene
to Oligocene
(38–29 Ma).
Volcanic field
A volcanic field is an area of the Earth's crust that is prone to localized volcanic activity. They usually contain 10 to 100 volcanoes, such as cinder cones and are usually in clusters. Lava flows may also occur...
in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, USA. It is located in the southern Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
and covered a roughly triangular area centered on the Thirtynine Mile volcanic area and extending from the Sawatch Range southeast to the northern Sangre de Christo Range and the Wet Mountains
Wet Mountains
The Wet Mountains are a small range of mountains in southern Colorado named for the amount of snow they receive in the winter. There are three variant names of this range: Cuerno Verde, Greenhorn Mountains, and Sierra Mojadas...
and northeast to the southern Front Range
Front Range
The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the north-central portion of the U.S. State of Colorado and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountered moving west along the 40th parallel north across...
south of Denver. The area covered by the volcanic products of the eruptions included some 22,000 km2 produced by at least ten volcanic centers or caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
s. The field overlaps the San Juan volcanic field
San Juan volcanic field
The San Juan volcanic field, located in southwestern Colorado, contains two distinct phases of volcanism. The earlier volcanism is Oligocene in age, and consists of largely intermediate composition lavas and breccias. A few ash flow tuffs also constitute this phase of volcanism. Later volcanism is...
to the west. The volcanic products date from late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
to Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
(38–29 Ma).
Notable geological features
| Name | Elevation | Coordinates | Age |
| Thirtynine Mile | - | 38.8322°N 105.5544°W | |
| Grizzly Peak Cauldron | - | 39.1°N 106.6°W | |
| Mount Aetna Cauldron | - | 38.6°N 106.3°W | |
| Bonanza Caldera | - | 38.295°N 106.1°W | |
| Marshall Creek Caldera | - | 38.4°N 106.3°W |