Dotsero
Maar in United States
Key Facts
Elevation
2,230 m (7,316 ft)
Type
Maar
Location
39.661°, -107.035°
Region
Basin and Range Volcanic Province
Rock Type
Basalt / Picro-Basalt
Tectonic Setting
Rift zone
Location
Loading map...
Overview
A small maar and scoria cone complex at Dotsero is located near the junction of the Colorado and Eagle Rivers west of the Gore Range. Highway I-70 cuts across a lava flow, but the most prominent feature of the complex is a 700 m wide and 400 m deep maar that was erupted about 4,150 radiocarbon years ago along a ridge consisting of evaporites and reddish oxidized sandstones of Pennsylvanian age. Small scoria cones were constructed along a NNE-SSW line on either side of the maar.
Small lahars preceded eruption of a basaltic lava flow that traveled 3 km down two narrow V-shaped valleys and spread out onto the floodplain of the Eagle River, diverting the river to the south side of the valley. Older Pleistocene basaltic lava flows occur nearby at Willow Peak, McCoy, and Triangle Peak.
Volcanic Hazards & Risk Assessment
Primary Hazards
Risk Level
Geological Composition & Structure
Rock Types
Tectonic Setting
Age & Formation
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 4226 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in North America Volcanic Regions
Quick Info
- •Smithsonian ID: 328010
- •Evidence: Eruption Dated
- •Epoch: Holocene
About the Photo
During the mid-Holocene a maar was formed in central Colorado near the junction of the Colorado and Eagle Rivers west of the Gore Range. The quarry in the foreground is cut into basaltic tephra deposits on the rim of the maar. The 700 m wide maar is 400 m deep and cuts a ridge of evaporites and reddish oxidized sandstones of Pennsylvanian age, which can be seen on the far crater wall. The maar was erupted about 4150 radiocarbon years ago and is the youngest volcanic feature of Colorado. The Eagle River lies to the south in the valley beyond the crater.
Photo by Lee Siebert, 1999 (Smithsonian Institution).
Authority Sources
Related Volcanoes
Basic Information
This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.