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Dotsero

Maar · United States · 2230m

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.
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: Photo by Lee Siebert, 1999 (Smithsonian Institution). · Wikimedia Commons
Type
Maar
Country
United States
Region
North America Volcanic Regions / Basin and Range Volcanic Province
Elevation
2230m
Coordinates
39.661, -107.035
Last eruption
-2200
Tectonic setting
Rift zone / Continental crust (> 25 km)
Landform
Minor (Basaltic)
Major rock type
Basalt / Picro-Basalt
Geological summary

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.

From Wikipedia

Dotsero Crater is an elongate, 2,300 ft (700 m) long by 1,300 ft (400 m) wide, maar incised into sedimentary strata of the side of a mountain, called Blowout Hill, and local, irregular, mountainous topography. At an elevation of 7,316 ft (2,230 m), its north rim lies about 330 ft (100 m) higher than its south rim. Dotsero Crater is about 1,300 ft (400 m) deep. It is part of a maar and scoria cone complex in which the associated scoria cones are constructed along a NNE-SSW line on either side of the maar and is perched near the upper edge of steep sided canyons about 1,000 ft (300 m) above the valley floor of the Eagle River. The axis of the maar and scoria cone complex aligns with the axis of a local syncline. Associated with the maar and scoria cones is a lahar and 2 mi (3.2 km)-long lava flow. Dotsero Crater lies northeast of Dotsero, Colorado near the junction of the Colorado River and the Eagle River.

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Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
2200 BCE~2200 BCE · 1 eruptions · max VEI 22200 BCE2200 BCE2199 BCE2199 BCE2199 BCE

Detailed timeline

  1. 2200 BCE (±300 yrs)VEI 2Geological estimate
    BCE 2200 – Ongoing

External links

⚠ For reference only. Not for emergency response.