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Iskut-Unuk River Cones

Pyroclastic cone · Canada · 1880m

Shallow ponds are seen across the surface of valley-filling lava flows of the Iskut-Unuk volcanic field. The flows traveled south 5 km where they crossed the border into Alaska and dammed the Blue River, forming several small lakes and traveling a total of approximately 22 km. The Iskut-Unuk River Cone Group consists of eight small basaltic centers at the southern end of the Stikine volcanic belt that range in age from about 70,000 to only a few hundred years old and form one of the youngest volcanic fields in Canada.
Shallow ponds are seen across the surface of valley-filling lava flows of the Iskut-Unuk volcanic field. The flows traveled south 5 km where they crossed the border into Alaska and dammed the Blue River, forming several small lakes and traveling a total of approximately 22 km. The Iskut-Unuk River Cone Group consists of eight small basaltic centers at the southern end of the Stikine volcanic belt that range in age from about 70,000 to only a few hundred years old and form one of the youngest volcanic fields in Canada. · Photo: Photo by Ben Edwards, 1997 (Dickinson College, Pennsylvania). · Wikimedia Commons
Type
Pyroclastic cone
Country
Canada
Region
North America Volcanic Regions / Northern Cordilleran Volcanic Province
Elevation
1880m
Coordinates
56.567, -130.750
Last eruption
1800
Tectonic setting
Intraplate / Continental crust (> 25 km)
Landform
Cluster
Major rock type
Basalt / Picro-Basalt
Geological summary

Eight small basaltic centers at the southern end of the Stikine volcanic belt near the Alaska border comprise the Iskut-Unuk River Cones group. Lava flows date back 70,000 years, but the subaerial vents produced cinder cones and lava flows that were probably all active between about 9,000 and a few hundred years ago. Five of the centers produced lava flows that traveled up to ~20 km down the Iskut and Unuk River valleys and their tributaries. The three remaining centers are products of ice-contact volcanism that formed pillow lava, hyaloclastite breccias, and scoria. The flows are similar in mineralogy and contain abundant crustal xenoliths. Vents in the Iskut River Canyon area produced at least 10 lava flows, and the Lava Fork vents at least three lava flows, the latest of which erupted within the past few hundred years.

From Wikipedia

The Iskut volcanic field is a group of volcanoes and lava flows on and adjacent to the Alaska–British Columbia border in the Boundary Ranges of the Coast Mountains. All the volcanoes in this volcanic field are situated in British Columbia along the Iskut and Unuk rivers and their tributaries, with lava flows having reached Alaska. The oldest volcanoes in the Iskut volcanic field are Little Bear Mountain and Hoodoo Mountain, which are 146,000 and 85,000 years old, respectively. Younger volcanic centres include Second Canyon, King Creek, Tom MacKay Creek, Snippaker Creek, Iskut Canyon, Cone Glacier, Cinder Mountain and Lava Fork, all of which formed in the last 70,000 years. All of the volcanoes are mafic in composition except for Hoodoo Mountain which consists of peralkaline rocks. The latest volcanic eruption took place from the Lava Fork volcano in 1800, although an uncertain 1904 eruption is also attributed to this volcano.

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Eruption history

Summary (VEI over time)
Click a bar to see individual eruptions
6830 BCE~6539 BCE · 1 eruptions · max VEI ?4792 BCE~4501 BCE · 1 eruptions · max VEI ?3628 BCE~3336 BCE · 1 eruptions · max VEI ?1881 BCE~1590 BCE · 1 eruptions · max VEI ?716 BCE~425 BCE · 1 eruptions · max VEI ?1322~1613 · 1 eruptions · max VEI ?1613~1904 · 2 eruptions · max VEI ?6830 BCE4792 BCE2463 BCE425 BCE1613

Detailed timeline

  1. 1904VEI ?Geological estimate
    1904 – Ongoing
    Lava Fork
  2. 1800VEI ?Geological estimate
    1800 – Ongoing
    Lava Fork
  3. 1590 (±50 yrs)VEI ?Geological estimate
    1590 – Ongoing
    Lava Fork
  4. 620 BCE (±150 yrs)VEI ?Geological estimate
    BCE 620 – Ongoing
    Iskut River
  5. 1830 BCE (±300 yrs)VEI ?Geological estimate
    BCE 1830 – Ongoing
    Iskut River
  6. 3450 BCE (±150 yrs)VEI ?Geological estimate
    BCE 3450 – Ongoing
    Iskut River
  7. 4700 BCE (±300 yrs)VEI ?Geological estimate
    BCE 4700 – Ongoing
    Iskut River
  8. 6830 BCE (±150 yrs)VEI ?Geological estimate
    BCE 6830 – Ongoing
    Iskut River

External links

⚠ For reference only. Not for emergency response.