Source: “Origin of the Iceland hotspot and the North Atlantic Igneous Province”, Korenaga, 2004, http://www.mantleplumes.org/

- Iceland “Tertiary Formation” is part of the North Atlantic Igneous Province- magmatic activity began around ~61 Ma- continental flood basalts from 61-56 Ma found from Baffin Island, W & E Greenland, N Ireland, and Scotland

Geologic Setting

Source: “Tertiary Volcanism in Iceland”, Harðarson et al., Jökull, 2008.

- WVZ and NVZ (western and northern volcanic zones) represent the current mid-ocean ridge track- EVZ is propagating to the south- SISZ = south Iceland seismic zone, connects WVZ and EVZ- EVZ represents a juvenile ridge zone; eventually the mid-ocean ridge will jump from the WVZ to the EVZ

Icelandic Rift Zones

Source: “The Faeroe-Iceland-Greenland Aseismic Ridge and the Western Boundary Undercurrent”, P. R. Vogt, Nature, Sep. 1972

- Greenland, Iceland, Faeroe “ridge” represents a hot-spot trail- proto-Iceland may have been formed off the east coast of Greenland (hot spot reached East Greenland coast between 40-35 Ma)- connected by a trail of small islands or a land bridge (supported by paleobotanical evidence, Grimmson et al. 2007)

Icelandic Hot Spot Track

Source: “Tertiary Volcanism in Iceland”, Harðarson et al., Jökull, 2008.

Tertiary = 16 to 3.3 MaPlio-Pliestocene = 3.3 to 0.78 MaUpper Pliestocene = 0.78 Ma to 15000 yr BPHolocene = 15000 yr BP to present

-- tertiary volcanoes = open, unfilled circles-- Plio-Pliestocene = crossed, unfilled circles-- active volcanoes = brown, filled circles

Icelandic Volcanoes

plinian eruption of Hekla in 1947(plume reached 28 km)

lava and tephra deposits coveringa small town by Eldfell eruption in

1973

a jökulhlaup glacial outwash plaindestroying a section of the ring road

(Highway 1)

Source: “Volcanic Hazards in Iceland”, Gudmundsson et al., Jökull, 2008.

Volcanic Hazards

Source: “Volcanic Hazards in Iceland”, Gudmundsson et al., Jökull, 2008.

-- tephra fallout isopach map-- fallout of >10 cm can cause roof cave-ins-- can cause problems with farming (as in 1619, 1873, 1903 eruptions of Grimsvötn)-- historical eruptions have had plumes from 8-15 km

-- map of historical and prehistoric lavas-- pyroclastic flows are not common, although the subplinian Hekla eruption in 2000 produced flows up to 5 km from the vent

Volcanic Hazards

-- jokülhlaups: glacial outwash floods-- can be caused by geothermal activity or by volcanic eruption-- 1 to 1.5 hours to notify and evacuate areas-- water depth exceeding 1 meter and flow velocities > 1 m/s-- 300,000 m3/s of material discharged

Source: “Volcanic Hazards in Iceland”, Gudmundsson et al., Jökull, 2008.

Jokülhlaups