THE GEOLOGICAL WONDERS OF ICELAND
DR. TAMIE J. JOVANELLY, GEOLOGIST AND AUTHOR
PLEASE NOTE THAT ALL OF THE DIAGRAMS IN THIS PRESENTATION WERE DESIGNED BY NATHAN MENNEN WHY ICELAND? WHY ICELAND? EG TALA EKKI ISLENSKU I DON’T SPEAK ICELANDIC
KEY
MYO= millions of years old MYA= millions of year ago
CE= Common Era BCE = Before Common Era
HOT SPOT SYMBOL A YOUNG ISLAND Iceland is 38 miles south of Artic Circle
Last Pangea cycle (circa 50 MYA) produces a magma plume, termed hot spot, that is ~200 miles in diameter
33 MYO flood basalts create island USGS Stock Figure plateau A YOUNG ISLAND Iceland is 38 miles south of Artic Circle
Last Pangea cycle (circa 50 MYA) produces a magma plume, termed hot spot, that is ~200 miles in diameter
33 MYO flood basalts create island plateau
Modified from Fitton et al.,1997 A YOUNG ISLAND Only 30% of the plateau is currently above sea level today (Gundmundsson, 2000)
Oldest rocks exposed on Iceland are only 13 MYO
Modified from Trønnes, 2002 PLATE TECTONIC RIFTING
Hot spot initiates divergent plate movement
NW migration of North American Plate and SW migration of Eurasian Plate equate to ~1 inch/year or 13 miles per million years (Geirsson et al., 2006)
Modified from Sæmundsson, 1979 PLATE TECTONIC RIFTING
NORTH AMERICAN PLATE
EURASIAN PLATE
Thingviller Almannaja A rift valley, also termed Almannaja is a tensional graben, separates the normal fault that is easily plate boundary hiked in the national park Modified from Sæmundsson, 1979 33 ACTIVE VOLCANOES 33 active volcanoes on an island the size of Virginia
Three main volcanic zones: NVZ, WVZ, EVZ
Volcanoes along EVZ are more influenced by the hot spot at modern day and are the most active
Modified from Thordarson and Larsen, 2007 33 ACTIVE VOLCANOES
Rootless cones Columnar basalt Pillow basalts One time explosion Solidification of magma Rapid cooling of lava in induced by water into hexagonal formations water; can be sea level indicator IMPRESSIVE EXPLOSIONS 80% of verified eruptions have taken place within EVZ (Thordarson and Larsen, 2006)
205 eruptions have taken place in historical time or 20-25 per century; 78% were explosive (Larsen and Eiriksson, 2008)
Tephrachronology is used as an important tracer for paleo eruptions Modified from Carey et al., 2010 IMPRESSIVE EXPLOSIONS
Hekla- The Queen Katla Eyjafjallajökull Has erupted 18X since Viking Has erupted 20X since Viking Connected to the magma settlement in 874 CE settlement in 874 CE chamber of neighbor, Katla 300 subglacial eruptions Last erupted March 2010 Last erupted in 2000. Repose canceling 100,000 flights prior ~ 10 years since 1970 since 10,000 BCE down to Europe EUROPE’S LARGEST REMAINING GLACIER- VATNAJÖKULL Initial expanse at 2.7 MYA to cover entire island by 26,000 years ago
~5,000 miles2 in size to-date or about 14% of the island
30 outlet glaciers and 4 hidden volcanoes EUROPE’S LARGEST REMAINING GLACIER- VATNAJÖKULL Initial expanse at 2.7 MYA to cover entire island by 26,000 years ago
~5,000 miles2 in size to-date or about 14% of the island
30 outlet glaciers and 4 hidden volcanoes JÖKHULAUPS
A flooding event that begins in a caldera due to the contact of meltwater with magma JÖKHULAUPS A volcano under Vatnajökull, called Grímsvötn, erupted in 1996 causing destruction on the Ring Road
No lives were lost due to in-place monitoring systems JÖKHULAUPS “Katlahlaups” are megaflooding events
The discharge estimated for the 1755 flood was equivalent to that of the Amazon River or 1,000,000 ft3/s SUSTAINABLE ENERGY The Blue Lagoon is a popular tourist destination
For the affordable price of only $70, you too can soak in geothermal waste water! SUSTAINABLE ENERGY Iceland is 100% sustainable on renewable energy!
87% hydro-electricity 13% geothermal SUSTAINABLE ENERGY Geothermal water also provides the best entertainment on the island
Geysirs! ACKNOWLEDGEMENTS • Joe Cook, wonderful husband • Nathan Mennen, figure design artist • Emily Larrimore, outset box author • Amanda Tomlinson and Mallory Paulk, references and glossary contributions • Russell Maddrey and Timothy Wooley, photo contributions • University of Nebraska Geoscience Faculty • Sigurđur Stefnisson, book cover photographer • Wiley Publisher, Editorial Staff, and reviewers REFERENCES Carey, R. J., Houghton, B. F., & Thordarson, T. (2010). Tephra dispersal and eruption dynamics of wet and dry phases of the 1875 eruption of Askja Volcano, Iceland. Bulletin of Volcanology, 72(3), 259-278.
Fitton, J. G., Saunders, A. D., Norry, M. J., Hardarson, B. S., & Taylor, R. N. (1997). Thermal and chemical structure of the Iceland plume. Earth and Planetary Science Letters, 153(3-4), 197-208.
Geirsson, H., Árnadóttir, T., Völksen, C., Jiang, W., Sturkell, E., Villemin, T., ... & Stefánsson, R. (2006). Current plate movements across the Mid‐Atlantic Ridge determined from 5 years of continuous GPS measurements in Iceland. Journal of Geophysical Research: Solid Earth, 111(B9).
Gudmundsson, A. (2000). Dynamics of volcanic systems in Iceland: example of tectonism and volcanism at juxtaposed hot spot and mid-ocean ridge systems. Annual Review of Earth and Planetary Sciences, 28(1), 107-140.
Sæmundsson, K. (1979). Outline of the geology of Iceland, Jökull, 29, 7–28. Schuler Et Al.: Krafla Seismicity And Focal Mechanisms X-39.
Thordarson, T., & Larsen, G. (2007). Volcanism in Iceland in historical time: Volcano types, eruption styles and eruptive history. Journal of Geodynamics, 43(1), 118-152. REFERENCES
Trønnes, R. G. (2002). Geology and geodynamics of Iceland. Nordic Volcanological Institute, University of Iceland, 1-19. QUESTIONS, COMMENTS, SHORT STORIES? CONTACT ME Visit my author website at www.geologyoficeland.com or email me at [email protected] WANT TO GO TO ICELAND?
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