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Roger Weller, geology instructor

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Iceland
by TaylorPuckett
Physical Geology
Fall 2013
                  

  

The Icelandic Golden Circle
 

          In the country of Iceland near the capital of Reykjavik and looping into south Iceland contains some wondrous landmarks. The route is about 300 km travel distance with several geological hotspots. Some attractions include the waterfall Gullfoss, the geothermal active valley of Haukadalur which holds the geysers Geysir and Strokkur, the volcano crater Kerid, the Hveragerdi greenhouse village and the Nesjavellir geothermal power plant.

 

          The first stop on this Golden route is the biggest and most amazing waterfall I have seen, Gullfoss. The waterfalls name actually translates to “golden falls” and is twenty one meters in height. The waterfall is a part of the river Hvita and the source to the river comes from a glacier Langjokull north of the river which deposits sediment and other debris into the rather rapid waters. Because of the sediment and mineral rich deposits, the water becomes a brown color in river and when the sun reflects upon it the river turns a golden color. Gullfoss has two tiers that happened to be formed at the end of the ice age; the hard rock on top is lava rock, coming from the volcanoes. The lower tier is made of moraine which is a multi-layered sediment rock that was collected by a glacier. Because it is not well compacted it is easily erodible. The waterfall is also a cataract segmented water fall, meaning it moves fast and has a large volume of water going over the crest. The crest contains two parts, the top of it has fast flowing rapids and the bottom of the crest is a gorge that runs one and a half miles down. This waterfall was formed where the water had followed a fissure in the lava rock, making a passageway. During the twentieth century and even before the people of Iceland wanted to exploit all the natural resources especially Gullfoss to create hydroelectricity but instead it is now protected by Icelandic law and has become a national park.


Photos by Taylor Puckett
 

          The next stop is to Iceland’s famous geyser Strokkur Geysir. The geyser is one of the most active and persistent geysers in the world. Strokkur Geysir lies in the geothermal active valley of Haukadalur and at the base of the hill Laugarjall. The actual word geyser comes from the Icelandic term “geysa” which means to gush. Strokkur Geysir was first reported to “gush” in 1789 after an earthquake which made its eruptions constant until 1896 when another earthquake discontinued the geyser. However in 1963 the local people unblocked the plumbing system and the geyser has been active ever since. The most famous but rarely active sister geyser named Geysir also is at the base of the hill and has been recorded to have been active since 1294. Strokkur eruptions are about five to ten minute intervals and the gush can reach up to thirty meters in height. The pool of water above is full and pulsates up and down. A geyser needs a heat source which is the cooling magma below as well as a water source and permeable rocks and a pressure tight chamber. The geyser is in a highly silicic rhyolitic rock, where over heated water dissolves the silica from these rocks under a deep surface. The causing pressure comes from deposited geyserite which is hydrated silicon dioxide basically a form of opal. This seals the geyser’s “plumbing system” thus allowing it to pressurize.
 

 
Photos taken by Taylor Puckett


 


 

Top of the hill Laugarjall: taken by Mckenzie Ramsay


 


 

 
Top of Laugarjull: taken by Taylor Puckett 

 

          The first natural wonder to the golden circle is the volcanic crater of kerid. Most of the year the crater is filled with ice covered water but while I was there in March 2013 the water was thawed and very blue. The crater itself is remains from a volcano that has said to have exploded three thousand years ago but geologists are now failing to find evidence at all that it even had exploded; they are now saying that it was once a cone volcano that erupted and emptied its magma. When the magma left, the cone collapsed into the now empty magma chamber. The pool of water seen from the rim is actually at the same level as the water table so the collection of water is not from rainfall. The water is a vivid aqua color because of the rich minerals in the soil. The surrounding rim and slope contains little to none vegetation. This crater is widely known because of its age and it’s still intact visible caldera. The caldera is one hundred and eighty feet deep and five hundred and sixty feet wide and eight hundred and ninety feet across. The volcanic rock that it’s made of is actually not your typical black; instead it’s a red color rock.
 


 


 


 

 
Photos by Taylor Puckett

 

          The last stop is the continent divide where the Eurasian and north American plates meet. This historic site is in Thingvellir National Park, this site is also where the world’s longest running parliament stands and was established in nine thirty AD, settling along the North American and Eurasian tectonic plates. Usually volcanic seams that push continents apart are found at the bottom of the sea, but this is not the case in Iceland. The Silfra rift as it is called divides the east from the west and where the two plates drift a part about two centimeters per year. You are able to see the divide either above the ocean or below. Many people often dive here because you can dive in the crack between the American and Eurasian continents. The water in the divide is absolutely pristine and you are able to drink from it. The reason for the plates being in Iceland is because the country sits near the mid-Atlantic ridge which is a part of the world’s undersea mountain system that forms new crust. Iceland actually formed by coincidence from the spreading boundaries of the North American and European plates and a hotspot plume. When the plates drift apart this causes volcanoes and filled rift valleys.
 


 


 



 


 


 


 

 
Photos taken by Taylor Puckett

 

Some more pictures from Iceland: All taken by Taylor Puckett


 


 


 


 

 

 


 


 


 


 


 


 


 


 

Works cited:

http://icelandontheweb.com/Iceland_nature/Geology_of_Iceland/

http://www.dive.is/Diving_Iceland.php?page=Silfra

http://www.iceland.is/the-big-picture/nature-environment/geography/

http://www.livescience.com/31566-iceland-tectonic-plates-meet.html

http://chestertoncurriculum.org.uk/geography/wp-content/uploads/2009/04/Tom-Bramwell-Gulfoss.pdf