Iceland’s Western Rift Zone – Field trip
The interaction of the Mid-Atlantic Ridge (MAR) and the mantle plume under Iceland is responsible for a complex plate boundary pattern in Iceland that is in continuous development. Rift jumps have occurred in response to gradual drift of the MAR relative to the mantle plume. The different branches o...
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| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.534.6727 http://www.norvol.hi.is/~thora/summer2003/notes/WVZ.pdf |
| Summary: | The interaction of the Mid-Atlantic Ridge (MAR) and the mantle plume under Iceland is responsible for a complex plate boundary pattern in Iceland that is in continuous development. Rift jumps have occurred in response to gradual drift of the MAR relative to the mantle plume. The different branches of the plate boundary in South Iceland include the oblique spreading Reykjanes Peninsula plate boundary (the structural onland continuation of the submarine Reykjanes Ridge), the overlapping western and eastern rift zones, and the South Iceland Seismic Zone linking the southern ends of the western and eastern rift zones. The South Iceland Seismic Zone is a transform zone taking up motion between the Reykjanes Peninsula and the Eastern Rift Zone. GPS-measurements show that currently most of the spreading in South Iceland is accommodated by the ERZ, but little in the WRZ. Left-lateral shear is accumulating across the SISZ where majority of the 2 cm/year of relative plate motion appears to be accommodated. West of the SISZ, the Reykjanes Peninsula oblique rift accommodates the plate motion. On this field trip we will come into the western rift zone at the Hengill triple junction. It is the junction of the Reykjanes Peninsula oblique rift, the western rift zone and the SISZ. The three plates meeting at this place are the North American plate, the Eurasian plate, and the Hreppar microplate, located between the western and eastern rift zone. The Hengill triple junction is named after the Hengill central volcano which is the main volcanic production focus in the area, and is associated with a high-temperature geothermal area. The Hengill volcanic system encompasses the Hengill central volcano and its transecting fissure swarm, extending from the coast south of Hengill to the north of Lake Þingvallavatn. Stops during the field trip include Nesjavellir, south of Lake Þingvallavatn, and at Þingvellir, north of Lake Þingvallavatn. The geology of the area is described in details in the appended article by Kristján Sæmundsson ... |
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