Geology at Latrabjarg Cliff, Breidafjord, Iceland

Discussion in 'Landscapes, Architecture, and Cityscapes' started by bobhoge, Jun 29, 2007.

  1. We had a great example of how these volcanic islands are formed when we sailed past Latrabjarg Cliff, Breidafjord, on our voyage around Iceland.

    Iceland is located on the mid-atlantic ridge, where the ocean is opening up at about the same rate as your fingernails grow. Half of the island is attached to North America and half to Europe.

    First you get lots of volcanic eruptions each laying down a layer of basalt and a layer of ash. Since the basalt and ash erode at different rates, the weathering along a cliff will show the layers:
    [​IMG]

    Sometimes you get a lot of erosion:
    [​IMG]

    There are also a lot of earthquakes that open up cracks and fisures in the layers. When another eruption happens the hot magma will work up through the fisure to reach the surface since it is the weak spot. When it cools it leaves a dyke of new material intruding through the old layers:
    [​IMG]

    You can see the line of newer material sticking up all the way to the top of the hill:
    [​IMG]

    A closer look at the dyke going up through a couple of layers:
    [​IMG]

    Lindblad almost always has a geologist as one of the experts aboard. He got a workout on this trip.

    Bob & Nan
     
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