July 1st, 2012 by Joshua S Hill
For me, as someone who covers environmental science daily, I have found that at times there are stories that don’t actually reveal anything monumental about our planet, but are nonetheless utterly fascinating. One such story is the debate revolving around the formation of curvy mountain ranges like the Appalachian range in Pennsylvania in the US or the Cantabrian Arc in Spain and northern Africa.
How did they form?
Scientists have been debating this question for decades now: were they uplifted in their current curvy formation or were they originally straight and later curved.
An international group of researchers from Spain, Canada, and the United States, led by Dr. Gabriel Gutiérrez-Alonso, have presented a compelling study of one of the best examples of curved mountain ranges: the Cantabrian Arc in Spain and northern Africa.
Their research saw them collect an extensive collection of fault and joint orientation data and directions of the ancient geomagnetic field as recorded by rocks from the Paleozoic era in modern day Spain.
The Cantabrian Arc was formed during the collision of Gondwanaland and Laurentia, a collision that created the supercontinent known as Pangea.
What they found, in short, was that the curved pattern of the Cantabrian Arc was caused by the bending of an originally straight mountain range.
The main line of evidence supporting this view is the patterns of rotation that are obtained from the directions of the ancient geomagnetic field recorded by the rocks of these mountain ranges. Combined with an analysis of the faults and joints in the rocks, and the ages of rocks that have variations in the amount of rotation indicated by the magnetic directions, the age of the bending of the Cantabrian Arc is confined to a relatively narrow window of geological time between 315 and 300 million years ago.
For anyone interested enough, the full article which was published in the journal GSA Today is available to read for free (PDF), and definitely well worth your time.
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