Geology, Palaeontology & Archaeology / Re: What is the name for this form of arch-like geological structure with fractures?« on: 16/09/2018 01:01:43 »
Great photo. I've been to the Azores, but never to Corvo. My recollection is that Corvo (and the rest of the Azores) are volcanic, and that Corvo is a caldera, with both ash, welded ash and some basalt units. I think Ophiolite is correct in calling this a geomorphic feature- I would term it an "arch". Since the island is composed of recent volcanic rocks that have undergone very little strain, this feature is not an anticline. I seem to remember some discussion of this feature being the remnants of a lava tube, the fractures being "joints" that form during contraction of the lava due to cooling.
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