A Friday fold from the legendary region of Cinque Terre, on Italy’s northwest coast:
This comes to us courtesy of my friend Callan Swenson – yes, there’s another Callan out there! – who’s there this week on vacation. This is near the village of Vernazza. The Other Callan is not a geologist, though, so we’re on our own to figure out the story of these outcrops. From a quick investigation online, it looks like this is a region where the Ligurian nappes have deformed the local rocks. There are ophiolites further to the north, but these appear to be a package of turbidites. Unfortunately, I can’t squeeze much useful information from the 1:1,250,000 scale Geological Map of Italy online. Oh well, chances are that at least a dozen of this blog’s reader have been to the site, and can share their knowledge in the comments below… Please, enlighten us!
(And: Happy Friday!)
Many of the rock outcrops along the “Lover’s Walk” in Cinque Terre are classic examples of tectonic melanges similar to those in coastal northern California. In outcrop, you can see the elongation and flattening of individual clasts within the matrix. It’s also possible that this particular outcrop is an exposure of a portion of the La Spezia fold. http://www.italy-tours-in-nature.com/cinque-terre-geology.html
Here’s a link paper on melanges mentioning those in cinque terre. https://www.researchgate.net/profile/Andrea_Festa/publication/233810940_Melanges_and_melange-forming_processes_A_historical_overview_and_new_concepts/links/55031cba0cf2d60c0e64ca0a/Melanges-and-melange-forming-processes-A-historical-overview-and-new-concepts.pdf
Thanks Erik!
I suggest that these stratified rocks are part of the “macigno,” the earliest of the three foredeeps that record the eastward advance of the Ligurian nappe. Age: about Oligocene to early Miocene. Erik is correct: I’ve seen excellent olistostromal melange on the Via dell’amore near Riomaggiore.
Callan, I learned everything I know about the rocks at cinque terre (admittedly little) from Darrel. he’s the expert.