O Baleo beach
The amphibolites that trace the Rheic Ocean
O Baleo beach is a 400-metre shell-shaped sandy beach surrounded by cliffs, located next to Pantín beach, a must-see for surf lovers. The rocks that frame Baleo beach are amphibolites belonging to the Purrido Ophiolite, corresponding to the oceanic crust of the now disappeared Rheic Ocean.
The dating of amphibolites from the Purrido Ophiolite has led to an interesting scientific challenge. These rocks contain minerals (zircons) initially dated as the oldest in the Cabo Ortegal Complex, between 1,100 and 1,600 million years ago (Ma). However, it was later discovered that the same amphibolites also contain younger zircons, dated at 395 million years. Bringing these two ages together sparked an interesting debate at the limits of scientific knowledge. It is currently believed that the ophiolite rocks were formed 395 million years ago, an age consistent with the rest of the Complex. The older zircons probably come from the lithospheric mantle, from the area where the precursor magmas of the amphibolites were generated.
