Santa Maria: The island with two faces

🏝️ Santa Maria - The island of two geological lives

Santa Maria is the oldest island in the Azores, formed around 6 million years ago. It has a unique history: after being born of island volcanism, it was largely submerged under the ocean, before re-emerging. This particular destiny has left an island marked by two distinct geological chapters.

In the southern and eastern plains, time and erosion have sculpted gentle reliefs, where marine sedimentary strata, sometimes rich in fossils, can be seen. These deposits confirm that Santa Maria was once an emerged ocean floor, providing unique evidence of the encounter between volcanism and the ocean.

One of the most astonishing landscapes is the Barreiro da Faneca, nicknamed the "red desert". Its ferruginous clays are the result of intense chemical alteration of basalts in an ancient humid tropical climate. This bright red soil is a veritable window onto a vanished palaeoclimate.

The north and west of the island, on the other hand, retain the memory of more recent volcanism. Basaltic flows, steep slopes and effusive craters are closer to the classic image of the volcanic Azores. This striking contrast between fossilised marine sediments and young volcanic rocks makes Santa Maria a "double island", a veritable open-air geology textbook.

To visit Santa Maria is to cross millions of years of earth dynamics in just a few kilometres: erosion, volcanism, sedimentation, submersion and resurgence. Few places in the world can boast such a diversity of geological archives.