How did sediments from the ancient Tethys Sea contribute to the Apennines?

The majority of the geologic units forming the Apennine Range consist of marine sedimentary rocks that were deposited over the southern margin of the Tethys Sea during the Mesozoic Era (approximately 250 to 65 million years ago).1

These deposits, which include shales, sandstones, and limestones, were accumulated on the continental margins of the ancient ocean. As the Italian peninsula—a promontory of the African continent—moved and collided with Europe, these sedimentary layers were subjected to intense tectonic forces.12

The Apennines were subsequently built through the folding and faulting of these accumulated marine sediments. The resulting thrust-belt structure reflects the complex interaction between the African and European tectonic plates, which effectively uplifted and deformed the ancient seafloor material to create the modern mountain chain.21