Transcription
Look here. 150 million years ago, Italy was more or less here. Sicily was attached to Africa, and Sardinia and Corsica to France. Today, prepare your popcorn, sit on the couch, turn on the television, because I'm going to tell you the geological history of Italy, starting from about 250 million years ago. Knowing the basics of our country's geological history, I assure you, besides being extremely stimulating, it truly gives us a different, more aware perspective. To truly understand Italy's geological history, we need to do something a bit counterintuitive, which is to forget about Italy, forget about the peninsula, the Alps, the Apennines, the Mediterranean, because at the beginning, they simply didn't exist. A small parenthesis, before we delve deeper, give me 30 seconds to introduce the sponsor of this video, whom I thank for supporting our outreach. Go! This video is sponsored by Edenred. If you have a company or a VAT number, you know how crucial it is to optimize expenses. Edenred Ticket Restaurant meal vouchers are 100% deductible for companies and 75% for freelancers. It's a very convenient solution, tax-exempt for employees, and accepted in supermarkets, discount stores, restaurants, and food delivery services within the Edenred network, which counts over 300,000 establishments. Furthermore, they can also be used via an app. Below in the description, you will find this link www.ticketresturant.it/geop where there is a dedicated promotion. Thank you very much, and let's get back to us. Let's go back in time about 250-300 million years ago. We are between the end of the Paleozoic and the beginning of the Mesozoic. Two great geological eras. The Earth was in a completely different configuration than what we know today. All the continents we now see separated, namely Eurasia, Africa, America, Antarctica, Australia, were fused together into a single enormous block, Pangea. Around this supercontinent, there was a single large ocean that we call Panthalassa. After all, Panthalassa derives from "pan" meaning all, and "thalassa" meaning sea, so, in short, all sea, because it was indeed all one single large sea. At this point, I would ask myself, "But where is Italy?" I don't see it, where is it? You don't see it because, as I told you, it doesn't exist yet. For now, I'll tell you to keep an eye on this branch of the ocean. This branch of the ocean that is to the east and that is as if it wants to enter between the Eurasian continent and Africa. Well, this branch, which we call the Tethys, the Tethys Ocean, is the place where Italy will take shape, where the history of our beloved territory will begin, where the Alps and the Apennines will later develop, but we'll get there step by step, we'll get there, let's enjoy it. From about 250 to 200 million years ago, Pangea begins to fragment. Tectonic forces cause an initial rupture and a consequent phase of great tectonic extension. North America begins to detach from South America and Africa. Now, let's enter that branch of the Tethys Ocean I was talking about earlier. Let's zoom in, let's look closely at this image because it already tells us a lot. The first thing that catches the eye are the little drawings of Sicily and Sardinia, the islands that are often forgotten today, I'll introduce them to you first. See their position? No, it's not random; they were divided, as you can see. But what am I saying, divided? They were part of two worlds, two different continents. Sicily was, in effect, part of the northern part, the northern part of the African continent, that is, the great block of Gondwana, which was the southern part of Pangea. So yes, Sicily is literally a fragment of the African continent. Geologically, Sicily is a piece of Africa. Sardinia, Sardinia and Corsica, on the other hand, tell a completely different story. They were part of the European continent. They are a piece of Europe, understood as continents, precisely. So, between us, they were attached to the southern part of present-day France. So Sicily comes from the south, it's African; Sardinia and Corsica are European, they are French. Well, having said that, where is the peninsula? Where is Italy? It's not visible. You don't see it? Adria, hold on! Look. Adria, this little whitish, silent piece that we barely considered until a second ago. Is that true or not? Well, this Adria is the true silent protagonist of this image. Adria is a continental block, it's a microplate that at that time, we are still around about 220 million years ago, was wedged between Africa and Europe. It's not Africa, it's not Europe; it's a sort of geological no-man's-land. And it is here, on Adria, that most of what will become Italy is located. As you can see, this microplate Adria was submerged, it was underwater, and you should know that almost all sedimentary rocks, in this case, carbonate rocks, form underwater. And it is in this very environment that the Triassic carbonate rocks are born. We are talking about those limestones and dolomites that we find today at high altitudes in the Alps, in the Apennines, and in many areas of Italy. Many of our mountains, but this is true worldwide, are born on the seabed. In our case, shallow, tropical seabeds. They were tropical then. So, when today we walk on the Dolomites, on the Eastern Alps, or on certain Apennine ridges, we are walking on rocks that were once the seabeds of the Adria microplate in the Tethys Ocean. I mean, what a thing, what a thing. Now, before we go to see what happens in the Jurassic, I want to remind you that my new book has been released, titled "Pausa" (Pause). The book contains 101 pills of science and culture for when we put down our phones. Let's face it, we all take a thousand pauses with our phones, and we'll probably continue to do so. I absolutely don't want to demonize the mobile phone; that would be inconsistent. However, every now and then, out of the 100 pauses we take with our phones, my suggestion is to take one with a book because it's good for us, it relaxes our eyes, and it might help us rediscover the desire to read. I am very happy to say that it is one of the best-selling books of 2025 in Italy and hopefully in 2026 as well. You can find it on Amazon; I'll leave the link in the description. Feel free to read the reviews so you can get an idea. Thanks again, and let's return to our incredible story. We arrive at the Jurassic, so about 180-150 million years ago. Here, the story accelerates, and it does so irreversibly. The fissures that at the end of the Triassic had begun to tear the heart of Pangea continue to widen, so all the pieces, all the continents, effectively begin to move apart. They are no longer simple fractures; they become true systems called rifts, meaning opening, and then drift, meaning moving apart. And at a certain point, the key transition happens. In the Middle Jurassic, between 180 and 160 million years ago, America definitively separates from Africa. Thus, the Central Atlantic Ocean is born. In this same period, along with the opening of the great Central Atlantic Ocean, the Adria microplate also tears and detaches from the European continent. And right there in between, between Adria and the European continent, a new, small but deep and very important ocean is born. It's an ocean you've probably never heard of. It's the Ligurian-Piedmontese Ocean. It's a large oceanic depression where new oceanic crust forms. To understand, deep down there are volcanoes that emit magma, lava that becomes new oceanic crust. And it is here that something fundamental for Italy's future happens. On the seabed of the Ligurian-Piedmontese Ocean, rocks are formed that we find today in the Alps, rocks that we consider anomalous in mountains. Why? Because we are talking about basalts, gabbros, serpentinites, portions of the mantle, rocks that are not born on continents but are born in oceans. So when you hear "Mountains were often once oceans," can that be true? Absolutely yes. And this is an emblematic case. Today, these rocks, these oceanic rocks at the bottom of the ocean, we find them in the Alps and the Apennines at thousands of meters of altitude. I mean, imagine the first geologists who perhaps studied the Alps; you go to high altitudes, to high mountains, and you find rocks typical of deep oceans. I would have gone crazy. Fortunately, science and geology have made progress and have allowed us to understand. Well, that ocean, that Ligurian-Piedmontese Ocean, which was deep in the past, has been squeezed, squeezed, crushed by tectonic forces, and when you squeeze in geology, what happens? A relief is created, in this case, the Alps. Let's take another step in geological time and arrive at about 130 million years ago. At this point, the story changes direction. After a long phase of opening, the plate system enters a new configuration. Africa and America begin to separate even further south. Thus, the South Atlantic is born, but once again, this does not remain confined far from the Mediterranean; on the contrary, it has profound effects precisely on the Mediterranean. In fact, the African plate does not just move forward; it is performing a counter-clockwise rotation. And this detail is crucial, because what does this rotation cause? It causes Africa to progressively push the Adria block against Europe. And when two continents approach, what's in between has no escape. What I said a moment ago happens: squeezing, everything is crushed. So the Ligurian-Piedmontese Ocean, which had opened, deepened, and filled with oceanic rocks in the Jurassic, now finds itself in a vise, compressed and crushed between Africa and Europe. So the oceanic crust, denser and thinner than continental crust, begins to subduct. Little by little, the ocean is literally consumed, it descends beneath the African margin, thus entering subduction and beginning to disappear. It's the end of the Ligurian-Piedmontese Ocean, but it's also the beginning of something completely new. In place of the Ligurian-Piedmontese Ocean, a mountain range is born, a mountain range begins to be born, the Alps are born. And it's important to clarify one thing: the Alps are not born all at once, in one go; they are not born suddenly. Their formation is a long process that begins in this phase and continues for tens of millions of years, but the fundamental mechanism is already active, namely the collision between Africa, Adria, and Europe. From this moment on, a huge part of Italy's geological history will be dominated by this event. So Italy definitively stops being just sea and seabed; it begins to become mountains. After the birth of the Alps, the tectonic engine of the Mediterranean certainly doesn't stop; on the contrary, it changes its configuration again. We are between the Upper Oligocene and the Lower Miocene. We are talking about 25-20 million years ago. What happens in this phase? Something happens that is literally spectacular to me, but often little known. A piece of the European block, practically where France is today, detaches, separates from the European block, and literally begins to rotate counter-clockwise in the middle of the current Tyrrhenian Sea, which didn't exist yet then. It's a real, measurable rotation, which happens by pivoting on the area of the current Gulf of Genoa. It's like a compass. They were literally attached to France. Now, when a continental block rotates and moves away, it doesn't just simply move. Behind it, it breaks, everything shatters, and when everything shatters, it goes down, creating a depression, right? And depressed areas are occupied by water, and indeed, the Ligurian Sea is born there. The Ligurian Sea is practically the sea between Sardinia, Corsica, and France and Spain, to be clear, so it's the part west of Sardinia and Corsica that we might usually imagine as the Tyrrhenian Sea. It's not the Tyrrhenian Sea; geologically, it's the Ligurian Sea. Now, pay attention because here comes the poetry. Geological poetry. This movement of Sardinia and Corsica has another enormous consequence, but not to the west, to the east. It collides with the remnants of the Adria platform. The rocks are gradually compressed and tend to rise. It's like pushing a carpet against a wall. What's in front can't escape, so it folds, right? It crumples and rises. And it is precisely here that a new mountain range is born, the Apennines. The Apennines exist because Sardinia and Corsica crashed towards the Adria platform, which was to the east. So, yes, the Apennines are younger than the Alps and were formed in a completely different tectonic context. Here, there is no frontal collision between two continents as in the case of the Alps, but a progressive compression linked to the rotation of the Sardinian-Corsican block and subduction. In fact, the Adria platform subducts westward against the Sardinian-Corsican and Tyrrhenian block. So this collision continues, the Apennines rise, and Italy, which had been underwater until then, begins to emerge. But hold on, because the story isn't over yet. We still need to explain the birth of the Po Valley, of our main seas, namely the Adriatic Sea and the Tyrrhenian Sea. Let's start with the Adriatic Sea. The Adriatic Sea, in all probability, is precisely a consequence of the uplift of the Apennine chain. The Apennine chain, like all mountain ranges, weighs, guys, it weighs a lot, and this weight causes the crust underneath to bend, thus creating a fold, okay? A basin in front of the chain. This chain is precisely the skeleton of our country, right? What could a basin, a depression in front of the country, be called? Foreland basin. That's the technical term that at university it took me a year, two years to understand, and I believe all geology students take a month because it's an extremely complicated concept, but perhaps explained like this, I hope it can be understood. So the Adriatic Sea is shallow because it's a crustal flexure caused by the weight of the Apennine chain. It's practically a sort of little lake, right? And pay attention, the Po Valley is nothing more than the continuation of the Adriatic Sea. And in fact, in the Pliocene, about 4-5 million years ago, look at this reconstruction, the Adriatic Sea reached almost where present-day Genoa is. So, let's say Genoa had a sea on one side and a sea on the other. It was an incredible thing, wasn't it? Had you ever seen this? Beautiful. Now, now that we've also understood the Adriatic Sea, let's move behind the Apennine chain to see, to understand the formation of the Tyrrhenian Sea, which is younger in this area. In fact, between 15 million and 5 million years ago, there was a stretching of the crust. The crust tore apart, and a sea literally began to open, the Tyrrhenian Sea. Consider that geologically, the Tyrrhenian Sea is not a sea; it's an ocean. In fact, the peculiarity of an ocean, I talked about it in a video that I'll leave in the description, check it out, is that it's the result of a crustal rupture. It splits, hence rift, and the parts move apart, drift, and in between, new oceanic crust emerges. So, let's say the ocean is geologically a dynamic thing. The sea, on the other hand, is a little lake; it's dynamically static. And hold on, for volcano enthusiasts, this phase, the opening of the Tyrrhenian, is the phase that determines the birth of many Italian Tyrrhenian volcanoes: Vesuvius, Campi Flegrei, Marsili, etc., etc. What I've told you so far are the macro, the geological macro-events, but you have to imagine that geological history is much more complex than this. I'll give you an example by telling you what happened between 6 and 7 million years ago. About 7 million years ago, the progressive approach between Africa and Europe, along with a global drop in sea level and tectonic movements in the Mediterranean area, led to something that shook the Mediterranean: the closure of the Strait of Gibraltar, which was the only connection to the ocean. It closed, and therefore the Mediterranean became a closed sea, a basin. And if we leave a basin open to the air, what happens? The water evaporates. Well, that's what happened to the Mediterranean. The water level dropped drastically, leaving a large layer of salt on the seabed. All of this, this great evaporation, caused vast areas, now submerged, to emerge. Sicily and Africa were connected; Calabria and Sicily, what can I say, there was no need for a bridge, excuse the joke, the geography, well, it was totally distorted. Then, about 5.3 million years ago, thank heavens, or rather, thanks to tectonic forces, the Strait of Gibraltar reopened, and therefore the Atlantic began to flow back into the Mediterranean, and thank goodness. So the situation returned to perfect. How do you think we managed to reconstruct this event? This event called the Messinian? Well, thanks to those salt layers, which it is more appropriate to call evaporites, especially gypsum, which outcrops in many areas of Italy, from Sicily to Monferrato. These rocks, because they are rocks, are proof that the Mediterranean, for a brief but dramatic period, almost ceased to exist. If these evaporitic rocks hadn't existed, we wouldn't have been able to reconstruct this, this sensational geological curiosity. Well, many of you will be asking, "But in all this, you haven't told us about the volcanoes?" Our volcanoes emerged after all that I've told you, so they are very young from a geological point of view. In fact, Stromboli began to emerge and was submarine about 1 million years ago, Etna about 500,000 years ago, Vesuvius about probably 400,000 years ago, Campi Flegrei are probably even younger, about 80-100,000 years. So you realize how gigantic geological timescales are, right? To say 500,000 years ago is nothing. From a geological point of view, it's nothing; from a human point of view, it's a lot. My goodness, guys, how much we've covered. A super summary would be needed. And indeed, we've done it. Here it is. The history of Italy can be traced back to about 300-250 million years ago. There was Pangea; everything was united, a single supercontinent. Italy didn't exist, not present. 250-200 million years ago, everything broke apart; Pangea fragmented, split. The Tethys, a new ocean, was born. Adria appeared, a raft of crust linked to Africa. Adria is a platform, the future of our Italy, where there was a shallow tropical sea. The limestones of the future Dolomites and the future Alps formed. 180-150 million years ago, the Atlantic opened; Africa moved away from Europe. In between, the Ligurian-Piedmontese Ocean opened. Then, 130-65 million years ago, a U-turn: Africa changed its mind, began to rise and rotate against Europe and Adria. The previous ocean began to close and go under in subduction. The great collision was being prepared. 65-30 million years ago, the bang. The creation of the Alps. Total collision. Adria slammed into Europe. The ocean disappeared. The seabeds were shot upwards; the Alps rose. The North began to emerge from the water. 25-10 million years ago, the dance of the Sardinian-Corsican block. Sardinia and Corsica detached from France. They rotated eastward like a revolving door. This push crumpled the crust; the Apennines began to be born. 20 million years ago, 5 million years ago, Italy took shape. The Apennines rose and moved eastward gradually. Behind the push, the land stretched, tore, the Tyrrhenian Sea opened. On the other side, the Adriatic Sea had already been born. Central and Southern Italy began to emerge. 7 million years ago, the Mediterranean suddenly disappeared. Gibraltar closed; the sea evaporated; Italy became a desert of salt and gypsum. Then, fortunately, Gibraltar gave way, a mega-flood, and the sea returned. 2 million years ago, the Po Valley was a sea. Rivers filled it with stones and mud from the Alps, turning it into dry land, a plain. Final touches: Vesuvius, Etna, Campi Flegrei, etc., etc. And ding, Italy is finished. I mean, do you understand what territory you live in? Now you understand why it's called the beautiful country? Because geologically too, it has everything. I truly hope you enjoyed this video. I hope that when you next look at a map, a geographical map of Italy and Europe, you will see it with new eyes, thinking about the tectonic evolution we have seen together today. Thank you very much for staying with us until the end. Thank you indeed. If you want to support Jopop, I remind you that you can do so by joining our membership; you will give us a great hand. I look forward to seeing you next time, always here on Jopop, science in everyday life. Bye.