Geo-#giroditalia2023 - Stage 20. If geology is predictive for cycling, the GC will go upside down today. The peloton has entered the biggest geological mess of this Giro: the junction region between the Alps, the Carpathians, and the Dinarides. No rock remains unturned. At present, there is no active mountain building in the Carpathians: both sides of the mountains are part of Europe. Earthquake locations trace the active boundary between Adria (African Plate) and Eurasia from the southern Alps to the Dinarides, with Monte Lussari at the bend.

Geo-#giroditalia2023 - Stage 16. After the peloton leaves the road west of lake Garda, they will climb through some of the most beautiful natural building stone of Italy: the Ammonitico Rosso. You'll have seen them on plenty of floors and walls: red limestone full of ammonites! In the Jurassic the 'Greater Adria' continent was broken up and formed shallow ridges and deeper basins. The basins trapped sediments from land, so the ridges only received 'pelagic' sediments: sediments that rain down from the water column, mostly living organisms.

Geo-#giroditalia2023 - Stage 13. Today, we recommend the entire peloton to join the grupetto and look around: the Giro organization prepared a fantastic geological excursion! The race will lead from Adria to the 'Penninic Front' of the Central Alps, a former subduction zone! The Alps are piled-up rock packages of a few km thick that were offscraped from the European plate that subducted below Adria. The riders will cross remnants of two oceanic basins (the blue colors) and a small continent (the 'Brianconnais', in orange).

Geo-#giroditalia2023 - Stage 12. The peloton is leaving the Apennines, will race over Adria again, and then enters the Alps today. The difference between these mountain belts is not just geographical: geologically, they're entirely different beasts! But it's a complex geometry! As we saw last week, the Apennines formed because Adria, the continent that underlies the Adriatic Sea and that is part of the African Plate, subducted below Europe and its sediments were offscraped. In the Alps, however, it's the opposite: Europe subducted below Adria.

Geo-#giroditalia2023 - Stage 11. The peloton is going to race through an ocean today! We've reached the Ligurian 'ophiolites', the oceanic lithosphere remains below which the northern Apennines were offscraped and stacked up, which you may see as the black rocks along the race. Geologically, oceans, are not bodies of water, but the crust type that forms by magmatism at mid-ocean ridges. Continents continue into the sea as shelf and slope, and only then the ocean starts. The Apennines are shelf and slope rocks, the 'Ophiolites' are oceanic crust rocks.