Por Hannah Davies (IDL - Instituto Dom Luiz).
Abstract: In recent work (Davies et al., 2018; Green et al., 2017) we explored how the next supercontinent will form, and we showed that there is a link between the supercontinent cycle and the intensity of tides. A good example of this "Super-tidal cycle" is found in the Atlantic Ocean, which was microtidal after its inception, only to host the largest tidal ranges on Earth over the past 2 Ma. This is because the Atlantic is currently close to the right width to allow harmonic resonance of the dominating semi-diurnal tide. The continued opening of the Atlantic in the future will move the ocean out of resonance, leading to weakening of the tides regionally and globally. Here, we have used an established tidal model to simulate the evolution of the global tides for the next 250 Ma. Four different tectonic scenarios are proposed to answer the question above. All four scenarios confirm that the Atlantic will move out of resonance in the next 20 Ma, and the basins will take turns to become resonant. As the next supercontinent gathers the tides decrease globally in all scenarios, showing that Earth’s tides are near the equilibrium tides during a supercontinent. This shows that there is a fundamental link between tectonics and Earth’s tidal evolution with profound implications for the ocean’s energy budget, which in turn will likely control the intensity of ocean circulation, extreme climate events, nutrient dispersal, the potential for the ocean to evolve and host life, and Lunar recession rates.
