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> Co-author Professor Dietmar Müller from the University of Sydney said: Geology ruled climate at this time. We think the Sturtian ice age kicked in due to a do
by twojacobtwo 3y ago
> Co-author Professor Dietmar Müller from the University of Sydney said: Geology ruled climate at this time. We think the Sturtian ice age kicked in due to a double whammy: a plate tectonic reorganisation brought volcanic degassing to a minimum, while simultaneously a continental volcanic province in Canada started eroding away, consuming atmospheric CO2.
Research:
> Duration of Sturtian “Snowball Earth” glaciation linked to exceptionally low mid-ocean ridge outgassing’, Dutkiewicz, A. et al (Geology, 2024). DOI: 10.1130/G51669.1
- apothegm 3y agoHow would erosion consume CO2?
- philipkglass 3y agoIt's the carbonate-silicate cycle. Erosion of silicate rocks (which form most of the Earth's crust) by chemical weathering consumes CO2 from the atmosphere and turns it into thermodynamically stable carbonates. Those carbonates can eventually be subducted and their CO2 released again by heat from the Earth's interior. https://personal.ems.psu.edu/~jfk4/PersonalPage/ResInt2.htm https://personal.ems.psu.edu/~jfk4/PersonalPage/ResInt2.htm The carbonate-silicate cycle, which plays a key role in stabilizing Earth's climate over long time scales, is shown in Fig. 2. The cycle begins when atmospheric CO2 dissolves in rainwater, forming carbonic acid, H2CO3. Through a process termed "weathering", this weak acid dissolves silicate rocks on the continents, releasing Ca++, Mg++, HCO3- (bicarbonate), and SiO2 (dissolved silica) into solution. The products of weathering make their way down to the oceans in streams and rivers. There, organisms such as the planktonic foraminifera that live in the surface ocean use them to make shells out of calcium carbonate (CaCO3). When the organisms die, they fall down into the deep ocean, where most of the shells redissolve. Some of the calcium carbonate survives, however, and is buried in sediments on the seafloor. The seafloor spreads from the midocean ridges and, at some plate margins, is carried down subduction zones. The carbonate minerals recombine with SiO2, which by this time is the mineral quartz, to reform calcium and magnesium silicates and release gaseous CO2. This CO2 is vented into the atmosphere through volcanoes, thereby completing the cycle.
- apothegm 3y agoSo this basically also depends on a thriving population of shellfish to fix the carbon?
- philipkglass 3y agoCalcium carbonate can also spontaneously precipitate out of solution, but it takes greater extremes of temperature, concentration, or other chemical changes. Shellfish increase the rate at which dissolved calcium carbonate converts to solid calcium carbonate. That action increases the rate at which trapped carbon can be returned to the atmosphere via subduction and volcanic emissions, which means a higher equilibrium concentration of atmospheric CO2 and a warmer planet than we would have if the oceans were lifeless.
- apothegm 3y agoThank you for the explanations!
- eber 3y agoI believe the cycle they are referring to is: 2 CO2 + H2O + CaSiO3 -> Ca^2+ + 2HCO3- + SiO2 and Ca^2+ + 2HCO3- -> CaCO3 + CO2 + H2O https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cyc...
- richardjam73 3y agoChemical processes in rock can store or release gases. Erosion can expose rocks leading to this occurring.