The cooling rate also impacted Mg 2+ and Al 3+, but they were more impacted by the melt composition and crystallinity of the coexisting melt. These findings are consistent with those in experimental petrology and help us propose a better, more general geospeedometer. The partition coefficient of Ti between titanomagnetite and the melt (DTi) is negatively correlated with the apparent cooling rate. In Hannuoba samples, the cooling rate was found to affect cationic substitution in the titanomagnetite solid solution, and an increase in cooling rate led to a decrease in Ti 4+ and an increase in Fe 3+. We analyzed the chemical composition and crystal size distribution of titanomagnetite in ten Hannuoba alkaline basalt samples to determine the connection between the apparent cooling rate and titanomagnetite composition. The ratio of the maximum particle size to the area abundance of titanomagnetite, as determined by an analysis of previous studies on the texture of minerals, was negatively correlated with the apparent cooling rate. Titanomagnetite with variable crystal sizes can be observed in Hannuoba alkaline basalt, indicating disequilibrium crystallization processes (different cooling rates). However, recent studies on igneous textures and mineral compositions have shown that these processes probably occur under thermodynamic disequilibrium conditions. The nucleation and growth of crystals in igneous rocks is usually thought to occur under thermodynamic equilibrium conditions.
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