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Abstract:
Bauxites and kaolinites are widely known as typical exogenous type of mineral resources formed in warm temperatures and high precipitation through intense chemical weathering. Here, we combine geological records with climate simulations to establish quantitative relationships of bauxites and kaolinites with temperature and precipitation in two periods when bauxites and kaolinites largely formed, Carboniferous-Permian and Cretaceous-Paleogene. We show that bauxites formed with an average temperature of 27 °C and precipitation of 1814 mm y-1 in Carboniferous-Permian, and average temperature of 24°C and precipitation of 1130 mm y-1 in Cretaceous-Paleogene. Kaolinites formed with an average temperature of 25.5 °C and precipitation of 1517 mm y-1 in Carboniferous-Permian, and average temperature of 22 °C and precipitation of 1195 mm y-1 in Cretaceous-Paleogene. The results show that climate conditions of bauxites and kaolinites are different in icehouse and hothouse background. Bauxites formed in a higher temperature and precipitation ranges than kaolinites during Carboniferous-Permian. However, in Cretaceous-Paleogene, bauxites formed in higher temperature but lower precipitation than kaolinites. The results here have important implications for understanding chemical weathering processes and metallogeneses for forming bauxites and kaolinites.
