Atmospheric pCO2 since 60 Ma from records of seawater pH, calcium, and primary carbonate mineralogy

摘要: A 60 m.y. record of atmospheric p CO2 has been refined from knowledge (1) secular changes in the major ion composition seawater (particularly Ca and Mg) (2) oscillations mineralogy primary oceanic carbonate sediments. Both factors have had a significant impact on chemistry ocean buffer system. Calculated oscillated between values 100–300 ppm to maxima 1200–2500 40 Ma varied 100 300 25 present. The are significantly lower than previous estimates made pH data where total dissolved inorganic carbon was assumed constant more line with modeling stomatal index estimations for Tertiary.