With the conditions of a reducing atmosphere in the Hadean and early Archean, was the surface water on land masses probably of a basic pH [say about 8.0+] or an acidic
pH [ perhaps as low as 5, perhaps even 3!] Explain.
pH [ perhaps as low as 5, perhaps even 3!] Explain.
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Acidic pH:
Relatively soon (0.2 Ga) after the Earthformed, it is likely that major oceans appeared in ahot (100°C) reducing environment where carbondioxide was probably the dominant atmospheric gas,with PCO2, values reaching perhaps in excess of 10atm. During the Hadean Eon between 4.3 and 3.8 Ga BP,major changes in the concentration of atmospheric CO2 and associated temperature changes had a profound influence on the carbonate geochemistry ofthe Hadean Ocean.
In the early Hadean, seawater pH was probably about 5.8 ± 0.2, DIC may have reached close to 130 mM,and alkalinity was perhaps close to 30 mM. By the late Hadean, seawater pH probably had changed to close to neutral (6.8), and DIC and alkalinity were closer to present-day values.
Relatively soon (0.2 Ga) after the Earthformed, it is likely that major oceans appeared in ahot (100°C) reducing environment where carbondioxide was probably the dominant atmospheric gas,with PCO2, values reaching perhaps in excess of 10atm. During the Hadean Eon between 4.3 and 3.8 Ga BP,major changes in the concentration of atmospheric CO2 and associated temperature changes had a profound influence on the carbonate geochemistry ofthe Hadean Ocean.
In the early Hadean, seawater pH was probably about 5.8 ± 0.2, DIC may have reached close to 130 mM,and alkalinity was perhaps close to 30 mM. By the late Hadean, seawater pH probably had changed to close to neutral (6.8), and DIC and alkalinity were closer to present-day values.