後氷期のサンゴ礁への炭酸カルシウム堆積速度 Deposition of calcium carbonate into postglacial reefs: a test on a "coral reef hypothesis"
Calcium carbonate deposition in the ocean results in a release of CO<sub>2</sub> to the atmosphere. Based on this process, a "coral reef hypothesis" was proposed to explain postglacial CO<sub>2</sub> increase as a result of reef growth. The model assumed that if twice the mass of atmospheric carbon (2 ACM) were deposited into coral reefs between 15,000 and 10,000 years B. P., the accompanying release of CO<sub>2</sub> would account for 40 ppm increase of the atmospheric CO<sub>2</sub>. In this paper, calcium carbonate deposition rates into postglacial reefs with a time scale of 1000 years is calculated based on shallow core researches to test the hypothesis. The total reef mass is estimated to be 2 ACM. Calcium carbonate deposition rates of postglacial reefs attained their maximum between 5000 and 6000 years B. P. with a rate of 0.45 ACM for 1000 years. This major deposition phase does not match the period of observed CO<sub>2</sub> increase in the atmosphere. This discrepancy is not in agreement with the "coral reef hypothesis" .
地球化学 27(1), 37-42, 1993