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Start Over Author "Caldeira, Ken" Journal geophysical research letters
37 results on '"Caldeira, Ken"'

2. Antipodal hotspot pairs on the earth

Author

Rampino, Michael R and Caldeira, Ken

Subjects
Geophysics
Abstract

The results of statistical analyses performed on three published hotspot distributions suggest that significantly more hotspots occur as nearly antipodal pairs than is anticipated from a random distribution, or from their association with geoid highs and divergent plate margins. The observed number of antipodal hotspot pairs depends on the maximum allowable deviation from exact antipodality. At a maximum deviation of not greater than 700 km, 26 to 37 percent of hotspots form antipodal pairs in the published lists examined here, significantly more than would be expected from the general hotspot distribution. Two possible mechanisms that might create such a distribution include: (1) symmetry in the generation of mantle plumes, and (2) melting related to antipodal focusing of seismic energy from large-body impacts.

Published
1992

3. The mid-Cretaceous super plume, carbon dioxide, and global warming

Author

Caldeira, Ken and Rampino, Michael R

Subjects
Meteorology And Climatology
Abstract

Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. A carbonate-silicate cycle model is developed to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. CO2 emissions resulting from super-plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern preindustrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering-rate formulations, this would cause a global warming of from 2.8 to 7.7 C over today's glogal mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8 C to mid-Cretaceous warming. Thus, the combined effects of paleogeographic changes and super-plume related CO2 emissions could be in the range of 7.6 to 12.5 C, within the 6 to 14 C range previously estimated for mid-Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20 percent of the mid-Cretaceous increase in atmospheric CO2.

Published
1991

4. Carbon dioxide emissions from Deccan volcanism and a K/T boundary greenhouse effect

Author

Caldeira, Ken and Rampino, Michael R

Subjects
Geophysics
Abstract

A greenhouse warming caused by increased emissions of carbon dioxide from the Deccan Traps volcanism has been suggested as the cause of the terminal Cretaceous extinctions on land and in the sea. Total eruptive and noneruptive CO2 output by the Deccan eruptions (from 6 to 20 x 10 to the 16th moles) over a period of several hundred thousand years is estimated based on best estimates of the CO2 weight fraction of the original basalts and basaltic melts, the fraction of CO2 degassed, and the volume of the Deccan Traps eruptions. Results of a model designed to estimate the effects of increased CO2 on climate and ocean chemistry suggest that increases in atmospheric pCO2 due to Deccan Traps CO2 emissions would have been less than 75 ppm, leading to a predicted global warming of less than 1 C over several hundred thousand years. It is concluded that the direct climate effects of CO2 emissions from the Deccan eruptions would have been too weak to be an important factor in the end-Cretaceous mass extinctions.

Published
1990

21. Comment on “Modern‐age buildup of CO2 and its effects on seawater acidity and salinity” by Hugo A. Loáiciga

Author

Caldeira, Ken, primary, Archer, David, additional, Barry, James P., additional, Bellerby, Richard G. J., additional, Brewer, Peter G., additional, Cao, Long, additional, Dickson, Andrew G., additional, Doney, Scott C., additional, Elderfield, Harry, additional, Fabry, Victoria J., additional, Feely, Richard A., additional, Gattuso, Jean‐Pierre, additional, Haugan, Peter M., additional, Hoegh‐Guldberg, Ove, additional, Jain, Atul K., additional, Kleypas, Joan A., additional, Langdon, Chris, additional, Orr, James C., additional, Ridgwell, Andy, additional, Sabine, Christopher L., additional, Seibel, Brad A., additional, Shirayama, Yoshihisa, additional, Turley, Carol, additional, Watson, Andrew J., additional, and Zeebe, Richard E., additional

Published
2007
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37. Comment on 'Modern-age buildup of CO2 and its effects on seawater acidity and salinity' by Hugo A. Loáiciga.

Author

Caldeira, Ken, Archer, David, Barry, James P., Bellerby, Richard G. J., Brewer, Peter G., Cao, Long, Dickson, Andrew G., Doney, Scott C., Elderfield, Harry, Fabry, Victoria J., Feely, Richard A., Gattuso, Jean-Pierre, Haugan, Peter M., Hoegh-Guldberg, Ove, Jain, Atul K., Kleypas, Joan A., Langdon, Chris, Orr, James C., Ridgwell, Andy, and Sabine, Christopher L.

Published
2007
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