Post-125 Ma carbon storage associated with continent-continent collision: Comment and Reply
Kerrick, D.M. and K. Caldeira, Post-125 Ma carbon storage associated with continent-continent collision — comment. Geology 22, 381–382, 1994.
A reply to a paper that suggested that carbon storage during continent-continent collisions contributed to global cooling through a lowering of atmospheric carbon dioxide concentration. The previous study neglected several of the carbon cycle that could have counteracted the reduction.
Selverstone and Gutzler (1993) concluded that the transfer of carbon from the atmosphere to deep-seated metamorphic reservoirs during the Thethyan continent-continent collision may have contributed to post-125 Ma global cooling. However, because the long-term (>1 Myr) atmospheric CO2 content is controlled by the interplay between the flux of CO2 from Earth degassing vs. CO2 consumed by silicate-rock weathering (Berner et al., 1983), carbon sequestered in orogenic environments affects atmospheric CO2 only if it influences the rates of degassing (Kerrick and Caldeira, 1993) and/or weathering (Raymo and Ruddiman, 1992). We agree that there is net carbon storage in orogenic belts; nevertheless, collisional orogenesis can enhance CO2 degassing to the atmosphere because metamorphism in orogenic belts can liberate to the atmosphere CO2 that would have otherwise remained locked up in kerogen and carbonate rocks.