Did natural fission of 235U in the earth lead to formation of the supercontinent Columbia?

Geoscience Frontiers

关键词: Natural fission;    Archean;    Paleoproterozoic;    Columbia supercontinent;    Tectonics;   

DOI  :  10.1016/j.gsf.2012.03.005

来源: DOAJ

【 摘 要 】

Steady decline in the percentage of 235U in terrestrial uranium made natural fission impossible after about 1.8 Ga. Fission before 1.8 Ga disturbed the lead isotope system at various places worldwide, such as Oklo, Gabon, and may have caused the first lead isotope paradox. Fission in areas of high uranium concentration may also have generated enough heat to localize sparse Archean and Paleoproterozoic UHT belts. The oldest widespread orogenic systems formed at approximately 2.0–1.8 Ga after fission stopped contributing to the earth’s heat flow. These early orogenic systems partly created the supercontinent Columbia.

【 授权许可】

Unknown