Columbia (supercontinent)

Columbia (supercontinent)

Columbia, also known as Nuna and Hudsonland, was one of Earth's ancient supercontinents. It was first proposed by J.J.W. Rogers and M. Santosh (2002) and is thought to have existed approximately 1.8 to 1.5 billion years (Ga) ago in the Paleoproterozoic Era. Zhao et al. (2002) proposed that the assembly of the supercontinent Columbia (Nuna) was completed by global-scale collisional events during 2.1–1.8 Ga. It consisted of the proto-cratons that made up the former continents of Laurentia, Baltica, Ukrainian Shield, Amazonian Shield, Australia, and possibly Siberia, North China, and Kalaharia as well. The evidence of Columbia's existence is based upon geological and paleomagnetic data.