Late Archean to Early Paleoproterozoic global tectonics, environmental change and the rise of atmospheric oxygen

摘要

Analysis of the tectonostratigraphic records of Late Archean to Early Paleoproterozoic terranes indicates linkage between global tectonics, changing sea levels and environmental conditions. A Late Archean tectonic cycle started at similar to 2.78 Ga involving the breakup of a pre-existing continent (Vaalbara) and the most prodigious period of generation and preservation of juvenile continental crust recorded in Earth history during a period of plume breakout (similar to 2.72 to 2.65 Ga) accompanied by high sea levels. During this period, cratons formed by accretion of granitoid-greenstone terranes at convergent margins started to aggregate into larger continents (e.g. Kenorland). Lower sea levels between similar to 2.65 and 2.55 Ga were followed by a second (similar to 2.51 to 2.45 Ga) period of plume breakout resulting in a global peak in magmatism, high sea levels and deposition of banded iron fort-nations (BIF) on the trailing margins of the Pilbara and Kaapvaal cratons. Cratons in South Australia, Antarctica, India, and China record convergent margin magmatism, orogeny and high-grade metamorphism between 2.56 and 2.42 Ga. Continued aggregation of continental fragments (e.g. amalgamation of Indian cratons) may have formed the Earth's first supercontinent by similar to 2.4 Ga with a return to low sea levels and relative tectonic quiescence before the supercontinent started to breakup from similar to 2.32 Ga.