Rapid Growth of Continental Crust Between 2.2 to 1.8 Ga in the South American Platform: Integrated Australian, European, North American and SW USA Crustal Evolution Study

Abstract

The production of juvenile continental crust in the South American Platform (SAP) and other continents was larger in the Proterozoic than in the Archean. In the SAP the juvenile crust production was about 65% during the Proterozoic, while during the Archean it was around 34% of the total volume. Similar proportions are found in the Australian continent. The largest accretion from mantle to crust happened between 2.2 to 1.8 Ga and corresponded to 35% of the total volume of the present SAP continental crust. During the Archean an intense recycling between mantle and continental crust took place, while in the Paleoproterozoic the rate of mantle accretion to continental crust was larger than the assimilation. For the other continents (Europe and North America) the Paleoproterozoic was also the main accretion event. In the SW USA, rapid continental growth (about 45% of actual volume) occurred in a short time interval between 1.9-1.7 Ga. During Meso and Neoproterozoic little accretion of juvenile material occurred in the SAP, where crustal reworking predominated, but in Eurasia much juvenile continental crust was generated during the Phanerozoic in Central Asia.