Paleoproterozoic positive δ13Ccarb excursion in the northeastern Sino-Korean craton: Evidence of the Lomagundi Event

The 2.33-2.06 Ga positive delta C-13(carb) excursion, associated with environmental change and the breakup of the Kenorland or Superia supercontinent, is called the Lomagundi or Jatulian Event or Great Oxidation Event, and has been reported in many Early Precambrian cratons, but not yet in the Sino-Korean craton. The Guanmenshan Formation of the Liaohe Group occurs in the northeastern part of the Sino-Korean craton. delta C-13(carb) and delta O-18 values in 42 samples from this formation range from 3.5-5.9 parts per thousand (V-PDB), and 15.4-24.8 parts per thousand (V-SMOW), respectively, showing a clear positive delta C-13(carb), excursion that characterizes the Lomagundi Event. Thirty-five of the 42 samples with less hydrothermal alteration have higher delta C-13(carb) and delta O-18(carb) values than the other 7 samples obviously affected by fluid flow, confirming that it was fluid flow that reduced the delta C-13(carb) and delta O-18(carb) values. This positive delta C-13(carb) excursion places deposition of the Guanmenshan Formation within the age range of 2.33-2.06 Ga. (C) 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.