矿床地球化学国家重点实验室知识库

In this chapter, we review the early Paleoproterozoic sedimentary records in North China Craton (NCC) and elsewhere in the world. We also propose a sequence framework for the subprime events happened in sedimentary sphere, biosphere, hydrosphere and atmosphere during the period of 2.5 to 1.8 Ga, and give an introduction to the Great Oxidation Event (GOE). These events are characteristic of the GOE, and are assigned to two main stages: (1) the early-stage hydrosphere oxidation (2.5–2.3 Ga), represented by the precipitation of the banded iron formations (BIFs), and (2) the late-stage atmospheric oxygenation (2.3–1.8 Ga), indicated by sediments of thick carbonate strata with 2.22–2.06-Ga δ¹³C_carb positive excursion (Lomagundi Event), 2.25–1.95 Ga red beds, as well as the disappearance of BIFs at ca 1.8 Ga and prevail of black shales at 2.0–1.7 Ga. The 2.29–2.25-Ga Huronian Glaciation Event (HGE) demonstrated that the Earth’s superficial system oxidation had entered from hydrosphere into atmosphere. The 2.3-Ga turnpoint is a better Archean-Proterozoic boundary in Geological Time Chart.