A temporal and causal link between ca. 1380 Ma large igneous provinces and black shales; implications for the Mesoproterozoic time scale and paleoenvironment

• Published in: Geology (Boulder) 2018-11, Vol.46 (11), p.963-966
• Main Authors: Zhang Shuanhong, Zhang Shuanhong, Ernst, Richard E, Pei Junling, Pei Junling, Zhao Yue, Zhao Yue, Zhou Meifu, Zhou Meifu, Hu Guohui, Hu Guohui
• Format: Article
• Language: English
• Subjects: absolute age; Anoxia; Asia; Atmospheric oxygen; black shale; Calymmian; China; chronostratigraphy; clastic rocks; Climate; Climate change; Climate change influences; Climate effects; Columbia Supercontinent; Continental dynamics; Earth; Ectasian; Environmental effects; Extinction; Far East; Fossils; Geochronology; Geology; Global climate; large igneous provinces; lithostratigraphy; Mass extinctions; McArthur Basin; Mesoproterozoic; nesosilicates; North Australian Craton; North China Platform; oceanic anoxic events; Oceans; Oil shale; orthosilicates; Oxidoreductions; Oxygen; paleoenvironment; paleogeography; Petroleum geology; Phanerozoic; Precambrian; Proterozoic; Roper Group; sedimentary rocks; Shales; silicates; stratigraphic boundary; Stratigraphy; U/Pb; upper Precambrian; Velkerri Formation; Xiamaling Formation; zircon; zircon group
• ISSN: 0091-7613; 1943-2682
• DOI: 10.1130/G45210.1

Phanerozoic large igneous provinces (LIPs) have a significant influence on global climate changes and mass extinction events (MEEs). Most of the Global Boundary Stratotype Section and Points in the Phanerozoic international chronostratigraphic scale are coeval with LIPs and are marked in the sedimentary record by global-scale MEEs and/or by ocean anoxic events represented by black shales. However, due to limited knowledge on atmospheric oxygen concentrations, ocean redox conditions, and early fossils during the Meso-Neoproterozoic Eras prior to the Ediacaran period, little is known on the climate and environmental effects of LIPs during this period of a billion years, the so-called "Boring Billion" (1.8-0.8 Ga). Here we provide geochronological and geological evidence for a temporal and genetic link between the intense ca. 1380 Ma LIP activity (found on many crustal blocks) and coeval black shales in the Nuna (Columbia) supercontinent. We further propose that the ca. 1380 Ma LIPs and black shales widely distributed in the Nuna supercontinent represent a global-scale geological event and provide a robust natural marker for the Calymmian-Ectasian boundary at 1383 Ma. Further investigation of the temporal and genetic link between the LIPs and black shales at other times can contribute to understanding the variations in atmospheric oxygen concentrations and ocean redox conditions during the Boring Billion, during which virtually nothing of Earth's climate and MEEs is known.