Ciclos Biogeoquímicos do Carbono e Enxofre no Registro Ediacarano Brasileiro

Biological innovations associated with the Geochemical disturbances that characterize the Ediacaran geological record, marked by rapid transitions from icehouse to greenhouse conditions and the appearance of complex metazoan assemblages (e.g. Knoll et al., 2006; Narbonne et al., 2012), have been depicted in complex cause-and-effect relationships (e.g. Canfield et al., 2007; Campbell and Squire, 2010; Och and Shields-Zhou, 2012).

Abstract

The Ediacaran is known as a period of drastic climate change and biological innovations, marked by rapid transitions from icehouse to greenhouse conditions and the appearance of complex metazoan assemblages (e.g. Knoll et al., 2006; Narbonne et al., 2012).

Together with important plate tectonic reorganizations, all these events have been depicted in complex cause-and-effect relationships (e.g. Canfield et al., 2007; Campbell and Squire, 2010; Och and Shields-Zhou, 2012).

Remarkable isotope and elemental geochemical anomalies recorded in marine sedimentary rocks are among the main supporting evidence to reconstruct these paleoenvironmental and paleoceanographic conditions. In the last decades a large number of isotopic and geochemical studies in the Neoproterozoic were reported, mainly concerning carbon, strontium and sulfur isotopes, as well as elemental data (e.g. iron speciation and rare earth elements distributions; for a review, see Och and Shields-Zhou, 2012). The reproducibility of major geochemical disturbances worldwide has been explained by some authors by the occurrence of at least two events of oxidation of global significance for the Ediacaran: one in the aftermath of the Marinoan glaciation and the other in the middle to late Ediacaran Shuram-Wonoka anomaly (e.g. Hurtgen et al., 2006; Halverson and Hurtgen, 2007; Kaufman et al., 2007; Halverson and Shields-Zhou, 2011; Cui et al., 2015).

Introduction

The Ediacaran is known as a period of drastic climate change and biological innovations, marked by rapid transitions from icehouse to greenhouse conditions and the appearance of complex metazoan assemblages (e.g. Knoll et al., 2006; Narbonne et al., 2012).

Together with important plate tectonic reorganizations, all these events have been depicted in complex cause-and-effect relationships (e.g. Canfield et al., 2007; Campbell and Squire, 2010; Och and Shields-Zhou, 2012).

Remarkable isotope and elemental geochemical anomalies recorded in marine sedimentary rocks are among the main supporting evidence to reconstruct these paleoenvironmental and paleoceanographic conditions. In the last decades a large number of isotopic and geochemical studies in the Neoproterozoic were reported, mainly concerning carbon, strontium and sulfur isotopes, as well as elemental data (e.g. iron speciation and rare earth elements distributions; for a review, see Och and Shields-Zhou, 2012). The reproducibility of major geochemical disturbances worldwide has been explained by some authors by the occurrence of at least two events of oxidation of global significance for the Ediacaran: one in the aftermath of the Marinoan glaciation and the other in the middle to late Ediacaran Shuram-Wonoka anomaly (e.g. Hurtgen et al., 2006; Halverson and Hurtgen, 2007; Kaufman et al., 2007; Halverson and Shields-Zhou, 2011; Cui et al., 2015).