First- and second-order global sequence stratigraphic correlations and accommodation charts for the Kaapvaal, Karelian, São Francisco (-Congo) and Slave cratons : an introduction

Abstract

This work provides a pilot study of global sequence stratigraphic correlation for the Precambrian for five chosen cratons. Detailed chronostratigraphic charts summarize the supracrustal geological evolution of each craton, and are in the form of adapted Wheeler diagrams to enable estimation of first- and secondorder sequence stratigraphy for the cratons. Evidence within the Precambrian sedimentary record for events of apparent global significance is examined, across several preserved Precambrian cratons, utilising chronological data, inferred geodynamic and basin evolutionary histories, palaeosols, erosional hiatuses, and interpreted chemical, biochemical, palaeobiological, palaeoatmospheric and palaeoclimatic changes. The adapted Wheeler diagrams attempt to reflect time within hiatuses as well as within depositional sequences, in accord with the distinctly punctuated nature of the global stratigraphic record. The supercontinent cycle is examined for its antiquity and its application to Precambrian cratons, and a commentary is given on an emerging “conventional view” of the Precambrian wherein supercontinentality is seen as a global phenomenon by the Neoarchaean already (or alternatively only by ca. 2.0 Ga), on the nature of the “Great Oxidation Event” at ca. 2.4e2.3 Ga and possibly concomitant widespread glacial events at approximately the same time period. It is hoped that the present pilot study will stimulate an examination of accommodation changes over time for all ancient cratons, thus enabling a more comprehensive assessment of global correlations and high-order (first- and second-order) accommodation changes. This might lead to an improved appreciation of the inherent complexity of the individual facets making up the currently developing “conventional view” of Precambrian geological evolution.