Assessment of factors of periodicity in Phanerozoic carbonate accumulation

Abstract

Periodicity in the evolution of carbonate accumulation (CA) depends on settings and processes governed by three (vertical, latitudinal, and circum-continental) types of zonality. It is also controlled by oceanic hydrodynamics and variations in global paleorelief of the bottom [1]. The history of origin and evolution of carbonates is intricate and diverse. The role of predominant factors in many aspects of this process remains debatable so far [2]. The emergence of the plate tectonics theory and lithology of lithospheric plates [3] reduced the list of debatable points in this field. Nevertheless, quantitative assessments of global sedimentation processes in the ocean are insufficient. The present work is dedicated to the study of the Phanerozoic time series of global CA based on analysis of the available quantitative data on carbonates [4] by methods of the spectral analysis. The purpose of the work is to study the latent periodicity in the formation of limestone and dolomite sequences. The first paleoclimatic studies carried out by paleomagnetologists in the initial 1960s showed that Phanerozoic CAs are mainly concentrated in the tropical belts between 30 ° N and 30 ° S of the Northern and Southern hemispheres [5]. Based on new palinspastic reconstructions of the Phanerozoic drift of continents, the authors of [6] calculated dynamics in the latitudinal distribution of CA areas within these belts and assessed variations in sedimentation patterns. The results obtained demonstrated once again opposite patterns in accumulation of terrigenous and carbonate sequences in the Phanerozoic. For example, despite processes of erosion and redeposition with time, recent carbonate bodies gradually contracted relative to ancient accumulations. In contrast, terrigenous sedimentary bodies expanded. Correspondingly, authors of [6] proposed two scenarios for the distribution of CA areas. The initial distribution pattern is given after [4], whereas the reconstructed version with the consideration of erosion is based on original data [6]. We analyze both of these scenarios. The spectral analysis of carbonate time series was performed using two methods: the regression method (mainly, the method of maximal entropy combined with the method of least squares) and the wavelet analysis (wavelet of Morlet). We analyzed distribution areas and accumulation volumes of various carbonate sediments in the Phanerozoic (after [4]), temporal dependences of CA sources on carbon and calcium cycles, as well as some processes providing the influx of these elements to the ocean. Correspondingly, we estimated dynamics of CA in terms of the above-mentioned latitudinal zonality based on [6]. In total, we analyzed 29 time series. Together with previous results of the spectral analysis of sea level fluctuations and marine biota diversification [7, 8], the new correlations provide insights into variations in the CA environments related to dislocations of lithospheric plates.