Concepts, Models, and Observations of Climatic Controls on Sedimentation
Part 1 of this volume provides background information on the concepts of autocyclic and allocyclic processes as controls on stratigraphy, including the importance of climatic controls on sedimentation (Cecil). The first paper contains a classification for temporal climate change and a classification of seasonality of rainfall (in warm climates) based on monthly precipitation. Empirical models that relate seasonality of rainfall to fluvial transport of solids, fluvial transport of solutes, peat formation, and eolian transport are developed in the second paper (Cecil and Dulong). In addition, Part 1 presents data in support of the empirical sediment-supply models by discussing differences in solid and solute sediment supply in response to differences in seasonality of rainfall in selected river systems in Indonesia (Cecil et al.). Finally, Perlmutter and Plotnick relate variations in sediment supply to changes in climate induced by precession cycles of the earth’s orbit, and the presence or absence of polar ice, a pioneering concept they first presented in 1996 during a USGS sponsored workshop titled “Predictive Stratigraphic Analysis: Tectonic, Eustatic, and Climatic Controls on the Occurrence and Quality of Fossil Fuels”.
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Climate Controls on Stratigraphy
The role of climate as a primary control on stratigraphy is the cornerstone of this volume. The emphasis on climate is in distinct contrast to most previous studies, in which stratigraphic variability has been related to changes in sea level and in tectonic activity. Furthermore, the findings, derived from several years of detailed study of modern and ancient key geologic sections around the world, indicate that traditional depositional models generally do not fully explain the origin of fossil fuels. Although the results of the studies presented in this volume are intended to contribute to the disciplines of sedimentary geology and stratigraphy, the contributors recognize that their results may also contribute to a better understanding of global climate change. The theoretical background of climate control on sediment supply and stratigraphy is presented in the volume. With this background in place, detailed documentation and analysis of climate control on the lithologic variation of a single Middle Pennsylvanian.