Autogenic Dynamics and Self-Organization in Sedimentary Systems
Autogenic dynamics and self-organization in sedimentary systems are increasingly viewed as significant and important processes that drive erosion, sediment transport, and sediment accumulation across the Earth’s surface. These internal dynamics can dramatically modulate the formation of the stratigraphic record, form biologically constructed depositional packages, affect ecological patterning in time and space, and impact aspects of geochemical sedimentation and diagenesis. The notion that autogenic processes are local phenomena of short duration and distance is now recognized as false. Understanding autogenic dynamics in sedimentary systems is thus essential for deciphering the morphodynamics of moderns sedimentary systems, accurately reconstructing Earth history, and predicting the spatial and temporal distribution of sedimentary and paleobiologic features in the stratigraphic record. The thirteen papers in this volume present exciting new ideas and research related to autogenic dynamics and self-organization in sedimentology, stratigraphy, ecology, paleobiology, sedimentary geochemistry, and diagenesis. Five papers summarize the current state of thinking about autogenic processes and products in fluvial-deltaic, eolian, and carbonate depositional systems, and in paleobiologic and geochemical contexts. A second group of papers provide perspectives derived from numerical modeling and laboratory experiments. The final section consists of field studies that explore autogenic processes and autogenically modulated stratigraphy in five case studies covering modern and ancient fluvial, deltaic, and shelf settings. This SP should stimulate further research as to how self-organization might promote a better understanding of the sedimentary record.
Self-Organized Pattern Formation in Sedimentary Geochemical Systems
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Published:January 01, 2016
Abstract
Geochemical self-organization is a process whereby a geochemical system acquires oscillatory behaviors or spatially repetitive patterns through its own internal autogenic dynamics. The concept of self-organization provides a new perspective for understanding the formation of repetitive patterns in sedimentary rocks, without invoking any unjustified external periodic allogenic force or template. Geochemical self-organization requires a system to be far from equilibrium and to have a positive feedback among the physical and chemical processes involved. Identification of a plausible mechanism for a specific self-organizational phenomenon usually boils down to finding a positive feedback consistent with laboratory and field observations. In this paper, we review the concepts and principles of geochemical self-organization, highlight some of the driving mechanisms and examples that typify sedimentary geochemical systems, and consider some of the basic techniques for model analysis. Two specific examples, formation of banded iron formations and development of periodic patterns in the distribution of porosity in dolomites, are presented in some detail to illustrate the insights generated from numerical modeling and linear stability analysis. Last, we offer some speculations on other chemical sedimentary and diagenetic features that might have self-organizational origins. Testing those hypotheses will require new types of sampling strategies and analyses not normally employed by sedimentologists and sedimentary petrologists.
- banded iron formations
- burial
- carbonate rocks
- catalysis
- chemically precipitated rocks
- diagenesis
- dolostone
- dynamics
- feedback
- geochemistry
- iron formations
- iron oxides
- mechanism
- numerical models
- oscillations
- oxides
- patterns
- permeability
- porosity
- sedimentary rocks
- sediments
- self-organization
- trace elements
- autogenic processes
- linear stability analysis