On dynamic self-organization: examples from magmatic and other geochemical systems

Rabih F Sultan,M Abdel-Rahman,Abdel-Fattah Abdel-Fattah

doi:10.1590/s1679-78252013000100006

Rabih F Sultan, M Abdel-Rahman + Show 1 more

Open Access

https://doi.org/10.1590/s1679-78252013000100006

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Abstract

Standard Liesegang banding is the display of parallel bands of precipitate formed periodically when co-precipitate ions interdiffuse in a gel medium. The most striking resemblance with Liesegang patterns in Nature lies in the diverse scenery of banded textural features commonly observed in some geological materials, such as geodes, agates, malachites, as well as stratigraphic units of certain rock formations. Here, we explore the possible relationship between the Liesegang banding scenario and magmatic-type pattern formation, such as zonations in km-scale circular zoned plutons and anorogenic ring complexes, cyclic layering in large mafic - ultramafic layered intrusions and orbicular granites, as well as in mm-scale crystal zonations. We also investigate magmatic processes such as fractional crystallization, and the ranges of T and p that are compatible with operating conditions for Liesegang banding. For geochemical self-organization to operate via a Liesegang-type mechanism, a necessary condition is that the system be transiently out of equilibrium, and be described by complex nonlinear kinetic laws. We examine the viability of the development of geochemical patterns, in relation with the various requirements for the growth of Liesegang structures.

Highlights

One of the fascinating and visually most attractive phenomena, widely studied and documented in the physical chemistry literature, is that of periodic precipitation commonly known as Liesegang banding [1,2,3]
We focus on some magmatic systems with the aim of discussing whether the Liesegang phenomenon can be considered as a viable mechanism to produce patterns in geological materials at small as well as large scales, and to shed light on the relationship between magmatic processes and the Liesegang phenomenon
We attempt to see whether zonations characteristic of some large-scale circular zoned plutons and anorogenic alkaline ring complexes can be somehow related to a Liesegang – type mechanism operated at a large magma chamber level

Summary

INTRODUCTION

One of the fascinating and visually most attractive phenomena, widely studied and documented in the physical chemistry literature, is that of periodic precipitation commonly known as Liesegang banding [1,2,3]. A wide variety of similarities between simple Liesegang bands on a small, laboratory scale and a number of diverse geological features has been exemplified and reported in the literature [13,14,15,17] These have been explained via different scenarios and operating mechanisms. Abdel-Rahman / On Dynamic Self-Organization: Examples from Magmatic and Other Geochemical Systems 61 by Sadek and Sultan [17], which include geological materials and biological systems, along with applications in medicine, physics and engineering In this contribution, we focus on some magmatic systems with the aim of discussing whether the Liesegang phenomenon can be considered as a viable mechanism to produce patterns in geological materials at small as well as large scales, and to shed light on the relationship between magmatic processes and the Liesegang phenomenon

LIESEGANG PATTERNING IN CRYSTALS AND MAGMA CHAMBERS

Medium scale disequilibrium crystallization in zoned ring complexes

REACTION-TRANSPORT STEERED BANDING

OTHER EXAMPLES

CONCLUSIONS