Crystallization and Layering of the Skaergaard Intrusion

McBirney, Alexander R.; Noyes, Richard M.

doi:10.1093/petrology/20.3.487

Cited by 636 publications

(253 citation statements)

References 59 publications

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“…It is characterized by thin dark layers of chromite (FeCr 2 O 4 ) and olivine (Mg 2 SiO 4 ) grains alternating with thicker light-coloured layers composed of olivine alone over a scale of a few millimetres. Similar layering is also seen in other layered intrusions, such as the Skaergaard [23,24] where spinel (MgAl 2 O 4 ) bands alternate over a scale of 10 cm with bands of silicate minerals.…”

Section: (A) Liesegang Band Patterns In Igneous Systems (I) Layered Isupporting

confidence: 62%

Self-organized rhythmic patterns in geochemical systems

L’Heureux

2013

Phil. Trans. R. Soc. A.

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Chemical oscillating patterns are ubiquitous in geochemical systems. Although many such patterns result from systematic variations in the external environmental conditions, it is recognized that some patterns are due to intrinsic self-organized processes in a non-equilibrium nonlinear system with positive feedback. In rocks and minerals, periodic precipitation (Liesegang bands) and oscillatory zoning constitute good examples of patterns that can be explained using concepts from nonlinear dynamics. Generally, as the system parameters exceed some threshold values, the steady (time-independent) state characterizing the system loses its stability. The system then evolves towards other time-dependent solutions (‘attractors’) that may have an oscillatory behaviour or a complex chaotic one. In this review, we describe many of these pattern types taken from a variety of geological environments: eruptive, sedimentary, hydrothermal or metamorphic. One particular example (periodic precipitation of pyrite bands in an evolving sapropel sediment) is presented here for the first time. This will help in convincing the reader that the tools of nonlinear dynamics may be useful to understand the history of our planet.

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Section: (A) Liesegang Band Patterns In Igneous Systems (I) Layered Isupporting

confidence: 62%

Self-organized rhythmic patterns in geochemical systems

L’Heureux

2013

Phil. Trans. R. Soc. A.

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“…10b). Crystallization of abundant plagioclase at the bottom of the P-and Sirich melt would increase Fe in the residual magmas, so the chemical diffusion of Fe moved upwards and was in the same direction as heat transfer (McBirney and Noyes, 1979;Tegner et al, 2006). As the diffusion of Fe was slower than heat transfer in the magmas, a doublediffusion convection would form and result in multiple stratified magma layers in the magma chamber (McBirney and Noyes, 1979) (Fig.…”

Section: Magma Processes In the Formation Of The Mzbmentioning

confidence: 99%

Trace element compositions of apatite from the middle zone of the Panzhihua layered intrusion, SW China: Insights into the differentiation of a P- and Si-rich melt

Xing

Wang

2014

Lithos

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“…In the somewhat similar layered Skaergaard intrusion, McBirney and Noyes [25] distinguished four cooling stages, each governed by one dominant physico-chemical factor with progressively falling temperature: thermal diffusion, reaction rate at liquid-crystal interface and growth of large crystals at the expense of small, disappearing ones respectively. Mass exchange near the liquidus [the surface boundary between the crystallizing solid (crystals) and melt], coupled with some local perturbations in T and p may induce changes in the free energy.…”

Section: Large Scale Disequilibrium Crystallization (Layered Intrusions)mentioning

confidence: 99%

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

Sultan

Abdel‐Rahman

2013

Lat. Am. j. solids struct.

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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 selforganization 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. Keywords Liesegang, precipitate patterns, geochemical self-organization, magmatic ring complexes, layered intrusions.On dynamic self-organization: examples from magmatic and other geochemical systems INTRODUCTIONOne 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]. Liesegang bands of precipitate appear when a solution of a specific ion (say Cr 2 O 7 2 ) diffuses in a tubular gel medium containing its co-precipitate ion (such as Ag + ). The sparingly soluble Ag 2 Cr 2 O 7 precipitate forms a set of discotic strata perpendicular to the tube axis. A panorama of banded Liesegang patterns for different precipitate systems is displayed in Fig. 1. The mechanism of the Liesegang banding phenomenon is not one of universal character. Most scientists believe that the first band forms away from the first precipitation region, delayed by diffusion over a zone initially depleted in the diffusing ion, until the concentration product builds up and exceeds the supersaturation and nucleation thresholds. Then this cycle is repeated, and hence causes the formation of the next bands periodically, in a concerted scenario known as the supersaturation-nucleation-depletion cycle, first elucidated by Wilhelm Ostwald [4]. Another group of scientists believe that bands emerge from the break-up of a pre-formed uniform colloidal sol, due to a competitive particle growth mechanism mediated by the surface tensions of the various colloid particles having a broad distribution of sizes [5][6][7]. Due to larger surface tension, the small particles dissolve and the newly-formed aqueous species diffuse, driven by the concentration gradient t...

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Crystallization and Layering of the Skaergaard Intrusion

Cited by 636 publications

References 59 publications

Self-organized rhythmic patterns in geochemical systems

Self-organized rhythmic patterns in geochemical systems

Trace element compositions of apatite from the middle zone of the Panzhihua layered intrusion, SW China: Insights into the differentiation of a P- and Si-rich melt

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

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