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Layered intrusions and traffic jams

Paul D. Bons, Albrecht Baur, Marlina A. Elburg, Matthias J. Lindhuber, Michael A. W. Marks, Alvar Soesoo, Boudewijn P. van Milligen and Nicolas P. Walte
Layered intrusions and traffic jams
Geology (Boulder) (December 2014) 43 (1): 71-74


A wide range of explanations has been proposed for the origin of repetitive layering in mafic-ultramafic and in (per)alkaline intrusions. Here we propose that the interaction of mineral grains that sink and float in the crystallizing magma is an alternative mechanism that can explain many of the features of layered intrusions, without the need to invoke extrinsic factors. Similar to traffic jams on a motorway, small perturbations in crystal density develop that impede further ascent or descent of buoyant or heavy minerals, respectively. These "traffic jams" separate layers of magma from the rest of the magma chamber. The magma in the individual layers further evolves as a largely independent subsystem, with gravitational sorting organizing the mineral distribution within each layer. Layering can develop in the intermediate range between full mineral separation in low-viscosity or slowly cooling magma chambers and homogeneous crystallization in high-viscosity or fastcooling chambers. This self-organization mechanism provides a novel explanation for the formation of rhythmic layering in low-viscosity magmas, for example in the Ilimaussaq igneous complex in southwest Greenland.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 43
Serial Issue: 1
Title: Layered intrusions and traffic jams
Affiliation: Eberhard Karls University Tuebingen, Department of Geosciences, Tubingen, Germany
Pages: 71-74
Published: 20141204
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 37
Accession Number: 2015-002580
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: University of Johannesburg, ZAF, South AfricaTallinn University of Technology, EST, EstoniaCentro de Investigaciones Energeticas, Medioambientales y Tecnologicas, ESP, SpainUniversitaet Bayreuth, DEU, Germany
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201502
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