Solidification in mafic magma chambers
Lead Research Organisation:
University of Cambridge
Department Name: Earth Sciences
Abstract
When a chemically complex liquid solidifies it does so over a range of temperatures. During the solidification process a mushy layer develops, in which early-formed solid grains are surrounded by the remaining liquid. This liquid will have a different composition to the solid material, giving rise to numerous possibilities if that fluid were to move within the mush. If it flows to a part of the mush with which it is not in chemical equilibrium there is a complex interaction between the two. The fluid can dissolve the solid, or crystallise in the pore spaces, thus changing the permeability of the matrix and the composition of the solid phase. There may also be changes in pore structure, and thus permeability, due to deformation of the matrix - in the case of the Earth such deformation is most commonly caused by compaction, as the fluid is expelled under the influence of gravity. The problem of flow of reactive fluid is thus highly complex, with many interdependent simultaneous processes. The proposed work is aimed at tackling the first part of this complex problem - that of the progressive development of pore structure within the solidifying mush. We are going to use silicate magmas as a natural laboratory. Magma solidifies on the margins of magma chambers and initially forms a crystal mush through which melts move due to the effects of compaction or replenishment of the chamber. Solidified magmas preserve a record of pore geometry in the way the solid grains fit together. They can also preserve a record of the thermal history via details of the grain boundary orientations. The effects of reaction and diffusive exchange between the solid and the migrating liquid may also be preserved as compositional gradients within mineral grains. It is therefore possible to tease apart the various interacting processes which occurred during the solidification of the magma - thus providing the critical information necessary to understand reactive flow in other, less accessible, environments.
Organisations
Publications
Holness M. B.
(2011)
Cooling Rate Controls Dihedral Angles in Dolerite Sills
in AGU Fall Meeting Abstracts
Leuthold J.
(2012)
Melt-crystal interactions during crystal mush compaction (Rum layered intrusion, Scotland)
in AGU Fall Meeting Abstracts
Namur O.
(2012)
Lateral Reactive Infiltration in a Vertical Gabbroic Crystal Mush, Skaergaard Intrusion, East Greenland
in AGU Fall Meeting Abstracts
Holness Marian
(2016)
Microstructural indicators of convection in sills and dykes
in EGU General Assembly Conference Abstracts
Holness M. B.
(2012)
The thickness of crystal mushy layers on magma chamber floors
in EGU General Assembly Conference Abstracts
Holness Marian
(2014)
The effect of crystallization time on plagioclase grain shape
in EGU General Assembly Conference Abstracts
Holness Marian
(2013)
Disequilibrium dihedral angles as a proxy for cooling rate: new opportunities for decoding the effects of liquid migration in dolerites and basalts.
in EGU General Assembly Conference Abstracts
Holness Marian
(2013)
Disequilibrium dihedral angles in layered intrusions: the microstructural record of fractionation
in EGU General Assembly Conference Abstracts
Namur Olivier
(2013)
Solidification of interstitial melt in a gabbroic crystal mush: the Skaergaard intrusion, Greenland
in EGU General Assembly Conference Abstracts
Leuthold Julien
(2014)
Successive reactive liquid flow episodes in a layered intrusion (Unit 9, Rum Eastern Layered Intrusion, Scotland)
in EGU General Assembly Conference Abstracts
Holness M
(2011)
Melted Rocks under the Microscope: Microstructures and Their Interpretation
in Elements
Holness M
(2012)
Disequilibrium dihedral angles in dolerite sills: A new proxy for cooling rate
in Geology
Holness M
(2012)
Toward an understanding of disequilibrium dihedral angles in mafic rocks
in Journal of Geophysical Research: Solid Earth
Namur O
(2014)
Crystallization of Interstitial Liquid and Latent Heat Buffering in Solidifying Gabbros: Skaergaard Intrusion, Greenland
in Journal of Petrology
Humphreys M
(2009)
Chemical Evolution of Intercumulus Liquid, as Recorded in Plagioclase Overgrowth Rims from the Skaergaard Intrusion
in Journal of Petrology
Bufe N
(2014)
Contact Metamorphism of Precambrian Gneiss by the Skaergaard Intrusion
in Journal of Petrology
Tegner C
(2009)
Differentiation and Compaction in the Skaergaard Intrusion
in Journal of Petrology
Humphreys M
(2011)
Silicate Liquid Immiscibility within the Crystal Mush: Evidence from Ti in Plagioclase from the Skaergaard Intrusion
in Journal of Petrology
Holness M
(2015)
The Earliest History of the Skaergaard Magma Chamber: a Textural and Geochemical Study of the Cambridge Drill Core
in Journal of Petrology
Holness M
(2017)
The Thickness of the Mushy Layer on the Floor of the Skaergaard Magma Chamber at Apatite Saturation
in Journal of Petrology
Namur O
(2013)
Lateral Reactive Infiltration in a Vertical Gabbroic Crystal Mush, Skaergaard Intrusion, East Greenland
in Journal of Petrology
Holness M
(2013)
Disequilibrium Dihedral Angles in Layered Intrusions: a Microstructural Record of Fractionation
in Journal of Petrology
Holness M
(2011)
Silicate Liquid Immiscibility within the Crystal Mush: Late-stage Magmatic Microstructures in the Skaergaard Intrusion, East Greenland
in Journal of Petrology
Description | Plagioclase grain shape is a function of how quickly the basalt cooled |
Exploitation Route | speedometer for basaltic intrusions. effects on crystal mush stability |
Sectors | Manufacturing including Industrial Biotechology |
Description | They will be used in later stages of this research grant |
First Year Of Impact | 2014 |
Sector | Other |
Impact Types | Cultural |