Please use this identifier to cite or link to this item: http://hdl.handle.net/2381/43039
Title: Structural signatures of igneous sheet intrusion propagation
Authors: Magee, Craig
Muirhead, James
Schofield, Nick
Walker, Richard J.
Galland, Olivier
Holford, Simon
Spacapan, Juan
Jackson, Christopher
McCarthy, William
First Published: 21-Jul-2018
Publisher: Elsevier
Citation: Journal of Structural Geology, 2018. In Press
Abstract: The geometry and distribution of planar igneous bodies (i.e. sheet intrusions), such as dykes, sills, and inclined sheets, has long been used to determine emplacement mechanics, define melt source locations, and reconstruct palaeostress conditions to shed light on various tectonic and magmatic processes. Since the 1970's we have recognised that sheet intrusions do not necessarily display a continuous, planar geometry, but commonly consist of segments. The morphology of these segments and their connectors is controlled by, and provide insights into, the behaviour of the host rock during emplacement. For example, tensile brittle fracturing leads to the formation of intrusive steps or bridge structures between adjacent segments. In contrast, brittle shear faulting, cataclastic and ductile flow processes, as well as heat-induced viscous flow or fluidization, promotes magma finger development. Textural indicators of magma flow (e.g., rock fabrics) reveal that segments are aligned parallel to the initial sheet propagation direction. Recognising and mapping segment long axes thus allows melt source location hypotheses, derived from sheet distribution and orientation, to be robustly tested. Despite the information that can be obtained from these structural signatures of sheet intrusion propagation, they are largely overlooked by the structural and volcanological communities. To highlight their utility, we briefly review the formation of sheet intrusion segments, discuss how they inform interpretations of magma emplacement, and outline future research directions.
DOI Link: 10.1016/j.jsg.2018.07.010
ISSN: 0191-8141
eISSN: 1873-1201
Links: https://www.sciencedirect.com/science/article/pii/S0191814118303821?via%3Dihub
http://hdl.handle.net/2381/43039
Embargo on file until: 21-Jul-2019
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2018, Elsevier. Deposited with reference to the publisher’s open access archiving policy. (http://www.rioxx.net/licenses/all-rights-reserved)
Description: The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.
Appears in Collections:Published Articles, Dept. of Geology

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