Nick Schofield, Craig Magee, Simon Holford, and Christopher Jacksonhttp://www.egu2013.eu

Holford, S.

Jackson, C.

Magee, C.

Schofield, N.

Adelaide Research &amp; Scholarship

PUBLISHED VERSION  http://hdl.handle.net/2440/84342   Nick Schofield, Craig Magee, Simon Holford, and Christopher Jackson Magma plumbing and emplacement mechanisms within sedimentary basins Geophysical Research Abstracts, Vol. 15, 2013; EGU2013-2251 © Author(s) 2013. CC Attribution 3.0 License.                    PERMISSIONS   http://creativecommons.org/licenses/by/3.0/       Geophysical Research AbstractsVol. 15, EGU2013-2251, 2013EGU General Assembly 2013© Author(s) 2013. CC Attribution 3.0 License.Magma Plumbing and Emplacement Mechanisms within SedimentaryBasinsNick Schofield (1), Craig Magee (2), Simon Holford (3), and Christopher Jackson (2)(1) Earth Sciences, School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston,Birmingham, B15 2TT, England (n.schofield@bham.ac.uk), (2) Department of Earth Science and Engineering, ImperialCollege, Prince Consort Road, London, SW7 2BP, England, UK, (3) Australian School of Petroleum Centre for Tectonics,Resources and Exploration (TRaX) University of Adelaide, Adelaide SA 5005In recent years our understanding of sub-volcanic magmatic plumbing systems has been revolutionised by thestudy of hydrocarbon industry 3D seismic reflection datasets from offshore sedimentary basins. In particular,3D seismic reflection data has provided important insights into sheet intrusion geometry and emplacementmechanisms as well as linkages and magma flow between multiple intrusions within sill-complexes. However,even high-quality 3D seismic reflection datasets have a limit to what they can resolve; thus, to allow a betterunderstanding of detailed emplacement mechanisms and to test the validity of subsurface-based interpretations, itis critical to bridge the resolution gap that exists between seismic and outcrop datasets.Magmatic sheet (sill) intrusions contribute significantly to the upper crustal magma transport network. Theemplacement mechanism of the magmatic sheets controls the final geometry of the intrusions and the characteris-tics of host rock deformation. Previous observations have highlighted the preponderance of brittle structures (e.g.intrusive steps and broken brides) associated with shallow-level sheet intrusions. However, recent studies havesuggested that non-brittle host rock behaviour also occurs, particularly related to the formation of magma fingersduring shallow-level sill intrusion. Importantly, these structures can provide insights into emplacement styleand magma flow directions. Here, we examine both brittle and non-brittle intrusion mechanisms and structuresusing both field- and 3D seismic-based observations from a series of widespread and variable magmatic systems.Non-brittle emplacement (i.e. magma finger and lobe development) appears to be primarily associated withviscous flow of the host rock during intrusion and is therefore intimately linked to the contemporaneous host rockrheology as well as magma dynamics. Purely brittle and non-brittle emplacement processes are found to be endmembers with many intrusions containing evidence of both behaviours.Deriving the host rock characteristics is therefore an important step in discerning potential diagnostic magma flowindicators and intrusion geometries within field-, seismic- and model-based studies. Incorporation of variable hostmaterial behaviours in numerical and analogue modelling, tuned using direct field observations, may consequentlyfurther our understanding of the controls on shallow-level intrusion.

Magma plumbing and emplacement mechanisms within sedimentary basins

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Magma plumbing and emplacement mechanisms within sedimentary basins

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Adelaide Research & Scholarship

Magma plumbing and emplacement mechanisms within sedimentary basins

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Adelaide Research &amp; Scholarship

Adelaide Research & Scholarship