Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-27T06:34:58.054Z Has data issue: false hasContentIssue false

The geometry and evolution of magma pathways through migmatites of the Halls Creek Orogen, Western Australia

Published online by Cambridge University Press:  05 July 2018

N. H. S. Oliver
Affiliation:
School of Applied Geology, Curtin University, GPO Box U1987, Perth, Australia, 6001
T. D. Barr
Affiliation:
Department of Earth Sciences, Monash University, Clayton, Victoria, Australia, 3168

Abstract

In the Halls Creek Orogen of north-western Australia, the distance of melt migration through migmatitic metasedimentary rocks and adjacent metabasites is partly constrained by relationships of leucosomes and small mafic magma veins to rock boundaries and structural elements. Stromatic leucosomes in metasediments are cut by a network of small extensional fractures and shear zones, oriented steeply during melt migration. These shear zones allowed cm- to 10 m-scale migration of felsic magma derived by in situ anatexis. In the adjacent metabasite layers, a similar shear array allowed injection of H2O-undersaturated mafic to ultramafic magma, locally dehydrating and chemically modifying these rocks. However, these mafic to ultramafic veinlets are too mafic to be explained by in situ anatexis, necessitating an external magma source. Also, the lack of felsic veinlets cutting metabasites, and mafic veinlets cutting metasediments, requires that vertical inter-connectivity of these fracture systems was restricted. We propose along-layer migration of mafic to ultramafic magma through the metabasite, assisted by horizontal connection of the shear zones. This migration occurred independantly of metre-scale felsic magma migration in the adjacent metasediments, even though these two deformation-assisted magma migration systems may have been operating at the same time.

Type
Petrology
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Blake, D.H. and Hoatson, D.M. (1993) Granite, gabbro and migmatite field relationships in the Proterozoic Lamboo Complex of the East Kimberley region, Western Australia. AGSO Journal of Australian Geology and Geophysics, 14, 319-30.Google Scholar
Bons, P.D. and Urai, J.L. (1994) Experimental deformation of two-phase rock analogues. Materials Sci. Eng., A175, 221-9.CrossRefGoogle Scholar
Brown, M. (1994) The generation, segregation, ascent and emplacement of granite magma: the migmatiteto-crustally-derived granite connection in thickened orogens. Earth Sci. Rev., 36, 83130.CrossRefGoogle Scholar
Brown, M., Averkin, Y.A., McLellan, E.L. and Sawyer, E.W. (1995) Melt segregation in migmatites. J. Geophys. Res., 100, 15655-79.CrossRefGoogle Scholar
Clemens, J.D. and Vielzeuf, D. (1987) Constraints on melting and magma production in the crust. Earth. Planet. Sci, Lett., 86, 287306.CrossRefGoogle Scholar
Clemens, J.D. (1990) The granulite-granite connection. In: Granulites and Crustal Evolution. (Vielzeuf, D. and Vidal, P., eds.) Dordrecht, Kluwer Academic Publishers, 311, 2536.CrossRefGoogle Scholar
Ellis, D.J. and Obata, M. (1992) Migmatite and melt segregation at Cooma, New South Wales. Trans. Roy. Soc. Edinburgh, 83, 95106.Google Scholar
Etheridge, M.A., Wall, V.J. and Vernon. (1983) The role of the fluid phase during regional metamorphism and deformation. J. Metamorph. Geol., 1. 205-26.CrossRefGoogle Scholar
Jaeger, J.C. (1964) Thermal effects of intrusions. Rev. Geophys., 2, 443-66.CrossRefGoogle Scholar
Johannes, W. and Holtz, F. (1990) Formation and composition of H2O-undersaturated granitic melts. In High-temperature Metamorphism and Crustal Anatexis. (Ashworth, J.R. and Brown, M., eds.) London, Allen and Unwin, 87104.CrossRefGoogle Scholar
Oliver, N.H.S. (1996) A review and classification of structural controls on fluid flow during regional metamorphism. J. Metamorph. Geol., 14, 477-92.CrossRefGoogle Scholar
Page, R.W. and Hancock, S.L. (1988) Geochronology of a rapid 1.85-1.86 Ga tectonic transition: Halls Creek orogen, northern Australia. Precambrian Res., 40/41, 447-67.CrossRefGoogle Scholar
Page, R.W. and Sun, S. (1994) Evolution of the Kimberley region, W. A. and adjacent Proterozoic Inliers – new geochronological constraints. Geol. Soc. Austral. Abstr., 37, 332-3.Google Scholar
Pattison, D.R.M. (1991) Infiltration-driven dehydration and anatexis in granulite facies metagabbro, Grenville Province, Ontario, Canada. J. Metamorph. Geol., 9, 315-32.CrossRefGoogle Scholar
Peacock, S.M., Rushmer, T. and Thompson, A.B. (1994) Partial melting of subducting oceanic crust. Earth. Planet. Sci. Lett., 121, 227-43.CrossRefGoogle Scholar
Powell, R. and Downes, J. (1990) Garnet prophyroblastbearing leucosomes in metapelites: mechanisms, phase diagrams, and an example from Broken Hill, Australia. In High-temperature Metamorphism and Crustal Anatexis. (Ashworth, J.R. and Brown, M., eds.) London, Unwin Hyman, 105-23.Google Scholar
Price, P.H. and Slack, M.R. (1954) The effect of latent heat on numerical solutions of the heat flow equation. Brit. J. Appl. Phys., 5, 285-7.CrossRefGoogle Scholar
Ramsay, J.G. (1980) Shear zone geometry: a review. J. Struct. Geol., 2, 8399.CrossRefGoogle Scholar
Ross, J.H., Bauer, S.J. and Hansen, F.D. (1987) Textural evolution of synthetic anhydrite-halite mylonites. Tectonophys., 140, 307-26.CrossRefGoogle Scholar
Rushmer, T. (1991) Partial melting of two amphibolites: Contrasting experimental results under fluid-absent conditions. Contrib. Mineral. Petrol., 107, 4159.CrossRefGoogle Scholar
Sawyer, E.W. (1991) Disequilibrium melting and the rate of melt-residuum separation during migmatization of mafic rocks from the Grenville Front, Quebec. J. Petrol., 32, 701-38.CrossRefGoogle Scholar
Sawyer, E.W. (1994) Melt segregation in the continental crust. Geology, 22, 1019-22.2.3.CO;2>CrossRefGoogle Scholar
Thornett, J.R. (1986) Evolution of a high-grade metamorphic terrain in the Proterozoic Halls Creek Mobile Zone, Western Australia. University of Western Australia, PhD Thesis (unpubl.).Google Scholar
Tyler, I.M., Griffin, T.J., Page, R.W. and Shaw, R.D. (1994) The Halls Creek Fault System: repeated reactivation of a major tectonic boundary within the north Australian craton. Geol. Soc. Austral. Abstr., 36, 167-8.Google Scholar
van der Molen, I. (1985) Interlayer material transport during layer-normal shortening. Part lI. Boudinage, pinch-and-swell and migmatite at Søndre Strømfjord Airport, west Greenland. Tectonophys., 115, 297313.CrossRefGoogle Scholar
Vernon, R.H., Clarke, G.L. and Collins, W.J. (1990) Local, mid-crustal granulite facies metamorphism and melting: an example in the Mount Stafford area, central Australia. In High-temperature Metamorphism and Crustal Anatexis. (Ashworth, J.R. and Brown, M., eds.) London, Unwin Hyman, 272319.CrossRefGoogle Scholar
Wickham, S. (1987) Crustal anatexis and granite petrogenesis during low-pressure regional metamorphism: the Trois Signeurs Massif, Pyrenees, France. J. Petrol., 28, 127-69.CrossRefGoogle Scholar