Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-23T06:52:41.208Z Has data issue: false hasContentIssue false

Dykes or diapirs?

Published online by Cambridge University Press:  03 November 2011

Nick Petford
Affiliation:
Nick Petford, School of Geological Sciences, Kingston University, Kingston-Upon-Thames, Surrey KT1 2EE,UK. E-mail: [email protected]

Abstract:

Until the last few years, diapirism reigned supreme among granitoid ascent mechanisms. Granitoid masses in a variety of material states, from pure melt through semi-molten crystal mushes to solid rock, were believed to have risen forcefully through the continental crust to their final emplacement levels in a way analogous to salt domes. The structural analogy between granite plutons and salt diapirs, which gained acceptance in the 1930s, has clearly been attractive despite the pessimistic outcomes of thermal models and, at best, ambiguous field evidence.

In contrast with traditional diapiric ascent, dyke transport of granitoid magmas has a number of important implications for the emplacement and geochemistry of granites that have yet to be fully explored. Rapid ascent rates of ≍ 10 2m/s predicted for granite melts in dykes (cf. m/a for diapirs) mean that felsic magmas can be transported through the continental crust in months rather than thousands (or even millions) of years, and that large plutons can in principle be filled in <104 a. Granitic melts are likely to rise adiabatically from their source regions, leading to the resorption of any entrained restitic material. Ascending melts in dykes close to their critical minimum widths may have little opportunity to assimilate significant amounts of country rock, and if source extraction is sufficiently rapid, most crustal contamination will be restricted to the site of emplacement. Rates of pluton and batholith inflation will be determined by the amount and rate of melt extraction at source.

The construction of large plutons and batholiths piecemeal from a number of magma pulses separated by periods of relative quiescence provides a means of reconciling rapid ascent rates with times for batholith construction based on average rates. Field and seismic evidence that shows batholiths as large, sheet-like structures with flat roofs and floors is consistent with a general model for plutons and batholiths as laccolith-type structures, fed from depth by dykes. The overall geometry of this type of structure helps ameliorate the space problem, which developed as a consequence of the unrealistic volumes of upwelling granite associated with the classical diapir model.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1996

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

Atherton, M. P. 1990. The Coastal Batholith of Peru: the product of rapid recycling of new crust formed within rifted continental margin. GEOL J 25, 337–49.Google Scholar
Baker, D. R. 1996. Granitic melt viscosities: empirical and configuration entropy models for their calculation. AM MIN 81, 126–34.CrossRefGoogle Scholar
Balk, R. 1937. Structural behavior of igneous rocks. GEOL SOC AM BULL 5, 177 pp.Google Scholar
Batchelor, G. K. 1967. An introduction to fluid dynamics. Cambridge: Cambridge University Press.Google Scholar
Bateman, R. 1985. Aureole deformation by flattening around a diapir during in situ ballooning: the Cannibal Creek granite. J GEOL 93, 293310.Google Scholar
Bergantz, G. W. 1989. Underplating and partial melting: implications for melt generation and extraction. SCIENCE 254, 1093–5.CrossRefGoogle Scholar
Berner, H., Ramberg, H.&Stephasson, O. 1972. Diapirism in theory and experiment. TECTONOPHYSICS 15, 197218.CrossRefGoogle Scholar
Brown, M. 1994. The generation, segregation ascent and emplacement of granite magma: the migmatite-to-crustally derived granite connection in thickened orogens. EARTH SCI REV 36, 83130.CrossRefGoogle Scholar
Brown, M., Rushmer, T.&Sawyer, E. W. 1995. Mechanisms and consequences of melt segregation from crustal protoliths. J GEOPHYS RES 100, 15 551–63.Google Scholar
Bruce, P. M.&Huppert, H. E. 1989. Thermal control of basaltic fissure eruptions. NATURE 342, 665–7.Google Scholar
Bruce, P. M.&Huppert, H. E. 1990. Solidification and melting along dykes by the laminar flow of basaltic magma. In Ryan, M. P. (ed.) Magma transport and storage, 87101. New York: Wiley.Google Scholar
Brun, J. P., Gapais, D., Cogne, J. P., Ledru, P.&Vingeresse, J. L. 1990. The Flamanville granite (northwestern France): an unequivocal example of a syntectonically expanding pluton. GEOL J 25, 271–86.CrossRefGoogle Scholar
Castro, A. 1987. On granitoid emplacement and related structures: a review. GEOL RUNDSCH 76, 101–24.Google Scholar
Clemens, J. D. 1989. The importance of residual source material (restite) in granite petrogenesis: a comment. J PETROL 30, 1313–6.CrossRefGoogle Scholar
Clemens, J. D.&Mawer, C. K. 1992. Granitic magma transport by fracture propagation. TECTONOPHYSICS 204, 339–60.Google Scholar
Clemens, J. D., Petford, N.&Mawer, C. K. 1996. Ascent mechanisms of granitic ascent: causes and consequences. MIN SOC SPEC PUB, in press.Google Scholar
Cloos, H. 1925. Einfuhrung in die tektonische Behandlung magmatischer Erscheinungen (Granittektonik). I. Spezieller Teil. Das Riesengebirge in Schlesien. Bau, und Bilding, und Oberflachengestaltung. Berlin: Borntraeger.Google Scholar
Coleman, D. S., Glazner, A. F., Miller, J. S., Bradford, K. J., Frost, T. P., Joye, J. L.&Bachl, C. A. 1995. Exposure of a late Cretaceous layered mafic–felsic magma system in the central Sierra Nevada batholith, California. CONTRIB MINERAL PETROL 120, 129–36.CrossRefGoogle Scholar
Corry, C. E. 1988. Laccoliths: mechanisms of emplacement and growth. GEOL SOC AM SPEC PUB 220.Google Scholar
Coward, M. P. 1976. Archean deformation patterns in southern Africa. PHIL TRANS R SOC LONDON 283, 313–31.Google Scholar
Daly, R. A. 1903. The mechanics of igneous intrusion. AM J SCI 16, 107–26.CrossRefGoogle Scholar
DeWaard, D. 1949. Tectonics of the Mt. Aigoual pluton in the southeastern Cevennes, France. PROC KON NED AKAD 52, 389402.Google Scholar
Dingwell, D. D., Bagdassarov, G. Y., Bussod, G. Y.&Webb, S. L. 1993. Magma rheology. In Scarfe, C. M. (ed.) Experiments at high pressure and applications to the earth's mantle. MINER ASSOC CAN SHORT COURSE HANDB 21, 131–96.Google Scholar
Dixon, J. M. 1975. Finite strain and progressive deformation in models of diapiric structures. TECTONOPHYSICS 28, 89124.CrossRefGoogle Scholar
Emerman, S. H.&Marrett, R. 1990. Why dikes? GEOLOGY 18, 231–3.2.3.CO;2>CrossRefGoogle Scholar
Eskola, P. 1949. The problems of mantled gneiss domes. Q J GEOL SOC LONDON 54, 461–76.Google Scholar
Evans, D. J., Rowley, W. J., Chadwick, R. A., Kimbell, G. S.&Millward, D. 1994. Seismic reflection data and the internal structure of the Lake District batholith. Cumbria, northern England. PROC YORKSHIRE GEOL SOC 50, 1124.CrossRefGoogle Scholar
Fyfe, W. S. 1970. Some thoughts on granitic magmas. In Newall, G. N.&Rast, N. (eds) Mechanism of igneous intrusion. GEOL J SPEC ISSUE 2, 201–16.Google Scholar
Gilbert, G. K. 1877. Geology of the Henry Mountains. Utah. US geographical and geological survey of the Rocky Mountains Region.Google Scholar
Grout, F. F. 1945. Scale models of structures related to batholiths. AM J SCI 243A, 260–84.Google Scholar
Hanson, B. R.&Glazner, A. F. 1995. Thermal requirements for extensional emplacement of granitoids. GEOLOGY 23, 213–6.Google Scholar
Holtz, F.&Johannes, W. 1994. Maximum and minimum water contents of granitic melts: implications for chemical and physical properties of ascending magmas. LITHOS 32, 149–59.Google Scholar
Huppert, H. E.&Sparks, R. S. J. 1988. The generation of granitic magmas by the intrusion of basalt into continental crust. J PETROL 29, 599624.CrossRefGoogle Scholar
Hutton, D. H. W. 1982. A tectonic model for the emplacement of the Main Donegal granite, NW Ireland. J GEOL SOC LONDON 139, 615–31.CrossRefGoogle Scholar
Hutton, D. H. W. 1992. Granite sheeted complexes: evidence for the dyking ascent mechanism. TRANS R SOC EDINBURGH EARTH SCI 83, 377–82.Google Scholar
Hutton, D. H. W.&Ingram, G. M. 1992. The Great Tonalite Sill of southeastern Alaska and British Columbia: emplacement into an active contractional high angle reverse shear zone (extended abstract). TRANS R SOC EDINBURGH EARTH SCI 83, 383–6.Google Scholar
Hutton, J. 1788. Theory of the Earth. TRANS R SOC EDINBURGH 1, 209.CrossRefGoogle Scholar
Inger, S.&Harris, N. B. W. 1992. Geochemical constraints on leucogranitic magmatism in the Langtang Valley, Himalaya. J PETROL 34, 345–68.CrossRefGoogle Scholar
Jackson, M. D.&Pollard, D. D. 1988. The laccolith stock controversy: new results from the southern Henry mountains, Utah. GEOL SOC AM BULL 100, 117–39.2.3.CO;2>CrossRefGoogle Scholar
Kerr, R. C.&Lister, J. R. 1991. The effects of shape on crystal settling and on the rheology of magmas. J GEOL 99, 457–67.CrossRefGoogle Scholar
Kerr, R. C.&Lister, J. R. 1995a. The lateral intrusion of silicic magmas into unconsolodated sediments: the Tennant Creek porphyry revisited. AUST J EARTH SCI 42, 223–4.CrossRefGoogle Scholar
Kerr, R. C.&Lister, J. R. 1995b. Comment on ‘On the relationship between dike width and magma viscosity’ by Y, Wada.J GEOPHYS RES 100, 15541.Google Scholar
Leake, B. E. 1978. Granite emplacement; the granites of Ireland and their origin. In Bowes, D. R.&Leake, B. E. (eds) Crustal evolution of northwestern Britain and adjacent regions. GEOL J SPEC PUBL 10, 221–48.Google Scholar
LeFort, P. 1981. Manaslu leucogranite: a collisional signature of the Himalaya, a model for its genesis and emplacement. J GEOPHYS RES 86, 10 545–68.Google Scholar
Lister, J. R.&Kerr, R. C. 1991. Fluid-mechanical models of crack propagation and their application to magma transport in dykes. J GEOPHYS RES 96, 10 04977.Google Scholar
Lister, J. R.&Dellar, P. J. 1996. Solidification of pressure driven flow in a finite rigid channel. J FLUID MECH (submitted).Google Scholar
Mahon, K. I., Harrison, T. M.&Drew, D. A. 1988. Ascent of a granitoid diapir in a temperature varying medium. J GEOPHYS RES 93, 1174–88.CrossRefGoogle Scholar
Marsh, B. D. 1982. On the mechanics of igneous diapirism. stoping and zone melting. AM J SCI 282, 808–55.Google Scholar
McCaffrey, K. J. W. 1992. Igneous emplacement in a transpressive shear zone: the Ox Mountains igneous complex. J GEOL SOC LONDON 149, 221–35.Google Scholar
Miller, C. F., Watson, E. B.&Harrison, M. T. 1988. Perspectives on the source, segregation and transport of granitoid magmas. TRANS R SOC EDINBURGH EARTH SCI 79, 135–56.Google Scholar
Mrazec, L. 1927. Les plis diapirs et le diapirisme en general. C R SEANCES INST GEOL ROUMANIE VI (1914-1915). 226–70.Google Scholar
Nicolesco, C. P. 1929. Anticlimax diapirs sedimentaries. volcaniques et plutoniques. BULL SOC GEOL FR 29, 21–4.Google Scholar
Noble, J. A. 1950. Evaluation of criteria for the forcible intrusion of magma. J GEOL 60, 3457.Google Scholar
Paterson, S. R.&Fowler, T. K. 1994. Re-examining pluton emplacement processes: reply. J STRUCT GEOL 16, 747–8.CrossRefGoogle Scholar
Paterson, S. R.&Tobisch, O. T. 1992. Rates of processes in magmatic arcs: implications for the timing and nature of pluton emplacement and wall rock deformation. J STRUCT GEOL 14, 291300.Google Scholar
Petford, N. 1995. Segregation of tonalitic and trondhjemitic melts in the continental crust: the mantle connection. J GEOPHYS RES 100, 15 735–43.Google Scholar
Petford, N.&Atherton, M. P. 1992. Granitoid emplacement and deformation along a major crustal lineament: the Cordillera Blanca, Peru. TECTONOPHYSICS 205, 171–85.Google Scholar
Petford, N., Kerr, R. C.&Lister, J. R. 1993. Dike transport of granitoid magmas. GEOLOGY 21, 845–8.2.3.CO;2>CrossRefGoogle Scholar
Petford, N., Lister, J. R.&Kerr, R. C. 1994. The ascent of felsic magmas in dykes. LITHOS 32, 161–8.Google Scholar
Pitcher, W. S. 1979. The nature, ascent and emplacement of granitic magmas. J GEOL SOC LONDON 136, 627–22.Google Scholar
Pitcher, W. S.&Berger, A. R. 1972. The geology of Donegal: a study of granite emplacement and unroofing. London: Wiley-Interscience.Google Scholar
Pitcher, W. S., Atherton, M. P., Cobbing, E. J.&Beckinsale, R. D. 1985. Magmatism at a plate edge: the Peruvian Andes. Glasgow: Blackie Halsted Press.CrossRefGoogle Scholar
Pollard, D. D.&Johnson, A. M. 1973. Mechanisms of growth of some laccolith intrusions in the Henry Mountains, Utah II. Bending and failure of overburden layers and sill formation. TECTONOPHYSICS 18, 311–45.CrossRefGoogle Scholar
Ramberg, H. 1967. Gravity deformation and the earth's crust as studied by centrifuge models. Academic Press, London.Google Scholar
Ramberg, H. 1970. The initiation, ascent and emplacement of magmas. In Newall, G. N.&Rast, N. (eds) Mechanism of igneous intrusion. GEOL J SPEC ISSUE 2, 261–86.Google Scholar
Ramberg, H. 1981. Gravity, Deformation and the earth's Crust in theory, experiments and geological application, 2nd edn. London: Academic Press.Google Scholar
Rast, N. 1970. The initiation, ascent and emplacement of magmas. In Newall, G. N.&Rast, N. (eds) Mechanism of igneous intrusion. GEOL J SPEC ISSUE 2, 332–69.Google Scholar
Read, H. H. 1947. Granites and granites. GEOL SOC AM MEM 28, 119.Google Scholar
Reddy, S. M., Searle, M. P.&Massey, J. A. 1993. Structural evolution of the High Himalayan gneiss sequence, Langtamng Valley, Nepal. In Treloar, P. J.&Searle, M. P. (eds) Himalayan tectonics. GEOL SOC LONDON SPEC PUBL 74, 375–89.Google Scholar
Ribe, N. M. 1983. Diapirism in the Earth's mantle: experiments on the motion of a hot sphere in a fluid with temperature dependent viscosity. J VOLCANOL GEOTHERM RES 16, 221–45.Google Scholar
Rosenberg, C, Berger, A.&Schmid, S. M. 1995. Observations from the floor of a granitoid pluton: a constraint on the driving force for final emplacement. GEOLOGY 23, 443–6.2.3.CO;2>CrossRefGoogle Scholar
Rubin, A. M. 1993. On the thermal viability of dykes leaving magma chambers. GEOPHYS RES LETT 20, 257–60.Google Scholar
Rubin, A. M. 1995. Getting granite dikes out of the source region. J GEOPHYS RES 100, 5911–29.CrossRefGoogle Scholar
Rutter, E.&Neumann, D. 1995. Experimental deformation of partially molten Westerly Granite under fluid-absent conditions, with implications for the extraction of granite magma. J GEOPHYS RES 100, 15 697715.Google Scholar
Sawyer, W. E. 1991. Disequilibrium melting and the rate of meltresiduum separation during migmatisation of mafic rocks from the Grenville Front, Quebec. J PETROL 32, 701–38.CrossRefGoogle Scholar
Schwerdtner, W. M. 1982. Salt stocks as natural analogues of Archean gneiss diapirs. GEOL RUNDSCH 71, 370–9.CrossRefGoogle Scholar
Schwerdtner, W. M. 1990. Structural tests of diapir hypotheses in Archean crust of Ontario. CAN J EARTH SCI 27, 387402.Google Scholar
Sederholm, J. J. 1926. On migmatites and associated Precambrian rocks of southwest Finland. II. BULL COMM GEOL FINLANDE 77, 141 pp.Google Scholar
Shaw, H. R. 1965. Comments on viscosity, crystal settling and convection in granitic magmas. AM J SCI 263, 120–53.Google Scholar
Shaw, H. R. 1972. Viscosities of magmatic silicate liquids: an empirical method of prediction. AM J SCI 272, 870–93.CrossRefGoogle Scholar
Shaw, H. R. 1980. Fracture mechanisms of magma transport from the mantle to the surface. In Hargraves, R. B. (ed.) Physics of magmatic processes, 201264. Princetown: Princetown University Press.Google Scholar
Sorgenfrei, T. 1971. On the granite problem and the similarity of salt and granite structures. GEOL FORH 93, 371435.CrossRefGoogle Scholar
Spence, D. A.&Turcotte, D. L. 1985. Magma-driven propagation of cracks. J GEOPHYS RES 90, 575–80.CrossRefGoogle Scholar
Spera, F. 1980. Aspects of magma transport. In Hargraves, R. B. (ed.) Physics of magmatic processes, 263323. Princetown: Princetown University Press.Google Scholar
Sykes, M. L.&Holloway, J. R. 1987. Evolution of granitic magmas during ascent: a phase equilibrium model. In Mysen, B. O. (ed.) Magmatic processes: physicochemical principles. GEOCHEM SOC SPEC PUBL 1, 447–61.Google Scholar
Tepper, J. H., Nelson, G. W., Bergantz, G. W.&Irving, A. J. 1992. Petrology of the Chilliwack Batholith, North Cascades, Washington: generation of calc-alkaline granitoids by melting of mafic lower crust with variable water fugasity. CONTRIB MINERAL PETROL 70, 299318.Google Scholar
Tritton, D. L. 1988. Physical fluid dynamics. Oxford: Oxford University Press.Google Scholar
Turcotte, D. L. 1982. Magma migration. ANNU REV EARTH PLANET SCI 10, 397408.Google Scholar
Turcotte, D. L. 1987. Physics of magma segregation processes. In Mysen, B. O. (ed.) Magmatic processes: physicochemical principles. GEOCHEM SOC SPEC PUBL 1, 6974.Google Scholar
Vigneresse, J. L. 1990. Use and misuse of geophysical data to determine the shape at depth of granitic intrusions. GEOL J 25, 249–60.Google Scholar
Wada, Y. 1994. On the relation between dike width and magma viscosity. J GEOPHYS RES 99, 17 743–55.Google Scholar
Webb, S. L.&Dingwell, D. B. 1990. The onset of non-Newtonian rheology of silicate melts, a fiber elongation study. PHYS CHEM MINERAL 17, 125–32.Google Scholar
Wegmann, C. E. 1930. Uber Diapirismus. BULL COMM GEOL FINLANDE 92, 5876.Google Scholar
Weinberg, R. F. 1994. Re-examining pluton emplacement processes: discussion. J STRUCT GEOL 16, 743–6.Google Scholar
Weinberg, R. F. 1996. The ascent mechanism of felsic magmas: news and views. TRANS R SOC EDINBURGH EARTH SCI 87, 000–000.Google Scholar
Weinberg, R. F.&Podladchikov, Y. Y. 1994. Diapiric ascent of magmas through power-law crust and mantle. J GEOPHYS RES 99, 9543–59.Google Scholar
Weinberg, R. F.&Podladchikov, Y. Y. 1995. The rise of solid-state diapirs. J STRUCT GEOL 17, 1183–95.Google Scholar
White, A. J. R., Williams, I. S.&Chapell, B. W. 1977. Geology of the Berridale 1: 100,000 sheet. GEOL SURV NEW SOUTH WALES 8625.Google Scholar
Wilson, L.&Head, J. W. 1981. Ascent and eruption of basaltic magma on the earth and the moon. J GEOPHYS RES 86, 29713001.Google Scholar