Skip to main content Accessibility help

Origin of infracrustal (I-type) granite magmas

  • B. W. Chappell (a1) and W. E. Stephens (a2)


I-type granites are produced by partial melting of older igneous rocks that are metaluminous and hence have not undergone any significant amount of chemical weathering. In the Lachlan Fold Belt of southeastern Australia and the Caledonian Fold Belt of Britain and Ireland there was a major magmatic event close to 400 Ma ago involving a massive introduction of heat into the crust. In both areas, that Caledonian-age event produced large volumes of I-type granite and related volcanic rocks. Granites of these two areas are not identical in character but they do show many similarities and are markedly different from many of the granites found in Mesozoic and younger fold belts. These younger, dominantly tonalitic, granites have compositions similar to those of the more felsic volcanic rocks forming at the present time above subduction zones. The Palaeozoic granites show little evidence of such a direct relationship to subduction. Within both the Caledonian and Lachlan belts there are some granites with a composition close to the younger tonalites. A particularly interesting case is that of the Tuross Head Tonalite of the Lachlan Fold Belt, which can be shown to have formed from slightly older source rocks by a process that we refer to as remagmatisation which has caused no significant change in composition. Since remagmatisation has reproduced the former source composition in the younger rocks, the wrong inference would result from the use of that composition to deduce the tectonic conditions at the time of formation of the tonalite. Granites, particularly the more mafic ones, will generally have compositions reflecting the compositions of their source rocks, and attempts to use granite compositions to reconstruct the tectonic environment at the time of formation of the granite may be looking instead at an older event. This is probably also the case for some andesites formed at continental margins.

Several arguments can be presented in favour of a general model for the production of I-type granite sources by underplating the crust, so that the source rocks are infracrustal. Such sources may contain a component of subducted sediments with the consequence that some of the compositional characteristics of sedimentary rocks may be present in I-type source rocks and in the granites derived from them. The small bodies of mafic granite and gabbro associated with island arc volcanism have an origin that can be related to the partial melting of subducted oceanic crust or of mantle material overlying such slabs and can be referred to as M-type. These rocks have compositions indistinguishable from those of the related volcanic rocks, except for a small component of cumulative material. The tonalitic I-type granites characteristic of the Cordillera are probably derived from such M-type rocks of basaltic to andesitic composition, which had been underplated beneath the crust. Some of the more mafic tonalites of the Caledonian-age fold belts may also have had a similar origin. More commonly, however, the plutonic rocks of the older belts are granodioritic and these probably represent the products of partial melting of older tonalitic I-type source rocks in the deep crust, these having compositions and origins analogous to the tonalites of the Cordillera. In this way, multiple episodes of partial melting, accompanied by fractionation of the magmas, can produce quite felsic rocks from original source rocks in the mantle or mantle wedge. These are essential processes in the evolution of the crust, since the first stages in this process produce new crust and the later magmatic events redistribute this material vertically without the addition of significant amounts of new crust.



Hide All
Bateman, P. C. 1983. A summary of critical relations in the central part of the Sierra Nevada batholith, California, U.S.A. In Roddick, J. A. (ed.) Circum-Pacific Plutonic Terranes. MEM GEOL SOC AM 159, 241254.
Borg, S. G., Stump, E., Chappell, B. W., McCulloch, M. T., Wyborn, D., Armstrong, R. L. & Holloway, J. R. 1987. Granitoids of northern Victoria Land, Antarctica: implications of chemical and isotopic variations to regional crustal structure and tectonics. AM J SCI 287, 127169.
Brown, G. C., Francis, E. H., Kennan, P. & Stillman, C. J. 1985. Caledonian igneous rocks of Britain and Ireland. In Harris, A. L. (ed.) The nature and timing of Orogenic activity in the Caledonian rocks of the British Isles. MEM GEOL SOC LONDON 9, 115.
Brown, P. E. 1983. Caledonian and earlier Magmatism. In Craig, G. Y. (ed.) Geology of Scotland, 167204. Edinburgh: Scottish Academic Press.
Cas, R. A. F. & Wright, J. V. 1987. Volcanic successions modern and ancient. London: Allen & Unwin.
Chappell, B. W. 1978. Granitoids from the Moonbi district, New England Batholith, eastern Australia. J GEOL SOC AUST 25, 267283.
Chappell, B. W. 1979. Granites as images of their source rocks. GEOL SOC AM PROG ABSTR 11, 400.
Chappell, B. W. 1984. Source rocks of I- and S-type granites in the Lachlan Fold Belt, southeastern Australia. PHILOS TRANS R SOC LONDON A310, 693707.
Chappell, B. W., White, A. J. R. & Wyborn, D. 1987. The importance of residual source material (restite) in granite petrogenesis. J PETROL 28, 11111138.
Chappell, B. W., White, A. J. R. & Hine, R. 1988a. Granite provinces and basement terranes in the Lachlan Fold Belt, southeastern Australia. AUST J EARTH SCI (in press).
Chappell, B. W., Beams, S. D., McCulloch, M. T. & White, A. J. R. 1988b. The Bega Batholith: a petrographically, chemically and isotopically asymmetrical plutonic compex of Devonian age in the Lachlan Fold Belt, southeastern Australia (in prep).
Chappell, B. W. & White, A. J. R. 1974. Two contrasting granite types. PAC GEOL 8, 173174.
Chappell, B. W. & White, A. J. R. 1984. I- and S-type granites in the Lachlan Fold Belt, southeastern Australia. In Keqin, Xu & Guangchi, Tu (eds) Geology of Granites and Their Metallogenic Relations, 87101. Beijing: Science Press.
Cobbing, E. J. & Pitcher, W. S. 1972. The Coastal Batholith of central Peru. J GEOL SOC LONDON 128, 421460.
Cobbing, E. J. & Pitcher, W. S. 1983. Andean plutonism in Peru and its relationship to volcanism and metallogenesis at a segmented plate edge. MEM GEOL SOC AM 159, 277291.
Collins, W. J., Beams, S. D., White, A. J. R. & Chappell, B. W. 1982. Nature and origin of A-type granites with particular reference to southeastern Australia. CONTRIB MINERAL PETROL 80, 189200.
Compston, W. & Chappell, B. W. 1979. Sr-isotope evolution of granitoid source rocks. In McElhinny, M. W. (ed.) The Earth: Its Origin, Structure and Evolution, 377426. London: Academic Press.
DePaolo, D. J. 1981. A neodymium and strontium isotopic study of the Mesozoic calc-alkaline granitic batholiths of the Sierra Nevada and Peninsular Ranges, California. J GEOPHYS RES 86, 1047010488.
Ewart, A. 1979. A review of the mineralogy and chemistry of Tertiary-Recent dacitic, latitic, rhyolitic, and related salic volcanic rocks. In Barker, F. (ed.) Trondhjemites, dacites and related rocks, 13121. Amsterdam: Elsevier.
Frost, C. D. & O'Nions, R. K. 1985. Caledonian magma genesis and crustal recycling. J PETROL 26, 515544.
Gray, C. M. 1984. An isotopic mixing model for the origin of granitic rocks in southeastern Australia. EARTH PLANET SCI LETT 70, 4760.
Griffin, T. J., White, A. J. R. & Chappell, B. W. 1978. The Moruya Batholith and geochemical contrasts between the Moruya and Jindabyne Suites. J GEOL SOC AUST 25, 235247.
Gromet, L. P. & Silver, L. T. 1987. REE variations across the Peninsular Ranges batholith: implications for batholithic petrogenesis and crustal growth in magmatic arcs. J PETROL 28, 75125.
Halliday, A. N., Fallick, A. E., Dickin, A. P., Mackenzie, A. B., Stephens, W. E. & Hildreth, W. 1983. The isotopic and chemical evolution of Mount St Helens. EARTH PLANET SCI LETT 63, 241256.
Halliday, A. N., Stephens, W. E., Hunter, R. H., Menzies, M. A., Dickin, A. P. & Hamilton, P. J. 1985. Isotopic and chemical constraints on the building of the deep Scottish lithosphere. SCOTT J GEOL 21, 465491.
Halliday, A. N. & Stephens, W. E. 1984. Crustal controls on the genesis of the 400 Ma old Caledonian granites. PHYS EARTH PLANET INT 35, 89104.
Hamilton, P. J., O'Nions, R. K. & Pankhurst, R. J. 1980. Isotopic evidence for the provenance of some Caledonian granites. NATURE 287, 279284.
Harmon, R. S., Halliday, A. N., Clayburn, J. A. P. & Stephens, W. E. 1984. Chemical and isotopic systematics of the Caledonian intrusions of Scotland and Northern England: a guide to magma source region and magma-crust interaction. PHILOS TRANS R SOC LONDON A310, 709742.
Harris, A. L. (ed.) 1985. The nature and timing of Orogenic activity in the Caledonian rocks of the British Isles. MEM GEOL SOC LONDON 9.
Hensel, H. D., McCulloch, M. T. & Chappell, B. W. 1985. The New England Batholith: constraints on its derivation from Nd and Sr isotopic studies of granitoids and country rocks. GEOCHIM COSMOCHIM ACTA 49, 369384.
Hine, R., Williams, I. S., Chappell, B. W. & White, A. J. R. 1978. Contrasts between I- and S-type granitoids of the Kosciusko Batholith. J GEOL SOC AUST 25, 219234.
Huppert, H. E. & Sparks, R. S. J. 1988. The generation of granitic magmas by intrusion of basalt into continental crust. J PETROL (in press).
Johnson, R. W. 1987. Delayed partial melting of subduction-modified magma sources in western Melanesia: new results from the late Cainozoic. Pacific Rim Congress 87, 211214. Melbourne: The Australasian Institute of Mining and Metallurgy.
Johnson, R. W. & Chappell, B. W. 1979. Chemical analyses of rocks from the late Cainozoic volcanoes of north-central New Britain and the Witu Islands, Papua New Guinea. REP BMR GEOL GEOPHYS 209.
Kistler, R. W. & Peterman, Z. E. 1973. Variations in Sr, Rb, K, Na and initial Sr87/Sr86 in Mesozoic granitic rocks and intruded wall rocks in central California. BULL GEOL SOC AM 84, 34893512.
Kistler, R. W. & Peterman, Z. E. 1978. Reconstruction of crustal blocks of California on the basis of initial strontium isotopic compositions of Mesozoic granitic rocks. PROF PAP US GEOL SURV 1071.
Larsen, E. S. 1948. Batholith and associated rocks of Corona, Elsinore, and San Luis Rey quadrangles, southern California. MEM GEOL SOC AM 29.
Le, Bas M. J. 1982. The Caledonian granites and diorites of England and Wales. In Sutherland, D. S. (ed.) Igneous rocks of the British Isles, 191201. New York: Wiley.
McBirney, A. R. & White, C. M. 1982. The Cascade province. In Thorpe, R. S. (ed.) Andesites, 115135. New York: Wiley.
McCulloch, M. T. & Chappell, B. W. 1982. Nd isotopic characteristics of S- and I-type granites. EARTH PLANET SCI LETT 58, 5164.
Murray, C. G. 1986. Metallogeny and tectonic development of the Tasman Fold Belt in Queensland. ORE GEOL REV 1, 315400.
O'Brien, C., Plant, J. A., Simpson, P. R. & Tarney, J. 1985. The geochemistry, metasomatism and petrogenesis of the granites of the English Lake District. J GEOL SOC LONDON 142, 11391157.
O'Connor, P. J. & Brück, P. M. 1978. Age and origin of the Leinster granite. J EARTH SCI R DUBLIN SOC 1, 105113.
Oliver, R. L. 1956. The origin of garnets in the Borrowdale Volcanic Series and associated rocks, English Lake District. GEOL MAG 93, 121139.
O'Neil, J. R. & Chappell, B. W. 1977. Oxygen and hydrogen isotope relations in the Berridale batholith. J GEOL SOC LONDON 133, 559571.
Pankhurst, R. J. & Sutherland, D. S. 1982. Caledonian granites and diorites of Scotland and Ireland. In Sutherland, D. S. (ed.) Igneous rocks of the British Isles, 149190. New York: Wiley.
Pearce, J. A., Harris, M. B. W. & Tindle, A. G. 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J PETROL 25, 956983.
Pidgeon, R. T. & Aftalion, M. 1978. Cogenetic and inherited zircon U-Pb systems in granites of Scotland and England, In Bowes, D. R. & Leake, B. W. (eds) Crustal Evolution in Northwestern Britain and Adjacent Regions. GEOL J SPECIAL ISSUE 10, 183220.
Pitcher, W. S. 1974. The Mesozoic and Cenozoic batholiths of Peru. PAC GEOL 8, 5162.
Pitcher, W. S. 1982. Granite type and tectonic environment. In Hsu, K. J. (ed.) Mountain Building Processes, 1940. London: Academic Press.
Plant, J. A., Brown, G. C., Simpson, P. R. & Smith, R. T. 1980. Signature of metalliferous granites in the Scottish Caledonides. TRANS INST MIN MET 89, B198210.
Richards, D. N. G. 1980. Palaeozoic granitoids of northeastern Australia. In Henderson, R. A. & Stephenson, P. J. (eds) The Geology and Geophysics of Northeastern Australia, 229246. Brisbane: Geological Society of Australia, Queensland Division.
Richards, J. R. & Singleton, O. P. 1981. Palaeozoic Victoria, Australia: igneous rocks, ages and their interpretation. J GEOL SOC AUST 28, 395421.
Rutherford, M. J., Sigurdsson, H., Carey, S. & Davis, A. 1985. The May 18, 1980, eruption of Mount St. Helens 1. Melt composition and experimental phase equilibria. J GEOPHYS RES 90, 29292947.
Shaw, S. E. & Flood, R. H. 1981. The New England Batholith, eastern Australia: geochemical variations in time and space. J GEOPHYS RES 86, 1053010544.
Silver, L. T., Taylor, H. P. & Chappell, B. W. 1979. Some petrological, geochemical and geochronological observations of the Peninsular Ranges batholith near the international border of the U.S.A. and Mexico, In Abbott, P. L. & Todd, V. R. (eds), GEOL SOC AM 1979 GUIDEB, 83110.
Silver, L. T. & Chappell, B. W. 1988. The Peninsular Ranges Batholith: an insight into the evolution of the Cordilleran batholiths of southwestern North America. TRANS R SOC EDINBURGH EARTH SCI 79, 105121.
Stephens, W. E. 1988. Granitoid plutonism in the Caledonian orogen of Europe. In Harris, A. L. & Fettes, D. J. (eds) The Caledonian-Appalachian Orogen. GEOL SOC LONDON SPEC PUBL 38, 389404.
Stephens, W. E. & Halliday, A. N. 1984. Geochemical contrasts between late Caledonian granitoid plutons of northern, central and southern Scotland. TRANS R SOC EDINBURGH EARTH SCI 75, 259273.
Stump, E., White, A. J. R. & Borg, S. G. 1986. Reconstruction of Australia and Antarctica: evidence from granites and recent mapping. EARTH PLANET SCI LETT 79, 348360.
Sweetman, T. M. 1987. The geochemistry of the Blackstairs Unit of the Leinster Granite, Ireland. J GEOL SOC LONDON 144, 971984.
Taylor, H. P. & Sheppard, S. M. F. 1986. Igneous rocks: I. Processes of isotopic fractionation and isotope systematics. In Valley, J. W., Taylor, H. P. & O'Neil, J. R. (eds) Stable isotopes in high temperature geological processes. MIN SOC AM REV MINERAL 16, 227271.
Taylor, S. R. & McLennan, S. M. 1985. The continental crust: its composition and evolution. Oxford: Blackwell.
Thirlwall, M. F. 1981. Implications for Caledonian plate tectonic models of chemical data from volcanic rocks of the British Old Red Sandstone. J GEOL SOC LONDON 138, 123138.
Thirlwall, M. F. 1982. Systematic variation in chemistry and Nd-Sr isotopes across a Caledonian calc-alkalíne volcanic arc:implications for source materials. EARTH PLANET SCI LETT 58, 2750.
Thirlwall, M. F. & Fitton, J. G. 1983. Sm-Nd garnet age for the Ordovician Borrowdale Volcanic Group, English Lake District. J GEOL SOC LONDON 140, 511518.
Tulloch, A. J. 1983. Granitoid rocks of New Zealand—a brief review. In Roddick, J. A. (ed.) Circum-Pacific Plutonic Terranes. MEM GEOL SOC AM 159, 520.
Wall, V. J., Clemens, J. D. & Clarke, D. B. 1987. Models for granitoid evolution and source compositions. J GEOL 95, 731749.
Whalen, J. B. 1980. Aspects of granites and associated mineralization. Ph.D. Thesis, The Australian National University, Canberra.
Whalen, J. B. 1985. Geochemistry of an island-arc plutonic suite: the Uasilau-Yau Yau Intrusive Complex, New Britain, P.N.G. J PETROL 26, 603632.
White, A. J. R., Williams, I. S. & Chappell, B. W. 1976. The Jindabyne thrust and its tectonic, physiographic and petrogenetic significance. J GEOL SOC AUST 23, 105112.
White, A. J. R., Clemens, J. C., Holloway, J. R., Silver, L. T., Chappell, B. W. & Wall, V. J. 1986. S-type granites and their probable absence in southwestern North America. GEOLOGY 14, 115118.
White, A. J. R. & Chappell, B. W. 1977. Ultrametamorphism and granitoid genesis. TECTONOPHYSICS 43, 722.
White, A. J. R. & Chappell, B. W. 1983. Granitoid types and their distribution in the Lachlan Fold Belt, southeastern Australia. In Roddick, J. A. (ed.) Circum-Pacific Plutonic Terranes. MEM GEOL SOC AM 159, 2134.
White, A. J. R. & Chappell, B. W. 1988. Some supracrustal (S-type) granites of the Lachlan Fold Belt. TRANS R SOC EDINBURGH EARTH SCI 79, 169181.
Williams, I. S., Compston, W., Chappell, B. W. & Shirahase, T. 1975. Rubidium-strontium age determinations on micas from a geologically controlled, composite batholith. J GEOL SOC AUST 22, 497505.
Williams, I. S., Chen, Y., Chappell, B. W. & Compston, W. 1988. Dating the sources of Bega Batholith granites by ion microprobe. GEOL SOC AUST ABSTR 21, 424.
Wones, D. R. 1980. A comparison between granitic plutons of New England, U.S.A. and the Sierra Nevada Batholith, California. In Wones, D. R. (ed.) The Caledonides in the USA. DEPT GEOL SCI VIRGINIA POLYTECH INST AND STATE UNIV MEM 2, 123130.
Wyborn, D., Chappell, B. W. & Johnston, R. M. 1981. Three S-type volcanic suites from the Lachlan Fold Belt, southeast Australia. J GEOPHYS RES 86, 1033510348.
Wyborn, D., Turner, B. S. & Chappell, B. W. 1987. The Boggy Plain Supersuite: a distinctive belt of I-type igneous rocks of potential economic significance in the Lachlan Fold Belt. AUST J EARTH SCI 34, 2143.
Wyborn, D. & Chappell, B. W. 1986. The petrogenetic significance of chemically related plutonic and volcanic rock units. GEOL MAG 123, 619628.
Wyborn, L. A. I., Page, R. W. & Parker, A. J. 1987. Geochemical and geochronological signatures in Australian Proterozoic igneous rocks. In Pharaoh, T. C., Beckinsale, R. D. & Rickard, D. (eds) Geochemistry and Mineralization of Proterozoic Volcanic Suites. GEOL SOC LONDON SPEC PUBL 33, 377394.
Wyborn, L. A. I., Wyborn, D., Chappell, B. W., Sheraton, J., Tarney, J. F., Collins, W. J. & Drummond, B. J. 1988. Geological evolution of granite compositions with time in the Australian continent—implications for tectonic and mantle processes. GEOL SOC AUST ABSTR 21, 434435.


Related content

Powered by UNSILO

Origin of infracrustal (I-type) granite magmas

  • B. W. Chappell (a1) and W. E. Stephens (a2)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.