Skip to main content Accessibility help

Pluton emplacement in arcs: a crustal-scale exchange process

  • Scott R. Paterson (a1), T. Kenneth Fowler (a2) and Robert B. Miller (a3)


Buddington (1959) pointed out that the construction of large crustal magma chambers involves complex internal processes as well as multiple country rock material transfer processes (MTPs), which reflect large horizontal, vertical and temporal gradients in physical conditions. Thus, we have attempted to determine the relative importance of different magmatic and country rock MTPs at various crustal depths, and whether country rock MTPs largely transport material vertically or horizontally, rather than seeking a single model of magma ascent and emplacement.

Partially preserved roofs of nine plutons and in some cases roof–wall transitions with roof emplacement depths of 1·5–11 km were mapped. During emplacement, these roofs were not deformed in a ductile manner, detached or extended by faults, or significantly uplifted. Instead, sharp, irregular, discordant contacts are the rule with stoped blocks often preserved immediately below the roof, even at depths of 10 km. The upper portions of these magma chambers are varied, sometimes preserving the crests of more evolved magmas or local zones of volatile-rich phases and complex zones of dyking and magma mingling. Magmatic structures near roofs display a wide variety of patterns and generally formed after emplacement. Transitions from gently dipping roofs to steep walls are abrupt. At shallow crustal levels, steep wall contacts have sharp, discordant, stepped patterns with locally preserved stoped blocks indicating that the chamber grew sideways in part by stoping. Around deeper plutons, an abrupt transition (sometimes within hundreds of metres) occurs in the country rock from discordant, brittle roofs to moderately concordant, walls deformed in a ductile manner defining narrow structural aureoles. Brittle or ductile faults are not present at roof–wall joins.

Near steep wall contacts at shallow to mid-crustal depths (5–15 km), vertical and horizontal deflections of pre-emplacement markers (e.g. bedding, faults, dykes), and ductile strains in narrow aureoles (0·1–0·3 body radii) give a complete range of bulk strain values that account for 0–100% of the needed space, but average around 30%, or less, particularly for larger batholiths. A lack of far-field deflection of these same markers rules out significant horizontal displacement outside the aureoles and requires that any near-field lateral shortening is accommodated by vertical flow. Lateral variations from ductile (inner aureole) to brittle (outer aureole) MTPs are typically observed. Compositional zoning is widespread within these magma bodies and is thought to represent separately evolved pulses that travelled up the same magma plumbing system. Magmatic foliations and lineations commonly cross-cut contacts between pulses and reflect the strain caused either by the late flow of melt or regional deformation.

Country rocks near the few examined mid- to deep crustal walls (10–30 km) are extensively deformed, with both discordant and concordant contacts present; however, the distinction between regional and emplacement-related deformation is less clear than for shallower plutons. Internal sheeting is more common, although elliptical masses are present. Lateral compositional variations are as large as vertical variations at shallower depths and occur over shorter distances. Magmatic foliations and lineations often reflect regional deformation rather than emplacement processes.

The lack of evidence for horizontal displacement outside the narrow, shallow to mid-crustal aureoles and the lack of lateral or upwards displacement of pluton roofs indicate that during emplacement most country rock is transported downwards in the region now occupied by the magma body and its aureole. The internal sheeting and zoning indicate that during the downwards flow of country rock, multiple pulses of magma travelled up the same magma system. If these relationships are widespread in arcs, magma emplacement is the driving mechanism for a huge crustal-scale exchange process.



Hide All
Ague, J. J.&Brimhall, G. H. 1988. Magmatic arc asymmetry and distribution of anomolous plutonic belts in the batholiths of California: effects of assimilation, crustal thickness, and depth of crystallization. BULL GEOL SOC AM 100, 912–27.
Allen, C. M 1992. A nested diapir model for the reversely zoned Turtle pluton, southeastern California. TRANS SOC EDINBURGH EARTH SCI 83, 179–90.
Ayuso, R. A 1984. Field relations, crystallization, and petrography of reversely zoned granitic pluton in the Bottle Lake Complex, Maine. US GEOL SURV PROF PAP 1320.
Barnes, C. G., Rice, J. M.&Gribble, R. F. 1986. Tilted plutons in the Klamath Mountains of California and Oregon. J GEOPHYS RES 91, 6059–71.
Barton, M. D., Staude, J. M., Snow, E. A.&Johnson, D. A. 1991. Aureole systematics, in contact metamorphism. AM MINERAL SOC REV MINERAL 26, 723847.
Bateman, P. C. 1992. Plutonism in the central part of the Sierra Nevada Batholith, California. US GEOL SURV PROF PAP 1483.
Bateman, P. C, Clark, L. D., Huber, N. K., Moore, J. G.&Rinehart, C. D. 1963. The Sierra Nevada batholith—a synthesis of recent work across the central part. US GEOL SURV PROF PAP 414D, D146.
Bateman, R. 1982. The zoned Bruinbin granitoid pluton and its aureole. J GEOL SOC AUST 29, 253–65.
Bergantz, G. W.&Dawes, R. 1994. Aspects of magma generation and ascent in the continental lithosphere. In Ryan, M. P. (ed.) Magmatic systems, 291317. San Diego: Academic Press.
Berger, A. R.&Pitcher, W. S. 1970. Structures in granite rocks: a commentary and critique on granite tectonics. PROC GEOL ASSOC 81, 441–61.
Best, M. G. 1963. Petrology and structural analysis of metamorphic rocks in the southwestern Sierra Nevada Foothills, California. UNIV CALIFORNIA PUBL GEOL SCI 42, 111–58.
Bouchez, J. L.&Diot, H. 1990. Nested granites in question: contrasted emplacement kinematics of independent magmas in the Zaer pluton, Morocco. GEOLOGY 18, 966–9.
Buddington, A. F. 1959. Granite emplacement with special reference to North America. GEOL SOC AM BULL 70, 671747.
Bykerk-Kauffman, A. 1990. Structural evolution of the northeastern Santa Catalina Mountains, Arizona: a glimpse of the pre-extension history of the Catalina Complex. Unpublished Ph.D. Dissertation, University of Arizona.
Clemens, J. D.&Mawer, C. K. 1992. Granitic magma transport by fracture propagation. TECTONOPHYSICS 204, 339–60.
Cobbing, E. J.&Pitcher, W. S. 1972. The coastal batholith of Peru. J GEOL SOC LONDON 128, 421–60.
Compton, R. 1955. Trondhjemite batholith near Bidwell Bar. California. GEOL SOC AM BULL 66, 944.
Crossland, A. 1994. Implications of roof structures for the emplacement of the Hall Canyon pluton, Panamint Mtns, California. GEOL SOC AM ABST PROGRAMS 26, A134.
Dawes, R. L. 1993. Mid-crustal, Late Cretaceous plutons of the North Cascades: petrogenesis and implications for the growth of continental crust. Unpublished Ph.D. Dissertation, University of Washington, Seattle.
Delaney, P. T.&Pollard, D. D. 1981. Deformation of host rocks and flow of magma during growth of minette dikes and breccia bearing intrusions near Ship Rock, New Mexico. US GEOL SURV PROF PAP 1202.
Dilles, J. H. 1987. The petrology of the Yenngton batholith, Nevada: evidence for the evolution of porphyry copper ore fluids. ECON GEOL 72, 769–95.
Dilles, J. H.&Wright, J. E. 1988. The chronology of early Mesozoic arc magmatism in the Yerington District of western Nevada and its regional implications. GEOL SOC AM BULL 100, 644–52.
Flood, R. H.&Shaw, S. E 1979. K-rich cumulate diorite at the base of a tilted granodiorite pluton from the New England Batholith, Australia. J GEOL 87, 417–25.
Fowler, T. K. Jr. 1994a. Granitoid emplacement into older plutonic host-rocks. GEOL SOC AM ABSTR PROGRAMS 26, A134.
Fowler, T. K. Jr. 1994b. Using geologic maps to constrain pluton emplacement mechanisms. GEOL SOC AM ABSTR PROGRAMS 26, 52.
Fowler, T. K Jr.&Paterson, S. R. Timing and nature of magmatic fabrics from structural relations around stoped blocks. J STRUCT GEOL, in press.
Fowler, T. K. Jr&Paterson, S. R., Crossland, A.&Yoshinobu, A. 1995. Pluton emplacement mechanisms: a view from the roof. In Brown, M.&Piccoli, P. M. (eds) The origin of granites and related rocks US GEOL SURV CIRC 1129, 57.
Fowler, T. K. Jr,Yoshinobu, A., Paterson, S. R., Tickyj, H., Llambias, E. J.&Sato, A. M. 1995. Chita pluton, San Juan Province. Argentina: 3D constraints on pluton emplacement by magmatic stoping. GEOL SOC AM ABSTR PROGRAMS 27, 7125.
Geissman, J. W., Van Der Voo, R.&Howard, K. L. Jr 1982. A paleomagnetic study of the structural deformation in the Yerington district, Nevada. AM J SCI 282, 1042–109.
Haeussler, P. J.&Paterson, S. R. 1993. Post-emplacement tilting and burial of the Guadalupe Igneous Complex, Sierra Nevada. California. GEOL SOC AM BULL 105, 1310–20.
Hopson, C. A.&Dellinger, D. A. 1987. Evolution of four-dimensional compositional zoning, illustrated by the diapiric Duncan Hill pluton, north cascades, Washington. GEOL SOC AM ABSTR PROGRAMS 19, 707.
Hopson, C. A., Gans, P. B., Baer, E., Blythe, A., Calvert, A.&Pinnow, J. 1994. Spirit Mountain Pluton, Southern Nevada: a progress report. GEOL SOC AM ABSTR PROGRAMS 26, 60.
Hutton, D. H. W. 1988. Granite emplacement mechanisms and tectonic controls: inferences from deformation studies. TRANS R SOC EDINBURGH 79, 245–55.
Hyndman, D. W., Silverman, R. E., Benoit, W. R.&Wold, R. 1982. The Phillipsburg batholith, western Montana. BUR MINES GEOL MEM 49.
John, B. E. 1988. Structural reconstruction and zonation of a tilted midcrustal magma chamber: the felsic Chemehuevi Mountains Plutonic Suite. GEOLOGY 16, 613–7.
Lister, J. R.&Kerr, R. C. 1991. Fluid-mechanical models of crack propogation and their application to magma transport in dikes. J GEOPHYS RES 96, 10049–77.
Mackin, J. H. 1947. Some structural features of the intrusions in the Iron Springs district. UTAH GEOL SOC GUIDE GEOL UTAH 2, 62.
Mahon, K. I., Harrison, T. M.&Drew, D. A. 1988. Ascent of a granitoid diapir in a temperature varying medium. J GEOPHYS RES 93, 117488.
Marsh, B. D. 1982. On the mechanics of igneous diapirism, stoping, and zone melting. AM J SCI 282, 808–55.
Miller, R. B.&Bowring, S. A. 1990. Structure and chronology of the Oval Peak batholith and adjacent rocks: implications for the Ross Lake fault zone, North Cascades, Washington. GEOL SOC AM BULL 102, 1361–77.
Nabelek, P. I., Papike, J. J.&Laul, J. C. 1986. The Notch Peak Granite stock, Utah: origin of reverse zoning and petrogenesis. J PETROL 27, 1035–9.
Paterson, S. R. 1992. Pluton emplacement processes: implications of the structural characteristics of pluton roofs. GEOL SOC AM ABSTR PROGRAMS 24, 73.
Paterson, S. R.&Fowler, T. K. Jr 1993. Re-examining pluton emplacement processes. J STRUCT GEOL 15, 191206.
Paterson, S. R.&Fowler, T. K. Jr 1995. Construction of magma chambers in arcs: a perspective from the country rock. GEOL SOC AM ABSTR PROGRAMS 27, 80.
Paterson, S. R.&Vernon, R. H. 1995. Bursting the bubble of ballooning plutons: a return to nested diapirs emplaced by multiple processes. GEOL SOC AM BULL 107, 1356–80.
Paterson, S. R., Vernon, R. H.&Fowler, T. K. Jr 1991a. Aureole tectonics. In Kerrick, D. M. (ed.) Contact metamorphism. MINERAL SOC AM REV MINERAL 26, 673722.
Paterson, S. R., Tobisch, O. T.&Vernon, R. H. 1991b. Emplacement and deformation of granitoids during volcanic arc construction in the Foothills terrane, central Sierra Nevada, California. TECTONOPHYSICS 191, 89110.
Paterson, S. R.Miller, R. B., Anderson, L. A., Lund, S., Bendixen, J., Taylor, N.&Fink, T. 1994. Emplacement and evolution of the Mt. Stuart batholith. In Swanson, D. A.&Haugerud, R. H. (eds) Geologic field trips in the Pacific Northwest: 1994 Geological Society of America Annual Meeting, 2F-147.
Pitcher, W. S. 1979. The nature, ascent and emplacement of granite magmas. J GEOL SOC LONDON 136, 627–62.
Pitcher, W. S. 1993. The nature and origin of granite. Glasgow: Blackie Academic and Professional.
Pitcher, W. S.&Berger, A. R. 1972. The geology of Donegal: a study of granite emplacement and unroofing. New York: Wiley.
Proffett, J. M. Jr 1977. Cenozoic geology of the Yerington district. Nevada, and implications for the nature and origin of basin and range faulting. GEOL SOC AM BULL 88, 247–66.
Proffett, J. M.&Dilles, J. H. 1984. Geologic map of the Yerington district, Nevada. Nevada Bureau of Mines and Geology Map 77. 1:24,000 scale.
Reiners, P. W., Nelson, B. K.&Ghiorso, M. K. 1995. Assimilation of the felsic crust by basaltic magma: thermal limits and extents of crustal contamination of mantle-derived magmas. GEOLOGY 23, 563–66.
Rosenberg, C. L., Berger, A.&Schmid, S. M. 1995. Observations from the floor of a granitoid pluton: inferences on the driving force of final emplacement. GEOLOGY 23, 443–6.
Rubin, A. M. 1993. Getting granite dikes out of the source region. J GEOPHYS RES 100, 5911–29.
Saleeby, J. B. 1990. Progress in tectonic and petrogenetic studies in an exposed cross-section of young (≍100 Ma) continental crust. southern Sierra Nevada, California. In Salisbury, M. H.&Fountain, D. M. (eds) Exposed cross-sections of the continental crust, 137–58. Dordrecht: NATO Advanced Studies Institute/Kluwer Academic.
Sato, A. M. 1987. Chita granitic stock: a closed system crystallization. In 10 Congreso Geologico, Tucuman, Vol. 4, 6999.
Shaw, H. R. 1980. The fracture mechanism of magma transport from the mantle to the surface. In Hargraves, R. B. (ed.) Physics of magmatic processes, 201–64. Princeton: Princeton University Press.
Stein, E. 1994. Structures in the aureole of the Joshua Flat Pluton: implications for country rock flow patterns during emplacement. GEOL SOC AM ABSTR PROGRAMS 26, 95.
Stephens, W. E. 1992. Spatial, compositional, and Theological constraints on the origin of zoning in the Criffell pluton, Scotland. TRANS R SOC EDINBURGH EARTH SCI 83, 191–9.
Weinberg, R. F.&Podladchikov, Y. 1994. Diapiric ascent of magmas through power-law crust and mantle. J GEOPHYS RES 99, 9543–60.
Yuan, E. S.&Paterson, S. R. 1993. Evaluating flow from structures in plutons. GEOL SOC AM ABSTR PROGRAMS 25, 305.
Yoshinobu, A. S.&Paterson, S. R. 1995. Multiple space-making mechanisms and vertical material transfer in the Sierra Nevada batholith. GEOL SOC AM ABSTR PROGRAMS 27, 85.
Yoshinobu, A. S., Okaya, D. A., Paterson, S. R.&Fowler, T. K 1995. Testing fault-controlled magma emplacement mechanisms. US GEOL SURV CIRC 1129.



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