Hostname: page-component-5c6d5d7d68-wbk2r Total loading time: 0 Render date: 2024-08-22T02:36:34.203Z Has data issue: false hasContentIssue false
  • English
  • Français

Pluton emplacement by wall-rock thrusting, hanging-wall translation and extensional collapse: latest Devonian plutons of the Cobequid fault zone, Nova Scotia, Canada

Published online by Cambridge University Press:  01 May 2009

I. Koukouvelas ,
G. Pe-Piper  and
D. J. W. Piper
I. Koukouvelas
Affiliation:
Department of Geology, University of Patras, Patras, Greece
G. Pe-Piper
Affiliation:
Department of Geology, Saint Mary's University, Halifax, N.S. B3H 3C3, Canada
D. J. W. Piper
Affiliation:
Atlantic Geoscience Centre, Geological Survey of Canada, Bedford Institute of Oceanography, P. O. Box 1006, Dartmouth, N.S. B2Y 4A2, Canada
Get access Rights & Permissions [Opens in a new window]

Abstract

Latest Devonian A-type granite-gabbro plutons, in part ductilely deformed, are spatially associated with the strike-slip Cobequid fault zone. The youngest intrusions are close to the Cobequid fault zone, which was the main conduit for magma. Two phases of deformation accompanying magma emplacement are recognized. Early magmas intruded ductile rocks during left-lateral oblique thrust movements. A second stage of right-lateral oblique slip normal faulting accommodated uplift of the plutons when coarse granite was emplaced in the crestal regions. Cross-cutting late stage porphyries, granitic clasts in marginal basins cut by granitic dykes, and superposition of brittle on ductile structures all indicate rapid uplift of the plutons. The geometry of the Cobequid fault zone shows that pluton emplacement was not the result of extension in releasing bends during transcurrent shear. Rather, flower-structure high-angle faults acted as magma conduits and space was created by two processes: translation of wall rocks along thrust faults at depth, developing space away from the master fault zone and backward collapse of the uplifted magma chamber creating space towards the fault zone.

Type
Articles
Information
Geological Magazine , Volume 133 , Issue 3 , May 1996 , pp. 285 - 298
Copyright
Copyright © Cambridge University Press 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

Abers, G., & McCaffrey, R., 1988. Active deformation in the New Guinea fold and thrust belt: Seismological evidence for strike-slip faulting and basement-involved thrusting. Journal of Geophysical Research 93, 13332–54.CrossRefGoogle Scholar
Blanchard, M.-C., Jamieson, R. A., & More, E. B., 1984. Late Devonian—Early Carboniferous volcanism in western Cape Breton Island, Nova Scotia. Canadian Journal of Earth Sciences 21, 762–74.CrossRefGoogle Scholar
Castro, A., 1987. On granitoid emplacement and related structures. A review. Geologische Rundschau 76, 101–24.CrossRefGoogle Scholar
Clarke, D. B., & Halliday, A. N., 1980. Strontium isotope geology of the South Mountain Batholith, Nova Scotia. Geochimica et Cosmochica Acta 44, 1045–58.CrossRefGoogle Scholar
Doig, R., Murphy, J. B., Nance, R. D., & Stokes, T., 1991. Review of the geochronology of the Cobequid Highlands, Avalon composite terrane, Nova Scotia. Geological Survey of Canada Paper 91 –1D, 71–8.Google Scholar
Donohoe, H. V., & Wallace, P. I., 1982. Geological map of the Cobequid Highlands, Nova Scotia. Scale 1:50 000. Nova Scotia Department of Mines and Energy.Google Scholar
Donohoe, H. V. Jr, & Wallace, P. I., 1985. Repeated orogeny, faulting and stratigraphy of the Cobequid Highlands, Avalon Terrane of northern Nova Scotia. Geological Association of Canada —Mineralogical Association of Canada Joint Annual Meeting, Guidebook 3. Fredericton, N.B., 77 pp.Google Scholar
Durling, P. W., & Marillier, F. J. Y., 1990. Structural trends and basement rock subdivisions in the western Gulf of St. Lawrence, Northern Appalachians. Atlantic Geology 26, 79–95.Google Scholar
Eisbacher, G. H., 1969. Displacement and stress field along part of the Cobequid Fault, Nova Scotia. Canadian Journal of Earth Sciences 6, 1095–1104.CrossRefGoogle Scholar
Eisbacher, G. H., 1970. Deformation mechanisms of mylonitic rocks and fractured granites in the Cobequid Mountains, Nova Scotia, Canada. Geological Society of America Bulletin 81, 2009–20.CrossRefGoogle Scholar
Gates, A. E., Speer, J. A., & Pratt, T. L., 1988. The Alleghanian southern Appalachian piedmont: a transpressional model. Tectonics 7, 1307–24.CrossRefGoogle Scholar
Guineberteau, B., Bouchez, J.-L., & Vigneresse, J.-L., 1987. The Mortagne granite pluton (France) emplaced by pullapart along a shear zone: structural and gravimetric arguments and regional implication. Geological Society of America Bulletin 99, 763–70.2.0.CO;2>CrossRefGoogle Scholar
Hutton, D. W., 1988 a. Granite emplacement mechanisms and tectonic control: inferences from deformation studies. Transactions of the Royal Society of Edinburgh: Earth Sciences 79, 245–55.CrossRefGoogle Scholar
Hutton, D. H. W., 1988 b. Igneous emplacement in a shear-zone termination: the biotite granite at Strontian, Scotland. Geological Society of America Bulletin 100, 1392–9.2.3.CO;2>CrossRefGoogle Scholar
Jones, R. R., & Tanner, P. W. G., 1995. Strain partitioning in transpression zones. Journal of Structural Geology 17, 793–802.CrossRefGoogle Scholar
Karlstrom, K. E., Miller, C. F., Kingsbury, J. A., & Wooden, J. L., 1993. Pluton emplacement along an active ductile fault zone, Piute Mountains, southeastern California: interaction between deformational and solidification processes. Geological Society of America Bulletin 105, 213–30.2.3.CO;2>CrossRefGoogle Scholar
Keen, C. E., Kay, W. A., Keppie, J. D., Marillier, F. J. Y., Pe-Piper, G., & Waldron, J. G. F., 1991. Crustal characteristics of the Canadian Appalachians southwest of Nova Scotia, from deep marine reflection profiling. Canadian Journal of Earth Sciences 28, 1096–1111.CrossRefGoogle Scholar
Keppie, J. D., 1989. Northern Appalachian terranes and their accretionary history. Geological Society of America Special Paper 230, 159–92.CrossRefGoogle Scholar
Keppie, J. D., & Dallmeyer, R. D., 1987. Dating transcurrent terrane accretion: an example from the Meguma and Avalon composite terranes in the northern Appalachians. Tectonics 6, 831–41.CrossRefGoogle Scholar
Koukouvelas, I., & Pe-Piper, G., 1995. The role of granites in the evolution of the Folly Lake diorite, Cobequid Highlands, Nova Scotia. Geological Survey of Canada Paper 95 –1, 33–8.Google Scholar
Krogh, T. E., & Keppie, J. D., 1988. U—Pb ages of single zircon cores imply a Pan-African source for two Meguma granites. Geological Association of Canada—Mineralogical Association of Canada Program with Abstracts 13, A69.Google Scholar
Lynch, G., & Tremblay, C., 1994. Late Devonian-Carboniferous detachment faulting and extensional tectonics in western Cape Breton Island, Nova Scotia, Canada. Tectonophysics 238, 55–69.CrossRefGoogle Scholar
Martel, A. T., McGregor, D. C., & Utting, J., 1993. Stratigraphic significance of Upper Devonian and Lower Carboniferous miospores from the type area of the Horton Group, Nova Scotia. Canadian Journal of Earth Sciences 30, 1091–8.CrossRefGoogle Scholar
Mawer, C. K., & White, J. C., 1987. Sense of displacement on the Cobequid-Chedabucto fault system, Nova Scotia, Canada. Canadian Journal of Earth Sciences 24, 217–23.CrossRefGoogle Scholar
Muecke, G. K., Elias, P., & Reynolds, P. H., 1988. Hercynian/Alleghanian overprinting of an Acadian Terrane: 40Ar/39Ar studies in the Meguma Zone, Nova Scotia, Canada. Chemical Geology 73, 153–67.Google Scholar
Paterson, S. R., & Fowler, T. K. Jr, 1993 a. Reexamining pluton emplacement mechanisms. Journal of Structural Geology 15, 191–206.CrossRefGoogle Scholar
Paterson, S. R., & Fowler, T. K. Jr, 1993 b. Extensional plutonemplacement models: do they work for large plutonic complexes. Geology 21, 781–4.2.3.CO;2>CrossRefGoogle Scholar
Pe-Piper, G., 1991. Granite and associated mafic phases, North River pluton, Cobequid Highlands. Atlantic Geology 27, 15–28.CrossRefGoogle Scholar
Pe-Piper, G., & Koukouvelas, I., 1994. Earliest Carboniferous plutonism, western Cobequid Highlands, Nova Scotia. Geological Survey of Canada Paper 94 –1D, 103–7.Google Scholar
Pe-Piper, G., Piper, D. J. W., & Clerk, S. B., 1991. Persistent mafic igneous activity in an A-type granite pluton, Cobequid Highlands, Nova Scotia. Canadian Journal of Earth Sciences 28, 1058–72.CrossRefGoogle Scholar
Piper, D. J. W., 1994. Late Devonian-earliest Carboniferous basin formation and relationship to plutonism, Cobequid Highlands, Nova Scotia. Geological Survey of Canada Paper 94 –1, 109–12.Google Scholar
Piper, D. J. W., Pe-Piper, G., & Loncarevic, B. D., 1993. Devonian-Carboniferous deformation and igneous intrusion in the Cobequid Highlands. Atlantic Geology 29, 219–32.CrossRefGoogle Scholar
Sanderson, D. J., & Marchini, W. R. D., 1984. Transpression. Journal of Structural Geology 6, 449–58.CrossRefGoogle Scholar
Schmidt, M. W., 1992. Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Alin-hornblende barometer. Contributions to Mineralogy and Petrology 110, 304–10.CrossRefGoogle Scholar
Sylvester, A. G., 1988. Strike-slip faults. Geological Society of America Bulletin 100, 1666–1703.2.3.CO;2>CrossRefGoogle Scholar
Tanner, P. W. G., 1992. The duplex model: implications from a study of fiexural-slip duplexes. In Thrust tectonics (ed. McClay, K. R.), pp. 201–8. Chapman & Hall.CrossRefGoogle Scholar
Utting, J., Keppie, J. D., & Giles, P. S., 1989. Palynology and stratigraphy of the lower Carboniferous Horton Group, Nova Scotia. Geological Survey of Canada Bulletin 396, 117–43.Google Scholar
Waldron, J. G. F., Piper, D. J. W., & Pe-Piper, G., 1989. Deformation of the Cape Chignecto Pluton, Cobequid Highlands, Nova Scotia: thrusting at the Meguma—Avalon boundary. Atlantic Geology 25, 51–62.CrossRefGoogle Scholar
Weijermars, R., 1993. Estimates of paleostress orientation with deformation zones between two mobile plates. Geological Society of America Bulletin 105, 1491–1510.2.3.CO;2>CrossRefGoogle Scholar
Williams, H., 1979. Appalachian orogen in Canada. Canadian Journal of Earth Sciences 16, 792–807.CrossRefGoogle Scholar