Skip to main content Accessibility help
×
Home

Compressional and extensional tectonics in low-medium pressure granulites from the Larsemann Hills, East Antarctica

  • C. J. Carson (a1), P. G. H. M. Dirks (a2), M. Hand (a1), J. P. Sims (a1) and C. J. L. Wilson (a1)...

Abstract

Meta-sediments in the Larsemann Hills that preserve a coherent stratigraphy, form a cover sequence deposited upon basement of mafic–felsic granulite. Their outcrop pattern defines a 10 kilometre wide east–west trending synclinal trough structure in which basement–cover contacts differ in the north and the south, suggesting tectonic interleaving during a prograde, D1 thickening event. Subsequent conditions reached low-medium pressure granulite grade, and structures can be divided into two groups, D2 and D3, each defined by a unique lineation direction and shear sense. D2 structures which are associated with the dominant gneissic foliation in much of the Larsemann Hills, contain a moderately east-plunging lineation indicative of west-directed thrusting. D2 comprises a colinear fold sequence that evolved from early intrafolial folds to late upright folds. D3 structures are associated with a high-strain zone, to the south of the Larsemann Hills, where S3 is the dominant gneissic layering and folds sequences resemble D2 folding. Outside the D3 high-strain zone occurs a low-strain D3 window, preserving low-strain D3 structures (minor shear bands and upright folds) that partly re-orient D2 structures. All structures are truncated by a series of planar pegmatites and parallel D4 mylonite zones, recording extensional dextral displacements.

D2 assemblages include coexisting garnet–orthopyroxene pairs recording peak conditions of ∼ 7 kbar and ∼ 780°C. Subsequent retrograde decompression textures partly evolved during both D2 and D3 when conditions of ∼ 4–5 kbar and ∼ 750°C were attained. This is followed by D4 shear zones which formed around 3 kbar and ∼ 550°C.

It is tempting to combine D2–4 structures in one tectonic cycle involving prograde thrusting and thickening followed by retrograde extension and uplift. The available geochronological data, however, present a number of interpretations. For example, D2 was possibly associated with a clockwise P–T path at medium pressures around ∼ 1000 Ma, by correlation with similar structures developed in the Rauer Group, whilst D3 and D4 events occurred in response to extension and heating at low pressures at ∼ 550 Ma, associated with the emplacement of numerous granitoid bodies. Thus, decompression textures typical for the Larsemann Hills granulites maybe the combined effect of two separate events.

Copyright

Corresponding author

1Corresponding author.

Footnotes

Hide All
2

Present address: Dept. of Geology, University of Zimbabwe, P.O. Box MP167, Harare, Zimbabwe.

3

Present address: Dept. of Geology and Geophysics, Adelaide University, Adelaide, S.A. 5005, Australia.

Footnotes

References

Hide All
Bhattacharya, A., Mohanty, L., Maji, A., Sen, S. K., & Raith, M., 1992. Non-ideal mixing in the phlogopiteannite binary: constraints from experimental data on Mg–Fe partitioning and a reformulation of the biotitegarnet geothermometer. Contributions to Minearology and Petrology 11, 387–94.
Black, L. P., Harley, S. L., Sun, S. S., & McCulloch, M. T., 1987. The Rayner complex of East Antarctica: complex isotopic systematics within a Proterozoic mobile belt. Journal of Metamorphic Geology 5, 126.
Carson, C. J., Hand, M., & Dirks, P. H. G. M., 1995. Stable coexistence of grandidierite and kornerupine during medium pressure granulite facies metamorphism. Mineralogical Magazine. In press.
Clarke, G. L., & Powell, R., 1991. Decompressional coronas and symplectites in granulites of the Musgrave Complex, central Australia. Journal of Metamorphic Geology 9, 441–50.
Dirks, P. H. G. M., Carson, C. J., & Wilson, C. J. L., 1993. The deformation history of the Larsemann Hills, Prydz Bay; the importance of the Pan-African (500 Ma) in East Antarctica. Antarctic Science 5, 179–92.
Dirks, P. H. G. M., & Hand, M., 1995. Clarifying temperature-pressure paths via structures in granulite from the Bolingen Islands, Antarctica. Australian Journal of Earth Sciences. In press.
Dirks, P. H. G. M., Hoek, J. D., Wilson, C. J. L., & Sims, J. P., 1993. The Proterozoic deformation of the Vestfold Hills, East Antarctica: implications for the tectonic development of adjacent granulite belts. Precambrian Research 65, 277–95.
Fitzsimons, I. C. W., & Harley, S. L., 1991. Geological relationships in high-grade gneiss of the Brattstrand Bluffs coastline, Prydz Bay, east Antarctica. Australian Journal of Earth Sciences 38, 497519.
Fitzsimons, I. C. W., & Harley, S. L., 1992. Mineral reaction textures in high-grade gneisses: evidence for contrasting pressure-temperature paths in the Proterozoic Complex of East Antarctica. In Recent Progress in Antarctic Earth Science (eds Yoshida, Y., Kaminuma, K. and Shiraishi, K.), pp. 103–11. Tokyo: Terra Scientific Publishing.
Ganguly, J., & Saxena, S. K., 1984. Mixing properties of aluminosilicate garnets: constraints from natural and experimental data and application to geothermobarometry. American Mineralogist 69, 8897.
Grant, J. A. 1985. Phase Equilibria In partial melting of pelitic rocks. In Migmatites (ed. Ashworth, J. R.), pp. 86144. London: Blackie.
Harley, S. L., 1984 a. The solubility of alumina in orthopyroxene coexisting with garnet in FeO–MgO–Al2O3–SiO2 and CaO–FeO–MgO–Al2O3–SiO2. Journal of Petrology 25, 665–96.
Harley, S. L., 1984 b. An experimental study of the partitioning of Fe and Mg between garnet and orthopyroxene. Contributions to Mineralogy and Petrology 86, 359–73.
Harley, S. L., 1987. Precambrian geological relationships in high-grade gneisses of the Rauer Islands, East Antarctica. Australian Journal of Earth Sciences 34, 175207.
Harley, S. L., 1988. Proterozoic granulites from the Rauer Group, East Antarctica. I. Decompressional pressuretemperature Paths deduced from mafic and felsic gneisses. Journal of Petrology 29, 1059–95.
Harley, S. L., & Fitzsimons, I. C. W., 1991. Pressure–temperature evolution of metapelitic granulites in a polymetamorphic terrane: The Rauer Group, East Antarctica. Journal of Metamorphic Geology 9, 231–43.
Harley, S. L., Fitzsimons, I. C. W., Buick, I. S., & Watt, G., 1992. The significance of reworking, fluids and partial melting in granulite metamorphism, East Prydz Bay, Antarctica. In Recent Progress in Antarctic Earth Science (ed. Yoshida, Y., Kaminuma, K., and Shiraishi, K.), pp. 103–11. Tokyo: Terra Scientific Publishing.
Harley, S. L., & Green, D. H., 1982. Garnet-orthopyroxene barometry for granulites and peridotites. Nature 300, 697701.
Hoek, J. D., Dirks, P. H. G. M., & Passchier, C. W., 1992. A late-Proterozoic extensional-compressional tectonic cycle in East Antarctica. In Recent Progress in Antarctic Earth Sciences (eds Y., Yoshida, K., Kaminuma, and K., Shiraishi), pp. 137–43. Tokyo: Terra Scientific Publishing.
Kinny, P. D., Black, L. P., & Sheraton, J. W., 1993. Zircon ages and the distribution of Archean and Proterozoic rocks in the Rauer Islands. Antarctic Science 5, 193206.
Kober, B., 1986. Whole-Grain Evaporation For 207Pb/206Pb age investigations on single zircons using a doublefilament thermal ion source. Contributions to Mineralogy and Petrology 93, 482–90.
Kober, B., 1987. Single-Zircon Evaporation Combined With Pb + emitter bedding for 207Pb/206Pb-age investigations using thermal ion mass spectrometry, and implications to zirconology. Contributions to Mineralogy and Petrology 96, 6371.
Lanyon, R., Black, L. P., & Seitz, H.-M., 1993. U–Pb zircon dating of mafic dykes and its application to the Proterozoic geological history of the Vestfold Hills, East Antarctica. Contributions to Mineralogy and Petrology 115, 184203.
Mezger, K., Essene, E. J., & Halliday, A. N., 1992. Closure temperatures of the Sm–Nd sysdtem in metamorphic garnets. Transactions of the American Geophysical Union EOS 73, 373.
Motoyoshi, Y., Thost, D. E., & Hensen, B. J., 1991. Reaction textures in calc-silicate granulites from the Bolinger Islands, Prydz Bay, Antarctica: implications for the retrograde P–T path. Journal of Metamorphic Geology 9, 293300.
Newton, R. C., & Perkins, D. III, 1982. Thermodynamic calibration of geobarometers based on the assemblages garnet-plagioclase-orthopyroxene (clinopyroxene)-quartz. American Mineralogist 67, 203–22.
Nicols, G. T., & Berry, R. F., 1991. A decompressional P—T path, Reinbolt Hills, East Antarctica. Journal of Metamorphic Geology 9, 257–66.
Platt, J. P., & Vissers, R. L., 1980. Extensional structures in anisotropic rocks. Journal of Structural Geology 2, 397410.
Powell, R., & Holland, T. J. B., 1994. Optimal geothermometry and geobarometry. American Mineralogist 79, 120–33.
Ren, L., Zhao, Y., Liu, X., & Chen, T., 1992. Re-examination of the metamorphic evolution of the Larsemann Hills, East Antarctica. In Recent Progress in Antarctic Earth Sciences (eds Yoshida, Y., Kaminuma, K. and Shiraishi, K.), pp. 145–53. Tokyo: Terra Scientific Publishing.
Sandiford, M., Martin, N., Zhou, S., & Fraser, G., 1991. Mechanical consequences of granite emplacement during high-T, low-P metamorphism and the origin of ‘anticlockwise’ P–T paths. Earth and Planetary Science Letters 107, 164–72.
Sen, S. K., & Bhattacharya, A., 1984. An orthopyroxenegarnet thermometer and its application to the Madras charnockites. Contributions to Mineralogy and Petrology 88, 6471.
Sheraton, J. W., Black, L. P., & McCulloch, M. T., 1984. Regional geochemical and isotopic characteristics of high-grade metamorphics of the Prydz Bay area: the extent of Proterzoic reworking of Archaean continental crust in East Antarctica. Precambrian Research 26, 169–98.
Sims, J. P., Dirks, P. H. G. M., Carson, C. J., & Wilson, C. J. L., 1994. The structural evolution of the Rauer Group, East Antarctica; mafic dykes as passive markers in a composite Proterzoic terrain. Antarctic Science 6, 379–94.
Stüwe, K., Braun, H. M., & Peer, H., 1989. Geology and s⃛ructure of the Larsemann Hills area, East Antarctica. Australian Journal of Earth Sciences 36, 219–41.
Stüwe, K., & Powell, R., 1989 a. Low pressure granulite facies metamorphism in the Larsemann Hills area, East Antarctica; petrology and tectonic implications for the Prydz Bay area. Journal of Metamorphic Geology 7, 465–84.
Stüwe, K., & Powell, R., 1989 b. Metamorphic segregations associated with garnet and orthopyroxene porphyroblast growth: two examples from the Larsemann Hills, East Antarctica. Contributions to Mineralogy and Petrology 103, 523–30.
Thost, D. E., Hensen, B. J., & Motoyoshi, Y., 1991. Two-stage decompression in garnet-bearing mafic granulites from Sostrene Island, Prydz Bay, East Antarctica. Journal of Metamorphic Geology 9, 293300.
Thost, D. E., Motoyoshi, Y., & Hensen, B. J., 1988. Low pressure granulite metamorphism in the Bolingen Islands, East Antarctica. Terra Cognita 8, 247.
Tingey, R. J., 1981. Geological investigations in Antarctica 1968–1969: the Prydz Bay—Amery ice Shelf—Prince Charles Mountains area. Bureau of Mineral Resources, Australia, Record, 1981/34.
Zhao, Y., Li, J., Liu, X., Song, B., Zhang, Z., Fu, Y., Chen, T., Wang, Y., Ren, L., & Yao, Y., 1993. Early Palaeozoic (Pan-African) thermal event of the Larsemann Hills and its neighbours, Prydz Bay, East Antarctica (abstr.). In The Tectonics of East Antarctica, Conference Abstracts, Utrecht, 1993.
Zhao, Y., Song, B., Wang, Y., Ren, L., Li, J., & Chen, T., 1992. Geochronology of the late granite in the Larsemann Hills, East Antarctica. In Recent Progress in Antarctic Earth Science (eds Yoshida, Y., Kaminuma, K., and Shiraishi, K.), pp. 155–61. Tokyo: Terra Scientific Publishing.

Compressional and extensional tectonics in low-medium pressure granulites from the Larsemann Hills, East Antarctica

  • C. J. Carson (a1), P. G. H. M. Dirks (a2), M. Hand (a1), J. P. Sims (a1) and C. J. L. Wilson (a1)...

Metrics

Altmetric attention score

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