Abstract
We investigate the exhumation of ultrahigh pressure (UHP) and high-pressure (HP) rocks in the framework of a dynamic simulation that considers heat advection, heat conduction, heat production, and consequent time-dependent changes in the geothermal gradient. In the absence of lateral heating, rocks exhuming from great depth cool or decompress isothermally and the main cooling period follows the main period of exhumation. Even for a constant exhumation rate, UHP rocks undergo a two-stage cooling history at the end of which the pressure-temperature (P-T) paths of all rocks approach a steady state or “final” geotherm at crustal levels; the shape of the steady-state or final geotherm is mainly a function of exhumation rate. Reconstruction of pressure-temperature-time (P-T-t) paths permits a qualitative distinction between “fast” and “slow” UHP exhumation: fast exhumation is characterized by extremely rapid crustal cooling following small temperature increases or isothermal decompression, whereas slow exhumation is characterized by steady cooling following more modest heating. Rocks exhuming from different depths (e.g., crustal and mantle levels) follow substantially different PT paths (e.g., heating and cooling during decompression), even if all rocks in an orogen are exhumed by the same orogen-scale process.
P-T paths of UHP rocks of the Qinling-Dabie-Hong’an area of central China are consonant with our modeling in that the rocks exhumed from the greatest depth show nearly isothermal decompression, whereas more modestly buried rocks underwent heating during exhumation. The shapes of the P-T-t paths suggest an exhumation rate closer to 5 mm/a rather than 1 mm/a, and the apparent two-stage cooling history often interpreted for the Dabie area could have been produced by a single-stage, constant exhumation rate.
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References
Ames, L., Zhou, G., and Xiong, B. (1996) Geochronology and geochemistry of ultrahigh-pressure metamorphism with implications for collision of the Sino-Korean and Yangtze cratons, central China, Tectonics 15, 472–489.
Anderson, R.N., Delong, S.E., and Schwarz, W.M. (1978) Thermal model for subduction with dehydration in the downgoing slab, Journal of Geology 86, 731–739.
Andrews, D.J. and Sleep, N.H. (1974) Numerical modelling of tectonic flow behind island arcs, Geophysical Journal of the Royal Astronomical Society 38, 237–251.
Avigad, D. and Garfunkel, Z. (1991) Uplift and exhumation of high-pressure metamorphic terrains: the example of the Cycladic blueshist belt (Aegean Sea), Tectonophysics 187, 1–15.
Benfield, A.E. (1949) A problem of the temperature distribution in a moving medium, Quarterly of Applied Mathematics 6, 439–443.
Blythe, A.E. (this volume) Active tectonics and ultrahigh-pressure rocks, in B.R. Hacker and J.G. Liou (eds.), When Continents Collide: Geodynamics and Geochemistry of Ultrahigh-Pressure Rocks, Kluwer Academic Publishers, Dordrecht.
Burg, J.P., Davy, P., Nievergelt, P., Oberli, F., Seward, D., Diao, Z., and Meier, M. (1997) Exhumation during crustal folding in the Namche-Barwa syntaxis, Terra Nova 9, 53–56.
Carslaw, S. and Jaeger, J.C. (1959) Conduction of Heat in Solids, Oxford University Press, New York.
Chemenda, A.I., Mattauer, M., and Bokun, A.N. (1996) Continental subduction and a mechanism for exhumation of high-pressure metamorphic rocks: new modeling and field data from Oman, Earth and Planetary Science Letters 143, 173–182.
Chopin, C., Henry, C., and Michard, A. (1991) Geology and petrology of the coesite-bearing terrain, Dora Maira massif, western Alps, European Journal of Mineralogy 3, 263–291.
Cloos, M. (1982) Flow melanges: numerical modeling and geologic constraints on their origin in the Franciscan subduction complex, Geological Society of America Bulletin 93, 330–345.
Cloos, M. (1993) Lithospheric buoyancy and collisional orogenesis: subduction of oceanic plateaus, continental margins, island arcs, spreading ridges, and seamounts, Geological Society of America Bulletin 105, 715–737.
Craw, D., Koons, P.O., Winslow, D., Chamberlain, C.P., and Zeitler, P. (1994) Boiling fluids in a region of rapid uplift, Nanga Parbat massif, Pakistan, Earth and Planetary Science Letters 128, 169–182.
Davies, J.H. and von Blanckenburg, F. (1995) Slab breakoff: a model of lithosphere detachment and its test in the magmatism and deformation of collisional orogens, Earth and Planetary Science Letters 129, 85–102.
Draper, G. and Bone, R. (1981) Denudation rates, thermal evolution, and preservation of blueschist terrains, Journal of Geology 89, 601–613.
Eide, E.A. (1993) Petrology, geochronology, and structure of high-pressure metamorphic rocks in Hubei province, east-central China, and their relationship to continental collision. Stanford, p. 235. Stanford University, California.
Eide, L., McWilliams, M.O., and Liou, J.G. (1994) 40Ar/39Ar geochronologic constraints on the exhumation of HP-UHP metamorphic rocks in east-central China, Geology 22, 601–604.
England, P. and Molnar, P. (1990) Surface uplift, uplift of rocks, and exhumation of rocks, Geology 18, 1173–1177.
England, P.C. and Richardson, S.W. (1977) The influence of erosion upon the mineral facies of rocks from different metamorphic environments, Journal of the Geological Society of London 134, 201–213.
England, P.C. and Thompson, A.B. (1984) Pressure-temperature-time paths of regional metamorphism; I, Heat transfer during the evolution of regions of thickened continental crust, Journal of Petrology 25, 894–928.
Ernst, W.G. (1988) Tectonic history of subduction zones inferred from retrograde blueshist P-T paths, Geology 16, 1081–1085.
Ernst, W.G. and Peacock, S.M. (1996) A thermotectonic model for preservation of ultrahighpressure phases in metamorphosed continental crust, in G.E. Bebout, D.W. Scholl, S.H. Kirby, and J.P. Platt (eds.), Subduction Top to Bottom, American Geophysical Union, Washington, D.C., pp. 171–178.
Hacker, B.R. and Peacock, S.M. (1994) Creation, preservation, and exhumation of coesite-bearing, ultrahigh-pressure metamorphic rocks, in R.G. Coleman and X. Wang (eds.), Ultrahigh Pressure Metamorphism, Cambridge University Press, Cambridge, United Kingdom.
Hacker, B.R., Ratschbacher, L., Webb, L., and Dong, S. (1995) What brought them up? Exhumation of the Dabie Shan ultrahigh-pressure rocks, Geology 23, 743–746.
Hacker, B.R., Ratschbacher, L., Webb, L., Ireland, T., Walker, D., and Dong, S. (in press) U/Pb zircon ages constrain the architecture of the ultrahigh-pressure Qinling-Dabie Orogen, China, Earth and Planetary Science Letters.
Hacker, B.R. and Wang, Q.C. (1995) Ar/Ar geochronology of ultrahigh-pressure metamorphism in central China, Tectonics 14, 994–1006.
Henry, C., Michard, A., and Chopin, C. (1993) Geometry and structural evolution of ultra-highpressure and high-pressure rocks from the Dora-Maira Massif, Western Alps, Italy, Journal of Structural Geology 15, 965–981.
Hovius, N., Stark, C.P., and Allen, P.A. (1997) Sediment flux from a mountain belt derived by landslide mapping, Geology 25, 231–234.
Hsui, A.T. and Toksöz, M.N. (1979) The evolution of thermal structures beneath a subduction zone, Tectonophysics 60, 337–349.
Liou, J.G., Zhang, R.Y., Eide, E.A., Maruyama, S., Wang, X., and Ernst, W.G. (1996) Metamorphism and tectonics of high-P and ultrahigh-P belts in Dabie-Sulu Regions, eastern central China, in A. Yin and T.M. Harrison (eds.), The Tectonic Evolution of Asia, Rubey Volume IX, Cambridge University Press, Cambridge, United Kingdom, pp. 300–343.
Mancktelow, N.S. and Grasemann, B. (1997) Time-dependent effects of heat advection and topography on cooling histories during erosion, Tectonophysics 270, 167–195.
Michard, A., Chopin, C., and Hemy, C. (1993) Compression versus extension in the exhumation of the Dora-Maira coesite-bearing unit, Western Alps, Italy, Tectonophysics 221, 173–193.
Minear, J.W. and Toksöz, M.N. (1970) Thermal regime of a downgoing slab and new global tectonics, Journal of Geophysical Research 75, 1397–1419.
Molnar, P. and Gray, D. (1979) Subduction of continental lithosphere: some constraints and uncertainties, Geology 7, 58–62.
Nie, S., Yin, A., Rowley, D.B., and Jin, Y. (1994) Exhumation of the Dabie Shan ultrahighpressure rocks and accumulation of the Songpan-Ganzi flysch sequence, central China, Geology 22, 999–1002.
Okay, A.I. (1993) Petrology of a diamond and coesite-bearing metamorphic terrain: Dabie Shan, China, European Journal of Mineralogy 5, 659–675.
Peaceman, D.W. and Rachford, H.H. (1955) The numerical solution of parabolic and elliptic differential equations, Journal of the Indian Mathematical Society 3, 28–41.
Peacock, S.M. (1990) Numerical simulation of metamorphic pressure-temperature-time paths and fluid production in subducting slabs, Tectonics 9, 1197.
Peacock, S.M. (1996) Thermal and petrologic structure of subduction zones, in G.E. Bebout, D.W. Scholl, S.H. Kirby, and J.P. Platt (eds.), Subduction Top to Bottom, American Geophysical Union, Washington, D.C., pp. 119–134.
Peacock, S.M., Rushmer, T., and Thompson, A.B. (1994) Partial melting of subducting oceanic crust, Earth and Planetary Science Letters 121, 227–244.
Platt, J.P. (1987) The uplift of high-pressure low-temperature metamorphic rocks, Philosophical Transactions of the Royal Society of London A321, 87–l 03.
Rowley, D.B., Xue, F., Tucker, R.D., Peng, Z.X., Baker, J., and Davis, A. (1997) Ages of ultrahigh pressure metamorphism and protolith orthogneisses from the eastern Dabie Shan: U/Pb zircon geochronology, Earth and Planetary Science Letters 151, 191–203.
Rubie, D.C. (1984) A thermal-tectonic model for high-pressure metamorphism and deformation in the Sesia Zone, western Alps, Journal of Geology 92, 21–36.
Ruppel, C. and Hodges, K.V. (1994) Pressure-temperature-time paths from two-dimensional thermal models: prograde, retrograde, and inverted metamorphism, Tectonics 13, 17–44.
Sandiford, M. and Dymoke, P. (1991) Some remarks on the stability of blueschists and related high P — low T assemblages in continental orogens, Earth and Planetary Science Letters 102, 14–23.
Schmaedicke, E., Okrusch, M., and Schmidt, W. (1992) Eclogite-facies rocks in the Saxonian Erzgebirge, Germany; high pressure metamorphism under contrasting P-T conditions, Contributions to Mineralogy and Petrology 110, 226–241.
Spear, F.S., Selverstone, J., Hickmott, D., Crowley, P., and Hodges, K.V. (1984) P-T paths from garnet zoning: A new technique for deciphering tectonic processes in crystalline terranes, Geology 12, 87–90.
Stüwe, K. and Sandiford, M. (1995) Mantle-lithospheric deformation and crustal metamorphism with some speculations on the thermal and mechanical significance of the Tauern Event, Eastern Alps, Tectonophysics 242, 115–132.
Thompson, A.B. and England, P.C. (1984) Pressure-temperature-time paths of regional metamorphism II. Their inference and interpretation using mineral assemblages in metamorphic rocks, Journal of Petrology 25, 929–955.
Thompson, A.B., Schulmann, K., and Jezek, J. (1997) Extrusion tectonics and elevation of lower crustal metamorphic rocks in convergent orogens, Geology 25, 491–494.
van den Beukel, J. and Wortel, R. (1988) Thermo-mechanical modelling of arc-trench regions, Tectonophysics 154, 177–193.
Zhang, R.Y., Liou, J.G., and Cong, B. (1994) Petrogenesis of garnet-bearing ultramafic rocks and associated eclogites in the Su-Lu ultrahigh-P metamorphic terrane, eastern China, Journal of Metamorphic Geology 12, 169–186.
Zhang, R.Y., Liou, J.G., Ernst, W.G., Coleman, R.G., Sobolev, N.V., and Shatsky, V.S. (1997) Metamorphic evolution of diamond-bearing and associated rocks from the Kokchetav massif, northern Kazakhstan, Journal of Metamorphic Geology 15, 479–496.
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Grasemann, B., Ratschbacher, L., Hacker, B.R. (1998). Exhumation of Ultrahigh-Pressure Rocks: Thermal Boundary Conditions and Cooling History. In: Hacker, B.R., Liou, J.G. (eds) When Continents Collide: Geodynamics and Geochemistry of Ultrahigh-Pressure Rocks. Petrology and Structural Geology, vol 10. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9050-1_5
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DOI: https://doi.org/10.1007/978-94-015-9050-1_5
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