Thermal evolution of oblique orogens: gneiss domes, core complexes, and wrench zones
and: Yo-yo tectonics
The Nigde Massif of the Central Anatolian Crystalline Complex provides a window into the mid-crust of a highly oblique orogenic system and permits reconstruction of the tectonic and thermal history of the upper 20 km of continental crust during oblique motion. What are the rates and styles of thermal and structural processes during oblique deformation at different crustal levels? How does the style and timing of deformation change from the mid- to upper crust in zones of oblique deformation? Since the petrologic study of the massif is largely complete, we can evaluate the structural history of the complex in the context of metamorphic pressure-temperature paths. As part of the broad goal of understanding oblique continental orogens, we are documenting characteristics and rates of deformation and metamorphism during highly oblique deformation and building a conceptual model for crustal thickening and extension leading to the development of metamorphic core complexes in zones of wrenching.
An interesting result of this work is the recognition that the Nigde Massif rocks have experienced at least two complete cycles of burial and exhumation (yo-yo tectonics), most likely related to evolving transpression and transtension along the adjacent Ecemis Fault segment of the Central Anatolian Fault Zone.
Pressure-time diagram for the tectonic evolution of the Nigde massif. Depth is inferred from thermobarometric data (burial #1) and estimates from thermochronometry data and typical geothermal gradients (burial #2). This figure is modified from one in a manuscript that has been in review for a remarkably long time, but that may one day be published. Some of the PTt data are published in the papers listed below.
Publications
Whitney, D.L., Umhoefer, P.J., Teyssier, C., and Fayon, A.K. (2008) Yo-yo tectonics of the Ni?de Massif during wrenching in central Anatolia. Turkish Journal of Earth Sciences, 17, 209-217.
Umhoefer, P.J., Whitney, D.L., Teyssier, C., Fayon, A.K., Casale, G., and Heizler, M.T. (2007) Yo-yo tectonics in a wrench zone, central Anatolia. In: Till, A., Roeske, S., Sample, J., and Foster, D. (eds.), Exhumation and Continental Strike-Slip Fault Systems, Geological Society of America Special Paper 434, 35-58.
Whitney, D. L., Teyssier, C., and Heizler, M.T. (2007) Gneiss domes, metamorphic core complexes, and wrench zones: Thermal and structural evolution of the Ni?de Massif, central Anatolia. Tectonics, 26, TC5002, doi:10.1029/2006TC002040.
Fayon, A.K. and Whitney, D.L. (2007) Tectonic vs. magmatic processes and the resetting of apatite fission track ages: an example from the Nigde Massif, Turkey. Tectonophysics, 434, 1-13. doi: 10/1016/j.tecto.2007.01.003
Whitney, D.L., Teyssier, C., Fayon, A.K., Hamilton, M.A., Heizler, M. (2003) Tectonic controls on metamorphism, partial melting, and intrusion: timing of regional metamorphism and magmatism of the Nigde Massif, Turkey. Tectonophysics, 376, 37-60.
Fayon, A.K., Whitney, D.L., Teyssier, C., Dilek, Y., and Garver, J.I. (2001) Effects of plate convergence angle on timing and mechanisms of exhumation. Earth and Planetary Science Letters, 192, 191-205.
Whitney, D.L., Teyssier, C., Dilek, Y., and Fayon, A.K. (2001) Metamorphism of the Central Anatolian Crystalline Complex, Turkey: influence of orogen-normal collision vs. wrench-dominated tectonics on P-T-t paths. Journal of Metamorphic Geology, 19, 411-432.
Dilek, Y., and Whitney, D.L. (2000) Cenozoic crustal evolution in central Anatolia: extension, magmatism, and landscape development. In: Panayides, I., Xenophontos, C., and Malpas, J. (eds). Proceedings of the Third International Conference on the Geology of the Eastern Mediterranean. Geological Survey Department, Nicosia, Cyprus, 183-192.
Whitney, D.L., and Dilek, Y. (2000) Andalusite-sillimanite-quartz veins as indicators of low-pressure - high-temperature deformation during late-stage unroofing of a metamorphic core complex, Turkey. Journal of Metamorphic Geology, 18, 59-66.
Dilek, Y., Whitney, D.L., and Tekeli, O. (1999) Links between neotectonic processes and landscape evolution in an Alpine collision zone, south-central Turkey. Geomorphology, 118, 147-164.
Whitney, D.L., and Dilek, Y. (1998) Metamorphism during crustal thickening and extension in central Anatolia: the Nigde metamorphic core complex. Journal of Petrology, 39, 1385-1403.
Whitney, D.L., and Dilek, Y. (1998) Characterization and interpretation of P-T paths with multiple thermal peaks. In: What Drives Metamorphism and Metamorphic Reactions:? (eds Treloar, P.J. & O'Brien, P.) Geological Society of London Special Publications, 138, 47-54.
Whitney, D.L., and Dilek, Y. (1997) Core complex development in central Anatolia. Geology, 25, 1023-1026.
View of eastern margin of the Nigde Massif showing the metamorphic sequence (white marble and darker schists on left side), a faulted unconformity, and the overlying sedimentary sequence (dipping layers). East of the massif and cover is the Ecemis fault corridor (valley), and the Aladag Mountains carbonate nappes.