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Willingshofer et al. 1999
Willingshofer, E., van Wees, J.D., Cloetingh, S.A.P.L. and Neubauer, F. (1999). Thermomechanical consequences of Cretaceous continent-continent collision in the eastern Alps (Austria): Insights from two-dimensional modeling. Tectonics 18: doi: 10.1029/1999TC900017. issn: 0278-7407.

We use two-dimensional numerical modeling techniques to investigate the thermomechanical consequences of closure of the Meliata-Hallstatt ocean and consequent Cretaceous continent-continent collision in the eastern Alps (Austria). In the modeling a lower plate position of the Austro-Alpine (AA) continental block is adopted during collision with the Upper Juvavic-Silice block. The thermal structure of the lithosphere was calculated for major AA tectonic units (Upper, Middle, and Lower Austro-Alpine) by integration of the transient heat flow equation along an approximately NW-SE cross section east of the Tauern Window. Indications of the rheological evolution of the AA were determined by calculating strength profiles at key stages of the Cretaceous orogeny, making use of the thermal modeling predictions combined with rock mechanics data. Cooling in the upper plate and lower greenschist facies metamorphism within footwall parts of the lower Upper Austro-Alpine (UA) plate, related to SE directed underthrusting of the UA beneath the Upper Juvavic-Silice block at circa 100 Ma, were predicted by the numerical model. The observed pressure-temperature path for deeply buried Middle Austro-Alpine (MA) upper crustal units and their subsequent isothermal exhumation are best reproduced assuming a pressure peak at 95 Ma and exhumation rates ranging between 4 and 7.5 mm yr-1. From the modeling results, we deduce that the temperature evolution during eclogite exhumation is primarily dependent on rates of tectonic movements and largely independent of the mode of exhumation (thrusting versus erosion). Furthermore, very rapid postmetamorphic exhumation of southern Lower Austro-Alpine (LA) units is predicted in order to account for subsequent cooling. This is constrained by 40Ar/39Ar data. The cooling paths of MA and LA rocks appear to be primarily controlled by their near-surface positions at the end of the Cretaceous rather than by other processes such as concurrent underthrusting. Upward advection of heat by rapid exhumation induced thermal weakening of the thickened crust. The inferred weakness of the central parts of the orogenic system may play an important role during detachment-related tectonic unroofing, orogenic collapse, and concomitant basin formation (central Alpine Gosau basins). ¿ 1999 American Geophysical Union

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Tectonics
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American Geophysical Union
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