Alpine Thermal and Structural Evolution of the Highest External Crystalline Massif: the Mont Blanc
TECTONICS, VOL. 24, TC4002, doi:10.1029/2004TC001676, 2005 Alpine thermal and structural evolution of the highest external crystalline massif: The Mont Blanc P. H. Leloup,1 N. Arnaud,2 E. R. Sobel,3 and R. Lacassin4 Received 5 May 2004; revised 14 October 2004; accepted 15 March 2005; published 1 July 2005. [1] The alpine structural evolution of the Mont Blanc, nappes and formed a backstop, inducing the formation highest point of the Alps (4810 m), and of the of the Jura arc. In that part of the external Alps, NW- surrounding area has been reexamined. The Mont SE shortening with minor dextral NE-SW motions Blanc and the Aiguilles Rouges external crystalline appears to have been continuous from 22 Ma until at massifs are windows of Variscan basement within the least 4 Ma but may be still active today. A sequential Penninic and Helvetic nappes. New structural, history of the alpine structural evolution of the units 40Ar/39Ar, and fission track data combined with a now outcropping NW of the Pennine thrust is compilation of earlier P-T estimates and geo- proposed. Citation: Leloup, P. H., N. Arnaud, E. R. Sobel, chronological data give constraints on the amount and R. Lacassin (2005), Alpine thermal and structural evolution of and timing of the Mont Blanc and Aiguilles Rouges the highest external crystalline massif: The Mont Blanc, massifs exhumation. Alpine exhumation of the Tectonics, 24, TC4002, doi:10.1029/2004TC001676. Aiguilles Rouges was limited to the thickness of the overlying nappes (10 km), while rocks now outcropping in the Mont Blanc have been exhumed 1.
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