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Present-day Uplift of the Western Alps

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Present-day Uplift of the Western Alps

J-M Nocquet et al. Sci Rep.

Abstract

Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes.

Figures

Figure 1
Figure 1. Location map and geodetic results.
(a) Location map. Colour indicates the topography averaged using a 25 km-width Gaussian filter. MB: Mont Blanc massif. V: Vanoise massif. P: Pelvoux massif. Q: Queyras massif. M: Mercantour massif. (b) GPS Horizontal GPS velocity field. Error ellipses are at the 95% confidence level. (c) Adjusted levelling rates. Data are decimated every 10 km. (d) GPS vertical velocities. Black lines indicate 1-σ uncertainties. Orange, red and purple bars indicate uplift and blue ones subsidence. Levelling and GPS data are with respect to the Alpine foreland as described in the main text. Figure created with GMT v. 5.1 (http://gmt.soest.hawaii.edu/).
Figure 2
Figure 2. Vertical rate maps and models predictions.
(a) Vertical rate map from levelling data. (b) Vertical rate map from GPS data. (c) Levelling-GPS combined map of vertical rate. (d) Predicted uplift-rate map from all GIA contributions. (e) Uplift-rate map predicted from the response to erosion. (f) Predicted uplift-rate map from the sum of GIA and erosion contributions. (g) Residual geodetic rates once corrected for GIA and erosion contributions. (h) Same as g in map view. (i) Seismotectonic stress tensors superimposed on Fig. 2c. Dashed line in panel h indicates the location of the profile shown in Fig. 3. Figure created with GMT v. 5.1 (http://gmt.soest.hawaii.edu/).
Figure 3
Figure 3. Cross-section of vertical rates and deep structure beneath the northwestern Alps.
Cross-section location is shown in Fig. 2h. (a) Uplift rates. Green and blue dots are levelling and GPS rates respectively, with error bars (95% confidence level) indicated by the thin black vertical lines. The pink-coloured fill shows the GPS-levelling combined uplift-rate profile from Fig. 2c. The yellow fill shows the summed prediction of GIA and erosion models from Fig. 2f. (b) Topography along the cross section averaged using a 50 km-width Gaussian filter. (c) Upper mantle tomographic model from ref. . Figure created using Matplotlib v. 1.4 (http://matplotlib.org).

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References

    1. Tapponnier P. Evolution tectonique du systeme alpine en Mediterranee: Poincement et ecrasement rigide-plastique. Bull. Soc. Geol. Fr. 7, 437–460 (1977).
    1. Ménard G. & Molnar P. Budget of crustal shortening and subduction of continental crust in the Alps. Tectonophysics 10, 231–244 (1991).
    1. Schmid S. M. & Kissling E. The arc of the western Alps in the light of geophysical data on deep crustal structure. Tectonics 19, 62 (2000).
    1. Wortel M. J. & Spakman W. Subduction and slab detachment in the Mediterranean-Carpathian region. Science 290, 1910–1917 (2000). - PubMed
    1. Nocquet J.-M. & Calais E. Geodetic Measurements of Crustal Deformation in the Western Mediterranean and Europe. Pure Appl. Geophys. 161, 661–681 (2004).

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