Dating bedrock gorge incision in the French Western Alps (Ecrins-Pelvoux massif) using cosmogenic 10 Be
2009; Wiley; Volume: 22; Issue: 1 Linguagem: Inglês
10.1111/j.1365-3121.2009.00911.x
ISSN1365-3121
AutoresPierre G. Valla, Peter van der Beek, Julien Carcaillet,
Tópico(s)Landslides and related hazards
ResumoTerra NovaVolume 22, Issue 1 p. 18-25 Free Access Dating bedrock gorge incision in the French Western Alps (Ecrins-Pelvoux massif) using cosmogenic 10Be Pierre G. Valla, Pierre G. Valla Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this authorPeter A. Van Der Beek, Peter A. Van Der Beek Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this authorJulien Carcaillet, Julien Carcaillet Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this author Pierre G. Valla, Pierre G. Valla Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this authorPeter A. Van Der Beek, Peter A. Van Der Beek Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this authorJulien Carcaillet, Julien Carcaillet Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, FranceSearch for more papers by this author First published: 04 January 2010 https://doi.org/10.1111/j.1365-3121.2009.00911.xCitations: 38 P. G. Valla, Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier, BP 53, 38041 Grenoble, France. Tel.: +33 476 63 54 64; fax: +33 476 51 40 58; e-mail: pierre.valla@e.ujf-grenoble.fr AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Terra Nova, 22, 18–25, 2010 Abstract We report in-situ produced 10Be data from the Gorge du Diable (French Western Alps) to date and quantify bedrock gorge incision into a glacial hanging valley. We sampled gorge sidewalls and the active channel bed to derive both long-term and present-day incision rates. 10Be ages of sidewall profiles reveal rapid incision through the late Holocene (ca 5 ka) at rates ranging from 6.5 to 13 mm yr−1. Present-day incision rates are significantly lower and vary from 0.5 to 3 mm yr−1 within the gorge. Our data imply either delayed initiation of gorge incision after final ice retreat from internal Alpine valleys at ca 12 ka, or post-glacial surface reburial of the gorge. Our results suggest that fluvial incision rates >1 cm yr−1 into crystalline bedrock may be encountered in transient landscape features induced by glacial-interglacial transitions. Introduction Present-day landscapes result from the integrated effect of past and current geomorphic processes and are generally in a transient state, as opposed to the ideal 'steady state' (e.g. Whipple, 2001) in which surface processes have reached an equilibrium with respect to tectonic and climate forcing. Quaternary climate cooling (e.g. Raymo, 1994) and fluctuations between glacial and interglacial periods have led to significant landscape changes governed by both glacial and fluvial processes, the relative efficiencies of which are currently poorly quantified (e.g. Whipple et al., 1999; Brocklehurst and Whipple, 2002; Montgomery, 2002). In mountainous regions, the conjunctive occurrence of both glacial features that were formed during glaciations and fluvial markers of post-glacial processes raises the question of the landscape response time to climate oscillations. Studies of late Quaternary valley fills (e.g. Hinderer, 2001) or post-glacial fluvial incision rates (Brocard et al., 2003) imply that relief rejuvenation has been significant since the last glaciation. In this context, inner gorges (Korup and Schlunegger, 2007) or smaller bedrock gorges incising glacial valleys (Montjuvent, 1978) can be used as markers of fluvial incision in relief development. Such gorges have commonly been interpreted as transient features (Schlunegger and Schneider, 2005), but their origin and evolution remain debated. One of the major questions concerns the origin and persistence of such gorges throughout Quaternary times (Korup and Schlunegger, 2007). One hypothesis argues that bedrock gorges are post-glacial features and their incision started after the last glacier retreat. An alternative hypothesis suggests that gorges are much older landscape elements and that their incision was initiated at the onset of the Quaternary glacial-interglacial cycles (e.g. Montjuvent, 1978). Assuming a postglacial origin of these gorges implies long-term gorge incision rates of several mm to cm yr−1 through crystalline bedrock (e.g. Korup and Schlunegger, 2007; Valla et al., in press). Such high rates may be realistic in a context of landscape rejuvenation in response to deglaciation (Hinderer, 2001); however, an older origin of bedrock gorges cannot be excluded and absolute dating of gorge deepening is needed to resolve this debate. Here, we report in-situ produced 10Be data to date the incision of a bedrock gorge (Gorge du Diable, Ecrins-Pelvoux massif, French western Alps; Fig. 1). We collected samples both on vertical gorge sidewalls and along the present-day active channel (Fig. 2). We selected the Diable stream because it presents one of the few gorges in the area allowing direct access to gorge sidewalls and to the active channel. Moreover, the initial glacial valley can be relatively precisely reconstructed (Valla et al., in press). Cosmic ray exposure (CRE) ages for vertical profiles provide insights into long-term gorge incision (Schaller et al., 2005; Ouimet et al., 2008), which can be compared with present-day incision rates calculated from samples collected along the active channel (Seidl et al., 1997; Weissel and Seidl, 1998). We discuss our results on long-term and present-day incision rates of bedrock gorges in terms of their implications for relief inheritance, rejuvenation and landscape response time. Figure 1Open in figure viewerPowerPoint Digital Elevation Model (Institut Geographique National, 50 m resolution) of the study area, showing major summits (La Meije: 3983 m; Barre des Ecrins: 4102 m) and valleys (Romanche and Vénéon). Box indicates location of Fig. 2a. Eastings and northings are WGS 84 longitude and latitude, in degrees. Inset shows location within France. Figure 2Open in figure viewerPowerPoint Aerial photograph and longitudinal profile of the Diable stream showing sampling sites. (a) Aerial photograph (Institut Geographique National) of the lower Diable catchment with sampling locations; black box indicates location of Fig. 5d. (b) Diable stream profile (open circles and dashed curve). Inset shows zoom on the gorge reach with locations of the two vertical profiles (P1, P2; red stars) and active bed sampling sites (B1, B2 and B3; yellow stars). See text and Fig. 3 for details. Geological and geomorphic setting The Ecrins-Pelvoux massif is one of the 'External Crystalline Massifs' (ECM) of the Western Alps. It consists of blocks of European crystalline basement that were exhumed along crustal-scale faults (Ford, 1996; Dumont et al., 2008) and are separated by remnants of inverted Jurassic extensional basins. Present-day rock-uplift rates in the Western Alps show local maxima within the ECM, reaching up to 1 mm yr−1 (Jouanne et al., 1995; Kähle et al., 1997). It has been argued that a significant part of the present-day rock-uplift signal may be attributable to isostatic rebound induced by deglaciation (Gudmundsson, 1994) and/or increased erosion rates during Pliocene-Quaternary times (Cederbom et al., 2004; Champagnac et al., 2007, 2009). The Ecrins-Pelvoux massif comprises high alpine relief, with several peaks around 4000 m and valley bottoms at ∼1000 m. The massif was extensively glaciated during Quaternary times. Major valleys were occupied by large valley glaciers, which have widened and overdeepened them (Montjuvent, 1974, 1978; van der Beek and Bourbon, 2008). Glacial overdeepenings such as the Bourg d'Oisans trough (Fig. 1) were subsequently filled by late-glacial and post-glacial lake sediments (Hinderer, 2001; Nicoud et al., 2002) and present-day longitudinal valley profiles show a succession of characteristic valley steps and flats (Montjuvent, 1974, 1978). Glacial hanging valleys occur at tributary junctions with the trunk valley (e.g. Anderson et al., 2006) and their terminations are commonly marked by waterfalls or bedrock gorges that indicate substantial incision. Gorges present highly incised, narrow and steep bedrock channels with dominant step-pool and boulder-cascade bed morphologies. The present-day active channels display fluvial abrasion features (Fig. 3c), such as smooth and polished bedrock surfaces, ripples and potholes (e.g. Whipple et al., 2000a). Metre-scale blocks derived from the gorge sidewalls (Fig. 5a) or surrounding hillslopes are frequent and suggest important hillslope-channel coupling (Korup and Schlunegger, 2007; Valla et al., in press). Figure 3Open in figure viewerPowerPoint Field photographs showing bedrock gorge morphologies and sampling strategy. (a) View of the Gorge du Diable at sampling site P1. (b) Schematic sketch illustrating Diable stream, gorge sidewalls (black crosses and grey dashes), active channel and sediments, and sampling sites along the gorge sidewall (red stars). (c) Abrasion forms of the active channel at sampling site B1 (yellow star). (d) Sampling along gorge sidewall at site P2 (sampling sites indicated by red stars). Figure 5Open in figure viewerPowerPoint Field photographs showing geomorphic configuration of the gorge. (a) View of active channel at sampling site P2 showing metre-scale blocks derived from both surrounding topography and gorge sidewalls. (b) Profile P2 showing potential rock-fall scar (red star corresponds to VAV-04 sample). (c) Planar surface at sampling site B3 (yellow star) above a pool. (d) Photograph of surrounding topography close to the gorge (<100 m, see Fig. 2a for location) showing a high rock cliff and scree-slope deposits resulting from abundant rock-fall events. Sampling methodology and preparation We have sampled active channel sites located both upstream from and within the gorge (B1, B2 and B3, Fig. 2b), choosing well-developed and polished abrasion forms (Fig. 3c) as targets to ensure that our samples record present-day stream incision with minimum passive exposure. As we are unable to estimate the thickness and duration of temporary sediment cover in the active channel, we assume permanent bedrock exposure to fluvial incision when calculating erosion rates. Vertical profiles along gorge sidewalls were chosen in the upper gorge reach (P1, Fig. 3a,b) and just upstream of the confluence with the Vénéon trunk valley (P2, Fig. 3d). We collected 4–5 samples along ∼30 m of wall profiles (Fig. 3b,d). Abraded and polished surfaces along gorge sidewalls suggest that they have not experienced subsequent erosion and allow calculating minimum CRE ages. Samples collected at the bottom of our profiles (VAM-01 and VAV-01; Table 1) have been used to derive both erosion rates and apparent exposure ages. Table 1. Cosmogenic nuclide data. Sample – Elevation (m) WGS 84 Latitude (°N) WGS 84 Longitude (°E) Height above present day river bed (m) Surface production rate* Geomorphic scaling factor† Corrected production rate‡ 10Be concentration (103) atoms g−1 quartz§ Exposure ages (10Be-ka) Present-day estimated erosion rates (mm yr−1) Value Uncertainty Value Uncertainty Value Uncertainty Site P1 (1630 m) 44°57′50″/6°10′40″ VAM-01 0 17.15 0.56 ± 0.08 9.18 ± 1.33 3.04 0.73 0.33 0.10 2.81 0.91 VAM-02 8.5 17.15 0.63 ± 0.07 10.42 ± 1.14 8.84 2.01 0.85 0.22 – – VAM-03 13.5 17.15 0.72 ± 0.06 11.92 ± 1.03 17.16 3.77 1.44 0.35 – – VAM-04 20.5 17.15 0.75 ± 0.06 12.43 ± 1.01 39.47 7.89 3.18 0.72 – – Site P2 (1390 m) 44°57′28″/6°10′22″ VAV-01 0 14.31 0.38 ± 0.08 5.35 ± 1.09 1.94 0.47 0.36 0.12 3.07 0.89 VAV-02 6.5 14.31 0.28 ± 0.07 3.90 ± 0.97 5.51 1.28 1.41 0.49 – – VAV-03 14 14.31 0.39 ± 0.07 5.51 ± 1.01 4.41 0.99 0.80 0.24 – – VAV-04 20 14.31 0.58 ± 0.06 8.12 ± 0.78 7.16 1.72 0.88 0.24 – – VAV-05 28 14.31 0.92 ± 0.04 12.88 ± 0.58 50.58 10.01 3.93 0.84 – – Site B1 (1640 m) 44°57′55″/6°10′44″ 0 17.28 0.67 ± 0.09 11.12 ± 1.43 16.58 5.43 – – 0.68 0.24 Site B2 (1450 m) 44°57′36″/6°10′25″ 0 14.99 0.23 ± 0.07 3.26 ± 1.04 3.59 0.78 – – 0.92 0.36 Site B3 (1400 m) 44°57′29″/6°10′22″ 0 14.40 0.35 ± 0.08 4.87 ± 1.15 10.39 2.93 – – 0.47 0.18 *Surface production rates (atoms g−1quartz yr−1) scaled for latitudinal and altitudinal effects from Stone (2000). †Geomorphic scaling factors have been calculated following the method of Dunne et al. (1999) with a ±5° uncertainty to our geomorphic shielding measurements. ‡Sample production rate (atoms g−1quartz yr−1) corrected for sample location within the gorge (geomorphic scaling factor) and sample thickness. §Analytical uncertainties are based on counting statistics, a conservative estimate of 3% instrumental variability and a ∼20% uncertainty in the chemical blank correction. Extraction of in-situ produced 10Be followed procedures described by Brown et al. (1991). Measurements were performed at the ASTER AMS Facility in Aix-en-Provence, France. The data were calibrated directly against NIST standard reference material 4325 using a 10Be/9Be ratio of 2.79 ± 0.03 × 10−11 and 10Be half-life (T1/2) of 1.36 ± 0.07 × 106 years, as recently determined by Nishiizumi et al. (2007). 10Be production rates were calculated with a modern high-latitude sea-level value of 4.5 ± 0.3 atoms g−1(quartz) yr−1 (Balco et al., 2008). For each sample, we adjusted production rates for latitude and elevation using the Stone (2000) polynomials, took in account cosmic-ray attenuation induced by sample thickness ( 1 cm yr−1, in agreement with morphometric (Korup and Schlunegger, 2007) and numerical modelling (Valla et al., in press) studies. We infer that bedrock gorges incising glacial hanging valleys respond rapidly to glacial-interglacial cycles and can be used as markers of recent post-glacial processes. Although this study focuses on a single bedrock gorge and other gorges should be investigated to produce more data and better understand the post-glacial evolution of these transient features, our first results show that the Gorge du Diable is post-glacial in origin and that high incision rates of up to cm yr−1 may occur locally in transient landscapes. Acknowledgements This study is part of PV's PhD project at Université Joseph Fourier in the framework of the ERD-Alps project funded by the Agence Nationale de la Recherche (project No. ANR-08-BLAN-0303-01 awarded to PvdB). We thank R. Delunel and X. Robert for invaluable field assistance and R. Braucher for help during sample preparation. The staff member of the ASTER AMS facility is acknowledged for technical assistance during 10Be measurements. We thank reviewers Stefano Andreucci, Jo De Waele and Fritz Schlunegger and associate editor Vincenzo Pascucci for constructive reviews that helped to improve the manuscript. References Anderson, R.S., Molnar, P. and Kessler, M.A., 2006. Features of glacial valley profiles simply explained. J. Geophys. Res., 111, 10. 1029/2005JF000344. Wiley Online LibraryWeb of Science®Google Scholar Balco, G., Stone, J.O., Lifton, N.A. and Dunai, T.J., 2008. A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements. Quat. Geochronol., 3, 174– 195. CrossrefWeb of Science®Google Scholar Van Der Beek, P. and Bourbon, P., 2008. A quantification of the glacial imprint on relief development in the French Western Alps. Geomorphology, 97, 52– 72. CrossrefWeb of Science®Google Scholar Brocard, G.Y., Van Der Beek, P.A., Bourles, D.L., Siame, L.L. and Mugnier, J.-L., 2003. Long-term fluvial incision rates and postglacial river relaxation time in the French Western Alps from 10Be dating of alluvial terraces with assessment of inheritance, soil development and wind ablation effects. Earth Planet. Sci. Lett., 209, 197– 214. CrossrefCASWeb of Science®Google Scholar Brocklehurst, S.H. and Whipple, K.X., 2002. Glacial erosion and relief production in the Eastern Sierra Nevada, California. Geomorphology, 42, 1– 24. CrossrefWeb of Science®Google Scholar Brown, E.T., Edmond, J.M., Raisbeck, G.M., Yiou, F., Kurz, M.D. and Brook, E.J., 1991. Examination of surface exposure ages of moraines in Arena Valley, Antarctica, using in situ produced 10Be and 26Al. Geochim. Cosmochim. Acta, 55, 2269– 2283. CrossrefCASWeb of Science®Google Scholar Cederbom, C.E., Sinclair, H.D., Schlunegger, F. and Rahn, M., 2004. Climate-induced rebound and exhumation of the European Alps. Geology, 32, 709– 712. CrossrefWeb of Science®Google Scholar Champagnac, J.-D., Molnar, P., Anderson, R.S., Sue, C. and Delacou, B., 2007. Quaternary erosion-induced isostatic rebound in the western Alps. Geology, 35, 195– 198. CrossrefWeb of Science®Google Scholar Champagnac, J.-D., Schlunegger, F., Norton, K., Van Blanckenburg, F., Abbühl, L.M. and Schwab, M., 2009. Erosion-driven uplift of the modern Central Alps. Tectonophysics, 474, 236– 249. CrossrefWeb of Science®Google Scholar Delunel, R., Van Der Beek, P.A., Bourlès, D.L. and Carcaillet, J., 2008. Frost-shattering processes increase denudation at catchment scales: results from in-situ produced 10Be measurement in stream sediments (French Western Alps). Eos Trans. AGU, 89, H54D-04 . Fall Meet. Suppl., Abstract. Google Scholar Dumont, T., Champagnac, J.-D., Crouzet, C. and Rochat, P., 2008. Multistage Alpine shortening in Central Dauphiné (French Western Alps): the record of Alpine collision and implications for pre-Alpine restoration. Swiss Journal of Geosciences, 101, 1661– 8726. CrossrefWeb of Science®Google Scholar Dunne, A., Elmore, D. and Muzikar, P., 1999. Scaling of cosmogenic nuclide production rates for geometric shielding and attenuation at depth on sloped surface. Geomorphology, 27, 3– 11. CrossrefWeb of Science®Google Scholar Ford, M., 1996. Kinematics and geometry of early Alpine, basement involved folds, SW Pelvoux Massif, SE France. Eclogae Geol. Helv., 89, 269– 295. Web of Science®Google Scholar Gudmundsson, G.H., 1994. An order of magnitude estimate of the current uplift rates in Switzerland caused by the Würm alpine deglaciation. Eclogae Geol. Helv., 87, 545– 557. Web of Science®Google Scholar Hinderer, M., 2001. Late Quaternary denudation of the Alps; valley and lake fillings and modern river loads. Geodin. Acta, 14, 231– 263. CrossrefWeb of Science®Google Scholar Ivy-Ochs, S., Schlüchter, C., Kubik, P.W., Synal, H.-A., Beer, J. and Kerschner, H., 1996. The exposure age of an Egesen moraine at Julier Pass, Switzerland, measured with the cosmogenic radionuclides 10Be, 26Al, 36Cl. Eclogae Geol. Helv., 89, 1049– 1063. Google Scholar Ivy-Ochs, S., Schäfer, J., Kubik, P.W., Synal, H.-A. and Schlüchter, C., 2004. Timing of deglaciation on the northern Alpine foreland (Switzerland). Eclogae Geol. Helv., 97, 47– 55. CrossrefWeb of Science®Google Scholar Jouanne, F., Ménard, G. and Darmendrail, X., 1995. Present-day vertical displacements in the north-western Alps and southern Jura Mountains: data from levelling comparisons. Tectonics, 14, 606– 616. Wiley Online LibraryWeb of Science®Google Scholar Kähle, H.G., Geiger, A., Bürki, B., Gubler, E., Marti, U., Wirth, B., Rothacher, M., Gurther, W., Beutler, G., Bauersima, I. and Pfiffner, O.A., 1997. Recent crustal movements, geoid and density distribution: contribution from integrated satellite and terrestrial measurements. In: Results of the National Research Program, 20. ( O.A. Pfiffner, P. Lehner and P. Heitzmann, et al. eds), Birkhäuser, Basel, 251– 259 (NRP 20). Google Scholar Kelly, M.A., Ivy-Ochs, S., Kubik, P.W., Van Blanckenburg, F. and Schlüchter, C., 2006. Chronology of deglaciation based on 10Be dates of glacial erosional features in the Grimsel Pass region, central Swiss Alps. Boreas, 35, 634– 643. Wiley Online LibraryWeb of Science®Google Scholar Korup, O. and Schlunegger, F., 2007. Bedrock landsliding, river incision, and transience of geomorphic hillslope-channel coupling: Evidence from inner gorges in the Swiss Alps. J. Geophys. Res., 112, 10. 1029/2006JF000710. Wiley Online LibraryWeb of Science®Google Scholar Montgomery, D.R., 2002. Valley formation by fluvial and glacial erosion. Geology, 30, 1047– 1050. CrossrefWeb of Science®Google Scholar Montjuvent, G., 1974. Considérations sur le relief glaciaire à propos des Alpes du Dauphiné. Rev. Géogr. Phys. Géol. Dynam., 16, 465– 502. Google Scholar Montjuvent, G., 1978. Le Drac. Morphologie, stratigraphie et chronologie quaternaires d'un bassin alpin. Editions du CNRS. Centre National de la Recherche Scientifique, Paris, 433 pp. Google Scholar Nicoud, G., Royer, G., Corbin, J.-C., Lemeille, F. and Paillet, A., 2002. Glacial erosion and infilling of the Isère valley during the recent Quaternary. New results from borehole GMB1 in the Grenoble area (France). Geologie de la France, 4, 39– 50. Google Scholar Nishiizumi, K., Imamura, M., Caffee, M.W., Southon, J.R., Finkel, R.C. and McAninch, J., 2007. Absolute calibration of 10Be AMS standards. Nucl. Instrum. Methods Phys. Res. B, 258, 403– 413. CrossrefCASWeb of Science®Google Scholar Noël, H., Garbolino, E., Brauer, A., Lallier-Vergès, E., De Beaulieu, J.-L. and Disnar, J.-R., 2001. Human impact and soil erosion during the last 5000 yrs as recorded in lacustrine sedimentary organic matter at Lac d'Annecy, the French Alps. J. Paleolimnol., 25, 229– 244. CrossrefWeb of Science®Google Scholar Norton, K.P., Von Blanckenburg, F., Schlunegger, F., Schwab, M. and Kubik, P.W., 2008. Cosmogenic nuclide-based investigation of spatial erosion and hillslope channel coupling in the transient foreland of the Swiss Alps. Geomorphology, 95, 474– 486. CrossrefWeb of Science®Google Scholar Ouimet, W.B., Whipple, K.X., Crosby, B.T., Johnson, J.P. and Schildgen, T.F., 2008. Epigenetic gorges in fluvial landscapes. Earth Surf. Proc. Land., 33, 1993– 2009. Wiley Online LibraryWeb of Science®Google Scholar Raymo, M.E., 1994. The initiation of Nothern-Hemisphere glaciation. Annu. Rev. Earth Planet. Sci., 22, 353– 383. CrossrefWeb of Science®Google Scholar Schaller, M., Hovius, N., Willett, S.D., Ivy-Ochs, S., Synal, H.-A. and Chen, M.-C., 2005. Fluvial bedrock incision in the active mountain belt of Taiwan from in situ-produced cosmogenic nuclides. Earth Surf. Proc. Land., 30, 955– 971. Wiley Online LibraryCASWeb of Science®Google Scholar Schlunegger, F. and Schneider, H., 2005. Relief-rejuvenation and topographic length scales in a fluvial drainage basin, Napf area, Central Switzerland. Geomorphology, 69, 102– 117. CrossrefWeb of Science®Google Scholar Seidl, M.A., Finkel, R.C., Caffee, M.W., Hudson, B.G. and Dietrich, W.E., 1997. Cosmogenic isotope analysis applied to river longitudinal profile evolution: Problems and interpretations. Earth Surf. Proc. Land., 22, 195– 209. Wiley Online LibraryCASWeb of Science®Google Scholar Seward, D., Ford, M. and Bürgisser, J., Williams, E.A. and Meckel III, L.D., 1999. Preliminary results of fission-track analyses in the southern Pelvoux area, SE France. In: ( G. Gosso, F. Jadoul, M. Sella and M.I. Spalla, eds), 3rd Workshop on Alpine Geological Studies, Biella-Oropa September 29 - October 1, 1997, Memorie di Scienze Geologiche, 51, 25– 31. Google Scholar Stone, J.O., 2000. Air pressure and cosmogenic isotope production. J. Geophys. Res., 105, 23753– 23759. Wiley Online LibraryCASWeb of Science®Google Scholar Valla, P.G., Van Der Beek, P.A. and Lague, D., 2009. Fluvial incision into bedrock: insights from morphometric analysis and numerical modeling of gorges incising glacial hanging valleys (western Alps, France). J. Geophys. Res., (in press). Google Scholar Vernon, A.J., Van Der Beek, P.A., Sinclair, H.D. and Rahn, M., 2008. Increase in late Neogene denudation of the European Alps confirmed by analysis of a fission-track thermochronology database. Earth Planet. Sci. Lett., 270, 316– 329. CrossrefCASWeb of Science®Google Scholar Weissel, J.K. and Seidl, M.A., 1998. Inland propagation of erosional escarpments and river profile evolution across the southeast Australian passive continental margin. In: Rivers over Rock: Fluvial Processes in Bedrock Channels, ( K.J. Tinkler and E.E. Wohl eds), pp. 189– 206. American Geophysical Union, Washington DC. Geophysical Monograph 107. Wiley Online LibraryGoogle Scholar Whipple, K.X., 2001. Fluvial landscape response time: How plausible is steady-state denudation? Am. J. Sci., 301, 313– 325. CrossrefWeb of Science®Google Scholar Whipple, K.X. and Tucker, G.E., 1999. Dynamics of the stream-power river incision model: Implications for height limits of mountain ranges, landscape response timescales, and research needs. J. Geophys. Res., 104, 17,661– 17,674. Wiley Online LibraryWeb of Science®Google Scholar Whipple, K.X., Kirby, E. and Brocklehurst, S.H., 1999. Geomorphic limits to climate-induced increases in topographic relief. Nature, 401, 39– 43. CrossrefCASWeb of Science®Google Scholar Whipple, K.X., Hancock, G.S. and Anderson, R.S., 2000a. River incision into bedrock: Mechanics and relative efficacy of plucking, abrasion, and cavitation. Geol. Soc. Am. Bull., 112, 490– 503. CrossrefWeb of Science®Google Scholar Whipple, K.X., Snyder, N.P. and Dollenmayer, K., 2000b. Rates and processes of bedrock incision by the Upper Ukak River since the 1912 Novarupta ash flow in the Valley of Ten Thousand Smokes, Alaska. Geology, 28, 835– 838. CrossrefWeb of Science®Google Scholar Wittmann, H., Von Blanckenburg, F., Kruesmann, T. et al. , 2007. Relation between rock uplift and denudation from cosmogenic nuclides in river sediment in the Central Alps of Switzerland. J. Geophys. Res., 112, doi: 10.1029/2006JF000729. Wiley Online LibraryWeb of Science®Google Scholar Citing Literature Volume22, Issue1February 2010Pages 18-25 FiguresReferencesRelatedInformation
Referência(s)