Exhumation of the Western Alpine collisional wedge: new thermochronological data

Table 1: Raman spectroscopy of carbonaceous material data. GPS coordinates in WGS84 system, number of spectra (n), mean R2 ratio (Beyssac et al., 2002a) or RA1 ratio (Lahfid et al., 2010) reliant on best fit during post-processing using the software PeakFit following the methods described in Beyssac et al. (2002b) and Lahfid et al. (2010) with corresponding standard deviation, and calculated temperature with standard error (SE). Standard error is the standard deviation divided by √n. The absolute error on temperature is ±50 °C (Beyssac et al., 2002b). (a) Method from Lahfid et al. (2010) and (b) Method from Beyssac et al. (2002b). For very disordered graphitic carbon that is found in least metamorphosed rocks, we assign T Table 2: Zircon fission-track data from Belledonne and Grandes Rousses massifs, western Alps. All samples were counted at 1250 x dry (x 100 objective, 1.25 tube factor, 10 oculars) by J.B. Girault using a zeta (IRMM541) of 120.42 ± 3.23 (± 1SE); all ages are reported as central ages (Galbraith and Laslett, 1993). GPS coordinates in WGS84 system. Massif: NBDi = North Belledonne internal unit; NBDe = North Belledonne external unit, CBD = Central Belledonne, SBD = South Belledonne, GR =Grandes Rousses; N = number of grains counted; ρs = spontaneous track density; ρi = induced track density; Ns, Ni = number of tracks counted to determine the reported track densities; P(χ2) = Chi-square probability that the single grain ages represent one population.Table 3: Apatite fission-track data from Belledonne massif, western Alps. All samples were counted at 1250 x dry (x 100 objective, 1.25 tube factor, 10 oculars) by M. Balvay using a zeta (CN-5) of 273.35 ± 12.05 (± 1SE); all ages are reported as central ages (Galbraith and Laslett, 1993). Latitude and Longitude in WGS84 reference frame. Massif: NBDi = North Belledonne internal unit; NBDe = North Belledonne external unit, CBD = Central Belledonne, SBD = South Belledonne, GR =Grandes Rousses; N = number of grains counted; ρs = spontaneous track density; ρi = induced track density; Ns, Ni = number of tracks counted to determine the reported track densities; P(χ2) = Chi-square probability that the single grain ages represent one population.Table 4: (U-T-Sm/He) on zircons data (ZHe) from Belledonne and Grandes Rousses massifs, western Alps. Latitude and Longitude in WGS84 reference frame. Massif: NBDi = North Belledonne internal unit; NBDe = North Belledonne external unit, CBD = Central Belledonne, SBD = South Belledonne, GR = Grandes RoussesSupplemental data 1: Age/elevation distribution of the thermochronological data (AFT, ZHe and ZFT) from (e) North External Belledonne (dark blue dots), (f) North Internal Belledonne (light blue dots) and (g) South Belledonne (yellow dots). One elevation range of LT thermochronological data was selected at ~1800m with, when possible, ZFT, ZHe and AFT data for thermal inversion modelling. (d) Grandes Rousses (purple dots) with full range scale. South Belledonne and Grandes Rousses: AFT data from Sabil (1995).Supplemental data 2: Termal histories modelled with HeFTy sofware for the (e) North Belledonne external unit at ~1800m, (f) North Belledonne external unit at 1800m and (g) South Belledonne massif at ~2200m. T–t paths are statistically evaluated and categorized by their value of goodness of ft (GOF). ‘Acceptable’ results, in green, correspond to a 0.05 GOF value and ‘good’ results, in purple, correspond to 0.5 GOF (Ketcham, 2005).Supplemental data 3: Age/elevation distribution of zircon fssion-track (ZFT) ages available for Aiguilles Rouges (Soom, 1990) and Mont Blanc (Glotzbach et al., 2011): gray diamond-shaped, Belledonne (this study): orange circle, Pelvoux – Meije massifs (van der Beek et al., 2010): yellow square, Grandes Rousses (this study): pink circle and Argentera (Bigot-Cormier et al., 2002): grey square.