Supplementary File 1 
					Analytical methods 
Analytical Methods: Geochronology
Sample CET-2 was analyzed by LA-ICPMS. Zircons were separated from psammitic sample CET-2 at the Complutense University of Madrid following conventional techniques. Details of the separation procedure can be found in Fernández-Suárez et al. (2002) and Jeffries et al. (2003). Separated zircons were examined optically under a binocular microscope, and representative grains were picked and mounted in epoxy resin. The mount was ground down so that equatorial sections of most of the grains were exposed, and then polished to high quality. Grains were imaged by cathodoluminescence (CL) in a JEOL 5900LV scanning electron microscope (SEM) at the Natural History Museum, London (NHM). Finally, the mounts were cleaned by immersion in an ultrasonic bath containing a dilute HNO3 acid, and dried before being introduced to the laser ablation chamber. Analytical instrumentation, analytical protocol and methodology, data reduction, age calculation and common Pb correction followed those described in Fernández-Suárez et al. (2002), Jeffries et al. (2003) and Murphy et al. (2004).  
Nominal laser beam diameter was 30m for >75% of the analyses, but where the area to be analysed was deemed to be large enough a 45m beam was used to ensure the analysis was collected with the optimal signal strength that the analyte volume allowed. Data were collected in discrete runs of 20 analyses, comprising 12 unknowns bracketed before and after by 4 analyses of the standard zircon 91500 (Wiedenbeck et al. 1995). Concordia age calculations, and concordia and frequency histograms/probability density distribution plots were performed using Isoplot v.3.00 (Ludwig, 2003).
Selected zircon grains from the quarz-augen granite sample (CET-3) were mounted in epoxy, polished, imaged in cathodoluminescence and photographed under reflected light, then gold-coated prior to analysis. Uranium-lead isotopic analyses were conducted on the SHRIMP-RG (sensitive high resolution ion microprobe–reverse geometry) at Stanford University following techniques described in DeGraaff-Surpless et al. (2002). Uranium and Thorium concentrations were measured relative to the CZ3 zircon standard and isotopic ratios and concentrations were measured relative to the R33 zircon standard from a quartz diorite of the Braintree complex, Vermont (J. Wooden, unpublished data). Data were reduced with the SQUID v.1.02 program of Ludwig (2001) and plotted with Isoplot Ex, v.3.00 (Ludwig, 2003). Errors in Table 1 are quoted at 1-sigma and ellipses on concordia diagrams are shown at the 68.3% confidence level.  
Additional References:
LUDWIG K.R. 2001. SQUID 1.00. A user's Manual. Berkeley Geochronology Center., Special Publication No. 2, 17 pp.
LUDWIG K.R 2003.  Isoplot 3.00. Berkeley Geochronology Center Special Publication No. 4, 70 pp. 
WIEDENBECK, M., ALLÉ, P., CORFU, F., GRIFFIN, W.L., MEIER, M., ORBELI, F., VON QUADT, A., RODDICK J.C., & SPIEGEL, W., 1995. Three natural zircon standards for U-Th-Pb, Lu-Hf, trace element and REE analyses. Geostandards Newsletter, 19, 1-23.