Zircon U/Pb LA ICP MS geochronology
Analytical methods
For zircon extraction 10 to 15 kg of fresh material was sampled from each outcrop. In order to extract the zircon grains the material was subjected to the classical crushing, milling, gravitational separation, heavy liquids treatment and magnetic separation procedures. Up to 30 magmatic and at least 100 detrital crystals were selected using a stereomicroscope and then mounted in 25 mm epoxy and polished. Well crystallized zircons from each magmatic sample were carefully selected avoiding cracked or corroded grains or those with inclusions. When possible, populations of zircon were separated within magmatic samples, based on grain features (e.g. sample 181 transparent and opaque populations). Zircons from detrital samples were randomly selected, irrespective of shape, colour, transparency, dimensions, etc., in order to have a better representation of the source regions and to avoid any bias induced by selection criteria. 
The CL imaging was conducted at the Laboratory of Radiogenic Isotope Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, using a JEOL JXA8100 Superprobe microanalyzer equipped with a GATAN MONO CL3 detector.
Some of the LA-ICP-MS measurements were performed at the China’s University of Geosciences in Wuhan and University of Xian, using an Agilent 7500 ICP-MS attached with a Coherent GeoLas Pro 193 nm Excimer laser-probe. The spot diameter was of 32 and 24 microns, depending on the grain size. For grains of the same sample the same spot diameter was used. The ablation pits were approximate 20 microns in depth. Each grain analysis consisted of 20 seconds background acquisition without laser firing followed by 40 seconds ablation time with a 8 pulses per second repetition rate and finally 40 seconds argon flushing of the ablated material. In order to correct the elemental fractionation, after each set of five or ten unknown measurements double analyses of 91500 zircon and NIST610 glass external standards respectively were carried out, using the same operating conditions. Also, the analysis of every sample started and ended in reverse order with measurements of NIST610 and 91500 followed by CHEM, GJ-1 and YS1 zircon references for trace elements compositions. For offline data reduction GLITTER software (developed by the ARC National Key Centre for Geochemical Evolution and Metallogeny of Continents – GEMOC - at Macquarie University, Australia) was used. Further common lead corrections were done using the method proposed by Andersen (2002).
The remainder of the measurements were conducted by laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) at the Arizona LaserChron Center (Department of Geosciences, University of Arizona). The analyses involve ablation of zircon with a New Wave/Lambda Physik DUV193 Excimer laser (operating at a wavelength of 193 nm) using a spot diameter of 35 or 50 microns. The ablated material is carried with helium gas into the plasma source of a GV Instruments Isoprobe, which is equipped with a flight tube of sufficient width that U, Th, and Pb isotopes are measured simultaneously. All measurements are made in static mode, using Faraday detectors for 238U and 232Th, an ion-counting channel for 204Pb, and either faraday collectors or ion counting channels for 208-206Pb. Ion yields are ~1 mv per ppm. Each analysis consists of one 12-second integration on peaks with the laser off (for backgrounds), 12 one-second integrations with the laser firing, and a 30 second delay to purge the previous sample and prepare for the next analysis. The ablation pit is ~12 microns in depth.
For each analysis, the errors in determining 206Pb/238U and 206Pb/204Pb result in a measurement error of ~1% (at 2 σ level) in the 206Pb/238U age. The errors in measurement of 206Pb/207Pb and 206Pb/204Pb also result in ~1% (2 σ) uncertainty in age for grains that are >1.0 Ga, but are substantially larger for younger grains due to low intensity of the 207Pb signal. For most analyses, the cross-over in precision of 206Pb/238U and 206Pb/207Pb ages occurs at ~1.0 Ga. 
Common Pb correction is accomplished by using the measured 204Pb and assuming an initial Pb composition from Stacey and Kramers (1975) (with uncertainties of 1.0 for 206Pb/204Pb and 0.3 for 207Pb/204Pb). Our measurement of 204Pb is unaffected by the presence of 204Hg because backgrounds are measured on peaks (thereby subtracting any background 204Hg and 204Pb), and because very little Hg is present in the argon gas.. Analyses of zircon standards of known isotopic and U-Pb composition were conducted in most cases after each set of five unknown measurements to correct for elemental isotopic fractionation.
Inter-element fractionation of Pb/U is generally ~20%, whereas apparent fractionation of Pb isotopes is generally <2%. In-run analysis of fragments of a large zircon crystal (generally every fifth measurement) with known age of 564 ± 4 Ma (2σ error) is used to correct for this fractionation. The uncertainty resulting from the calibration correction is generally ~1% (2σ) for both 206Pb/207Pb and 206Pb/238U ages. 
The analytical data are reported in supplementary data Table 1. Uncertainties shown in these tables are at the 1σ level, and include only measurement errors. The analyses used in best ages diagrams are also shown on Pb/U concordia diagrams (insets in Figure 5). 
The reported ages are determined from the weighted mean (Ludwig, 2003) of the 206Pb/238U or 206Pb/207Pb ages of the concordant and overlapping analyses (Figure 5). Two uncertainties are reported on these plots. The smaller uncertainty (labeled “mean”) is based on the scatter and precision of the set of 206Pb/238U or 206Pb/207Pb ages, weighted according to their measurement errors (shown at 1σ). The larger uncertainty (labeled “age”), which is the reported uncertainty of the age, is determined as the quadratic sum of the weighted mean error plus the total systematic error for the set of analyses. The systematic error, which includes contributions from the standard calibration, age of the calibration standard, composition of common Pb, and U decay constants, is generally ~1-2% (2 σ).
For the detrital samples, the interpreted ages are based on 206Pb/238U for <1000 Ma grains and on 206Pb/ 207Pb for >1000 Ma grains. This division at 1000 Ma results from the increasing uncertainty of 206Pb/238U ages and the decreasing uncertainty of 206Pb/207Pb ages as a function of age. Analyses that are >30% discordant (by comparison of 206Pb/ 238U and 206Pb/207Pb ages) or >5% reverse discordant are not considered further. The resulting interpreted ages are shown on age vs frequency diagrams. 
Samples description
Someş terrane
Samples 165, 166 and 167 were collected from an orthogneiss layer cropping out along the Iara valley, upstream the Valea Iara village (Fig. 2, Appendix 1). This body is situated at the lowermost known part of the Someş terrane. It contains quartz, plagioclase, microcline, muscovite, little biotite, apatite, Fe-oxides, orthite, zircon and sometimes tourmaline. Pegmatites appear in some places and nebulitic structures occur in some outcrops. They certify an incipient anatexis of the rock body. A planar fabric is also present in its mica-rich parts.
Sample 185 was collected from a metatuff layer situated at the upper part of the Someş terrane, in the Bistra valley (Fig. 2, Appendix 1). It contains quartz, plagioclase, little microcline, muscovite, biotite, Fe-oxides, zircon. Secondary chlorite formed on biotite expense and rutile inclusions in chlorite may also be found. The planar fabric is evidenced by alternating quartz-feldspar rich and muscovite-chlorite rich bands. The retrogression is due to Variscan events.
Baia de Arieş terrane
Sample 171 is an augen gneiss collected from the Pociovaliştea rivulet, a right tributary of the Runc river upstream Ocoliş village (Fig.2, Appendix 1). The gneiss body is situated at the base of the Alpine Baia de Arieş nappe in that region. It contains quartz, plagioclase, microcline augen up to 3 cm long, biotite, little muscovite, Fe-oxides, apatite, epidote, orthite, zircon. The penetrative planar-linear fabric is defined by the flattened and elongated K-feldspar crystals wrapped in mica flakes.
Samples 186, 268 and 269 were collected from the Lupşa porphyroid closed to Lupşa village, along the Arieş river (Fig. 2, Appendix 1). It is situated above a black quartzite sequence at the middle part of the Baia de Arieş terrane. The porphyritic aspect is due to the quartz porphyroclasts up to 5 mm in diameter. Beside quartz, it also contain plagioclase, biotite, epidote, orthite, Fe-oxides and zircons. There is no microcline or muscovite present. The fabric is a rough foliation defined by the common orientation of phyllosilicates.
Sample 178 was collected from the Mihoieşti metagranites, located at the confluence of the Arieşul Mare and Arieşul Mic rivers (Fig. 2, Appendix 1). The layer is situated below the black quartzite sequence, not far to the Alpine Baia de Arieş nappe base. The metagranite is a coarse grain rock, containing quartz, plagioclase, microcline, muscovite, little biotite, epidote, Fe-oxides and zircon. The rock is slightly foliated due to the flattening of the feldspar grains.
Sample 181 was collected from the Muncelu metagranites, near the Biharia summit, on the right slope of the Arieşul Mic valley (Fig. 2, Appendix 1). Its position, aspect and mineralogy are similar to the Mihoieşti metagranite.
Sample 324 was collected from a paragneiss layer near Baia de Arieş town. The paragneiss is situated at the middle part of the Baia de Arieş terrane. It contains quartz, plagioclase, biotite, garnet, rutile, tourmaline, magnetite and zircon. The rock is strongly foliated.
Biharia terrane
Samples 170, 290 and 291 were collected from the Lunca Largă metagranites outcropping in the Runc valley, upstream Lunca Largă village (Fig.2, Appendix 1). They are located at the known lower part of the Biharia terrane. These rocks contain quartz, plagioclase, epidote, zoisite, muscovite, chlorite, biotite, Fe-oxides, and zircon. They have a gneissose aspect with a well defined foliation due to a strong segregation between the micas on one side and quartz-feldspar on the other side.
Samples 327, 328 and 328B were collected from metabasite layers situated above the Lunca Largă metagranites, in the Runc valley (Fig.2, Appendix 1). These rocks are strongly foliated showing a planar fabric and contain chlorite, muscovite, albite, epidote, quartz, biotite, garnet, titanite, magnetite and zircon.

References
Andersen, T. 2002. Correction of common lead in U–Pb analyses that do not report 204Pb. Chemical Geology, 192, 59-79.
Ludwig K. R., 2003. Isoplot/Ex, rev. 2.49: A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronological Center, Special Publication, No. 1a, 58p.
Stacey, J. S. & Kramers, J. D., 1975. Approximation of terestrial lead isotope evolution by a two stage model. Earth and Planet. Sci. Letters, 26, 207-221.