Analytical methods 
Electron Microprobe analysis
Mineral compositions were obtained on a Jeol JXA 8900 RL microprobe in the Department of Geosciences, University of Mainz, operated at 15 kV and 12 nA, beam size 2 μm and using Albite (Na), Al2O3 (Al), Cr2O3 (Cr), Fe2O3 (Fe), MnTiO3 (Mn, Ti), Cr2O3 (Cr), Orthoclase (K), Wollastonite (Ca, Si), as calibration standards. Fe3+ in orthopyroxene, amphibole and garnet was calculated after normalization to 4 cations and 6 oxygens (Morimoto et al. 1988), 23 oxygens (Leake et al., 1997), 16 cations and 24 oxygens (Fetotal=Fe3+) per formula unit (pfu), respectively. Feldspar (Fetotal=Fe3+), mica (Fetotal=Fe2+), chlorite (Fetotal=Fe2+) and titanite (Fetotal=Fe3+) were normalized to 8, 22, 28 and 5 oxygens, respectively. Mineral and endmember abbreviations are after Kretz (1983). The atomic ratio Mg/(Mg+Fe2+) is termed Mg#. Back-scattered electron (BSE) and elemental (Si, Ti, Al, Cr, Fe, Mn, Mg, Ca, Na, K) X-ray intensity images were obtained with the same machine operated at 15 keV and 250 nA, a focused beam, step (pixel) size of 2-3 μm, and counting time of 60 ms/pixel. The maps of Na, Al, Si, Mg, K, Ca, Ti, Cr, Fe, Mn and Ni were measured by means of WDS. Maps of other elements were measured by means of EDS. Images presented consist of the X-ray-Kα signal of the analyzed element and are expressed in counts (colour code). However, it should be noted that this limitation is largely overcome if atomic fractions (or mole fractions) are used to illustrate mineral composition. In all qualitative and quantitative map images, mineral phases not considered for illustration are masked out, and the resulting images are overlain onto a reference grey-scale BSE image having the same spatial resolution (pixels) that contains the basic textural information of the scanned areas.

Whole-rock geochemistry
Major (AGC 221, 415, 417, 419) and trace elements, including some rare earth element (REE) concentrations by wavelength-dispersive X-ray florescence spectrometry, using a Philips MagiX Pro X-ray spectrometer equipped with an Rh-anode tube at the University of Mainz. The rock powders were ignited for ≥ 3 h at 1000 °C to turn all FeO into Fe2O3 and to expel water and CO2, with the aim to gravimetrically determine the loss on ignition (LOI). Glass beads for major element determination were produced by mixing 4.8 g of LiB4O7 with 0.8 g of ignited powder (7:1 dilution) and fused in platinum crucibles at ca. 1200 °C. Trace elements were determined on two powder pellets for each rock sample with calibration based on standard BCR-1; Table 1 contains the arithmetic average for samples of this study.

Lu-Hf/Sm-Nd dating on garnets
The same preparation procedure as for zircons was applied for the garnets in samples AGC221 and 415 up to magnetic separation. To estimate the required amount of garnet for adequately measuring Lu and Hf concentrations, in-situ garnet trace element measurements were performed with an Agilent 7500ce quadrupole ICP-MS, coupled with a NewWave Research UP-213 laser ablation unit in the Department of Geosciences, University of Mainz. Data acquisition was accomplished in a rapid, peak-jumping mode with one point per peak at 10 ms dwell time. Internal standards were 43Ca and 44Ca for garnet and standard glass reference material NIST SRM 612 was used as an internal standard. Data reduction was performed by using the software “Glitter”. During the analytical session, measurement of USGS reference glass BCR-2G was used to monitor instrumental performance and stability (Nehring et al. 2010). Garnet monofractions of ca. 100 mg were manually separated under a binocular microscope from 120-180 μm sieve fractions. Five fractions were prepared with different garnet purity grades. Three clean garnet fractions with no inclusions and one medium clean fraction with some inclusions and one “dirty” fraction (biotite inclusions and residua of biotite selvedges on garnet) were dissolved using a selective digestion procedure (tabletop digestion). The aim of this procedure is to resolve the major silicate phases of the separates without refractory phases as zircon or rutile (Lagos et al. 2007). This is important because the dissolution of zircon may affect the precision of the garnet Lu-Hf ages and rutile of the garnet Sm-Nd ages (Scherer et al. 2000). The tabletop digestion procedure often results in high precision Lu-Hf ages (e.g., Lagos et al. 2007; Herwartz et al. 2008; 2012; Schmidt et al. 2008; 2011; Smit et al. 2010; Kirchenbaur et al. 2012). A way to control as to whether zircon may alter the Lu-Hf isochron age of garnets is the use of a sub-sample. The sub-sample was digested for three days in steel jacketed high-pressure PARR® bombs (bomb digestion) in a 1:1 mixture of HNO3-HF to dissolve the entire sample with all refractory phases (e.g., Lagos et al. 2007; Herwartz et al. 2008; Kirchenbaur et al. 2012). Subsequently, the powder was dried down with one ml of perchloric acid. Prior to digestion, mineral separates and the whole-rock powder were spiked with mixed 176Lu-180Lu and 149Sm-150Nd tracers. Using Ln-Spec resin column chemistry (Münker et al. 2001) Lu and Hf were then separated from the rock matrix. The Lu-Hf separation and the clean-up for the Hf fraction involves seven different steps that are described in detail in Münker et al. (2001), Weyer et al. (2002), and Herwartz et al. (2011). Sm-Nd separation was carried out using the REE-rich matrix cut left over from the Hf separation, using BioRad® AG50W-X8 cation resin (200-400 mesh) and Eichrom Ln-spec resin (Pin and Zalduegui 1997; Kirchenbaur et al. 2012). Lu-Hf and Sm-Nd measurements of separated garnets and whole-rock powder were carried out on a Finnigan Neptune MC-ICP-MS at the joint isotope laboratory of Cologne/Bonn Universities at the Steinmann-Institute, Bonn. The 176Hf/177Hf ratios are reported relative to 176Hf/177Hf = 0.282160 for the Münster Ames Hf standard (isotopically indistinguishable from JMC-475), and 143Nd/144Nd ratios are reported relative to 143Nd/144Nd of the LaJolla standard of 0.518859. Isobaric interferences of 176Yb and 176Hf on 176Lu as well as 180Ta and 180W on 180Hf were corrected using interference-free isotopes and the natural abundances. For the purpose of calculating Lu-Hf isochron regressions, the 2-σ external uncertainties on 176Hf/177Hf were estimated using the method of Bizzarro et al. (2003) where the external reproducibility was estimated by the empirical relationship of 2σ. External reproducibility was approximately 4 σm, where σm is the standard error of an individual analysis. The given 2σ external reproducibility for 176Lu/177Hf includes error propagation for over- or under-spiked samples. Ages were calculated using ISOPLOT version 2.49 (Ludwig 2001) and λ176Lu = 1.867 × 10-11 a-1 (Scherer et al. 2001; Söderlund et al. 2004). External error on 147Sm/144Nd was 0.2% and on 143Nd/144Nd was 0.4 e units (0.000020). Daily value for the LaJolla standard (20 ppb) for 143Nd/144Nd was 0.511835. Blanks for Lu and Hf were <20 pg and <50 pg and for Sm and Nd were <50 pg, respectively, and are insignificant.

U-Pb zircon dating
Fresh whole-rock samples were crushed using a splitter jaw crusher and steel roller mill and then sieved to separate the >250μm fraction at the Max-Planck-Institute of Geochemistry, Mainz. Some material from each sample was pulverized for whole-rock geochemical analysis using an agate vibratory disk mill. The remainder was run over a Wilfley table for heavy mineral separation, followed by concentration of the non-magnetic fraction using a Frantz magnetic separator and panning for zircons. Final handpicking and microscopic inspection of the separates resulted in pure zircon concentrates that were prepared as grain mounts (embedded in epoxy) for isotopic analysis. Zircon standard M257 (Nasdala et al. 2008) was mounted together with zircons from sample AGC261. The mount w ground down and polished so that the zircon cores were exposed, and zircons were photographed under cathodoluminescence (CL) to enable easy and best location on the mount during isotopic analyses. CL images of zircon sample AGC415 (Figs. 9-10) were obtained on a JEOL JXA-8900RL microprobe at the University of Mainz, using operating conditions of 15 kV accelerating voltage and 12 nA beam current. CL images of zircons from sample AGC261 were obtained on a 305 Hitachi SEM S-3000N equipped with a Gatan ChromaCL detector and a DigiSan II data306 recorder in the Beijing SHRIMP Center, and operating conditions were 9 kV and 99 μA.

LA-ICP-MS procedure 
Zircon grains extracted from a Shiselweni paragneiss AGC415 were analyzed by LA-ICP-MS in the Department of Geosciences, University of Mainz, using an Argilent 7500ce, coupled with a 213 nm New Wave UP213 Nd:YAG laser ablation system. The laser ablation system featured a Large Format Cell (LFC), allowing investigation of several samples together with a range of different standard mounts under near-identical conditions at very fast wash-out (one order of magnitude drop in signal in 0.3 sec). Analyses were carried out with a beam diameter of 30 μm and a 10 Hz repetition rate. During each analysis the background was measured for 25 seconds, followed by an ablation time of 30 s, resulting in pits ca. 30 μm deep. The analytical data are presented in Table 5 where the isotopic ratios and ages are shown with 2-σ errors. In-situ zircon trace element measurements were also performed with a beam diameter of ca. 40 μm. Standard zircon GJ-1 (Jackson et al. 2004) was used as a primary standard for correction of 207Pb/235U, 206Pb/238U and 208Pb/232Th ratios as well as for calculation of U and Th concentrations. Off-line data reduction was performed by PepiAGE, version C9 (Dunkl et al. 2009). Pooled ages were plotted and calculated using ISOPLOT/Excel “Add-In” version 4.11 (Ludwig 2012). The accuracy of 207Pb/235U, 206Pb/238U and 208Pb/232Th ages is currently given as 1.5 % (2σ), based on long-term monitoring of several zircon standards (PL, 91500, Mud Tank; see Topuz et al. 2010). During data collection, discordant ages for the following zircon standards giving upper intercepts are as follows: North Plug 2702 ±16 Ma (n=9, MSWD=1.00, probability of fit=0.43), Kaap Valley Tonalite 3257±50 Ma (n=6, MSWD=1.8, probability of fit 0.12). TIMS ages for both standards are generally within error: North Plug 2719±1 Ma (Davis, unpublished data) Kaap Valley Tonalite 3227 ±1 Ma (Kamo & Davis, 1994). The measurement of the High Hill Falls standard with an upper intercept age of 2814±100 Ma (n=5, MSWD=2.5, probability of fit=0.061) is a poor result, because the TIMS age of this standard is 2748±1 Ma (Davis unpublished data). Instrumental parameters and further analytical details on U/Pb zircon dating in Mainz are described in Zack et al. (2011).

SHRIMP II procedure 
Isotopic analyses of zircons from sample AGC261 were performed on the Beijing SHRIMP II ion microprobe whose instrumental characteristics are identical to that installed in Perth, Australia, as described by De Laeter & Kennedy (1998). The analytical procedures are outlined in Compston et al. (1992), Claoué-Long et al. (1995), Nelson (1997) and Williams (1998). Prior to each analysis, the surface of the analysis site was cleaned by rastering of the primary beam for 3 min. to reduce or eliminate surface common Pb. The reduced 206Pb/238U ratios were normalized to 0.09101, which is equivalent to the adopted age of 561.3 Ma for the standard M257 (Nasdala et al., 2008). Pb/U ratios in the unknown samples were corrected using the ln(Pb/U)/ln(UO/U) relationship as measured in standard M257 and as outlined in Compston et al. (1984) and Nelson (1997). The 1s error in the ratio 206Pb/238U during analysis of 34 standard zircons during this study was 1.6 %. Primary beam intensity was 8.6 nA, and a Köhler aperture of 100 µm diameter was used, giving a slightly elliptical spot size of about 30 µm. Peak resolution was about 5003, enabling clear separation of the 208Pb-peak from the HfO peak. Analyses of samples and standards were alternated to allow assessment of Pb+/U+ discrimination. Raw data reduction and error assessment followed the method described by Nelson (1997). Common Pb corrections were applied using the 204Pb-correction method and assuming the isotopic composition of Broken Hill, because common Pb is thought to be surface-related (Kinny, 1986). The analytical data are presented in Table 6. Errors given on individual analyses are based on counting statistics and are at the 1s level and include the uncertainty of the standard added in quadrature. Errors for the pooled analyses in Fig. 11 are at 2s.

Bizzarro, M., Baker, J. A., Haack, H., et al. 2003. Early history of Earth’s crust-mantle system inferred from hafnium isotopes in chondrites. Nature, 421, 931–933.
Claoué-Long, J. C., Compston, W., Roberts, J. & Fanning, C. M. 1995. Two Carboniferous ages: a comparison of SHRIMP zircon dating with conventional zircon ages and 40Ar/39Ar analyses. Society of Sedimentary Geolology, Special Publication, 54, 3–21.
Compston, W., Williams, I. S. & Meyer, C. 1984. U-Pb Geochronology of Zircons From Lunar Breccia 73217 Usin A Sensitive High Mass-Resolution Ion Microprobe. Proceedings of the Fourteenth Lunar and Planetary Science Conference, Part 2: Journal of Geophysical Research, 89, Supplement, B525 B534.
Compston, W., Williams, I. S., Kirschvink, J. L., Zhang, Z. & Ma, G. 1992. Zircon U-Pb ages for the Early Cambrian time scale. Journal of the Geological Society of London, 149, 171–184.
De Laeter, J. R. & Kennedy, A. K. 1998. A double focusing mass spectrometer for geochronology. International Journal of  Mass Spectrometry, 178, 43–50.
Dunkl, I., Mikes, T., Frei, D., Gerdes, H. & von Eynatten, H., 2009. PepiAGE: data reduction program for time-resolved U/Pb analyses – Introduction and call for test and discussion. University of Goettingen Publication, 1–15.
Herwartz, D., Münker, C., Scherer, E. E., Nagel, T. J., Pleuger, J. & Froitzheim, N., 2008. Lu-Hf geochronology of eclogites from the Balma Unit (Pennine Alps): implications for Alpine platetectonic reconstructions. Swiss Journal of Geosciences, 101, 173–189.
Herwartz D., Tütken T., Münker C., Jochum K. P., Stoll B. & Sander P. M. 2011. Timescales and mechanisms of REE and Hf uptake in fossil bones. Geochimica et Cosmochimica Acta, 75, 82–105.
Herwartz D., Skublov S. G., Berezin A. V. & Melnik A. E. 2012. First Lu-Hf garnet ages of eclogites from the Belmorian Mobile Belt, Kola Peninsula, Russia. Doklady Akademii Nauk, 443, 221–224.
Jackson, S., Pearson, N. J., Griffin, W. L. & Belousova, E. A. 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircon geochronology. Chemical Geology, 211, 47–69.
Kamo, S. L. & Davis, D. W. 1994. Reassessment of Archean crust development in the Barberton Mountain Land, South Africa, based on U-Pb dating. Tectonics, 13, 167–192.
Kinny, P. D. 1986. 3820 Ma zircons from a tonalitic Amitsoq gneiss in the Godthab district of southern West Greenland. Earth and Planetary Science Letters, 79, 337–347.
Kirchenbaur, M., Münker, C., Schuth, S., Garbe-Schönberg, D. & Marchev, P. 2012. Tectonomagmatic constraint on the sources of Eastern Mediterranean K-rich lavas. Journal of Petrology, 53, 27–65.
Kretz, R. 1983. Symbols for rock-forming minerals. American Mineralogist, 68, 277–279.
Lagos, M., Scherer, E. E., Tomaschek, F., Münker, C., Keiter, M., Berndt, J. & Ballhaus, C. 2007. High precision Lu-Hf geochronology of Eocene eclogite-facies rocks from Syros, Cyclades, Greece. Chemical Geology, 243, 16–35.
Leake, B. E., Woolley, A. R., Arps, C. E. S., et al. 1997. Nomenclature of amphiboles: Report of the Subcommitee on Ampjiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names. American Mineralogist, 82, 1019–1037.
Ludwig, K. R. 2012. User’s Manual for Isoplot/Ex, v.3.75, A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronological Center Special Publications, 5.
Morimoto, N. 1988. Nomenclature of pyroxenes. Mineralogical Magazine, 52, 535–550.
Münker, C., Weyer, S., Scherer, E. & Mezger, K. 2001. Separation of high field strength elements (Nb, Ta, Zr, Hf) and Lu from rock samples for MC-ICPMS measurements. Geochemistry, Geophysics, Geosystems, 2.
Nasdala, L., Hofmeister, W., Norberg, N., et al. 2008. Zircon M257 - a homogeneous natural reference material for the ion microprobe U-Pb analysis of zircon. Geostandards and Geoanalytical Research, 32, 247-265.
Nehring, F., Foley, S. F. & Hölttä, P.. 2010. Trace element partioning in the granulite facies. Contributions to Mineralogy and Petrology, 159, 493–519.
Nelson, D. R. 1997. Compilation of SHRIMP U-Pb zircon geochronology data, 1996. Geological Survey of Western Australia, Record 1997/2.
Pin, C. & Zalduegui, J. F. S. 1997. Sequential separation of light rare-earth elements, thorium and uranium by miniaturized extraction chromatography: application to isotopic analyses of silicate rocks. Analytica Chimica Acta, 339, 79–89.
Scherer, E. E., Kenneth, L. C. & Blichert-Toft, J. 2000. Lu-Hf geochronology: Closure temperature relative to the Sm-Nd system and effects of trace mineral inclusion. Geochimica et Cosmochimica Acta, 64, 3413–3432.
Schmidt, A., Weyer, S., Mezger, K., Scherer, E., Xiao, Y., Hoefs, J. & Brey, G. P. 2008. Rapid eclogitisation of the Dabie-Sulu UHP terrane: Constraints from Lu-Hf garnet geochronology. Earth Planet Science Letters, 273, 203–213.
Schmidt, A., Mezger, K. & O'Brien, P. J. 2011. The time of eclogite formation in the ultrahigh-pressure rocks of the Sulu terrane: constraints from Lu-Hf garnet geochronology. Lithos, 125, 743–756.
Smit, M. A., Scherer, E. E., Bröcker, M. & van Roermund, H. L. M. 2010. Timing of eclogite facies metamorphism in the southernmost Scandinavian Caledonides by Lu-Hf and Sm-Nd geochronology. Contributions to Mineralogy and Petrology, 159, 521–539.
Söderlund, U., Patchett, J. P., Vervoort, J. & Isachsen, C. E. 2004. The Lu-176 decay constant determined by Lu-Hf and U-Pb isotope systematics of Precambrian mafic intrusions. Earth and Planetary Science Letters, 219, 311–324.
Topuz, G., Altherr, R., Siebel, W., Schwarz, W. H., Zack, T., Hasözbek, A., Barth, M., et al. 2010. Carboniferous high-potassium I-type granitoid magmatism in the Eastern Pontides: The Gümüşhane pluton  (NE Turkey). Lithos, 116, 92–110.
Weyer, S., Münker, C., Rehkämpfer, M. & Mezger, K. 2002. Determination of ultra-low Nb, Ta, Zr and Hf concentrations and the chondritic Zr/Hf and Nb/Ta ratios by isotope dilution analyses with multiple collector ICP-MS. Chemical Geology, 187, 295–313.
Williams, I. S. 1998. U–Th–Pb geochronology by ion microprobe. In: McKibben, M. A., Shanks III, W. C. & Ridley, W. I. (eds) Applications of microanalytical techniques to understanding mineralizing processes. Reviews in Economic Geology, 7, 1–35.
Zack, T., Stockli, G., Luvizotto, G. L., Barth, M. G., Belousova, E., Wolfe, M. R. & Hinton, R. W. 2011. In situ U-Pb rutile dating by La-ICP-MS: 208Pb correction and prospects for geological applications. Contributions to Mineralogy and Petrology, 162, 515–530.