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Appendix 1: analytical methods
XRF:
Fresh samples from the different lithologies studied were crushed into a fine powder
using a hydraulic press and an agate mill. For major elements (> 0.1 wt%), a mixture of
the sample powders with lithium tetraborate (1.2g sample/6g Li2B4O7) was fused at
1200°C in a Au-Pt crucible. For trace elements (< 0.1 % or 1000 ppm), a mixture of the
sample powder with a drop of Mowiol (polyvinylic alcohol with 2 % distilled H2O) was
compressed at 5 tons. All the elements, except total iron (FeO*), H2O and CO2, were
analyzed by X-ray fluorescence with a PHILIPS PW 2400 X-ray fluorescence
spectrometer at the University of Lausanne. The detection of the spectra was obtained by
diffracted scintillation of LiF, TAP, Ge and Pe crystals. Major elements were analyzed
for 6 minutes, trace elements for 40 minutes or 3 hours (high-precision trace elements). In
terms of correction, we sued alpha factor and DeJongh (Philips) matrix-effect corrections
for major elements and Compton-type correction for trace elements. The precision of the
analysis was 1-5% for major elements, and between 5-10% for trace elements.
Ten majors components were analyzed: SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO,
Na2O, K2O and P2O5. The sum was recalculated to 100% anhydrous. The 21 trace
elements measured by the standard method were: Nb, Zr, Y, U, Th, Sr, Pb, Ga, Zn, Cu,
Ni, Co, V, Ce, Nd, Ba, La, S, Hf, Sc and As. Sixteen trace elements were analyzed with
long-counting technique (Nb, Zr, Y, U, Th, Sr, Pb, Ga, Zn, Ni, Cr, V, Ce, Ba, La), and
results were used for all duplicate elements.
EMPA:
All the following mineral phases were analyzed at University of Lausanne, with the
microprobes Cameca SX50 and Jeol 8600 Superprobe.
Feldspars:
The following elements were analyzed: Fe, Mg, Sr, Si, K, Na, Ca, Al, Ba. Time of 20 to
30 seconds on peaks, and 5 to 15 seconds on the background were counted, under a
current of 15kV and an intensity of 15 nA.
Amphiboles:
The following elements were analyzed: Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, F, and Cl.
Analytical parameters were identical to feldspars.
Micas:
The following elements were analyzed: Fe, Mg, Sr, Si, K, Na, Ca, Al, Ba, F and Cl.Time
of 20 to 30 seconds on peaks, and 5 to 15 seconds on the background were counted,
under a current of 15kV and an intensity of 10 nA. Volatile elements such as Na, Cl and
F were analyzed first.
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Fe-Ti oxides:
The following elements were analyzed: Fe, Mg, Mn, Si, Ti, Al, Cr and V. Time of 20
seconds on peaks, and 10 seconds on the background were counted, under a current of 15
to 20kV and an intensity of 15 nA.
Melt inclusions and glasses:
The following elements were analyzed: Fe, Mg, Mn, Si, K, Na, Ca, Al, Ti, Ba, P, S, Cl
and F. Time of 20 to 30 seconds on peaks, and 5 to 15 seconds on the background were
counted, under a current of 15kV and an intensity of 10 nA. Volatile elements such as
Na, F, Cl and S were analyzed first.
Zircons:
Zircons were analyzed at University of Washington using a Jeol 733. The following
elements were analyzed: Hf, Fe, P, Ce, Yb, Y (stochiometric concentration were used for
Zr and Si). Counting times on peaks were 180 sec for Hf and Yb (LIF-spectrometer) and
Ce and Ti (PET-spectrometer), and 360 sec for P and Y (TAP-spectrometer), respectively
95 to 15 seconds on the background), under a current of 15 kV and an intensity of 200
nA.
SHRIMP:
Several samples from the KPT, Nisyros Upper and Lower Pumice units, Nikia lava flow
and Yali rhyolite were selected for trace element analysis. Zircons were separated using
standard procedures at University of Washington, mounted in epoxy, polished, and
imaged by cathodoluminescence on an Hitachi 3400 scanning electron microscope at
University of Puget Sound. Spots on the zircons 30–40 μm in diameter were analyzed
using the USGS/Stanford Sensitive High Resolution Ion Microprobe, Reverse Geometry
(SHRIMP-RG). Zircon standard MAD was used as the trace element concentration
standard.
LA MC ICP-MS
Sample Preparation and Analysis
The preparation of the samples for in-situ, multi-grain, and whole rock analysis of
Hf isotopes and composition was conducted in the facilities of the Earth and Space
Sciences department at the University of Washington. For Hf analysis, zircons were
separated from the rhyolitic material via crushing, sieving, flotation of the <250m
fraction with a gold pan, magnetic separation with hand magnets and a Frantz magnetic
separator, heavy liquid separation in low viscosity sodium polytungstate (Na6(H2W12O40),
Geoliquids inc.), and 3-4 days of bathing in 48% HF (ACS grade) to dissolve unwanted
phases, especially monazite (similar optical behavior), from the zircon aliquot.
Dissolution of zircons for solution analysis of Hf isotope composition was
conducted in large Parr bombs (Parr Instrument Co., Moline, IL; Parrish 1987) loaded
with eight 1ml microcapsules, which each hold 3-5 zircons of one sample. The whole
procedure was conducted as designed for zircon Pb-isotope analysis, including the
cleaning of the microcapsules and bombs with alternating steps of 6M HCl and 24M HF
(Seastar high-purity subboiling grade). The zircons were digested in 0.2 ml of 24M HF in
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each microcapsule, and 6 ml of 24M HF in the Teflon liner, at 220C for 65h. The zircon
digests were flushed out of the microcapsules, which then were rinsed three times with
24M HF. After drying the sample it was taken up in a mixture of 1M HCl and 4M HF,
and the hafnium was separated from the digests on the second column following the
procedure of (Blichert-Toft et al. 1997) by using a modified succession of HCl and HF
with varying acidities. Hf separates were dissolved in 2% HNO3 and analyzed with
sample introduction by desolvating nebulizer, following the same conditions and
procedures as used during the in-situ analyses (see below).
Laser and Multicollector ICP-MS Configuration and Analysis
A LA-MC-ICPMS system comprising a UP193 solid state NewWave laser
attached to a Nu Plasma HR multicollector-ICPMS was used for zircon Hf isotope
analyses (on grain mounts). The New Wave UP193 solid state Nd-YAG laser source is
attached to the Nu Plasma HR multicollector via the desolvating nebulizer (DSN). During
the entire measurement, DI water was passed through the DSN. Ablated samples are
introduced from the laser into the line after the DSN with an Ar gas carrier. Between
analyses and prior to each sample change the tubing coming from the DSN was washed
out using 2% HNO3 for 2-5 min. The tubing from the laser to the main line is kept short
(< 30 cm) since it is not washed out. This portion is replaced prior to each laser session.
After each sample change the sample chamber is purged for 3min to avoid blowing out
the torch by remaining air. Analyses are continued after the signal of the liquid standard
JMC 475 has stabilized and additional acid and RODI H2O washouts have finished.
Hf laser analyses were conducted in a bracketing sequence to monitor the
instrumental drift and to enable external standard corrections. Each bracket comprised a
sequence of solution standard > solid standard (Plesovice zircon; Slama et al. 2008) > 1-5
samples > solid standard > solution standard (JMC 475). Plesovice zircons were checked
for Hf heterogeneities prior to usage via multiple random continuous line scans. Typical
measurement conditions for samples and standards are listed in Table 1. The cup
configuration for Hf isotope analysis is presented in Table 2.
Corrections and Error Propagation
Correction of the 176Hf/177Hf ratio for isobaric interferences by 176Yb and 176 Lu and of
the 180Hf/177Hf ratio for 180W and 180Ta follow the same protocol during laser and solution
analyses. Corrections for instrumental mass fractionation were calculated using the
exponential law of Russell et al. 1978.
Each solid standard (Table 3) was corrected externally for machine drift through
the liquid standard results before standard corrections were applied to each sample. For
machine drift corrections of the Plesovice standard, the JMC 475 standard value of
176
Hf/177Hf = 0.282157 was used for normalization. Hf values were calculated with the
chondritic value given by Blichert-Toft and Albarède (1997) of 176Hf/177Hf = 0.282772.
No age corrections were applied since Hf ingrowth is insignificant over the ages of the
samples of <1 Ma (Bachmann et al. 2010).
The actual measurement errors were propagated by using this equation:
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2
 samplemeas   s.d.STDmeas1 x 
samplecorr
 

samplecorr
 samplemeas   AvgSTDmeas1 x 
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2
with samplecorr meaning the sample result has undergone interference, drift, and standard
corrections, STD standing for the Plesovice zircon standard or JMC 475 Hf solution
standard, respectively. Laser result errors were propagated by using the average and
standard deviation of all Plesovice zircon standard analyses of each day (each analysis
being drift corrected for the JMC 475 and then corrected for the true Plesovice value) in
brackets between the two standards around it. Whole rock and zircon digest errors were
propagated similarly by using the average and standard deviation of all JMC 475 analyses
(each interference corrected value bracketed between the two interference and true value
corrected ones around it).
According to Kamenov et al. (2008) the precision and accuracy of Hf isotope data
obtained through interference corrections for Lu and Yb is better than ±1 epsilon unit for
corrections of  20% between the raw 176Hf/177Hf ratio and the internally corrected ratio
(in ideal synthetic zircons). For corrections up to 60%, the uncertainty increases to +/- 4
Hf, and to +/- 9 Hf for corrections of up to 80%. We therefore only use those results
that have <40% corrections to limit the uncertainty. MSWDs (mean standard weighted
deviations) presented in Table 2 of the main text are calculated accordingly only from
values that fulfill this criterion. In addition the calculation of the errors for Hf is based
on the degree of correction. The accuracy of results for samples is limited by the
discrepancy in Yb corrections between Plesovice (8%) and most samples (<40%). A
standard with higher Yb and Lu corrections than Plesovice could be incorporated in the
standard correction process to increase the accuracy (Vervoort et al. 2007).
The accuracy and precision of the laser ablation system is validated by the
repeated measurement of the Plesovice standard throughout all measurement sessions.
All Plesovice standard analyses yield an average of 0.282471±0.000008 (n=104) that is
within the 2 error of the true value of Slama et al. (2008) of 0.282482±0.000013,
suggesting homogenous 176Hf/177Hf and 176Yb/177Hf compositions (Figure 1). This
homogeneity is required to ensure reliable Yb corrections. While standard analyses
cluster tightly in 176Hf/177Hf vs. 176Yb/177Hf space around the true 176Hf/177Hf ratio of
0.282482, with 176Yb/177Hf ratios of 0.0244, zircons from the Aegean volcanic rocks
scatter between 0.282209 and 0.283088 (Figure 1 and Table Appendix 2), with a
176
Yb/177Hf ratio of up to 0.32. According to Griffin et al. (2000), a lack of correlation as
shown in figure 1 is an indicator that the corrections imposed to the 176Hf/177Hf ratio
result in accurate and precise data.
References:
Bachmann O, Schoene B, Schnyder C, Spikings R (2010) 40Ar/39Ar and U/Pb dating of
young rhyolites in the Kos-Nisyros volcanic complex, Eastern Aegean Arc
(Greece): age discordance due to excess 40Ar in biotite. Geochem. Geophys.
Geosyst 11, Q0AA08, doi:10.1029/2010GC003073.
Blichert-Toft J, Albarède F (1997) The Lu-Hf isotope geochemistry of chondrites and the
evolution of the mantle-crust system. Earth and Planetary Science Letters 148(12):243-258
Bachmann et al
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Blichert-Toft J, Chauvel C, Albarède F (1997) Separation of Hf and Lu for high-precision
isotope analysis of rock samples by magnetic sector-multiple collector ICP-MS.
Contributions to Mineralogy and Petrology 127:248-260
Griffin WL, Pearson NJ, Belousova E, Jackson SE, van Achterbergh E, O'Reilly SY,
Shee SR (2000) The Hf isotope composition of cratonic mantle: LAM-MCICPMS analysis of zircon megacrysts in kimberlites. Geochimica et
Cosmochimica Acta 64(1):133-147
Kamenov GD, Mueller PA, Mazdab FK (2008) Using synthetic zircons to test the
reliability of the Lu-Yb isobaric interference correction of Hf isotopic
measurements during laser ablation MC-ICP-MS analyses. In: AGU Fall
Conference, vol 89 (53) Abstract V13A-2093. Eos Trans., San Francisco
Russell WA, Papanastassiou DA, Tombrello TA (1978) Ca isotope fractionation on the
Earth and other solar system materials. Geochimica et Cosmochimica Acta
42(8):1075-1090
Slama J, Kosler J, Condon DJ, Crowley JL, Gerdes A, Hanchar JM, Horstwood MSA,
Morris GA, Nasdala L, Norberg N, Schaltegger U, Schoene B, Tubrett MN,
Whitehouse MJ (2008) Plesovice zircon -- A new natural reference material for
U-Pb and Hf isotopic microanalysis. Chemical Geology 249(1-2):1-35
Vervoort JD, DuFrane SA, Hart GL (2007) An assessment of the total uncertainty in Hf
analyses by LA-MC-ICPMS. In: AGU Fall meeting, vol 88(52) Abstract V51B0569. San Francisco
Bachmann et al
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0.35
Plesovice
0.3
176Yb/177Hf
KPT
0.25
KS
0.2
Nis
Nikia
0.15
Yali
0.1
0.05
0
0.2820
0.2824
0.2828
0.2832
176Hf/177Hf
Figure 1: Comparison of 176Yb/177Hf vs. 176Hf/177Hf of standard analyses (Plesovice; Slama et al. 2008)
and sample analyses. Correction of 176Hf for 176Yb and 176Lu was conducted by using the -Hf
fractionation factor. Absence of correlation between 176Yb/177Hf and 176Hf/177Hf suggest a reliable Yb
correction (Griffin et al., 2000).
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Table 1: Instrumentation parameters during laser analysis
Coolant Ar gas flow rate
Auxiliary Ar gas flow rate
Carrier He gas flow rate
Forward RF power
Reflected RF power
Interface cones
Analyzer vacuum
Acceleration voltage
Focusing optics
Repetition rate
Spot size
Energy density
Typical total Hf sensitivity
Optimized for laser
Optimized for solutions
13 l/min
0.80 l/min
0.80 l/min
1300 W
<11 W
Nickel
8 x 10-9 mbar
10 Hz
35-100 nm
1-6 J/cm2
8 V for 100 ppb
18 V for 100 ppb
Table 2: Cup configuration during laser ablation
H6
Hf
H5
H4
181
H3
180
H2
179
H1
178
Ax
177
L1
176
L2
175
IC0
L3
173
IC1
L4
171
IC2
L5
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Table 3: 176Hf/177Hf ratios of Plesovice standard zircons (Slama et al. 2007) determined over the
whole range of Hf analysis presented in this paper; the average (n=104) is given in the second to last
row, the result for one multi-grain digest is given in the last row
Sample
Plesovice Hf std #1
090121_Plesovice_M1C4_#2
Plesovice Hf std #3
Plesovice Hf std #4
Plesovice Hf std #5
Plesovice Hf std #6
Plesovice Hf std #7
Plesovice Hf std #8
Plesovice Hf std #9
Plesovice Hf std #10
Plesovice Hf std #11
Plesovice Hf std #12
Plesovice Hf std #13
Plesovice Hf std #14
Plesovice Hf std #15
Plesovice Hf std #17
090123 Plesovice M1C #1
090123 Plesovice M1C #2
090123 Plesovice M1C #3
090123 Plesovice M1C #4
090123 Plesovice M1C #5
090123 Plesovice M1C #6
090123 Plesovice M1C #7
090123 Plesovice M1C #8
090123 Plesovice M1C #9
090123 Plesovice M1C #10
090123 Plesovice M1C #11
090124 Plesovice M1C4 #1
090124 Plesovice M1C4 #2
090124 Plesovice M1C4 #3
090124 Plesovice M1C1 #5
090124 Plesovice M1C3 #6
090124 Plesovice M1C3 #7
090124 Plesovice M1C3 #9
090124 Plesovice M1C3 #10
090124 Plesovice M1C3 #11
090124 Plesovice M1C3 #12
090124 Plesovice M1C3 #13
090125 Plesovice M1C3 #1
090125 Plesovice M1C3 #2
090125 Plesovice M1C3 #3
090125 Plesovice M1C3 #4
090125 Plesovice M1C3 #5
090125 Plesovice M1C3 #6
090125 Plesovice M1C3 #7
090125 Plesovice M1C3 #9
090125 Plesovice M1C3 #10
090519_Plesovice_M1C1_#1
090519_Plesovice_M1C1_#2
090519_Plesovice_M1C1_#3
090519_Plesovice_M1C1_#4
090519_Plesovice_M1C1_#5
Average
090714_Plesovice_#VIII digest
176
Hf/177Hf
corrected
0.282420
0.282468
0.282519
0.282480
0.282494
0.282472
0.282522
0.282511
0.282511
0.282489
0.282452
0.282478
0.282507
0.282515
0.282557
0.282469
0.282443
0.282400
0.282455
0.282539
0.282422
0.282436
0.282513
0.282445
0.282526
0.282518
0.282421
0.282408
0.282512
0.282475
0.282595
0.282386
0.282415
0.282469
0.282507
0.282457
0.282414
0.282465
0.282501
0.282433
0.282433
0.282383
0.282394
0.282443
0.282425
0.282471
0.282503
0.282440
0.282514
0.282473
0.282482
0.282493
0.282471
0.282480
Sample
090519_Plesovice_M1C1_#6
090519_Plesovice_M1C1_#8
090519_Plesovice_M1C1_#9
090519_Plesovice_M1C1_#10
090520_Plesovice_M1C1_#1
090520_Plesovice_M1C1_#2
090520_Plesovice_M1C1_#3
090520_Plesovice_M1C1_#4
090520_Plesovice_M1C1_#5
090520_Plesovice_M1C1_#6
090520_Plesovice_M1C1_#7
090520_Plesovice_M1C1_#8
090520_Plesovice_M1C1_#9
090520_Plesovice_M1C1_#10
090520_Plesovice_M1C1_#11
090520_Plesovice_M1C1_#12
090520_Plesovice_M1C3_#13
090520_Plesovice_M1C3_#14
090521_Plesovice_M1C5_#1
090521_Plesovice_M1C5_#2
090521_Plesovice_M1C5_#3
090521_Plesovice_M1C5_#4
090521_Plesovice_M1C5_#5
090521_Plesovice_M1C5_#6
090521_Plesovice_M1C5_#7
090521_Plesovice_M1C5_#8
090521_Plesovice_M1C5_#9
090521_Plesovice_M1C5_#10
090521_Plesovice_M1C5_#11
090521_Plesovice_M1C5_#12
090521_Plesovice_M1C5_#13
090521_Plesovice_M1C5_#14
090521_Plesovice_M1C5_#15
090522_Plesovice_M1C5_#1
090522_Plesovice_M1C5_#2
090522_Plesovice_M1C5_#3
090522_Plesovice_M1C5_#4
090522_Plesovice_M1C5_#5
090522_Plesovice_M1C5_#6
090522_Plesovice_M1C5_#7
090522_Plesovice_M1C3_#8
090522_Plesovice_M1C3_#9
090523_Plesovice_M1C3_#1
090523_Plesovice_M1C3_#2
090523_Plesovice_M1C3_#3
090523_Plesovice_M1C3_#4
090523_Plesovice_M1C3_#5
090523_Plesovice_M1C3_#6
090523_Plesovice_M1C3_#7
090523_Plesovice_M1C3_#8
090523_Plesovice_M1C3_#9
090523_Plesovice_M1C3_#10
2 s.d.
1 s.d.
176
Hf/177Hf
corrected
0.282533
0.282467
0.282491
0.282462
0.282454
0.282442
0.282448
0.282481
0.282481
0.282471
0.282493
0.282438
0.282494
0.282517
0.282493
0.282441
0.282464
0.282474
0.282402
0.282478
0.282487
0.282482
0.282503
0.282486
0.282535
0.282487
0.282420
0.282474
0.282429
0.282429
0.282502
0.282472
0.282503
0.282472
0.282424
0.282481
0.282438
0.282469
0.282487
0.282526
0.282556
0.282469
0.282462
0.282470
0.282451
0.282401
0.282521
0.282433
0.282507
0.282499
0.282416
0.282354
0.000008
0.000022