Differentiated impact melt sheets may be a potential source
of Hadean detrital zircon
Gavin G. Kenny1, Martin J. Whitehouse2, and Balz S. Kamber1
1Department of Geology, School of Natural Sciences, Trinity College Dublin, Dublin 2,
Ireland
2Department of Geosciences, Swedish Museum of Natural History, 104 05 Stockholm,
Sweden ABSTRACT
Constraining the origin and history of very ancient detrital zircons has unique potential for furthering our knowledge of Earth’s very early crust and Hadean
geodynamics. Previous applications of the Ti-in-zircon thermometer to >4 Ga zircons have identified a population with relatively low crystallization temperatures (!!"#!"#$) of ~685 °C. This could possibly indicate wet minimum-melting conditions producing granitic melts, implying very different Hadean terrestrial geology from other rocky planets. Here we report the first comprehensive ion microprobe study of zircons from a transect through the differentiated Sudbury impact melt sheet. The new zircon Ti contents and corresponding !!"#!"#$ fully overlap with those of the Hadean zircon population.
Previous studies, which measured Ti in impact melt sheet zircons did not find this wide range because they analyzed samples only from a restricted portion of the melt sheet and because they used laser ablation analyses that can overestimate true Ti content. It is important to note that internal differentiation of the impact melt is likely a prerequisite for the observed low !!"#!"#$ in zircons from the most evolved rocks. On Earth, melt sheet
differentiation is strongest in subaqueous impact basins. Thus, not all Hadean detrital zircon with low Ti necessarily formed during melting at plate boundaries but at least some could also have crystallized in melt sheets caused by intense meteorite
bombardment of the early, hydrosphere-covered protocrust. INTRODUCTION
In the absence of widespread rocks older than 4 Ga, Hadean detrital zircons up to ca. 4.4 Ga (Valley et al., 2014a), found in Archean metasedimentary rocks, constitute the only direct evidence of geodynamics on early Earth. The first application of the newly discovered thermometer based on the titanium (Ti) content in zircon was thus to this early detrital zircon population. Watson and Harrison (2005) found that the >4.0 Ga population displays a sharp peak in Ti contents of ~5 ppm, corresponding to a Ti-in-zircon
crystallization temperature (!!"#!"#$) of ~685 °C. Further Ti-in-zircon analyses of Hadean zircons (e.g., Harrison and Schmitt, 2007; Trail et al., 2007; Fu et al., 2008) and
recalibration of the thermometer (Ferry and Watson, 2007) have not greatly affected this distribution. Watson and Harrison (2005) argued that the sharp peak in Ti contents, and corresponding !!"#!"#$, represents a regulated melting mechanism reoccurring throughout the Hadean and that together with apparently ‘felsic’ mineral inclusion assemblages (Maas et al., 1992; Cavosie et al., 2004; Hopkins et al., 2008; Bell et al., 2015) this suggests zircon crystallization in granitic melts sensu stricto (s.s.) of crustal anatectic origin. This was further argued to imply extremely early plate tectonic interactions similar to those in operation today. Alternatively, unrelated to zircon Ti contents and inclusion assemblages, others have argued for a granite sensu lato origin for the Hadean zircons. Bouvier et al. (2012) noted that early zircon Li contents and δ7Li values are
distinct from those of zircons crystallized from mantle-derived melts, but similar to those of Archean tonalitic granitoids, suggesting growth in “proto-continental crust”.
Regarding the s.s. granite origin hypothesis, a number of studies have conclusively shown that the modal compositions of inclusions in zircon are not representative of those in the whole rock (e.g., Nutman and Hiess, 2009; Jennings et al., 2011). Most notably, Darling et al. (2009) showed that zircons which crystallized in mafic melts may display ‘felsic’ inclusion assemblages containing quartz, biotite and alkali feldspar due to the often relatively late crystallization of the mineral in residual liquids. While the relatively high abundance of muscovite in Hadean zircons (Hopkins et al., 2008; Bell et al., 2015) deserves further research, this has never been shown as indicative of a granitic host rock. In their comprehensive study of the Ti-in-zircon thermometer, Fu et al. (2008) showed that the !!"#!"#$ of Hadean zircon is not unique to felsic rocks by documenting a number of mafic rock suites with !!"#!"#$ identical to the Hadean grains.
In light of these findings and the clear importance of meteorite bombardment on early Earth, two studies (Darling et al., 2009; Wielicki et al., 2012) have attempted to test whether Hadean zircons could have crystallized in impact melt sheets by using younger impact analogues and modeling. These studies have the limitations that Darling et al. (2009) measured Ti content not by ion microprobe but by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICPMS); and that Wielicki et al. (2012) sampled a restricted portion of the Sudbury melt sheet, missing all the more evolved rock types. Here, we present a new, more comprehensive ion microprobe investigation of zircon covering the full stratigraphy of the differentiated Sudbury impact melt sheet in an
attempt to more thoroughly test the hypothesis that differentiated impact melt sheets may have been a major source of the Hadean detrital zircon population.
SAMPLES
The 2.5–3.0-km-thick impact melt sheet at Sudbury cooled over ~250,000– 500,000 yr (Ivanov and Deutsch, 1999; Davis, 2008), allowing the complex to differentiate into a mafic base (norite), intermediate middle layer (quartz gabbro) and more felsic top (granophyre).
Zircons were separated from 12 samples (five norite, one quartz gabbro and six granophyre) from the southern limb of the impact melt sheet, collected along the transect previously studied by Lightfoot and Zotov (2005) and Darling et al. (2009), and one sample (norite) from the northern limb for comparison (Fig. 1). The zircons are generally euhedral and quite equant with long axes <250 µm, and vary from entirely
cathodoluminescence (CL)-dark to displaying simple oscillatory zoning, consistent with previous observations (Fig. DR1 in GSA Data Repository1) (Darling et al., 2009;
Wielicki et al., 2012).
ANALYTICAL METHODS
Titanium concentrations in zircon were determined by secondary ion mass
spectrometry (SIMS) on the CAMECA IMS1280 ion microprobe at the Swedish Museum of Natural History, Stockholm. NIST610 glass (434 ppm Ti) was used as the calibration reference material (RM) with 91500 (5.2 ± 1.5 ppm Ti; 1 standard deviation [SD]; n = 15; Fu et al., 2008) and Temora-2 (10.2 ± 3.6 ppm Ti; 1 SD; n = 16; Fu et al., 2008) analyzed as zircon quality control materials (QCM). The zircons were later re-polished to remove the SIMS pits and re-analyzed for Ti simultaneously with a selection of rare earth
elements (REE) by LA-ICPMS at Trinity College Dublin. NIST610 was again used as the RM and fresh chips of 91500 and Temora-2 were analyzed as QCM. In a separate
analytical session all grains were U-Pb age dated by LA-ICPMS to confirm that they date to the established 1.85 Ga age of the impact melt sheet (Davis, 2008). Full analytical methods can be found in the Data Repository.
RESULTS
!!"#!"#$ was calculated from measured Ti contents using the calibration of Ferry and Watson (2007):
log ppm Ti = 5.711 ± 0.072 −!"##±!"
! ! − log !SiO! + log !TiO! . (1)
The exact geological significance of the calculated !!"#!"#$ is uncertain, given the effects of variably reduced aTiO2 or aSiO2, variable pressure, possible deviations from Henry’s Law, and subsolidus Ti exchange (Fu et al., 2008). Corrections for reduced
aTiO2 or aSiO2, and variable pressure are generally not applied to the Hadean detrital zircons due to lacking geological context (although many grains do contain quartz inclusions, buffering aSiO2 to 1 at the time of crystallization, and there are rare instances of rutile inclusions buffering aTiO2 to 1; Bell et al., 2015). Consequently, because the ultimate goal of our study was to compare our measured Ti contents (and corresponding !!"#!"#$) in melt sheet zircons with those of the Hadean zircons, we applied the same assumptions to our grains and did not attempt to correct for reduced aTiO2 or aSiO2, and pressure. Thus, calculated !!"#!"#$ are not intended to accurately determine crystallization in the melt sheet but for comparison with the Hadean zircon data. However, we note that
aSiO2 would be constrained to 1 in all studied samples because of consistent presence of magmatic quartz, and aTiO2 would be constrained to 1 in the quartz gabbro unit due to
the presence of rutile (Fig. DR2). In the remainder of the melt sheet titanite and ilmenite occur, constraining aTiO2 to > ~0.6 meaning that !!"#!"#$ may be underestimated by up to ~60–70 °C.
Ti-in-Zircon Thermometry by SIMS
Both QCM analyzed during the SIMS analytical session returned Ti contents in agreement with previously published values (see methods above). Ti concentrations in 91500 were 5.0 ± 0.2 ppm (n = 14; all standard deviations are reported at 1 SD) while Temora-2 yielded 10.7 ± 2.0 ppm (n = 9). Most new SIMS measurements of zircon from the impact melt sheet fall within the range of 1–90 ppm, corresponding to crystallization temperatures of ~600–1000 °C. Outlying higher Ti values up to >6000 ppm are generally associated with Ti-rich mineral inclusions, visible in CL. Individual samples display much tighter ranges of values and the mean Ti concentration measured in each sample generally decreases with increasing stratigraphic height (Fig. 2), as previously noted by Darling et al. (2009) in their LA-ICPMS data set. The notable exceptions are the two stratigraphically highest samples (14GGK131 and 14GGK132) which display anomalously high Ti values (42.0 ± 16.8 ppm [n = 12] and 50.7 ± 16.7 ppm [n = 5], respectively). Given the fact that these grains are extremely altered in CL (Fig. DR1) and invariably enriched in light REE (LREE; Fig. DR3) we confidently attribute their
anomalous Ti concentrations to post-crystallization alteration. Excluding these samples, mean Ti contents vary from 13.1 ± 3.9 ppm (n = 14), corresponding to a !!"#!"#$ of 768 ± 31 °C, in the stratigraphically lowest sample (14GGK107) through to 2.0 ± 0.6 ppm (n = 9), corresponding to 612 ± 21 °C, in the highest remaining sample (14GGK129). The single sample analyzed from the North Range of the Sudbury crater (GSM104) has a
mean Ti concentration of 6.2 ± 2.9 ppm (n = 13), corresponding to 697 ± 32 °C. The granophyre has a mean value of 678 ± 48 °C (n = 53) while the norite has a mean of 742 ± 47 °C (n = 56).
Ti-in-Zircon Thermometry by LA-ICPMS
After the ion microprobe analyses, Ti was also measured by LA-ICPMS to provide a comparison with the published data of Darling et al. (2009), which were noted to be higher than the new ion microprobe data and previous such data (Wielicki et al., 2012). Both QCM analyzed during the LA-ICPMS analytical session returned Ti contents in agreement with previously published values: 91500 yielded 5.2 ± 0.7 ppm (n = 24) while Temora-2 yielded 10.8 ± 2.0 ppm (n = 26). However, 78% of LA-ICPMS measurements of Ti in the unknown zircons from the Sudbury transect produced Ti values that were distinguishably higher (at 1 SD analytical uncertainty) than the corresponding SIMS result.
Rare Earth Element Compositions
Most analyzed zircons from the melt sheet display REE patterns typical of
igneous crustal zircon, with a smooth trend of increasing abundance from LREE to heavy REE (HREE) apart from Ce and Eu anomalies (Hoskin and Schaltegger, 2003). However, all analyzed grains from the two stratigraphically highest samples (14GGK131 and 14GGK132) consistently show extreme LREE-enrichment, here interpreted as pervasive alteration. Consequently the relatively elevated Ti contents of these grains (Fig. 2) are not considered representative of the original magmatic Ti composition and are not considered further.
DISCUSSION
Our new ion microprobe data show that differentiation of a large body of impact melt can produce zircons with magmatic Ti contents fully overlapping the range observed in the Hadean detrital zircon population. The impact melt sheet at Sudbury displays Ti contents in unaltered zircon ranging from 1.2 ± 0.1 ppm to c. 20 ppm, corresponding to apparent !!"#!"#$ values of 578 ± 17 °C to ~815 °C, compared to the Hadean detrital zircon population which has reported Ti contents varying from 1.3 ppm (Trail et al., 2007) to over 20 ppm (Watson and Harrison, 2005; Fu et al., 2008), with most Ti contents greater than ~20 ppm associated with cracks or other crystal imperfections (Harrison and
Schmitt, 2007).
Two previous studies of impact melt sheet zircons did not find the same Ti contents and thus reached the opposite conclusion to our study: namely that impact melt sheets were unlikely major sources of Hadean zircon on the basis of Ti contents. This apparent contradiction has two main reasons. Firstly, we sampled much higher into the differentiated melt sheet than the earlier ion microprobe study by Wielicki et al. (2012). These authors reported average Ti contents of 10.0 ± 3.7 and 11.7 ± 7.2 ppm for two samples of the lowermost norite unit. While our new data for this unit agree, Wielicki et al. (2012) did not discover the clear trend of upward decrease in zircon Ti content and lower apparent !!"#!"#$.
The second reason is that Darling et al. (2009), who studied ten samples spanning a much greater range of stratigraphy than Wielicki et al. (2012), used LA-ICPMS for their analysis. The LA-ICPMS technique yielded apparent Ti contents of no less than 6.5 ppm, corresponding to !!"#!"#$ of ~700 °C, in contrast to our SIMS values as low as 1.2
ppm (~580 °C). The empirical mismatch between LA-ICPMS and ion microprobe Ti content in unknown zircons at Sudbury is also seen in our new comparative data and demands an explanation. Wielicki et al. (2012) hypothesized that the much larger volume of material sampled by LA-ICPMS might increase the likelihood of encountering
extraneous Ti hosted in cracks or inclusions. However, this proposal does not adequately explain all observations of LA-ICPMS data sets, including Ti changing with stratigraphic height or with growth zoning within single crystals. It also does not fully explain why LA-ICPMS yields accurate data for QCM 91500 and Temora-2.
In an effort to offer a more consistent explanation for the elevated Ti content by LA-ICMS, we investigated all the Ti signals of our LA-ICPMS analyses. When plotted as the Ti/Zr intensity ratio, a consistent picture emerged. In RM zircon there is no resolvable downhole fractionation (Fig. DR4). Relatively constant down-hole Ti/Zr traces also characterize sample zircons for which ion microprobe and LA-ICPMS Ti data agree. By contrast, sample zircons for which LA-ICPMS yielded higher apparent Ti contents than ion microprobe all showed a down-hole increase in Ti/Zr intensity ratio. This suggests that the higher Ti values might be artifacts of down-hole elemental fractionation in less-crystalline unknown zircons but a full physical explanation for the observed pattern is beyond the scope of this contribution. We stress that the study of Darling et al. (2009) was undertaken with entirely different LA-ICPMS instrumentation and protocol and we cannot speculate whether down-hole fractionation also affected their analyses.
Regardless, until this issue is resolved, terrestrial analogue studies for Hadean zircon need to use ion microprobe Ti data.
The crystallized Sudbury impact melt sheet is not a perfect analogue for Hadean impact melt bodies because it has a dioritic bulk composition, whereas planetary
protocrusts are envisaged to be more mafic. However, petrological modeling suggests that significant volumes of intermediate-felsic melt can form from initially basaltic impact melt (Grieve et al., 2006), thus producing a wide range of zircon crystallization temperatures and Ti contents. Importantly, at Sudbury the impact melt is overlain by a 1.5-km-thick complex series of breccias and tuffs, produced by repeated explosive
interaction of impact melt with water (Grieve et al., 2010). This deposit provided the melt sheet with sufficient insulation to cool slowly over c. 250,000–500,000 yr (Ivanov and Deutsch, 1999; Davis, 2008) and differentiate, resulting in the wide range of Ti contents and !!"#!"#$ observed in this study. This suggests that a hydrosphere may be necessary to produce a wide range of relatively low !!"#!"#$ in impact melt sheets. This is consistent with other evidence for the early existence of the terrestrial hydrosphere (e.g., Valley et al., 2002) as well as the lack of magmatic differentiation in large lunar impact melt sheets (e.g., the Orientale basin; Spudis et al., 2014) and thus higher Ti contents in lunar zircons (Valley et al., 2014b).
In the norite unit at Sudbury, !!"#!"#$ obtained by ion microprobe is ~100 °C higher than the zircon saturation model temperature,!!"#!"#$, (Watson and Harrison, 1983) at ~650 °C (Lightfoot and Zotov, 2005; Darling et al., 2009). This is typical of the offset observed in many rocks (Harrison et al., 2007). However, in the granophyre unit the calculated !!"#!"#$ of ~680 °C is over 150 °C lower than the !!"#!"#$ of ~850 °C (Lightfoot and Zotov, 2005; Darling et al., 2009). Darling et al. (2009) first noticed this offset and suggested that the composition of the granophyre could be outside the experimentally calibrated
range of Zr saturation studies (Watson and Harrison, 1983). Further work is clearly needed to explain the empirical finding that !!"#!"#$ can be over 150 °C lower than !
!"#!"# in the late stage felsic melts of a differentiated impact melt sheet, despite early-cooling mafic melt following the expected trend of !!"#!"#$ > !
!"#!"#. In light of this, the assumption that !!"#!"#$ = !
!"#!"# + 50 °C in the models of Wielicki et al. (2012), and Wielicki and
Harrison (2015), may not be justified and their findings of relatively high model T!"#!"#$ for impact melts derived from Archean crust (~783 °C) may be based on unsubstantiated assumptions.
Our study shows that impact melt sheets cannot be ruled out as a possible source of the Hadean zircon population on the basis of their Ti contents (Fig. 3). Given the detrital nature of the Hadean zircon population, it is almost certainly not representative of the true distribution of zircons in the Hadean crust (Nebel et al., 2014). The dominant low-!!"#!"#$ population may be a result of preferential selection of certain grains during sedimentary transport or preferential sourcing from a limited provenance area. Our findings are consistent with the latest bombardment model of the Hadean Earth (Marchi et al., 2014) in which the age distribution of Hadean zircons matches the modeled production of impact-generated melt on early Earth.
Titanium contents, and corresponding !!"#!"#$, in the Hadean zircon population may not uniquely require wet, minimum-melting conditions on the early Earth and the implied plate tectonic interactions, but may also have been produced in melt sheets caused by the intense meteorite bombardment of an early, hydrosphere-covered protocrust.
ACKNOWLEDGMENTS
This research was supported by an Irish Research Council ‘Embark’ Initiative scholarship to Kenny, and Science Foundation Ireland grant SFI/12/ERC/E2499 to Kamber. We thank P. Guyett, E. O’Sullivan, and T. Ubide for assistance with sample collection, and J. Petrus and T. Jørgensen for stimulating discussions on impact-related zircon. Three journal reviewers are thanked for their insightful comments which helped to improve the manuscript. This is Nordsim contribution # 449.
REFERENCES CITED
Ames, D.E., Davidson, A., Buckle, J.L., and Card, K.D., 2005, Geology, Sudbury
bedrock compilation, Ontario: Geological Survey of Canada Open File Report 4570. Bell, E.A., Boehnke, P., Hopkins-Wielicki, M.D., and Harrison, T.M., 2015,
Distinguishing primary and secondary inclusion assemblages in Jack Hills zircons: Lithos, v. 234–235, p. 15–26, doi:10.1016/j.lithos.2015.07.014.
Botev, Z.I., Grotowski, J.F., and Kroese, D.P., 2010, Kernel density estimation via diffusion: Annals of Statistics, v. 38, p. 2916–2957, doi:10.1214/10-AOS799. Bouvier, A.-S., Ushikubo, T., Kita, N., Cavosie, A., Kozdon, R., and Valley, J., 2012, Li
isotopes and trace elements as a petrogenetic tracer in zircon: insights from Archean TTGs and sanukitoids: Contributions to Mineralogy and Petrology, v. 163, p. 745– 768, doi:10.1007/s00410-011-0697-1.
Cavosie, A.J., Wilde, S.A., Liu, D., Weiblen, P.W., and Valley, J.W., 2004, Internal zoning and U–Th–Pb chemistry of Jack Hills detrital zircons: A mineral record of early Archean to Mesoproterozoic (4348–1576 Ma) magmatism: Precambrian Research, v. 135, p. 251–279, doi:10.1016/j.precamres.2004.09.001.
Darling, J.R., Storey, C.D., and Hawkesworth, C.J., 2009, Impact melt sheet zircons and their implications for the Hadean crust: Geology, v. 37, p. 927–930,
doi:10.1130/G30251A.1.
Davis, D.W., 2008, Sub-million-year age resolution of Precambrian igneous events by thermal extraction-thermal ionization mass spectrometer Pb dating of zircon: Application to crystallization of the Sudbury impact melt sheet: Geology, v. 36, p. 383–386, doi:10.1130/G24502A.1.
Ferry, J.M., and Watson, E.B., 2007, New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers: Contributions to Mineralogy and Petrology, v. 154, p. 429–437, doi:10.1007/s00410-007-0201-0. Fu, B., Page, F.Z., Cavosie, A., Fournelle, J., Kita, N., Lackey, J., Wilde, S., and Valley,
J., 2008, Ti-in-zircon thermometry: applications and limitations: Contributions to Mineralogy and Petrology, v. 156, p. 197–215, doi:10.1007/s00410-008-0281-5. Grieve, R.A.F., Cintala, M.J., and Therriault, A.M., 2006, Large-scale Impacts and the
Evolution of the Earth’s Crust: The Early Years: Geological Society of America Special Papers, v. 405, p. 23–31.
Grieve, R.A.F., Ames, D.E., Morgan, J.V., and Artemieva, N., 2010, The evolution of the Onaping Formation at the Sudbury impact structure: Meteoritics & Planetary
Science, v. 45, p. 759–782, doi:10.1111/j.1945-5100.2010.01057.x.
Harrison, T.M., and Schmitt, A.K., 2007, High sensitivity mapping of Ti distributions in Hadean zircons: Earth and Planetary Science Letters, v. 261, p. 9–19,
Harrison, T.M., Watson, E.B., and Aikman, A.B., 2007, Temperature spectra of zircon crystallization in plutonic rocks: Geology, v. 35, p. 635–638,
doi:10.1130/G23505A.1.
Hopkins, M., Harrison, T.M., and Manning, C.E., 2008, Low heat flow inferred from >4-Gyr zircons suggests Hadean plate boundary interactions: Nature, v. 456, p. 493– 496, doi:10.1038/nature07465.
Hoskin, P.W.O., and Schaltegger, U., 2003, The composition of zircon and igneous and metamorphic petrogenesis: Reviews in Mineralogy and Geochemistry, v. 53, p. 27– 62, doi:10.2113/0530027.
Ivanov, B.A., and Deutsch, A., 1999, Sudbury Impact Event: Cratering Mechanics and Thermal History: Geological Society of America Special Papers, v. 339, p. 389–397. Jennings, E.S., Marschall, H.R., Hawkesworth, C.J., and Storey, C.D., 2011,
Characterization of magma from inclusions in zircon: Apatite and biotite work well, feldspar less so: Geology, v. 39, p. 863–866, doi:10.1130/G32037.1.
Lightfoot, P.C., and Zotov, I.A., 2005, Geology and geochemistry of the Sudbury Igneous Complex, Ontario, Canada: Origin of nickel sulfide mineralization associated with an impact-generated melt sheet: Geology of Ore Deposits, v. 47, p. 349–381.
Maas, R., Kinny, P.D., Williams, I.S., Froude, D.O., and Compston, W., 1992, The Earth’s oldest known crust: A geochronological and geochemical study of 3900– 4200 Ma old detrital zircons from Mt. Narryer and Jack Hills, Western Australia: Geochimica et Cosmochimica Acta, v. 56, p. 1281–1300, doi:10.1016/0016-7037(92)90062-N.
Marchi, S., Bottke, W.F., Elkins-Tanton, L.T., Bierhaus, M., Wuennemann, K., Morbidelli, A., and Kring, D.A., 2014, Widespread mixing and burial of Earth’s Hadean crust by asteroid impacts: Nature, v. 511, p. 578–582,
doi:10.1038/nature13539.
Nebel, O., Rapp, R.P., and Yaxley, G.M., 2014, The role of detrital zircons in Hadean crustal research: Lithos, v. 190–191, p. 313–327, doi:10.1016/j.lithos.2013.12.010. Nutman, A.P., and Hiess, J., 2009, A granitic inclusion suite within igneous zircons from
a 3.81 Ga tonalite (W. Greenland): Restrictions for Hadean crustal evolution studies using detrital zircons: Chemical Geology, v. 261, p. 77–82,
doi:10.1016/j.chemgeo.2008.09.005.
Spudis, P.D., Martin, D.J.P., and Kramer, G., 2014, Geology and composition of the Orientale Basin impact melt sheet: Journal of Geophysical Research: Planets, v. 119, p. 19–29, doi:10.1002/2013JE004521.
Trail, D., Mojzsis, S.J., Harrison, T.M., Schmitt, A.K., Watson, E.B., and Young, E.D., 2007, Constraints on Hadean zircon protoliths from oxygen isotopes,
Ti-thermometry, and rare earth elements: Geochemistry Geophysics Geosystems, v. 8, doi:10.1029/2006GC001449.
Valley, J.W., Peck, W.H., King, E.M., and Wilde, S.A., 2002, A cool early Earth: Geology, v. 30, p. 351–354,
doi:10.1130/0091-7613(2002)030<0351:ACEE>2.0.CO;2.
Valley, J.W., et al., 2014a, Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography: Nature Geoscience, v. 7, p. 219–223,
Valley, J.W., Spicuzza, M.J., and Ushikubo, T., 2014b, Correlated δ18O and [Ti] in lunar zircons: a terrestrial perspective for magma temperatures and water content on the Moon: Contributions to Mineralogy and Petrology, v. 167, p. 1–15,
doi:10.1007/s00410-013-0956-4.
Watson, E.B., and Harrison, T.M., 1983, Zircon saturation revisited: Temperature and composition effects in a variety of crustal magma types: Earth and Planetary Science Letters, v. 64, p. 295–304, doi:10.1016/0012-821X(83)90211-X.
Watson, E.B., and Harrison, T.M., 2005, Zircon thermometer reveals minimum melting conditions on earliest Earth: Science, v. 308, p. 841–844,
doi:10.1126/science.1110873.
Wielicki, M.M., Harrison, T.M., and Schmitt, A.K., 2012, Geochemical signatures and magmatic stability of terrestrial impact produced zircon: Earth and Planetary Science Letters, v. 321, p. 20–31, doi:10.1016/j.epsl.2012.01.009.
Wielicki, M.M., and Harrison, T.M., 2015, Zircon Formation in Impact Melts:
Complications for Deciphering Planetary Impact Histories: Geological Society of America Special Papers, v. 518, p. 127–134.
FIGURES
Figure 1. Map of sampling locations in the Sudbury impact melt sheet (Canada). Location of sample GSM104 from the North Range is shown in inset map. Lakes are shown in white. Maps modified from Ames et al. (2005).
Figure 2. Ti-in-zircon crystallization temperature (!!"#!"#$) for Ti content measured by secondary ion mass spectrometry. Average error of 13 °C (1 SD) includes uncertainty introduced when calculating Ti-in-zircon crystallization temperature from Ti content. Outliers, shown in gray, were excluded when calculating sample means, which are shown by open symbols. Elevated Ti contents of uppermost two samples are related to alteration (see text). Nor.—norite; Q.G—quartz gabbro; Gran—granophyre; alt. —altered.
Figure 3. Comparison of Ti (and Ti-in-zircon crystallization temperature, T!"#!"#$)
distribution in the Hadean zircon population with that of melt sheet zircons at Sudbury. Curves represent all analyses and not grain averages. Analyses with Ti >100 ppm have been excluded. The following numbers refer to: number of analyses/number of grains analyzed/number of samples. Hadean data compiled from Fu et al. (2008), Harrison and Schmitt (2007), Trail et al. (2007), and Watson and Harrison (2005): 286/134/34;
Sudbury transect (this study) 124/124/10; Sudbury granophyre only (this study) 54/54/4; Sudbury samples (Wielicki et al., 2012) 26/26/2; Sudbury transect (Darling et al., 2009) 144/120/10. All data obtained by ion microprobe except Darling et al. (2009) which is LA-ICPMS data. Kernel density estimates (KDE) were produced in MATLAB using the free software package of Botev et al. (2010) which implements an automatic bandwidth selection method.
1GSA Data Repository item 2016143, full analytical methods, Figure DR1 (CL images of melt sheet zircons), Figure DR2 (images of Ti-bearing phases), Figure DR3 (zircon REE diagrams), Figure DR4 (variation in Ti/Zr during LA-ICPMS analyses), and Table DR1 (Ti and REE data), is available online at www.geosociety.org/pubs/ft2016.htm, or on request from editing@geosociety.org or Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301, USA.
Text DR2. Full analytical methods.
Following CL imaging, Ti concentrations in zircon were determined by secondary ion mass spectrometry (SIMS) on the CAMECA IMS1280 large geometry ion
microprobe at the Swedish Museum of Natural History. Ti was measured on the 49Ti peak due to Zr2+ interferences on 46Ti, 47Ti and 48Ti and possible interferences of 50Cr and 50V on 50Ti, although these are probably minimal (Coogan and Hinton, 2006). An O2- primary beam of c. 4.5 nA was used to sample a c. 15 µm spot. Sputtered
secondary ions were admitted to the mass spectrometer via high transmission transfer ion optics and measured in peak-hopping mode in either a Faraday detector (28Si) or low-noise, ion-counting electron multiplier (30Si and 49Ti) at a mass resolution (M/ΔM) of 3000. The 28Si signal was used only for beam centering at the start of the analysis, following a pre-sputter to remove the Au coating. NIST610 glass (434 ± 14.7 ppm Ti; 1 standard deviation [SD]; (Pearce et al., 1997)) was used as the
calibration reference material (RM) with 91500 (5.2 ± 1.5 ppm Ti; 1SD; n=15; (Fu et al., 2008)) and Temora-2 (10.2 ± 3.6 ppm Ti; 1SD; n=16; (Fu et al., 2008)) analyzed as quality control materials (QCM). In order to account for matrix differences between NIST standard glass, used as the RM, and zircon previous workers have applied correction factors to their zircon results – e.g. Fu et al. (2008) applied a correction factor of 1.16 to all of their zircon Ti measurements, based on their observation of a 16 % difference in “relative sensitivity factor” (RSF) between NIST and zircon. In contrast, by energy filtering the 30Si and 49Ti species (at -90 eV using a 30 eV bandpass), we here obtained perfectly accurate results for the zircon QCM 91500 and Temora-2 which are indistinguishable from previously published values, including the final, corrected, values of Fu et al. (2008), without the need for any post-analysis correction. Following SIMS analysis, the zircons were then polished down approximately 3-4 µm to remove the SIMS analysis pits. Ti was then measured simultaneously with a selection of rare earth elements (REE) were then measured by LA-ICPMS using a Photon Machines Analyte Excite 193 nm ArF laser coupled to a Thermo Scientific iCAP Qc at Trinity College Dublin. NIST610 was again used as the RM and fresh chips of 91500 and Temora-2 were analyzed as QCM. Zr was used as an internal standard. In a separate analytical session all grains were U-Pb age dated by LA-ICPMS to confirm they date to the established 1.85 Ga age of the impact melt sheet (Davis, 2008) and are not inherited. A 24 µm-diameter circular spot was used for all LA-ICPMS analyses.
Additional references
Pearce, N. J. G., Perkins, W. T., Westgate, J. A., Gorton, M. P., Jackson, S. E., Neal, C. R., and Chenery, S. P., 1997, A Compilation of New and Published Major and Trace Element Data for NIST SRM 610 and NIST SRM 612 Glass Reference Materials: Geostandards Newsletter, v. 21, no. 1, p. 115-144.
Figure DR1. Example CL images of zircon from the Sudbury melt sheet. A: A CL-dark zircon from the
norite. B: A zircon from the granophyre displaying fine igneous growth zoning. C: A zircon from the granophyre displaying subtle igneous growth zoning close to its perimeter. D: An extremely altered zircon from close to the top of the melt sheet. All scale bars 50 µm.
Figure DR2. Examples of Ti-bearing phases observed in the Sudbury melt sheet. A: An example of Ti-bearing titanite with its distinctive pyramidal form in the
Granophyre unit. Image taken in plane polarized light. B: An example of rutile found in mineral separates from the Quartz Gabbro. C: Scanning Electron Microscopy image of location selected for qualitative energy-dispersive X-ray analysis (EDS) on grain shown in B. D. EDS energy spectrum for analysis location shown in C. Ti and O peaks confirm the presence of a Ti-oxide in the Sudbury melt sheet. The C peak is due to carbon coating of the sample to prevent electron charging. All scale bars 50 µm.
Figure DR3. Chondrite-normalized abundances of REE in Sudbury melt sheet zircons. Normalization uses the chondrite values of Anders and Grevesse (1989).
Elements are spaced according to their effective ionic radii in eightfold coordination (Shannon, 1976), indicated in picometres on the upper x-axis. Blue: norite; green: quartz gabbro; red: granophyre.
Anders, E., and Grevesse, N., 1989, Abundances of the elements: Meteoritic and solar: Geochimica et Cosmochimica Acta, v. 53, no. 1, p. 197‐214.
Shannon, R. D., 1976, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides: Acta Crystallographica Section A: Crystal Physics, Diffraction, Theoretical and General Crystallography, v. 32, p. 751‐767.
Figure DR4. Downhole variation in Ti/Zr ratio during laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) analyses of Ti in zircon. Traces
represent the five period moving average of the geometric mean of background-corrected signal ratios. Note that the Y-axis represents ablation time and cannot be strictly equated with depth, as ablation progresses more effectively in zircon of lower crystallinity. A: Quality control material (QCM) standard zircons 91500 (mean of n=24 analyses) and Temora-2 (n=26) show no appreciable Ti/Zr fractionation with ablation progress. This is consistent with the accurate measurement of Ti in these natural standards by LA-ICPMS, yielding results indistinguishable from SIMS. B: Comparative down-hole evolution of Ti/Zr in three sample zircons shows two contrasting types of behavior. First, unknown zircons in which Ti measured by LA-ICPMS was distinguishably higher (at 1 SD analytical uncertainty) than Ti measured by SIMS consistently show consistent trends of increasing Ti/Zr ratios down-hole. This is illustrated with samples 14GGK110 (n=12) and GSM073 (n=17). In the sample 14GGK110, for example, all apparent Ti concentrations by LA-ICPMS were distinguishably higher than the corresponding SIMS analysis. Second, for the samples in which Ti concentrations by LA-ICPMS and SIMS are generally in better
agreement, there is no clear down-hole Ti/Zr increase. This is shown for sample 14GGK118 (n=12; excluding one outlier).
The inspection of down-hole Ti/Zr signals suggests that the over-estimation of Ti content in some sample zircons analyzed in this study is related to more efficient transport and ionization of Ti with increasing pit depth compared to the calibration and quality control zircons. This contrasts with the proposal of Wielicki et al. (2011) who attributed the offset between SIMS and LA-ICPMS to the larger sampling volume of LA-ICPMS, thereby enhancing the probability of encountering discrete zones of extraneously high Ti.
Down-hole elemental fractionation is widely recognized as one of the most significant difficulties associated with LA-ICPMS of zircon, particularly in U/Pb dating (e.g. Allen and Campbell, 2012; Marillo-Sialer et al., 2014). A factor that contributes to this problem and distinguishes zircon from many other silicates, is the alpha-dose-induced lattice damage, which in many sample zircons is much higher than in standard zircons. As a result of these “matrix effects”, different zircons ablate at different rates, resulting in different pit depths and concomitant different elemental behavior over the course of the ablation. It remains to be addressed to which extent the apparent down-hole inter-element fractionation is related to the difficulty of transporting aerosols from the pit to the plasma and/or to the particle size distribution of ablated zircon, and/or the efficiency with which different elements are ionized from particles produced from zircon of different crystallinity.
Regardless, in the present dataset, it is clear that the over-estimation of Ti
concentration in some LA-ICPMS analyses can be attributed to the uncorrected for down-hole increase in Ti/Zr ratio. This is be consistent with a number of observations, including: 1) LA-ICPMS analyses of Ti in QCM standard zircons (such as 91500 and Temora-2) return values in agreement with published ion microprobe data (as
standard zircons have accumulated relatively low alpha-dose-induced lattice damage, resulting in predictable ablation and no fractionation between Ti and Zr); 2) multiple analyses on single unknown zircons by LA-ICPMS may still show systematic variation from core to rim (this would not be expected if higher Ti values were a result of encountering extraneous Ti); 3) LA-ICPMS studies are likely to still pick up real stratigraphic variation in zircon Ti content, despite potentially being offset to higher values than would be measured by SIMS. This final point is significant as it is one of the reasons that LA-ICPMS studies of Ti in zircon should not be dismissed as inherently problematic. However, caution should clearly be applied when comparing LA-ICPMS and SIMS data for Ti concentrations in zircon.
Additional references
Allen, C. M., and Campbell, I. H., 2012, Identification and elimination of a
matrix-induced systematic error in LA–ICP–MS 206Pb/238U dating of zircon:
Chemical Geology, v. 332–333, p. 157-165.
Marillo-Sialer, E., Woodhead, J., Hergt, J., Greig, A., Guillong, M., Gleadow, A., Evans, N., and Paton, C., 2014, The zircon 'matrix effect': evidence for an ablation rate control on the accuracy of U-Pb age determinations by LA-ICP-MS: Journal of Analytical Atomic Spectrometry, v. 29, no. 6, p. 981-989.
20 16 14 3 Ta bl e D R1 T i a nd RE E da ta Sam pl e/ SIMS F+W 2 00 7 LA -IC PMS F+W 2 00 7 N or m al ize d (A nd er s an d G re ve ss e 19 89 ) Spot unit Eas tin g* N or th in g* Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD La Ce Pr Nd Sm Eu Gd Dy Er Yb *N AD 83 U TM zo ne 1 7N G K_1 4G G K1 07 _T i-zr n_@1 N or ite (Q uar tz-ric h) 484424 5145043 13. 75 0. 31 777 13 23. 30 1. 10 832 14 3. 11 328 14 37 171 51 606 1553 3323 4782 G K_1 4G G K1 07 _T i-zr n_@0 2 N or ite (Q uar tz-ric h) 484424 5145043 12. 15 0. 28 764 13 20. 10 1. 45 816 15 15. 00 163 52 87 224 386 531 1323 3121 4966 G K_1 4G G K1 07 _T i-zr n_@0 3 N or ite (Q uar tz-ric h) 484424 5145043 7. 72 0. 23 722 12 11. 80 0. 75 762 14 1. 09 288 22 63 284 53 977 2794 6425 9175 G K_1 4G G K1 07 _T i-zr n_@0 4 N or ite (Q uar tz-ric h) 484424 5145043 6. 80 0. 19 711 12 10. 80 0. 85 753 14 1. 03 206 15 45 205 46 745 2048 4632 6732 G K_1 4G G K1 07 _T i-zr n_@0 5 N or ite (Q uar tz-ric h) 484424 5145043 12. 93 0. 30 770 13 13. 90 0. 80 778 14 1. 24 190 9 22 106 34 360 1104 2838 4868 G K_1 4G G K1 07 _T i-zr n_@0 6 N or ite (Q uar tz-ric h) 484424 5145043 11. 75 0. 28 761 12 11. 30 0. 80 757 14 0. 26 148 10 31 162 26 521 1607 4147 6788 G K_1 4G G K1 07 _T i-zr n_@0 7 N or ite (Q uar tz-ric h) 484424 5145043 13. 95 0. 35 778 13 11. 60 1. 20 760 16 5. 84 195 16 39 172 52 581 2044 5356 8646 G K_1 4G G K1 07 _T i-zr n_@0 8 N or ite (Q uar tz-ric h) 484424 5145043 18. 53 0. 39 807 13 21. 70 1. 35 824 15 12. 78 144 28 53 166 147 433 1047 2096 3083 G K_1 4G G K1 07 _T i-zr n_@0 9 N or ite (Q uar tz-ric h) 484424 5145043 19. 93 0. 45 815 13 17. 30 1. 25 800 15 23. 01 264 70 112 303 330 885 2464 5456 8615 G K_1 4G G K1 07 _T i-zr n_@1 0 N or ite (Q uar tz-ric h) 484424 5145043 11. 81 0. 34 762 13 14. 60 0. 75 783 14 1. 24 212 19 50 241 60 860 2180 4386 6283 G K_1 4G G K1 07 _T i-zr n_@1 1 N or ite (Q uar tz-ric h) 484424 5145043 8. 17 0. 21 727 12 9. 80 0. 70 744 14 0. 13 116 6 21 121 23 418 1117 2366 3483 G K_1 4G G K1 07 _T i-zr n_@1 2 N or ite (Q uar tz-ric h) 484424 5145043 12. 90 1. 17 770 15 11. 90 0. 90 762 14 8. 18 137 26 51 150 138 454 1220 2889 4757 G K_1 4G G K1 07 _T i-zr n_@1 3 N or ite (Q uar tz-ric h) 484424 5145043 15. 54 0. 39 789 13 19. 70 1. 15 814 15 0. 91 327 15 44 198 46 804 2501 5840 7834 G K_1 4G G K1 07 _T i-zr n_@1 4 N or ite (Q uar tz-ric h) 484424 5145043 16. 92 0. 38 798 13 18. 40 0. 65 806 14 0. 20 225 7 22 109 25 381 1034 2284 3403 G K_1 4G G K1 10 _T i-zr n_@1 No rit e 484398 5145216 6. 20 0. 18 703 12 16. 90 1. 45 798 16 18. 58 230 40 74 212 364 540 1327 2832 4338 G K_1 4G G K1 10 _T i-zr n_@0 2 No rit e 484398 5145216 4. 75 0. 15 680 11 7. 60 0. 85 721 15 1. 01 143 13 36 169 97 551 1520 3210 4825 G K_1 4G G K1 10 _T i-zr n_@0 3 No rit e 484398 5145216 5. 07 0. 16 686 11 8. 10 1. 20 726 18 0. 23 228 13 41 228 29 760 2233 5009 7778 G K_1 4G G K1 10 _T i-zr n_@0 4 No rit e 484398 5145216 5. 35 0. 16 690 11 7. 00 0. 70 713 14 0. 26 143 10 33 164 24 576 1611 3593 5145 G K_1 4G G K1 10 _T i-zr n_@0 5 No rit e 484398 5145216 11. 21 0. 27 757 12 22. 40 1. 10 828 14 0. 37 187 8 25 131 30 455 1290 3134 4788 G K_1 4G G K1 10 _T i-zr n_@0 6 No rit e 484398 5145216 6. 32 0. 19 704 12 11. 80 1. 25 762 16 6. 73 161 31 58 186 164 573 1541 3235 4942 G K_1 4G G K1 10 _T i-zr n_@0 7 No rit e 484398 5145216 13. 24 0. 36 773 13 17. 00 1. 90 798 17 20. 37 287 58 106 283 618 783 2435 6583 9766 G K_1 4G G K1 10 _T i-zr n_@0 8 No rit e 484398 5145216 1. 96 0. 09 613 10 4. 90 0. 60 683 15 0. 51 142 7 23 143 25 521 1467 3480 5268 G K_1 4G G K1 10 _T i-zr n_@0 9 No rit e 484398 5145216 6. 74 0. 21 710 12 10. 80 0. 65 753 13 0. 49 246 17 54 263 38 915 2485 5437 7846 G K_1 4G G K1 10 _T i-zr n_@1 0 No rit e 484398 5145216 6. 23 0. 19 703 12 7. 30 0. 70 717 14 0. 09 177 4 13 77 11 302 959 2391 3932 G K_1 4G G K1 10 _T i-zr n_@1 1 No rit e 484398 5145216 11. 04 0. 27 755 12 13. 50 0. 70 775 14 1. 47 438 31 90 438 71 1673 4211 8716 11711 G K_1 4G G K1 10 _T i-zr n_@1 2 No rit e 484398 5145216 9. 06 0. 23 737 12 18. 50 1. 20 807 15 64. 76 212 104 148 229 857 456 919 2058 3698 G K_1 4G G K1 12 _T i-zr n_@0 1 No rit e 484354 5145675 6. 45 0. 19 706 12 13. 10 0. 75 772 14 0. 63 249 11 34 157 28 627 1636 3499 5040 G K_1 4G G K1 12 _T i-zr n_@0 2 No rit e 484354 5145675 12. 97 0. 31 771 13 16. 20 0. 85 793 14 1. 67 620 38 116 617 109 2004 4619 8263 10763 G K_1 4G G K1 12 _T i-zr n_@0 3 No rit e 484354 5145675 11. 30 0. 28 757 12 15. 90 0. 95 791 14 0. 99 329 23 70 351 64 1233 2950 5790 7932 G K_1 4G G K1 12 _T i-zr n_@0 4 No rit e 484354 5145675 10. 81 0. 26 753 12 14. 10 0. 90 779 14 0. 93 431 26 73 396 68 1394 3354 6463 8425 G K_1 4G G K1 12 _T i-zr n_@0 5 No rit e 484354 5145675 8. 91 0. 23 735 12 9. 50 0. 60 741 13 0. 63 350 20 62 322 51 1135 3004 6174 8505 G K_1 4G G K1 12 _T i-zr n_@0 6 No rit e 484354 5145675 4. 46 0. 15 675 11 8. 50 0. 70 731 14 0. 41 152 8 25 151 23 538 1483 3172 4517 G K_1 4G G K1 12 _T i-zr n_@0 7 No rit e 484354 5145675 10. 01 0. 25 746 12 8. 90 0. 75 735 14 1. 68 157 15 41 165 34 546 1677 4317 6812 G K_1 4G G K1 12 _T i-zr n_@0 8 No rit e 484354 5145675 1. 96 0. 09 613 10 7. 00 0. 80 713 15 0. 40 312 12 42 236 33 832 2365 5192 7625 G K_1 4G G K1 12 _T i-zr n_@0 9 No rit e 484354 5145675 7. 45 0. 21 719 12 9. 90 0. 65 745 13 0. 34 202 14 45 220 32 762 1978 4147 5600 G K_1 4G G K1 12 _T i-zr n_@1 0 No rit e 484354 5145675 12. 15 0. 31 764 13 21. 50 1. 30 823 15 1. 15 331 21 61 381 74 1333 3210 5922 7828 G K_1 4G G K1 12 _T i-zr n_@1 1 No rit e 484354 5145675 11. 49 0. 27 759 12 12. 70 0. 70 769 14 4. 86 182 23 52 228 65 680 1698 3335 4511 G K_1 4G G K1 12 _T i-zr n_@1 2 No rit e 484354 5145675 14. 26 0. 32 780 13 16. 60 0. 90 796 14 2. 17 214 18 48 277 70 1068 2480 4852 6357 G K_1 4G G K1 12 _T i-zr n_@1 3 No rit e 484354 5145675 309. 98 10. 35 1218 22 650. 00 22. 50 1383 27 16. 96 111 36 44 113 111 256 622 1309 2215 G K_1 4G G K1 12 _T i-zr n_@1 4 No rit e 484354 5145675 7. 73 0. 21 722 12 10. 00 0. 60 746 13 0. 13 138 5 21 126 22 478 1244 2549 3452 G K_1 4G G K1 18 _T i-zr n_@1 No rit e 484230 5146788 11. 00 0. 27 755 12 12. 50 0. 80 767 14 0. 47 205 13 43 217 30 872 2151 3877 4966 G K_1 4G G K1 18 _T i-zr n_@0 2 No rit e 484230 5146788 14. 91 0. 37 785 13 15. 30 0. 70 787 14 1. 06 473 25 79 494 64 1663 3568 6193 7477 G K_1 4G G K1 18 _T i-zr n_@0 3 No rit e 484230 5146788 10. 17 0. 25 747 12 18. 70 1. 40 808 15 4. 99 183 30 65 208 49 640 1796 3549 4505 G K_1 4G G K1 18 _T i-zr n_@0 4 No rit e 484230 5146788 11. 45 0. 28 759 12 12. 50 0. 80 767 14 0. 60 259 17 50 283 36 1160 2662 4890 6049 G K_1 4G G K1 18 _T i-zr n_@0 5 No rit e 484230 5146788 15. 96 0. 39 792 13 19. 20 0. 95 811 14 0. 79 266 18 53 297 48 1226 2995 5488 6708 G K_1 4G G K1 18 _T i-zr n_@0 6 No rit e 484230 5146788 9. 72 0. 24 743 12 11. 80 0. 65 762 13 0. 91 358 21 63 358 52 1541 3712 6558 8062 G K_1 4G G K1 18 _T i-zr n_@0 7 No rit e 484230 5146788 13. 09 0. 30 772 13 14. 70 0. 70 783 14 0. 49 193 14 41 223 32 843 2068 3870 4788 G K_1 4G G K1 18 _T i-zr n_@0 8 No rit e 484230 5146788 12. 76 0. 30 769 13 12. 90 0. 70 770 14 0. 66 303 19 56 325 43 1302 3070 5532 6966 G K_1 4G G K1 18 _T i-zr n_@0 9 No rit e 484230 5146788 15. 66 0. 35 790 13 21. 00 0. 80 821 14 15. 76 276 30 55 234 47 712 1644 3027 3895 G K_1 4G G K1 18 _T i-zr n_@1 0 No rit e 484230 5146788 10. 56 0. 26 751 12 15. 90 0. 65 791 13 1. 58 675 37 103 487 58 1857 4306 8024 10289 G K_1 4G G K1 18 _T i-zr n_@1 1 No rit e 484230 5146788 1. 66 0. 10 601 11 4. 90 0. 60 683 15 0. 18 182 9 30 164 17 556 1471 3096 4640 G K_1 4G G K1 18 _T i-zr n_@1 2 No rit e 484230 5146788 15. 98 0. 39 792 13 41. 70 2. 55 900 17 8. 48 302 28 64 290 60 946 2110 3713 4898 G K_1 4G G K1 18 _T i-zr n_@1 3 No rit e 484230 5146788 20. 60 0. 98 818 14 49. 00 5. 50 921 21 35. 79 373 56 99 355 62 1043 2431 4355 5631 G K_1 4G G K1 21 _T i-zr n_@1 No rit e 484184 5147468 8. 66 0. 23 732 12 18. 50 1. 10 807 14 2. 56 540 30 96 553 49 1872 4508 8527 11231 G K_1 4G G K1 21 _T i-zr n_@2 No rit e 484184 5147468 48. 08 0. 88 918 15 40. 60 1. 25 897 15 157. 65 1956 1284 1112 487 254 214 108 128 287 G K_1 4G G K1 21 _T i-zr n_@3 No rit e 484184 5147468 8. 95 0. 23 735 12 14. 40 1. 30 781 16 9. 59 723 15 35 220 14 800 2283 5381 8658 G K_1 4G G K1 21 _T i-zr n_@4 No rit e 484184 5147468 19. 11 1. 00 810 14 8. 70 1. 05 733 16 5. 71 176 19 43 195 118 612 1475 3103 7458
20 16 14 3 Ta bl e D R1 T i a nd RE E da ta Sam pl e/ SIMS F+W 2 00 7 LA -IC PMS F+W 2 00 7 N or m al ize d (A nd er s an d G re ve ss e 19 89 ) Spot unit Eas tin g* N or th in g* Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD La Ce Pr Nd Sm Eu Gd Dy Er Yb *N AD 83 U TM zo ne 1 7N G K_1 4G G K1 21 _T i-zr n_@5 No rit e 484184 5147468 12. 80 0. 35 769 13 7. 20 0. 70 716 14 5. 20 158 8 13 47 27 202 1030 4110 11015 G K_1 4G G K1 21 _T i-zr n_@6 No rit e 484184 5147468 1764. 52 31. 36 1675 34 2780. 00 265. 00 1844 55 108. 65 275 138 210 426 209 696 1351 2876 4985 G K_1 4G G K1 21 _T i-zr n_@7 No rit e 484184 5147468 6. 70 0. 45 710 13 21. 40 2. 25 823 18 234. 34 403 246 334 462 677 570 919 2366 4474 G K_1 4G G K1 21 _T i-zr n_@8 No rit e 484184 5147468 180. 51 4. 95 1116 20 332. 00 13. 50 1232 23 275. 24 565 618 913 1557 2766 1775 1430 2253 4406 G K_1 4G G K1 23 _T i-zr n_@1 Q uar tz G ab br o 484165 5148518 29. 96 0. 88 860 14 18. 00 2. 15 804 18 45. 16 220 59 82 247 80 789 2320 6010 12000 G K_1 4G G K1 23 _T i-zr n_@0 2 Q uar tz G ab br o 484165 5148518 6. 06 0. 18 701 12 7. 30 0. 85 717 15 16. 83 75 29 48 180 51 662 1768 3883 5483 G K_1 4G G K1 23 _T i-zr n_@0 3 Q uar tz G ab br o 484165 5148518 45. 41 0. 91 911 15 20. 80 1. 45 820 15 16. 53 224 19 42 222 31 878 2892 6614 10492 G K_1 4G G K1 23 _T i-zr n_@0 4 Q uar tz G ab br o 484165 5148518 12. 66 0. 35 768 13 74. 20 3. 50 977 18 5496. 38 3282 3221 2608 1475 879 1043 1508 3109 4837 G K_1 4G G K1 23 _T i-zr n_@0 5 Q uar tz G ab br o 484165 5148518 9. 77 0. 27 744 12 13. 20 0. 65 773 13 2. 55 24 10 27 109 30 358 861 1919 2935 G K_1 4G G K1 23 _T i-zr n_@0 6 Q uar tz G ab br o 484165 5148518 6. 79 0. 21 711 12 19. 30 2. 55 811 19 323. 82 288 186 228 355 104 987 2505 5444 8123 G K_1 4G G K1 23 _T i-zr n_@0 7 Q uar tz G ab br o 484165 5148518 7. 30 0. 20 717 12 18. 60 2. 80 808 21 6. 60 7 3 3 7 5 31 111 319 680 G K_1 4G G K1 23 _T i-zr n_@0 8 Q uar tz G ab br o 484165 5148518 8. 84 0. 44 734 13 6. 80 0. 65 711 14 3. 20 110 8 14 71 10 311 1084 2763 4548 G K_1 4G G K1 23 _T i-zr n_@0 9 Q uar tz G ab br o 484165 5148518 2. 64 0. 11 634 11 5. 90 1. 10 698 19 21. 69 91 49 66 80 64 149 353 829 1532 G K_1 4G G K1 23 _T i-zr n_@1 0 Q uar tz G ab br o 484165 5148518 25. 21 1. 78 841 16 14. 20 1. 25 780 15 64. 34 183 135 128 199 105 215 470 1171 2609 G K_1 4G G K1 23 _T i-zr n_@1 1 Q uar tz G ab br o 484165 5148518 4. 12 0. 14 669 11 68. 00 11. 50 964 28 11. 29 109 27 41 132 93 412 1265 2889 5108 G K_1 4G G K1 25 _T i-zr n_@1 G ran op hy re 484265 5149033 6. 56 0. 19 708 12 9. 60 0. 55 742 13 0. 13 24 3 11 59 10 203 548 1347 2222 G K_1 4G G K1 25 _T i-zr n_@0 2 G ran op hy re 484265 5149033 7. 06 0. 20 714 12 7. 90 0. 70 724 14 3. 20 32 8 24 101 21 342 911 1970 3138 G K_1 4G G K1 25 _T i-zr n_@0 3 G ran op hy re 484265 5149033 8. 47 0. 24 730 12 9. 50 0. 55 741 13 0. 29 24 8 27 114 26 374 914 2014 3065 G K_1 4G G K1 25 _T i-zr n_@0 4 G ran op hy re 484265 5149033 8. 39 0. 22 729 12 8. 90 0. 80 735 14 1. 31 25 9 28 120 25 371 887 2020 2948 G K_1 4G G K1 25 _T i-zr n_@0 5 G ran op hy re 484265 5149033 10. 48 0. 44 750 13 11. 70 0. 70 761 14 26. 84 48 30 44 115 26 346 873 1951 3028 G K_1 4G G K1 25 _T i-zr n_@0 6 G ran op hy re 484265 5149033 8. 80 0. 23 734 12 9. 40 0. 65 740 14 15. 76 40 23 40 122 26 393 968 2115 3243 G K_1 4G G K1 25 _T i-zr n_@0 7 G ran op hy re 484265 5149033 10. 02 0. 25 746 12 36. 40 2. 60 884 17 80. 95 90 56 55 90 20 269 661 1485 2388 G K_1 4G G K1 25 _T i-zr n_@0 8 G ran op hy re 484265 5149033 7. 93 0. 21 724 12 11. 70 0. 70 761 14 289. 73 333 266 252 244 48 409 871 1938 2966 G K_1 4G G K1 25 _T i-zr n_@0 9 G ran op hy re 484265 5149033 9. 10 0. 23 737 12 11. 50 0. 75 759 14 3. 66 30 9 20 89 21 312 754 1705 2665 G K_1 4G G K1 25 _T i-zr n_@1 0 G ran op hy re 484265 5149033 6378. 24 104. 91 2245 53 603. 00 42. 00 1365 30 28. 63 31 24 28 63 19 185 515 1095 1822 G K_1 4G G K1 25 _T i-zr n_@1 1 G ran op hy re 484265 5149033 7. 73 0. 24 722 12 14. 60 2. 00 783 19 0. 06 21 3 11 65 13 229 595 1388 2222 G K_1 4G G K1 25 _T i-zr n_@1 2 G ran op hy re 484265 5149033 8. 24 0. 22 728 12 10. 40 0. 70 749 14 4. 39 33 14 32 120 26 397 1022 2234 3471 G K_1 4G G K1 25 _T i-zr n_@1 3 G ran op hy re 484265 5149033 8. 55 0. 23 731 12 9. 80 0. 55 744 13 0. 23 24 7 23 99 22 327 869 1901 3009 G K_1 4G G K1 25 _T i-zr n_@1 4 G ran op hy re 484265 5149033 12. 08 0. 33 764 13 14. 70 1. 00 783 14 22. 16 55 40 50 133 43 338 890 1894 2775 G K_G SM0 73 _T i-zr n_@1 G ran op hy re 484367 5149463 4. 08 0. 14 668 11 4. 10 0. 55 668 15 0. 62 171 17 57 366 23 1531 4433 9748 14425 G K_G SM0 73 _T i-zr n_@0 2 G ran op hy re 484367 5149463 5. 10 0. 22 686 12 5. 90 0. 65 698 15 2. 56 75 11 30 165 13 604 1623 3593 5569 G K_G SM0 73 _T i-zr n_@0 3 G ran op hy re 484367 5149463 3. 84 0. 13 663 11 4. 70 0. 65 679 16 4. 94 88 19 43 229 25 870 2410 5286 8074 G K_G SM0 73 _T i-zr n_@0 4 G ran op hy re 484367 5149463 5. 62 0. 34 694 12 49. 70 2. 50 922 16 89. 05 184 116 133 318 78 880 2394 5362 8615 G K_G SM0 73 _T i-zr n_@0 5 G ran op hy re 484367 5149463 10. 59 0. 26 751 12 11. 70 0. 80 761 14 1. 33 137 23 67 412 46 1531 3815 7930 11858 G K_G SM0 73 _T i-zr n_@0 6 G ran op hy re 484367 5149463 8. 39 0. 22 730 12 9. 40 1. 25 740 17 6. 05 176 35 79 385 61 1490 4026 8716 12862 G K_G SM0 73 _T i-zr n_@0 7 G ran op hy re 484367 5149463 6. 46 0. 18 706 12 10. 00 0. 85 746 14 1. 63 78 19 48 273 33 1017 2592 5840 8652 G K_G SM0 73 _T i-zr n_@0 8 G ran op hy re 484367 5149463 3. 67 0. 14 660 11 5. 40 0. 55 691 14 0. 37 87 10 35 222 16 915 2522 5765 8425 G K_G SM0 73 _T i-zr n_@0 9 G ran op hy re 484367 5149463 5. 92 0. 17 699 12 12. 50 1. 30 767 16 11. 50 133 45 84 394 82 1434 3626 8055 11631 G K_G SM0 73 _T i-zr n_@1 0 G ran op hy re 484367 5149463 5. 23 0. 16 688 11 7. 40 0. 75 718 15 11. 67 68 31 49 197 35 661 1784 4053 6105 G K_G SM0 73 _T i-zr n_@1 1 G ran op hy re 484367 5149463 83. 36 2. 01 993 17 6. 10 1. 50 701 24 66. 89 250 131 162 358 148 860 2588 5890 9662 G K_G SM0 73 _T i-zr n_@1 2 G ran op hy re 484367 5149463 3. 89 0. 13 664 11 5. 80 0. 55 697 14 0. 60 104 13 47 263 20 1077 2897 6432 9778 G K_G SM0 73 _T i-zr n_@1 3 G ran op hy re 484367 5149463 5. 59 0. 18 694 11 6. 60 0. 60 708 14 0. 46 49 10 33 175 20 634 1656 3537 5538 G K_G SM0 73 _T i-zr n_@1 4 G ran op hy re 484367 5149463 6. 45 0. 18 706 12 19. 90 1. 75 815 16 48. 15 274 84 107 291 73 763 1904 4229 6191 G K_G SM0 73 _T i-zr n_@1 5 G ran op hy re 484367 5149463 5. 79 0. 18 697 11 16. 30 1. 90 794 18 43. 89 312 155 212 721 314 2060 5233 10636 16554 G K_G SM0 73 _T i-zr n_@1 6 G ran op hy re 484367 5149463 4. 66 0. 15 679 11 6. 70 0. 75 709 15 0. 56 117 16 48 284 21 1139 3169 6916 10394 G K_G SM0 73 _T i-zr n_@1 7 G ran op hy re 484367 5149463 6. 88 0. 20 712 12 12. 50 1. 30 767 16 1. 52 272 21 60 286 33 1190 3160 6822 10055 G K_1 4G G K1 28 _T i-zr n_@1 G ran op hy re 484454 5149961 6. 88 0. 74 712 15 5. 80 0. 70 697 15 0. 42 63 4 13 93 6 422 1434 3531 5292 G K_1 4G G K1 28 _T i-zr n_@0 2 G ran op hy re 484454 5149961 3. 08 0. 14 646 11 9. 40 1. 10 740 16 9. 80 55 7 11 56 5 218 828 2190 3717 G K_1 4G G K1 28 _T i-zr n_@0 3 G ran op hy re 484454 5149961 3. 84 0. 13 663 11 4. 80 0. 60 681 15 0. 54 18 1 1 13 2 65 251 736 1446 G K_1 4G G K1 28 _T i-zr n_@0 4 G ran op hy re 484454 5149961 2. 88 0. 11 641 11 5. 50 0. 65 693 15 0. 03 26 1 3 26 2 113 400 1196 2086 G K_1 4G G K1 28 _T i-zr n_@0 5 G ran op hy re 484454 5149961 3. 48 0. 16 655 11 4. 80 0. 70 681 16 2. 73 91 12 24 139 15 570 1693 4292 6382 G K_1 4G G K1 28 _T i-zr n_@0 6 G ran op hy re 484454 5149961 3. 13 0. 16 647 11 4. 28 0. 44 672 14 0. 03 23 1 3 25 2 103 375 1032 1858 G K_1 4G G K1 28 _T i-zr n_@0 7 G ran op hy re 484454 5149961 3. 03 0. 16 645 11 3. 40 0. 75 654 20 0. 26 115 9 34 239 13 1048 3164 7577 11102 G K_1 4G G K1 28 _T i-zr n_@0 8 G ran op hy re 484454 5149961 3. 79 0. 16 662 11 5. 40 0. 60 691 15 1. 01 14 1 1 7 1 39 174 524 1121 G K_1 4G G K1 28 _T i-zr n_@0 9 G ran op hy re 484454 5149961 3. 15 0. 12 648 11 19. 20 2. 55 811 19 12. 44 32 10 8 23 5 85 310 887 1551 G K_1 4G G K1 28 _T i-zr n_@1 0 G ran op hy re 484454 5149961 4. 09 0. 14 668 11 4. 20 0. 60 670 16 0. 19 104 8 29 206 12 900 2769 6161 9003 G K_1 4G G K1 28 _T i-zr n_@1 1 G ran op hy re 484454 5149961 3. 42 0. 13 654 11 5. 30 0. 65 689 15 0. 43 223 16 53 408 24 1770 5406 11768 15877
20 16 14 3 Ta bl e D R1 T i a nd RE E da ta Sam pl e/ SIMS F+W 2 00 7 LA -IC PMS F+W 2 00 7 N or m al ize d (A nd er s an d G re ve ss e 19 89 ) Spot unit Eas tin g* N or th in g* Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD La Ce Pr Nd Sm Eu Gd Dy Er Yb *N AD 83 U TM zo ne 1 7N G K_1 4G G K1 28 _T i-zr n_@1 2 G ran op hy re 484454 5149961 5. 60 0. 17 694 11 8. 40 0. 65 730 14 1. 55 40 12 32 145 19 558 1483 3455 5151 G K_1 4G G K1 28 _T i-zr n_@1 3 G ran op hy re 484454 5149961 3. 19 0. 12 649 11 4. 90 0. 55 683 14 0. 76 107 10 30 222 21 921 2814 6432 8985 G K_1 4G G K1 28 _T i-zr n_@1 4 G ran op hy re 484454 5149961 2. 37 0. 10 626 11 3. 40 0. 55 654 16 0. 92 36 2 5 39 3 184 676 1819 2991 G K_1 4G G K1 28 _T i-zr n_@1 5 G ran op hy re 484454 5149961 1. 15 0. 07 576 10 7. 80 0. 95 723 16 2812. 10 1592 1044 829 401 221 302 490 1322 2480 G K_1 4G G K1 29 _T i-zr n_@1 G ran op hy re 484559 5150371 2. 99 0. 12 644 11 8. 80 1. 70 734 21 27. 44 100 25 28 65 30 271 1220 4323 8511 G K_1 4G G K1 29 _T i-zr n_@2 G ran op hy re 484559 5150371 1. 63 0. 08 600 10 4. 00 1. 00 666 23 3. 58 52 4 5 23 6 111 612 2404 4252 G K_1 4G G K1 29 _T i-zr n_@3 G ran op hy re 484559 5150371 2. 06 0. 09 616 10 0. 70 0. 95 545 83 11. 08 40 6 6 16 4 95 503 2240 4812 G K_1 4G G K1 29 _T i-zr n_@4 G ran op hy re 484559 5150371 1. 18 0. 07 578 10 2. 10 0. 60 618 23 1. 96 59 3 8 57 1 275 1154 2920 4788 G K_1 4G G K1 29 _T i-zr n_@5 G ran op hy re 484559 5150371 2. 76 0. 11 638 11 6. 80 1. 70 711 25 4. 69 85 7 16 97 8 385 1454 5110 10775 G K_1 4G G K1 29 _T i-zr n_@6 G ran op hy re 484559 5150371 1. 89 0. 09 610 10 3. 40 0. 65 654 18 1. 49 109 11 27 134 6 458 1574 3914 6517 G K_1 4G G K1 29 _T i-zr n_@7 G ran op hy re 484559 5150371 2. 25 0. 10 622 11 0. 90 1. 10 561 77 6. 35 48 5 7 34 4 168 663 2102 3502 G K_1 4G G K1 29 _T i-zr n_@8 G ran op hy re 484559 5150371 1. 87 0. 09 609 10 2. 60 0. 85 633 26 10. 65 98 10 17 71 4 315 1207 3379 5778 G K_1 4G G K1 29 _T i-zr n_@9 G ran op hy re 484559 5150371 96. 38 4. 56 1015 18 13. 90 2. 00 778 19 14. 27 97 9 13 61 8 289 1273 4185 7908 G K_1 4G G K1 29 _T i-zr n_@1 0 G ran op hy re 484559 5150371 1. 43 0. 07 591 10 6. 60 1. 40 708 22 54. 96 105 68 72 118 168 209 544 1825 5182 G K_1 4G G K1 32 _T i-zr n_@1 G ran op hy re 484658 5150719 42. 02 1. 03 901 15 39. 00 1. 60 892 15 21. 39 28 27 23 37 49 56 274 1230 4738 G K_1 4G G K1 32 _T i-zr n_@2 G ran op hy re 484658 5150719 75. 61 1. 34 979 16 104. 90 4. 10 1028 18 60. 08 152 119 126 275 302 319 964 2398 6603 G K_1 4G G K1 32 _T i-zr n_@3 G ran op hy re 484658 5150719 41. 69 0. 80 900 15 51. 10 2. 10 926 16 55. 60 125 73 69 107 104 133 443 1422 4911 G K_1 4G G K1 32 _T i-zr n_@5 G ran op hy re 484658 5150719 34. 49 0. 85 877 15 70. 70 4. 60 970 18 35. 62 115 74 79 139 98 192 721 1831 4634 G K_1 4G G K1 32 _T i-zr n_@6 G ran op hy re 484658 5150719 59. 49 1. 35 946 16 114. 00 6. 50 1040 20 78. 40 108 87 86 135 91 189 537 1378 3742 G K_1 4G G K1 31 _T i-zr n_@1 G ran op hy re 484727 5151173 23. 07 0. 47 831 14 39. 40 2. 10 893 16 9. 54 28 17 16 30 20 45 164 975 4375 G K_1 4G G K1 31 _T i-zr n_@0 3 G ran op hy re 484727 5151173 55. 85 2. 04 938 16 45. 00 1. 80 910 16 18. 92 30 29 35 48 22 58 156 887 4191 G K_1 4G G K1 31 _T i-zr n_@0 4 G ran op hy re 484727 5151173 39. 94 0. 77 895 15 55. 30 2. 00 936 16 27. 27 36 28 29 40 21 54 230 1359 5926 G K_1 4G G K1 31 _T i-zr n_@0 5 G ran op hy re 484727 5151173 34. 80 0. 67 878 15 42. 30 1. 95 902 16 40. 22 54 59 70 101 59 88 181 774 3822 G K_1 4G G K1 31 _T i-zr n_@0 6 G ran op hy re 484727 5151173 26. 37 0. 57 846 14 35. 20 1. 30 879 15 19. 26 25 21 23 27 15 43 120 775 3717 G K_1 4G G K1 31 _T i-zr n_@0 7 G ran op hy re 484727 5151173 39. 30 0. 79 893 15 69. 80 2. 75 968 17 40. 35 63 52 55 78 50 102 337 1303 4634 G K_1 4G G K1 31 _T i-zr n_@0 8 G ran op hy re 484727 5151173 30. 38 0. 59 862 14 44. 50 1. 35 908 15 8. 01 13 11 14 24 21 42 150 1065 5120 G K_1 4G G K1 31 _T i-zr n_@0 9 G ran op hy re 484727 5151173 67. 85 1. 31 964 16 38. 60 1. 50 891 15 19. 09 31 25 30 46 24 61 176 1026 4849 G K_1 4G G K1 31 _T i-zr n_@1 0 G ran op hy re 484727 5151173 41. 27 1. 01 899 15 61. 40 2. 80 950 17 77. 12 107 96 99 158 118 213 610 1737 4880 G K_1 4G G K1 31 _T i-zr n_@1 1 G ran op hy re 484727 5151173 29. 04 0. 61 857 14 104. 00 7. 00 1026 20 20. 20 32 23 29 43 33 73 218 1240 4985 G K_1 4G G K1 31 _T i-zr n_@1 2 G ran op hy re 484727 5151173 77. 33 1. 50 983 17 63. 20 2. 70 954 17 50. 40 79 61 61 100 139 137 352 1466 5526 G K_1 4G G K1 31 _T i-zr n_@1 3 G ran op hy re 484727 5151173 38. 64 0. 73 891 15 36. 20 1. 70 883 15 22. 50 21 27 28 41 31 63 215 1284 5822 G K_G SM1 04 _T i-zr n_@1 N or ite (N or th Ran ge ) 467182 5162511 4. 31 0. 14 672 11 6. 40 0. 60 705 14 0. 04 143 2 8 63 7 259 828 2171 3594 G K_G SM1 04 _T i-zr n_@0 2 N or ite (N or th Ran ge ) 467182 5162511 5. 34 0. 17 690 11 6. 10 0. 55 701 14 0. 06 196 4 13 81 9 329 1018 2517 4154 G K_G SM1 04 _T i-zr n_@0 3 N or ite (N or th Ran ge ) 467182 5162511 9. 01 0. 23 736 12 5. 10 0. 65 686 15 0. 46 177 13 36 179 17 703 2110 5003 7446 G K_G SM1 04 _T i-zr n_@0 4 N or ite (N or th Ran ge ) 467182 5162511 14. 49 1. 60 782 17 8. 40 1. 15 730 17 52. 83 342 45 65 303 60 1104 2950 6174 9200 G K_G SM1 04 _T i-zr n_@0 5 N or ite (N or th Ran ge ) 467182 5162511 4. 51 0. 19 676 11 4. 40 0. 60 674 15 0. 16 238 4 15 98 9 383 1174 3033 5194 G K_G SM1 04 _T i-zr n_@0 6 N or ite (N or th Ran ge ) 467182 5162511 7. 65 0. 21 721 12 8. 20 0. 75 727 14 0. 37 325 8 23 137 14 534 1529 3379 5317 G K_G SM1 04 _T i-zr n_@0 7 N or ite (N or th Ran ge ) 467182 5162511 5. 56 0. 17 693 11 10. 70 0. 70 752 14 4. 73 244 14 39 190 25 791 2262 5060 7612 G K_G SM1 04 _T i-zr n_@0 8 N or ite (N or th Ran ge ) 467182 5162511 3. 94 0. 13 665 11 6. 10 0. 65 701 15 0. 12 136 8 29 143 16 539 1487 3474 5422 G K_G SM1 04 _T i-zr n_@0 9 N or ite (N or th Ran ge ) 467182 5162511 6. 32 0. 22 704 12 7. 80 0. 65 723 14 39. 20 147 21 27 113 16 422 1178 2643 3846 G K_G SM1 04 _T i-zr n_@1 0 N or ite (N or th Ran ge ) 467182 5162511 4. 73 0. 15 680 11 9. 50 1. 10 741 16 4. 73 232 16 45 215 24 885 2736 6130 9145 G K_G SM1 04 _T i-zr n_@1 1 N or ite (N or th Ran ge ) 467182 5162511 4. 24 0. 15 671 11 6. 30 0. 65 704 14 0. 37 216 7 20 105 10 397 1224 2945 4548 G K_G SM1 04 _T i-zr n_@1 2 N or ite (N or th Ran ge ) 467182 5162511 4. 99 0. 15 684 11 7. 10 0. 60 715 14 0. 33 170 11 36 177 19 697 2089 4751 7268 G K_G SM1 04 _T i-zr n_@1 3 N or ite (N or th Ran ge ) 467182 5162511 5. 35 0. 16 690 11 6. 80 0. 70 711 15 24. 71 155 30 49 147 61 516 1475 3442 5680 SIMS st an dar ds 91500 4. 82 0. 15 682 18 91500 4. 92 0. 18 683 19 91500 4. 76 0. 15 680 18 91500 5. 34 0. 16 690 18 91500 5. 07 0. 16 686 18 91500 4. 86 0. 18 682 19 91500 5. 24 0. 16 688 18 91500 5. 32 0. 17 690 18 91500 5. 16 0. 16 687 18 91500 4. 76 0. 16 680 18
20 16 14 3 Ta bl e D R1 T i a nd RE E da ta Sam pl e/ SIMS F+W 2 00 7 LA -IC PMS F+W 2 00 7 N or m al ize d (A nd er s an d G re ve ss e 19 89 ) Spot unit Eas tin g* N or th in g* Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD La Ce Pr Nd Sm Eu Gd Dy Er Yb *N AD 83 U TM zo ne 1 7N 91500 4. 50 0. 18 676 19 91500 4. 84 0. 16 682 18 91500 5. 16 0. 16 687 18 91500 5. 00 0. 18 684 19 Te m or a-2 9. 17 0. 26 738 19 Te m or a-2 12. 45 0. 30 767 20 Te m or a-2 8. 63 0. 23 732 19 Te m or a-2 12. 28 0. 29 765 20 Te m or a-2 11. 89 0. 28 762 20 Te m or a-2 8. 60 0. 25 732 19 Te m or a-2 9. 78 0. 24 744 19 Te m or a-2 14. 17 0. 33 780 20 Te m or a-2 9. 28 0. 23 739 19 LA -IC PMS st an dar ds Te m or a-2 9. 70 0. 65 743 13 Te m or a-2 9. 90 0. 80 745 14 Te m or a-2 11. 90 0. 85 762 14 Te m or a-2 12. 70 0. 80 769 14 Te m or a-2 11. 80 0. 65 762 13 Te m or a-2 11. 30 0. 65 757 13 Te m or a-2 11. 10 0. 65 756 13 Te m or a-2 10. 30 0. 70 749 14 Te m or a-2 11. 60 0. 80 760 14 Te m or a-2 10. 10 0. 60 747 13 Te m or a-2 14. 60 0. 65 783 13 Te m or a-2 13. 10 0. 75 772 14 Te m or a-2 11. 90 0. 65 762 13 Te m or a-2 11. 20 0. 55 756 13 Te m or a-2 9. 10 0. 55 737 13 Te m or a-2 8. 90 0. 75 735 14 Te m or a-2 8. 90 0. 60 735 13 Te m or a-2 8. 30 0. 60 729 13 Te m or a-2 7. 70 0. 48 722 13 Te m or a-2 8. 30 0. 55 729 13 Te m or a-2 8. 30 0. 60 729 13 Te m or a-2 10. 30 0. 65 749 13 Te m or a-2 12. 30 0. 60 766 13 Te m or a-2 15. 70 0. 75 790 14 Te m or a-2 9. 30 0. 65 739 14 Te m or a-2 12. 00 0. 55 763 13 91500 6. 20 1. 90 703 29 91500 4. 60 2. 00 678 37 91500 6. 00 1. 90 700 29 91500 5. 20 3. 50 688 57 91500 5. 80 2. 10 697 33 91500 3. 80 2. 10 662 45 91500 4. 90 2. 10 683 37 91500 3. 80 2. 30 662 49 91500 5. 00 3. 40 685 57 91500 5. 20 2. 70 688 45 91500 5. 00 1. 60 685 29 91500 4. 90 1. 60 683 29 91500 6. 60 1. 50 708 23 91500 6. 10 1. 50 701 24 91500 4. 50 1. 50 676 29 91500 5. 70 1. 50 696 25 91500 4. 50 1. 30 676 26
20 16 14 3 Ta bl e D R1 T i a nd RE E da ta Sam pl e/ SIMS F+W 2 00 7 LA -IC PMS F+W 2 00 7 N or m al ize d (A nd er s an d G re ve ss e 19 89 ) Spot unit Eas tin g* N or th in g* Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD Ti (ppm ) ± 1 SD Te m p (d eg C) ± 1 SD La Ce Pr Nd Sm Eu Gd Dy Er Yb *N AD 83 U TM zo ne 1 7N 91500 4. 90 1. 50 683 28 91500 4. 80 1. 10 681 22 91500 5. 70 1. 40 696 24 91500 6. 10 1. 10 701 19 91500 4. 90 1. 20 683 23 91500 4. 90 1. 10 683 22 91500 5. 00 1. 20 685 23
