DATA REPOSITORY ITEM 2013172 - Geological Society of America · DATA REPOSITORY ITEM 2013172 Arkle et al. Sampling of glacial outwash samples Glacial outwash samples were collected

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DATA REPOSITORY ITEM 2013172

Arkle et al.

Sampling of glacial outwash samples

Glacial outwash samples were collected from as close to each glacier terminus as

possible. Sample locations and extent of the modern glaciers are shown in Figure DR1.

The Barry Glacier sample (P56) was collected from sediment-filled pools on top of a

roche moutonnée on the west side of Barry Arm in front of the glacier terminus. The

Harvard Glacier sample (P19) was collected along the fiord shoreline (above the high tide

line) on an active longitudinal bar on the 20 m in front of the east side of the glacier

terminus. The Knik Glacier sample (C1) was collected from south-flowing braided

streams that flow around and out of the north side of the glacier terminus. The

Matanuska Glacier sample (C4) was collected from the northeast side of the Matanuska

River about 100 m downstream from the glacier terminus. In all samples, gravelly

deposits were collected and panned in the field to concentrate dense sand-sized fractions.

Sample Processing

Bedrock samples were run through a jaw crusher and all samples were sieved to a

fraction of less than 300 µm. In bedrock and glacial outwash samples, apatite and zircon

were isolated with use of a water table, Frantz magnetic separator, and by two heavy

liquid density separations of lithium metatungstate and methylene iodide.

(U-Th)/He Analytical Methods

For apatite (U-Th)/He analysis, typically 4 to 7 apatite grains per sample

replicates were hand-picked under a binocular microscope with cross-polarized light and

inspected in ethanol to avoid inclusion-bearing grains. Euhedral apatite crystals with

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prism half-widths generally greater than about 45 µm were targeted. For zircon (U-

Th)/He analyses (samples P6, P16, and P24), four aliquots each containing three to four

similar-sized grains were selected. Crystal dimensions were measured at 250x

magnification. Isotopic concentrations were measured at California Institute of

Technology. The apparent or raw ages were determined by the equations from Wolf et al.

(1998), which were corrected for alpha ejection effects (Ft correction) following methods

described by Farley et al. (1996) and Farley (2002).

Several AHe samples show considerable intra-sample single grain age dispersion

(Table DR1). Half of the 38 samples show at least one grain that is a statistical outlier

relative to the other grains in that sample. This amounts to 27 outliers out of 166 single

ages. Nearly all of these outliers are older than the mean of the single grain ages in that

sample. These old age outliers are interpreted as caused by excess helium from

undetected high-uranium inclusion phases entrained in the apatite crystals. A grain was

excluded for samples with three or more replicates if it was outside ± 2σ range of the

other grains in that sample.

An additional contributor of excess helium may be from radiation damage, which

is primarily controlled by cooling rate, accumulation time, and effective uranium

concentration (eU) (Shuster el al., 2006; Shuster and Farley, 2009). The calculated eU

(Table DR1) was used as a proxy to determine the degree of radiation damage for

individual grains. The eU for individual grains was determined by the sum of the relative

apparent uranium contributions from uranium, thorium, and samarium: eU = [U] +

0.2302[Th] + 0.005[Sm] (Shuster el al., 2006; Flowers et al., 2009). The majority of

individual grains (~90%) show no relationship with eU. The remaining ~10% of grains

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that do positively correlate (P4, P5, P6, P32, P33, P42, P43, P45, and P62) have a high

eU value (>20 ppm) and cooled relatively slowly (~1 °C/m.y.) through the PRZ, allowing

radiation damage sufficient time to affect the grain (Shuster el al., 2006; Shuster and

Farley, 2009). All of these samples (with the exception of P62) are from rocks south of

the Contact fault, an area that cooled slowly through the AHe PRZ. Overall, only ~10%

of the total grains analyzed correlate with eU, indicating radiation damage does not

significantly affect the total grain population.

The four grains for sample P62 display two age populations of ~16.2 Ma and 6.7

Ma. This sample is from an age-elevation transect where AHe ages just above and below

are 5.1 to 8.2 Ma, thus the 6.7 Ma population is more reasonable for this sample and the

other age population is interpreted to be the result of excess helium (and/or radiation

damage). Sample W1 has two ages, but one of the single grain ages is unrealistically low

(0.4 Ma) considering an independently determined AHe from Buscher et al. (2008) from

the same outcrop is 14.9 Ma and similar to our other single grain age of 15.7 Ma. Two

samples with four single-grain ages each have one single-grain age that is significantly

younger than the other three ages (samples P4, P60). We exclude these young outlier

ages from the average age because they are outside the 2σ range of the other three grain

ages, but this does not significantly affect our results and interpretations. After culling

the excluded grain ages, 1 to 5 ages were used to determine average ages for each sample

(Table DR1). After outlier removal, the average relative standard deviation for 34 of the

AHe ages is ±17.2% (1σ). Four AHe ages reproduce poorly at >40% (1σ). Uncertainties

for the AHe ages are reported as ± 1 s.e. throughout the text and in the tables.

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Average ZHe ages were calculated from 4 aliquots containing 3 to 4 similar-sized

grains for each sample (Table DR1). Two samples (P6 and P24) show reproducible

internal consistency with an average age uncertainty of ± 12.7% (1σ). The internal age

consistency of the 4 aliquots from sample P16 reproduces poorly with >60% uncertainty

at ± 1σ. Grain aliquots P16-2 and P16-4 yield ZHe ages that are much younger than other

two aliquots may capture two different cooling histories or may be consequence of

radiation damage. These aliquots have the highest uranium and thorium concentrations

and are the youngest aliquot-grain ages, suggesting the age variation is likely due to the

effects of high radiation damage (Nasdala et al., 2004; Reiners, 2005). Additionally, the

single-grain ZHe age for P16-4 (5.8 ± 0.1 Ma) is less than the AFT age (6.5 ± 0.8 Ma)

(Table DR1 and DR2) for the same sample, which indicates the ZHe age is too young.

Thus, the youngest ZHe ages are culled from the mean age calculation and the sample is

reported as a conservative age estimate (25.3 ± 0.5 Ma) using grain aliquots P16-1 and

P16-3. After excluding the two outlier grains, the average reproducibility of the ZHe

samples is ±9% (1σ). Uncertainties for the ZHe ages are reported as ± 1 s.e. throughout

the text and in the tables.

Fission Track Analytical Methods

For apatite fission-track analysis, crystals were mounted in epoxy on glass slides,

ground, and polished, to expose the interior of the crystal for density counts. The mounts

were chemically etched in 5M HNO3 for 20 ± 1s at 22 ± 1°C to reveal spontaneous

tracks. Zicons were mounted in Teflon, then ground and polished. Zircon crystals were

etched in a eutectic melt of KOH-NaOH at 228± 1°C for 25 – 30 hours. Following the

external detector method (Gleadow, 1981), a thin sheet of low-U mica was mounted

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against the polished surface to record induced tracks. Neutron irradiations were done at

Oregon State University TRIGA Reactor. The neutron fluence was calculated from U-

rich Corning-5 (CN-5) dosimeter glasses that were placed at regular intervals between the

grain mounts. After irradiation, mica detectors were etched in 48% HF for 18 min at 22

°C to reveal induced tracks. All track density counts were done on an Olympus BX50

binocular microscope under transmitted (and reflected) light at 1250x magnification with

an FTStage 4.03a system (Dumitru, 1993).

Fission-track age determinations were made with the external-detector and zeta-

calibration methods (Hurford and Green, 1983; Hurford, 1990) using independently

determined zeta values (Gleadow, 1981; Dumitru, 2000; Reiners and Brandon, 2006).

The program FLUENCE v. 1.1 (Brandon, 1992; 1996) was used to interpolate the

effective fluence-monitor track density and uncertainty for each sample. For apatite

analyses, global weighted mean zetas of 347 ± 8 (J. Arkle) and 364.0 ± 6.4 (P.

Armstrong) were calculated with the Yale Program ZETAMEAN from Brandon (1992;

1996). For zircon analyses, global weighted mean zetas of 338.9 ± 6.2 (J. Brush) and

364.4 ± 6.1 (K. Sendziak). Fission-track ages were determined using ZETAAGE

(Brandon, 1992; 1996), which is well suited to deal with low-track-count grains, and with

the program TRACKKEY (Dunkl, 2002).

Suitable apatite grains were selected and fission tracks were counted in 20–30

grains for granitic samples and in about 40 grains for sandstone samples; many of the

sandstone grains contain no spontaneous tracks. Due to low spontaneous track densities,

horizontal confined track lengths were insufficient for measurement. We irradiated

representative apatite mounts samples from north and south of the Contact fault with Cf-

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252 to reveal more horizontal confined tracks. Track lengths were measured at 2000x

magnification. Table DR3 shows the C-axis corrected mean track lengths.

The Chi-square (χ2) test was used in apatite samples to indicate the probability

that a single grain age belongs to a single age population. A sample with a P(χ2)<5%

indicates a poly-modal single-grain age spread and the weighted mean is used. All

apatite samples passed the χ2 test and are reported as pooled ages, calculated from the

logarithmic mean of single-grain ages and age spread, with error ± 1σ (Table DR2)

(Galbraith and Laslett, 1993). All AFT ages reproduce well at ± 13.1% (1σ). The high

P(χ2 ) values (average 83.2%) suggest that all the samples were fully reset.

Fission tracks from up to 100 zircon grains from each of the four glacial outwash

detrital samples were counted. The age distributions were decomposed with a binomial

peak-fitting algorithm (Galbraith and Green, 1990; Brandon, 1992) using the program

Binomfit of Brandon (2002). Three or four age peaks were determined for each sample

(Figure DR2).

Inverse modeling of AFT and AHe data

We used HeFTy version 1.7 to model the temperature-time history of our AFT

and AHe data simultaneously for two representative samples from north and south of the

Contact fault. General discussions of principles and interpretations of HeFTy setup and

simulations are given in Ketcham (2005). The two samples were chosen for these areas

because they have the most complete data sets for modeling purposes and because they

each are samples of Oligocene granite. Sample P13 is from Esther Island and north of

the main strand of the Contact fault (Figure 2) and sample P34 is from Eshamy Bay in the

Prince William Sound south of the Contact fault. For the AFT modeling, the annealing

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and C-axis projection models of Ketcham et al. (2007) were used. The Dpar kinetic

parameter was used, with Dpar measurements for each age grain. The average Dpar for

each sample was used for length Dpar because horizontal confined tracks were present

only in Cf-252 irradiated grains. For the AHe modeling, the kinetic calibration of Farley

(2000) for Durango apatite and the alpha correction of Farley et al. (1996) were used.

Specific modeling parameters for each sample are given in Table DR3.

Figure DR3 shows screen shots of representative model runs with 10,000 Monte

Carlo simulations for each sample. We imposed only two constraints on the T-t histories:

(1) an initial temperature of >200°C at intrusion age (35-40 Ma) and (2) a final

temperature of 0°C (present-day surface temperature). The upper plot (sample P13)

shows many “good” (purple) and “acceptable” (green) fits. The good fits have merit

values of >0.5 and the acceptable fits have merit values of >0.05 – see Ketcham (2005).

The lower plot (sample P34) shows mostly “acceptable” histories with only one “good”

history. Thus the P13 simulations seem better constrained than P34, but the histories

from P34 cannot be ruled out.

References cited for the Data Repository: Brandon, M.T., 1992, Decomposition of fission-track grain age distributions: American

Journal of Science, v. 292, p. 535–564. Brandon, M.T., 1996, Probability density plot for fission-track grain-age samples:

Radiation Measurements, v. 26, p. 663–676. Brandon, M.T., 2002, Decomposition of mixed grain age distributions using Binomfit,

On Track, v. 24, p. 13–18. Buscher, J.T., Berger, A.L., and Spotila, J.A., 2008, Exhumation in the Chugach-Kenai

Mountain belt above the Aleutian subduction zone, southern Alaska, in Freymueller, J.T., Haeussler, P.J., Wesson, R., and Ekstrom, G., eds., Active Tectonics and Seismic Potential of Alaska: Geophysical Monograph Series 179, p. 151–166.

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Dumitru, T.A., 1993, A new computer-automated microscope stage system for fission-

track analysis: Nuclear Tracks and Radiation Measurements, v. 21, p. 575–580. Dumitru, T.A., 2000, Fission-track geochronology in Quaternary geology, in Noller, J.S.,

Sowers, J.M., and Lettis, W.R., eds., Quaternary geochronology: Methods and Applications: Washington, D.C., American Geophysical Union Ref Shelf, v. 4, p. 131–155.

Dunkl, I., 2002, Trackkey: A Windows program for calculation and graphical

presentation of fission track data: Computers & Geosciences, v. 28, p. 3–12. Farley, K.A., Wolf, R.A., and Silver, L.T., 1996, The effects of long alpha-stopping

distances on (U-Th)/He ages: Geochimica et Cosmochimica Acta, v. 60, p. 4223–4229.

Farley, K.A., 2002, (U-Th)/He dating: Techniques, Calibrations, and Applications, in

Porcelli, D., Ballentine, C.J., and Wieler, R., eds., Noble Gases in Geochemistry and Cosmochemistry: Reviews of Mineralogy: Mineralogical Society of America, v. 47, p. 819–844.

Flowers, R.M., Ketcham, R.A., Shuster, D.L., and Farley, K.A., 2009, Apatite (U-Th)/He

thermochronometry using a radiation damage accumulation and annealing model: Geochimica et Cosmochimica Acta, v. 73, p. 2347–2365.

Galbraith, R.F., and Green, P.F., 1990, On estimating the component ages in a finite

mixture: Nuclear Tracks and Radiation Measurements, v. 17, p. 197–206. Galbraith, R.F., and Laslett, G.M., 1993, Statistical models for mixed fission track ages:

Nuclear Tracks and Radiation Measurements, v. 21, p. 459–470. Gleadow, A.J.W., 1981, Fission track dating methods: What are the real alternatives?:

Nuclear Tracks, v. 5, p. 15–25. Hurford, A.J., 1990, International union of geological sciences subcommission on

geochronology recommendation for the standardization of fission track dating calibration and data reporting: Nuclear Tracks and Radiation Measurements, v. 17, p. 233–236.

Hurford, A.J., and Green, P.F., 1983, The zeta age calibration of fission-track dating:

Chemical Geology, v. 41, p. 285–317. Ketcham, R.A., 2005, Forward and inverse modeling of low-temperature

thermochronometry data, in Reiners, P.W., and Ehlers, T.A., eds., Low-Temperature Thermochronology: Techniques, Interpretations, and Applications: Chantilly, VA, Mineralogical Society of America, v. 58, p. 275-314.

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Ketcham, R.A., Carter, A.C., Donelick, R.A., Barbarand, J., Hurford, A.J., 2007,

Improved measurement of fission-track annealing in apatite using c-axis projection: American Mineralogist, v. 92, p. 789–798.

Nasdala, L., Reiners, P.W., Garver, J.I., Kennedy, A.K., Stern, R.A., Balan, E., and

Wirth, R., 2004, Incomplete retention of radiation damage in zircon from Sri Lanka: American Mineralogist, v. 89, p. 219–231.

Nelson, S.W., Dumoulin, J.A., and Miller, M.L., 1985, Geologic map of the Chugach

National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map, MF-1645-B, 16 p., 1 map.

Reiners, P.W., 2005, Zircon (U-Th)/He Thermochronometry, in Reiners, P.W., and

Ehlers, T.A., eds., Low-Temperature Thermochronology: Techniques, Interpretations, and Applications: Mineralogical Society of America, v. 58, p. 151–179.

Reiners, P.W., and Brandon, M.T., 2006, Using Thermochonology to understand

orogenic erosion: Annual Review of Earth and Planetary Sciences, v. 34, p. 419–466.

Shuster, D.L., Flowers, R.M., and Farley, K.A., 2006, The influence of natural radiation

damage on helium diffusion kinetics in apatite: Earth and Planetary Science Letters, v. 249, p. 148–161.

Shuster, D.L., and Farley, K.A., 2009, The influence of artificial radiation damage and

thermal annealing on helium diffusion kinetics in apatite: Geochimica et Cosmochimica Acta, v. 73, p. 183–196.

Wolf, R.A., Farley, K.A., and Kass, D.M., 1998, Modeling of the temperature sensitivity

of the apatite (U-Th)/He thermochronometer: Chemical Geology, v. 148, p. 105–114.

C1

C4

P19

P56

Matanuska Gl.

Knik Gl.

Barry Gl.

Harvard Gl.

MB

N

Anchorage

Figure DR1. Google Earth map showing locations (red dots) of glacial outwash samples. Sample numbers are next to sample locations and correspond to sample age distributions in Figure DR. Regions outlined with dashes are the approximate modern extent of each glacier. Note that the outlined regions are not the entire catchment of the drainage basin for each glacier. Star labelled MB is Mt. Marcus Baker.

100 km

Figure DR2. Single grain zircon �ssion-track age distributions (shaded regions) for Knik (a), Matanuska (b), Harvard (c), and Barry (d) glaciers. Thin curves are probablility density distributions. The bolder curves are binomial peak �ts computed using Binom�t 1.2 (Brandon, 2002). The numbered arrows above the peak �t curves show peak number. Ages for peak number and percentage of grains (in parentheses) are shown next to each curve.

PM1 PM2 PM3 PM4

FT grain age (Ma)

Den

sity

(%)

b.Matanuska Glacier (C4)n=63PM1 = 22.2 ± 5.9 Ma (1.6%) PM2 = 37.6 ± 2.7 Ma (17.0%)PM3 = 52.9 ± 3.5 Ma (47.6%)PM4 = 65.3 ± 4.7 Ma (33.8%)

P 1 P 2 P 3B BB

Den

sity

(%)

FT grain age (Ma)

d.Barry Glacier (P56)n = 100PB1 = 23.0 ± 1.3 Ma (43.5%)PB2 = 29.6 ± 1.8 Ma (50.9%)PB3 = 45.4 ± 3.5 Ma ( 5.6%)

P 1 P 2 P 3 P 4H HHH

Den

sity

(%)

FT grain age (Ma)

c. Harvard Glacier (P19)n = 100PH1 = 19.1 ± 2.0 Ma (5.2%)PH2 = 27.8 ± 1.4 Ma ( 54.1%)PH3 = 33.3 ± 2.6 Ma (32.8%)PH4 = 44.1 ± 3.8 Ma (7.9%)

FT grain age (Ma)

PK1 PK2 PK3 PK4D

ensi

ty (%

)

a.Knik Glacier (C1)n=100Pk1 = 24.0 ± 4.8 Ma (2.0%) Pk2 = 44.9 ± 1.4 Ma (45.9%)Pk3 = 61.4 ± 5.1 Ma (42.9%)Pk4 = 98.3 ± 10.6 Ma (9.2%)

FT grain age (Ma)

Figure DR3. Screen shots HeFTy inverse model runs for sample P13 (upper) and P34 (lower). All output information is given in Ketcham (2005). In each model, the only age constraints are 35-40 Ma for age of intrusions at T > 200 deg. C and present-day surface T of 0 deg. C. The T-t segment between these constraints is halved two times.

Table DR1. Apatite and zircon (U-Th)/He analytical data from the western Chugach Mountains and Prince William Sound, Alaska

Sample- # grains U Th Sm He eU Mass 1/2

Width Length Raw Age Corr Age Av Age

Grain (ppm) (ppm) (ppm) (nmol/g) (ppm)* (µg) (µm)† (µm) (Ma)# (Ma)** (Ma)§§

P2-1 1 16.7 35.4 2.1 206.0 0.6 25.9 1.7 49.4 96.4 0 4.6 0.67 6.9 6.0 0.5 1.0P2-2 1 65.6 68.0 1.0 114.0 2.1 81.9 1.5 46.7 157.3 0 4.7 0.70 6.7P2-3 1 19.0 32.8 1.7 112.8 0.6 27.1 1.8 49.8 115.7 0 4.4 0.69 6.3P2-4 1 14.5 31.4 2.2 141.5 0.3 22.4 1.2 40.0 151.1 0 2.9 0.65 4.4P2-5 1 13.6 27.8 2.0 162.7 0.4 20.8 2.6 42.4 213.8 0 4.0 0.69 5.9

P3-1 1 18.4 9.1 0.5 327.8 0.8 22.2 3.4 57.8 147.7 0 6.9 0.74 9.2 9.1 0.4 1.0P3-2 1 24.5 11.8 0.5 339.0 0.9 28.9 3.3 50.0 179.8 0 6.3 0.72 8.6P3-3 1 22.5 13.5 0.6 368.2 0.8 27.5 2.6 44.8 159.9 1 5.4 0.69 7.8P3-4 1 25.1 7.8 0.3 307.4 1.0 28.5 2.1 43.6 151.9 0 6.8 0.69 9.8P3-5 1 25.4 12.8 0.5 307.6 1.2 29.9 4.1 55.6 196.6 0 7.7 0.75 10.2

P4-1 1 14.3 24.1 1.7 425.4 3.4 22.0 1.7 46.9 125.9 0 30.3 0.68 43.8 X 20.7 2.7 5.4P4-2 1 4.9 13.2 2.7 295.4 0.9 9.4 3.3 53.6 178.4 0 19.9 0.73 27.0P4-3 1 4.8 5.5 1.1 263.7 0.4 7.4 2.3 49.4 143.9 0 10.5 0.70 14.5P4-5 1 5.0 14.9 3.0 376.4 0.1 10.3 1.2 36.3 122.7 0 2.4 0.61 3.8 XP4-6 1 16.6 31.7 1.9 426.0 2.2 26.0 3.0 47.5 176.5 0 16.2 0.70 22.8P4-7 1 7.0 19.2 2.8 202.5 2.7 12.4 8.3 58.4 191.9 1 42.5 0.75 56.4 XP4-8 1 4.1 7.2 1.7 252.2 0.5 7.1 3.8 63.1 142.8 0 13.9 0.75 18.3

P5-1 1 5.8 8.7 1.5 245.6 0.7 9.1 4.1 59.6 148.0 0 15.0 0.74 20.0 18.1 1.5 2.7P5-2 1 17.6 24.0 1.4 432.3 1.6 25.3 1.4 38.4 112.8 0 12.3 0.63 19.3P5-3 1 15.0 27.0 1.8 336.8 5.2 22.9 2.4 52.7 122.7 0 43.7 0.70 61.6 XP5-4 1 8.6 59.4 6.9 234.4 1.2 23.5 2.2 41.3 152.8 0 9.9 0.65 15.1P5-5 1 6.0 12.5 2.1 347.2 2.0 10.6 2.5 49.4 145.0 0 38.4 0.70 53.8 X

P6-1 1 36.5 22.1 0.6 383.8 1.1 43.5 4.2 52.1 228.6 0 4.8 0.74 6.5 5.6 0.6 1.4P6-2 1 152.5 24.7 0.2 424.8 3.3 160.3 1.8 53.7 104.1 0 3.8 0.70 5.5P6-3 1 22.8 12.6 0.6 430.7 0.4 27.8 1.3 49.1 100.0 0 2.9 0.68 4.2P6-4 1 28.8 12.4 0.4 341.7 1.0 33.4 4.4 62.4 161.0 0 5.6 0.76 7.4P6-5 1 32.1 16.3 0.5 450.6 0.6 38.1 1.8 47.6 130.9 0 3.1 0.69 4.5

P6-1 3 355.1 76.0 0.2 0.0 0.6 372.6 30.5 41.8 304.7 1 22.3 0.78 28.4 33.9 2.4 4.8P6-2 4 459.5 117.7 0.3 0.0 0.7 486.6 22.7 39.9 189.8 1 24.6 0.75 32.6P6-3 4 177.4 50.4 0.3 0.0 0.7 189.0 50.1 51.0 266.7 1 32.1 0.80 39.9P6-4 4 212.4 54.2 0.3 0.0 0.5 224.9 36.1 45.5 237.5 1 27.3 0.78 34.8

P7-1 1 18.1 19.8 1.1 723.2 1.1 26.3 1.0 37.0 98.6 0 8.4 0.61 13.4 15.0 3.8 6.7P7-2 1 15.2 14.2 0.9 756.9 1.5 22.2 0.7 40.5 106.3 0 14.7 0.64 22.3P7-3 1 15.6 14.3 0.9 751.3 0.6 22.6 0.8 36.8 90.7 0 5.8 0.60 9.3P7-4 1 24.3 14.5 0.6 813.0 14.2 31.7 1.1 40.5 108.3 0 90.1 0.64 136.8 XP7-5 1 20.2 14.1 0.7 896.5 2.8 27.9 0.4 41.6 87.6 0 21.0 0.63 32.4 X

P12-1 1 10.1 16.2 1.6 167.0 0.4 14.7 2.5 57.1 100.3 1 5.5 0.70 7.7 7.2 0.3 0.4P12-2 1 39.5 42.4 1.1 114.5 1.4 49.8 3.9 57.7 143.1 0 5.1 0.73 7.0P12-3 1 22.2 40.8 1.8 158.8 0.9 32.4 2.4 54.0 131.7 0 4.9 0.71 6.9P12-4 1 25.9 30.5 1.2 184.0 1.3 33.8 2.8 53.2 140.3 0 7.5 0.72 10.4 X

P13-1 1 49.3 39.0 0.8 300.6 1.2 59.8 2.3 47.8 114.9 0 3.8 0.68 5.6 4.8 0.2 0.5P13-2 1 39.7 33.3 0.8 322.1 0.9 49.0 2.2 46.5 127.6 0 3.3 0.69 4.8P13-3 1 17.6 16.1 0.9 220.1 0.3 22.4 2.1 49.0 136.6 0 2.9 0.70 4.2P13-4 1 49.2 33.8 0.7 275.0 1.0 58.3 3.1 56.5 145.6 0 3.3 0.73 4.5P13-5 1 48.7 34.9 0.7 260.8 1.1 58.0 2.6 45.1 184.4 0 3.6 0.70 5.1

P16-1 1 44.8 58.8 1.3 121.9 0.7 59.0 2.3 47.6 150.8 0 2.3 0.70 3.3 4.0 0.6 1.3P16-2 1 25.8 29.3 1.1 203.9 0.7 33.6 2.5 49.6 150.0 0 4.1 0.71 5.8P16-3 1 78.8 60.1 0.8 196.8 1.0 93.6 3.1 59.2 157.2 0 2.0 0.75 2.7P16-4 1 15.0 18.0 1.2 81.4 0.4 19.6 1.9 46.1 134.8 0 3.5 0.68 5.1P16-5 1 88.2 72.8 0.8 136.2 1.3 105.6 1.9 47.6 118.2 0 2.2 0.68 3.2

±1σ ±1 s.e.Th/U RE§ Ft Rej†

†

Sample- # grains U Th Sm He eU Mass 1/2

Width Length Raw Age Corr Age Av Age

Grain (ppm) (ppm) (ppm) (nmol/g) (ppm)* (µg) (µm)† (µm) (Ma)# (Ma)** (Ma)§§±1σ ±1

s.e.Th/U RE§ Ft Rej†

†

P16-1 4 637.0 135.5 0.2 0.0 0.5 668.2 17.3 37.3 166.2 0 18.3 0.74 24.8 25.3 0.5 0.7P16-3 4 908.6 107.7 0.1 0.0 1.2 933.4 27.2 43.3 195.2 0 19.9 0.77 25.8P16-2 4 916.2 221.6 0.2 0.0 0.7 967.2 43.0 52.1 211.8 0 7.4 0.80 9.2 XP16-4 4 1791.7 591.5 0.3 0.0 1.2 1927.9 52.5 56.2 219.4 1 4.7 0.82 5.8 X

P21-1 1 18.6 27.1 1.5 67.4 0.4 25.2 3.8 62.0 128.0 0 3.2 0.74 4.3 3.8 0.7 1.4P21-2 1 12.9 26.1 2.0 158.7 0.4 19.7 0.6 36.7 85.7 0 4.2 0.59 7.0 XP21-3 1 12.6 22.8 1.8 213.3 0.2 19.0 0.8 36.7 88.1 0 1.6 0.59 2.7P21-4 1 19.4 37.1 1.9 222.3 0.2 29.1 0.8 32.9 96.0 0 1.5 0.57 2.6P21-5 1 29.4 60.3 2.1 62.9 0.9 43.6 1.4 43.8 107.6 0 3.6 0.65 5.5

P24-1 1 11.2 33.5 3.0 228.2 0.5 20.1 1.2 38.2 100.1 0 4.3 0.61 7.0 X 4.2 0.3 0.6P24-2 1 23.2 39.3 1.7 467.6 0.4 34.6 1.3 39.1 120.2 0 2.4 0.64 3.7P24-3 1 17.6 41.4 2.4 265.4 0.4 28.4 1.2 42.2 104.1 0 2.7 0.64 4.3P24-4 1 97.1 57.8 0.6 261.6 1.8 111.8 0.8 36.8 87.6 0 3.0 0.60 5.0P24-5 1 17.5 41.0 2.3 288.9 0.4 28.4 1.4 43.4 122.3 0 2.4 0.64 3.7

P24-1 4 393.1 101.4 0.3 0.0 1.1 416.5 44.4 53.2 203.5 0 25.0 0.81 30.9 31.3 1.8 3.6P24-2 4 334.4 79.5 0.2 0.0 0.4 352.7 22.2 43.3 156.5 0 20.4 0.76 26.8P24-3 4 217.1 57.9 0.3 0.0 0.4 230.4 28.8 44.4 195.6 1 27.4 0.77 35.4P24-4 4 367.1 101.9 0.3 0.0 0.7 390.5 31.1 46.7 190.6 1 25.3 0.78 32.3

P31-1 1 8.1 8.1 1.0 246.1 0.2 11.2 1.5 47.4 104.8 1 3.7 0.67 5.4 4.0 0.6 1.1P31-2 1 5.7 7.2 1.3 228.6 0.1 8.5 3.1 48.8 161.8 0 1.9 0.71 2.6P31-3 1 3.5 6.7 1.9 211.8 0.2 6.1 1.7 53.8 86.3 1 5.3 0.68 7.7 XP31-4 1 5.3 5.9 1.1 192.4 0.1 7.7 2.1 51.0 106.0 0 2.8 0.69 4.0P31-5 1 5.1 5.8 1.1 191.8 0.1 7.4 2.1 51.0 106.0 0 2.9 0.69 4.1

P32-1 1 9.9 27.1 2.7 358.6 1.0 18.0 2.2 48.4 146.2 0 11.4 0.69 16.2 12.8 3.0 5.2P32-2 1 16.6 47.1 2.8 461.9 1.6 29.8 2.2 42.9 150.4 0 10.4 0.67 15.4P32-3 1 9.7 20.1 2.1 417.1 0.4 16.4 1.9 51.8 108.2 0 4.8 0.69 6.8P32-4 1 13.1 31.1 2.4 416.4 2.7 22.3 2.0 44.0 131.1 0 23.4 0.67 34.6 XP32-5 1 17.3 105.7 6.1 353.5 8.3 43.4 3.6 65.2 132.6 0 36.0 0.74 48.5 X

P33-1 1 9.6 22.9 2.4 368.2 0.7 16.7 2.2 53.1 145.8 0 7.8 0.71 10.8 10.1 1.2 2.6P33-2 1 13.2 17.1 1.3 345.6 0.9 18.8 2.3 46.0 143.5 0 9.3 0.69 13.4P33-3 1 14.2 19.6 1.4 369.1 0.5 20.5 2.6 49.8 156.1 0 4.7 0.71 6.6P33-4 1 17.9 15.4 0.9 304.9 1.0 23.0 4.7 63.9 184.8 0 8.6 0.77 11.2P33-5 1 19.4 28.2 1.5 409.2 0.9 27.9 2.6 59.8 112.2 0 6.3 0.72 8.7

P34-1 1 17.5 13.8 0.8 174.6 0.8 21.6 2.0 48.9 120.8 0 7.1 0.69 10.2 12.1 2.3 3.9P34-2 1 12.2 14.4 1.2 209.7 1.1 16.6 5.1 72.8 147.6 0 12.9 0.77 16.6P34-3 1 12.0 14.8 1.2 164.3 0.6 16.3 2.3 53.3 141.7 1 6.9 0.72 9.5

P35-1 1 20.9 56.2 2.7 138.4 0.1 34.5 2.1 45.4 142.3 0 0.8 0.68 1.1 1.4 0.1 0.2P35-2 1 3.3 25.0 7.6 76.8 0.0 9.4 2.1 53.5 107.0 1 1.0 0.68 1.4P35-3 1 43.9 81.6 1.9 79.8 0.3 63.1 1.4 46.1 98.9 0 1.0 0.66 1.5P35-4 1 45.1 53.0 1.2 140.7 0.3 58.0 5.2 60.7 164.6 0 1.0 0.75 1.3

P37-1 1 6.7 27.8 4.2 230.9 0.2 14.2 1.4 40.2 108.5 0 3.0 0.63 4.8 X 9.7 0.9 1.6P37-2 1 9.0 26.6 3.0 284.1 0.5 16.5 1.9 50.8 102.8 0 5.9 0.68 8.6P37-3 1 6.9 28.7 4.2 254.1 0.5 14.8 0.8 36.7 84.9 1 6.8 0.58 11.5P37-4 1 5.9 19.6 3.3 232.8 0.3 11.6 1.3 40.1 96.5 1 5.7 0.62 9.0

P42-1 1 6.2 17.8 2.9 256.5 0.3 11.6 1.7 50.6 84.6 1 4.4 0.66 6.6 16.0 5.0 10.0P42-2 1 12.0 36.3 3.0 378.3 0.5 22.2 0.6 30.3 90.9 1 4.7 0.54 8.5P42-3 1 13.6 81.9 6.0 345.1 2.4 34.2 1.5 42.3 98.7 0 13.5 0.63 21.4P42-4 1 9.1 60.5 6.7 266.1 1.9 24.3 0.7 32.4 80.8 0 14.8 0.54 27.4

Sample- # grains U Th Sm He eU Mass 1/2

Width Length Raw Age Corr Age Av Age

Grain (ppm) (ppm) (ppm) (nmol/g) (ppm)* (µg) (µm)† (µm) (Ma)# (Ma)** (Ma)§§±1σ ±1

s.e.Th/U RE§ Ft Rej†

†

P43-1 1 14.4 21.2 1.5 125.4 0.4 19.9 2.4 49.7 120.5 1 4.2 0.69 6.0 9.7 1.4 2.8P43-2 1 25.3 33.0 1.3 122.5 1.3 33.5 1.5 35.8 150.1 0 7.1 0.63 11.3P43-3 1 10.4 21.8 2.1 166.8 0.5 16.3 0.8 36.4 77.4 0 5.3 0.58 9.1

d 1 13.8 27.6 2.0 120.1 0.8 20.8 0.8 33.2 76.1 0 6.8 0.55 12.3

P44-1 1 22.2 8.0 0.4 149.0 0.7 24.8 3.7 51.9 170.3 0 5.1 0.73 7.0 6.6 0.4 0.8P44-2 1 23.8 11.4 0.5 177.1 0.7 27.4 3.2 46.6 124.8 0 5.1 0.69 7.4P44-3 1 20.0 5.4 0.3 135.1 0.5 21.9 2.2 46.4 173.6 1 3.9 0.71 5.5P44-4 1 30.1 11.6 0.4 133.5 0.8 33.5 2.6 50.8 127.7 0 4.6 0.71 6.5

P45-1 1 10.5 9.2 0.9 381.9 0.3 14.6 4.1 61.2 141.8 1 3.8 0.74 5.1 4.9 0.1 0.2P45-2 1 15.7 17.1 1.1 422.7 0.9 21.8 2.9 42.7 168.5 0 7.8 0.68 11.3 XP45-3 1 14.0 14.3 1.0 436.4 0.3 19.4 1.8 46.5 116.7 1 3.3 0.68 4.8P45-4 1 11.0 10.8 1.0 433.9 1.3 15.6 2.1 51.4 95.3 1 17.7 0.68 25.5 X

W1-1 1 0.4 9.9 24.1 146.6 0.0 3.4 1.3 63.0 112.7 0 0.3 0.71 0.4 X 15.7 1.7 1.7W1-2 1 12.3 8.4 0.7 187.5 1.0 15.2 7.5 78.1 206.5 0 12.7 0.80 15.7

P52-1 1 8.8 29.4 3.3 228.8 0.2 16.7 1.7 49.8 117.5 0 2.4 0.68 3.5 3.8 0.5 0.9P52-2 1 7.0 14.4 2.1 101.8 0.2 10.8 3.6 50.8 173.8 0 2.9 0.72 4.1P52-3 1 10.1 22.2 2.2 238.0 0.2 16.4 1.6 40.8 120.6 0 1.8 0.64 2.8P52-4 1 7.0 34.8 5.0 155.8 0.3 15.8 1.7 52.9 106.4 0 3.4 0.68 5.0

P53-1 1 18.7 25.4 1.4 55.2 0.4 24.8 1.3 42.3 122.9 0 2.8 0.66 4.2 5.3 0.5 0.9P53-2 1 8.2 10.9 1.3 142.8 0.2 11.5 1.5 46.8 112.6 0 4.0 0.67 5.9P53-3 1 27.1 34.9 1.3 363.9 0.8 37.0 2.2 48.6 152.8 0 4.1 0.70 5.7P53-4 1 92.6 72.1 0.8 160.5 3.4 110.0 1.6 44.9 104.7 0 5.6 0.66 8.5 X

P54-1 1 7.1 15.7 2.2 188.7 0.2 11.7 2.0 47.0 142.7 0 3.2 0.69 4.6 5.2 0.3 0.5P54-3 1 19.8 25.5 1.3 190.1 0.5 26.6 1.9 42.2 129.0 0 3.6 0.66 5.4P54-4 1 8.1 23.7 2.9 119.9 0.3 14.2 1.5 45.9 92.8 0 3.6 0.65 5.6

P58-1 1 17.7 29.6 1.7 172.0 0.6 25.4 2.5 49.0 159.0 0 4.6 0.71 6.4 6.4 0.04 0.1P58-2 1 11.5 13.7 1.2 109.9 3.0 15.2 1.6 43.2 128.4 1 36.7 0.67 54.6 XP58-3 1 71.7 63.0 0.9 185.1 2.2 87.1 3.5 56.4 170.9 0 4.7 0.74 6.3P58-4 1 27.5 43.3 1.6 142.2 0.9 38.2 1.4 42.0 128.2 0 4.2 0.66 6.3

P59-1 1 3.2 9.6 3.0 79.4 0.1 5.8 2.6 53.5 122.3 0 3.8 0.70 5.4 4.9 0.8 1.6P59-2 1 25.6 41.1 1.6 173.5 0.4 35.9 1.4 44.3 116.4 0 2.2 0.66 3.4P59-3 1 27.0 45.2 1.7 194.1 0.9 38.3 1.2 47.8 75.1 0 4.4 0.64 6.9P59-4 1 22.0 25.0 1.1 141.1 0.4 28.4 1.1 36.5 100.7 0 2.5 0.61 4.0

P60-1 1 16.5 22.5 1.4 62.1 0.4 22.0 1.4 47.5 98.2 0 3.0 0.67 4.5 X 8.2 0.8 1.3P60-2 1 14.4 15.4 1.1 237.0 0.6 19.2 0.9 41.4 73.5 0 5.9 0.61 9.6P60-3 1 13.1 15.5 1.2 89.0 0.4 17.1 2.1 47.2 122.5 0 4.8 0.68 7.0P60-4 1 25.8 18.2 0.7 91.1 0.9 30.4 2.0 48.7 120.6 0 5.5 0.69 8.0

P61-1 1 5.9 15.8 2.7 96.9 0.1 10.0 1.0 39.2 108.6 0 2.0 0.62 3.2 5.1 1.2 2.5P61-2 1 17.3 31.1 1.8 171.1 0.2 25.3 0.5 37.3 64.1 0 1.7 0.56 3.0P61-3 1 15.2 20.6 1.4 85.6 0.6 20.4 1.2 39.3 121.1 0 5.2 0.64 8.1P61-4 1 18.7 32.2 1.7 156.5 0.6 26.9 1.4 40.6 113.3 0 3.9 0.64 6.1

P62-1 1 11.4 23.5 2.1 242.7 1.2 18.0 4.0 57.5 159.0 0 12.7 0.74 17.1 X 6.7 0.2 0.3P62-2 1 28.4 36.6 1.3 185.0 0.9 37.8 2.0 45.1 132.2 0 4.7 0.68 6.8P62-3 1 17.3 36.8 2.1 291.6 1.4 27.3 1.2 39.3 95.2 0 9.5 0.62 15.3 XP62-4 1 7.9 15.3 1.9 226.2 0.3 12.5 1.8 39.8 124.3 0 4.2 0.64 6.5

Sample- # grains U Th Sm He eU Mass 1/2

Width Length Raw Age Corr Age Av Age

Grain (ppm) (ppm) (ppm) (nmol/g) (ppm)* (µg) (µm)† (µm) (Ma)# (Ma)** (Ma)§§±1σ ±1

s.e.Th/U RE§ Ft Rej†

†

P63-1 1 12.3 26.3 2.1 116.7 0.4 19.0 1.1 42.7 81.9 0 3.9 0.62 6.2 7.9 0.6 1.2P63-2 1 12.5 24.2 1.9 70.4 0.5 18.4 1.0 36.2 111.9 0 5.1 0.61 8.4P63-3 1 12.7 18.1 1.4 81.3 0.5 17.3 1.0 37.1 103.9 0 4.9 0.61 8.0P63-4 1 3.2 10.5 3.3 394.3 0.2 7.6 1.2 41.8 89.2 0 5.9 0.62 9.1

P64-1 1 20.6 31.1 1.5 241.5 0.5 29.0 1.2 38.4 121.2 0 3.6 0.63 5.6 5.9 0.1 0.2P64-2 1 148.2 61.8 0.4 382.8 3.5 164.4 1.3 41.8 103.8 0 3.9 0.65 6.1P64-3 1 39.1 36.4 0.9 251.4 1.0 48.7 1.4 42.6 124.6 0 4.0 0.66 6.0P64-4 1 11.5 36.8 3.2 113.7 0.7 20.5 3.1 56.0 137.0 0 6.3 0.72 8.7 X

P65-1 1 15.1 18.2 1.2 344.5 0.4 21.1 1.6 42.4 112.7 0 4.1 0.65 6.3 6.6 0.4 0.8P65-2 1 32.5 28.0 0.9 183.2 0.9 39.9 1.0 27.5 88.9 1 4.4 0.52 8.4 XP65-3 1 50.2 54.9 1.1 308.6 1.3 64.4 1.5 41.0 131.7 0 3.7 0.66 5.7P65-4 1 10.6 18.3 1.7 72.2 0.3 15.2 0.7 39.0 72.6 0 4.1 0.59 7.0P65-5 1 11.8 21.6 1.8 277.5 0.5 18.2 1.5 45.9 133.0 0 5.1 0.68 7.4

P66-1 1 18.9 45.3 2.4 124.2 0.9 30.0 1.1 44.0 88.9 0 5.6 0.64 8.8 7.6 0.7 1.6P66-2 1 18.8 36.2 1.9 261.5 0.5 28.5 1.0 37.0 100.4 0 3.3 0.61 5.4P66-3 1 90.2 55.8 0.6 166.2 3.0 103.8 0.9 33.6 92.0 0 5.4 0.58 9.2P66-4 1 13.7 30.3 2.2 102.4 0.5 21.2 0.6 33.3 80.1 0 4.4 0.56 7.8P66-5 1 12.2 12.4 1.0 309.8 0.6 16.6 0.9 35.2 83.2 0 7.3 0.58 12.2 XP66-6 1 17.2 13.6 0.8 101.0 0.5 20.8 1.7 47.9 126.8 0 4.6 0.69 6.6

P67-1 1 7.2 23.7 3.3 276.2 0.6 14.1 3.9 80.5 92.9 0 8.9 0.74 11.8 10.8 0.8 1.3P67-2 1 8.4 7.1 0.8 118.8 0.6 10.6 1.2 43.1 90.0 0 10.6 0.64 16.4 XP67-3 1 8.6 5.3 0.6 213.5 1.7 10.9 0.8 42.2 96.2 1 30.1 0.64 46.1 XP67-4 1 14.2 12.3 0.9 433.1 0.7 19.3 4.2 87.8 87.4 1 7.1 0.76 9.3P67-5 1 16.0 9.9 0.6 349.1 0.8 20.0 1.7 51.4 94.2 1 7.8 0.68 11.3

P68-1 1 41.7 37.1 0.9 232.5 1.7 51.4 0.6 43.6 89.7 0 6.0 0.64 9.4 8.4 1.0 1.4P68-4 1 20.2 21.7 1.1 68.0 0.7 25.5 2.4 51.3 138.5 1 5.2 0.71 7.4

P69-1 1 9.8 14.3 1.5 81.4 0.3 13.5 0.9 39.3 75.6 0 4.6 0.60 7.7 7.3 0.5 1.0P69-2 1 8.8 25.0 2.8 140.2 0.7 15.3 1.5 47.4 116.4 0 8.2 0.67 12.1 XP69-3 1 12.3 15.5 1.3 200.0 0.4 16.9 1.0 40.8 88.3 0 4.4 0.62 7.0P69-4 1 5.6 9.0 1.6 142.3 0.3 8.4 2.5 65.0 119.7 0 6.2 0.74 8.3P69-5 1 5.4 13.7 2.6 105.7 0.2 9.1 0.8 30.8 86.8 0 3.3 0.54 6.1

P70-1 1 164.8 145.3 0.9 201.6 4.3 199.2 1.9 59.7 104.3 0 4.0 0.72 5.5 4.7 0.5 0.9P70-2 1 11.5 28.5 2.5 277.5 0.4 19.4 4.0 73.8 144.6 0 4.3 0.77 5.5P70-3 1 168.9 106.8 0.6 192.9 2.6 194.5 1.3 44.7 106.8 0 2.4 0.66 3.7P70-4 1 35.9 30.4 0.8 297.1 0.7 44.3 3.0 61.1 139.2 0 3.2 0.74 4.2

Note: Bold and italic sample-grain numbers, ages, and errors are zircon (U-Th)/He samples. *eU is the effective uranium concentration determined by the relative apparent contributions from U, Th, and Sm (Shuster el al., 2006; Flowers et al., 2009). †Averaged prism half-width. §RE indicates helium extraction during a second heating. #Raw Age is the grain age before applying the Ft correction. **Corr Age is the grain age after dividing the raw age by the Ft correction. ††Outlier grains rejected. §§Av Age is the averaged corrected ages of every valid replicate reported as ± 1 standard error.

Sample Rock Type*

Lat. (oN)†

Long. (oW)†

Elv. (m)

ρs

(x106t/rcm2)§Ns

#ρi **

(x106tr/cm2)Ni

††ρd

(x106tr/cm2)§§Nd

## n*** P(χ2) ††† U §§§ (ppm)

Age (Ma)

±1σ (Ma)

P2 Tg 60.85 -148.43 500 0.107 71 2.104 1397 1.402 3506 30 98.6 20.2 12.4 1.5P3 Tg 60.79 -148.10 0 0.198 104 3.141 1652 1.411 3528 20 98.0 25.7 15.4 1.6P5 Tgg 60.88 -147.36 0 0.103 33 1.564 499 1.428 3571 20 87.4 12.6 16.4 3.0P6 Tgg 60.95 -147.41 0 0.408 298 4.818 3522 1.437 3592 30 6.9 40.9 21.1 1.4P12 Toc 61.05 -147.52 0 0.170 119 4.328 3025 1.463 3657 40 57.2 37.3 10.0 1.0P13 Tg 60.91 -148.01 0 0.150 135 3.582 3227 1.472 3679 30 99.2 29.3 10.7 1.0P16 Kvs 61.14 -147.83 0 0.070 67 2.767 2645 1.480 3701 40 100.0 23.5 6.5 0.8P21 Kvs 61.20 -147.71 0 0.046 35 1.852 1400 1.498 3744 40 99.9 14.8 6.5 1.1P24 Kvs 61.07 -148.12 0 0.110 55 2.315 1153 1.528 3819 40 93.5 17.9 12.6 1.8P31 Tg 60.97 -148.21 61 0.109 29 2.436 648 1.541 3851 20 97.9 18.5 12.0 2.3P32 Tg 60.51 -148.37 0 0.104 50 1.191 573 1.553 3884 20 82.7 8.5 23.5 3.5P33 Tg 60.67 -148.19 0 0.163 88 2.057 1113 1.566 3916 20 40.6 14.9 21.5 2.5P34 Tg 60.47 -147.96 0 0.607 164 4.385 1184 1.455 3637 20 61.6 38.6 36.6 3.2P35 Tos 59.96 -147.68 0 0.068 69 4.281 4332 1.592 3980 40 100.0 26.8 4.4 0.5P37 Toc 60.09 -147.91 0 0.156 35 1.249 281 1.441 3601 21 99.5 11.1 32.6 5.9P42 Tg 60.73 -147.97 0 0.175 77 1.205 529 1.415 3538 29 100.0 10.8 37.4 4.6P43 Tgd 60.81 -147.97 0 0.144 70 2.403 1168 1.402 3504 20 93.3 21.7 15.3 1.9P44 Tg 60.87 -147.93 0 0.137 80 2.840 1664 1.656 4141 30 67.8 19.83 13.8 1.6P45 Tg 60.89 -148.10 0 0.068 30 1.587 703 1.389 3471 20 63.9 13.7 10.8 2.0P53 Kvs 61.18 -147.87 0 0.097 77 3.371 2683 1.695 4238 40 90.6 26 8.4 1.0P54 Kvs 61.06 -148.00 0 0.053 48 1.854 1678 1.708 4270 40 92.0 12.9 8.5 1.3P58 Kvs 61.06 -148.25 0 0.157 94 3.572 2136 1.735 4337 40 99.4 23.4 13.3 1.4

Note: All samples were counted on an Olympus BX50 microscope fitted with an automated stage and a digitizing tablet from T. Dumitru. Fission track ages (±1σ) were determined using the Zeta method, and ages were calculated using the programs TRACKKEY (Dunkl, 2002) and ZETAAGE (Brandon 1992). *Rock type abbreviations are: (Tg) Eocene–Oligocene intrusions; (Tgg) Sanak-Baranof intrusions; (Tfd) Tertiary felsic intrusions; (Toc & Tos) Paleocene—mid Eocene Orca Group conglomerate and sandstone; (Kvs) Cretaceous Valdez sandstone. †Sample datum are reported in NAD 27. §ρs is the density of spontaneous tracks. #Ns is the number of spontaneous tracks counted. **ρi is the density of induced tracks. ††Ni is the number of induced tracks counted. §§ρd is the density of tracks on the fluence monitor (CN5). ##Nd is the interpolated number of tracks from the position of the sample in the irritation tube. ***n is the number of grains counted. †††P(χ2) is the Chi-squared probability (%). Ages with P(χ2) > 5% are reported as pooled ages and otherwise reported as central ages. §§§U is uranium concentration (ppm).

Table DR2. Apatite fission track analytical data from the western Chugach Mountains and Prince William Sound, Alaska

Table DR3. HeFTy modeling parameters for specific samples.

Sample AFT age (Ma)

AHe age (Ma)

Mean track length (µm)

Dpar range for ages (µm)

Dpar for lengths (µm)

Emplacement age (Ma)

P13 10.7± 1.0 (n=30)

4.8± 0.2 (n=5)

13.89± 1.08 (n=97)

1.10-1.93 1.52 35.5 ± 0.9

P34 36.6± 3.2 (n=20)

12.1± 2.3 (n=3)

13.68± 1.37 (n=51)

1.05-1.86 1.46 36.1 ± 0.9

Table notes: (1) Intrusion emplacement ages from Nelson et al. (1985) (2) Mean track lengths are Cf-252 corrected using Ketcham et al. (2007).