Table1_coordinates Coordinates for 40Ar/39Ar samples Table2_agesummary Summary table for 40Ar/39Ar data Table3_analyticaldata The 40Ar/39Ar analytical data associated with each recorded temperature
Layer, P.W., and Solie, D.N., 2008, 40Ar/39Ar ages from the Tyonek D-6 quadrangle and parts of Tyonek D-7, Tyonek D-5 and Tyonek C-6 quadrangles, Alaska: Raw Data File RDF 2008-4, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska - USA.Online Links:
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 1
Ordinates (y-coordinates) are specified to the nearest 1
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1927.
The ellipsoid used is Clarke 1866.
The semi-major axis of the ellipsoid used is 6378206.4.
The flattening of the ellipsoid used is 1/294.978698.
Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well.
| Range of values | |
|---|---|
| Minimum: | 534911 |
| Maximum: | 559281 |
| Units: | m |
| Range of values | |
|---|---|
| Minimum: | 6840075 |
| Maximum: | 6866077 |
| Units: | m |
| Range of values | |
|---|---|
| Minimum: | 61.6924 |
| Maximum: | 61.9254 |
| Units: | decimal degree |
| Range of values | |
|---|---|
| Minimum: | 151.8734 |
| Maximum: | 152.3361 |
| Units: | decimal degree |
Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well.
Material used for dating. Includes BI (biotite), HO (hornblende), WR (whole rock).
| Range of values | |
|---|---|
| Minimum: | 54.1 +/-0.5 |
| Maximum: | 99.5 +/-0.7 |
| Units: | Ma |
| Range of values | |
|---|---|
| Minimum: | 53.7 +/-0.4 |
| Maximum: | 101.0 +/-2.0 |
| Units: | Ma |
# of fractions, % 39Ar released, MSWD for each sample
Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well.
| Range of values | |
|---|---|
| Minimum: | 300 |
| Maximum: | 1700 |
| Units: | Degrees C |
| Range of values | |
|---|---|
| Minimum: | 0.0000 |
| Maximum: | 1.0000 |
| Range of values | |
|---|---|
| Minimum: | 2.5705 |
| Maximum: | 1134.98 |
| Range of values | |
|---|---|
| Minimum: | 0.0001 |
| Maximum: | 200.0000 |
| Range of values | |
|---|---|
| Minimum: | 0.0001 |
| Maximum: | 400.0000 |
| Range of values | |
|---|---|
| Minimum: | 0.0000 |
| Maximum: | 0.4000 |
| Range of values | |
|---|---|
| Minimum: | 0.0 |
| Maximum: | 220.0 |
| Range of values | |
|---|---|
| Minimum: | 0.0000 |
| Maximum: | 1000.0000 |
| Range of values | |
|---|---|
| Minimum: | 0.00000 |
| Maximum: | 0.80000 |
| Range of values | |
|---|---|
| Minimum: | -111.0000 |
| Maximum: | 140.0000 |
| Range of values | |
|---|---|
| Minimum: | 0.0 |
| Maximum: | 150.0 |
| Units: | Ma |
This research was supported by State funding to the Alaska Division of Geological & Geophysical Surveys. Additional Acknowledgments: 1990 DGGS field mapping and sample collection by DN. Solie, J.T. Kline (deceased), W.G. Gilbert, E.E. Harris, M.S. Robinson, S.A. Liss and K.K. DePalma. Review of draft manuscript by D.J. Szumigala.
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In 1990, DGGS conducted a preliminary geologic mapping project in the Tyonek D-6 and parts of the adjacent D-5, D-7 and C-6 quadrangles. DGGS published a preliminary geologic map and geochemical data resulting from that initial work in 1991 (Solie and others, 1991a and 1991b). At that time, the results from the 40Ar/39Ar age dating were pending. A brief discussion of the results was given in Layer and Solie (1991) and Solie and Layer (1993). The purpose of this DGGS Raw Data File is to present the 40Ar/39Ar results and make them available for use to others interested in the area.
Lanphere, M.A., Dalrymple, G.B., Fleck, R.J., and Pringle, M.S., 1990, Intercalibration of mineral standards for K/Ar and 40Ar/39Ar age measurements: EOS Transactions of the American Geophysical Union v. 71.
Layer, P.W., and Solie, D.N., 1991, Timing of igneous activity and basin formation, southern Alaska Range, as constrained by 40Ar/39Ar dating: EOS Transactions of the American Geophysical Union v.72, no. 44.
McDougall, I, and Harrison, T.M., 1999, Geochronology and Thermochronology by the 40Ar/39Ar method: Oxford University Press, Oxford.
Samson, S.D., and Alexander, E.C., 1987, Calibration of the interlaboratory 40Ar/39Ar dating standard, MMhb-1: Chemical Geology v. 66.
Solie, D.N., Kline, J.T., Gilbert, W.G., Robinson, M.S., Harris, E.E., and Liss, S.A., 1991, Analytical results from rock and pan concentrate samples, Tyonek D-6 and parts of adjacent quadrangles, Alaska: Public Data File PDF 91-1.Online Links:
Solie, D.N., Gilbert, W.G., Harris, E.E., J.T., Kline., Liss, S.A., and Robinson, M.S., 1991, Preliminary geologic map of Tyonek d-6 and eastern Tyonek D-7 quadrangles, Alaska: Public Data File PDF 91-10.Online Links:
Solie, D.N., and Layer, P.W., 1993, The Hayes Glacier Fault, southern Alaska Range: Evidence for post-paleocene movement: Professional Report PR 106, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
Solie, D.N., and Tannian, Fran, 1993, Short Notes on Alaskan Geology 1993: Professional Report PR 113, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.Online Links:
Steiger, R.H., and Jager, E, 1977, Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology: Earth and Planetary Science Letters v.36.
Data sources used in this process:
Data sources used in this process:
All field locations were visually determined by the geologists in the field and recorded on a 1:63,360 topographic map enlarged to a scale of 1:40,000. Coordinates were digitized visually from the field maps. DGGS submitted fourteen rock samples to the UAF Geochronology Laboratory for 40Ar/39Ar dating. Major oxide and selected trace element analyses for most of the samples are included in Solie and others (1991b). Separates for 40Ar/39Ar dating were prepared to >99.5% purity (visual inspection) using standard heavy liquid and magnetic separation techniques followed by hand-picking under a binocular microscope. Thin section examination of the samples prior to crushing indicated that the chosen minerals were free from alteration and sufficiently coarse-grained for mechanical separation. For all minerals, grains in the size range of 250 - 500 microns were used. For each sample, ~50-80 mg of biotite or 250-350 mg of hornblende or whole rock (phenocryst-free groundmass) was packaged in an aluminum foil tube and irradiated in position 5C at the McMaster University nuclear reactor, in Hamilton, Ontario. Approximately 20 samples were irradiated at a time. Six packages containing ~20 mg of the standard mineral mmhb-1 (Samson and Alexander, 1987) with an age of 513.9 Ma (Lanphere and others, 1990) were also irradiated with the samples to determine the irradiation parameter (J) and the flux gradient in the reactor. Samples and standards were analyzed 45 to 90 days after irradiation. The irradiated samples were step-heated on-line in a Modifications Ltd. low-blank furnace. Temperature control was better than 5 degrees and a maximum temperature in excess of 1600o C was achievable to ensure complete sample fusion. The extracted argon was purified in a two-stage process using a liquid nitrogen cold finger and two SAES Zr-Al getters. Prior to measurement of the Ar, the gas was collected on an activated charcoal finger. The purified Ar gas was measured using a Nuclide 6-60-SGA 15 cm mass spectrometer. The sensitivity of the spectrometer is 6.5 x 10-15 mol/mV and system noise is generally around 0.02 mV. System blanks are generally better than 1 X 10-14 mol for 40Ar. Argon isotopic measurements for both samples and standards were corrected for the system blanks, for decay of 37Ar and 39Ar, and for reactor-induced isotopic interferences. Ages were calculated using the equations and corrections from McDougall and Harrison (1999) and the constants from Steiger and Jaeger (1977) and are shown in Table 2 (age summary) and Table 3 (analytical data). All errors on analyses are reported at the 1-sigma level. For each mass spectrometer analysis, five Ar isotope abundances are measured. 36Ar is used to determine the amount of atmospheric or initial Ar in the sample, 37Ar provides an estimation of the Ca content in the mineral, 38Ar provides an estimation of the Cl content, 39Ar reflects the K content and 40Ar is a mixture of initial and radiogenic Ar. The age of the sample is proportional to the ratio of the amount of radiogenic 40Ar to the amount of 39Ar produced by neutron bombardment from 40K.
Sample locations were determined visually by geologist in the field, using a Brunton compass and altimeter and topographic map. Locations were then digitized visually from the field maps using ArcGIS v9.2.
This dataset includes all of the samples submitted for 40Ar/39Ar age date analyses from the Tyonek quadrangle which were collected by DGGS during the summer of 1990.
No topologic relationships are present in the data.
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Raw Data File 2008-4
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