AVO Logo
Site Map | FAQ |
Alaska Volcano Observatory
 
You are here: Home > Samples > UT497

SAMPLE INFO : UT497
Sample ID:UT497
Station ID:Gold_Hill_II
Latitude:64.9
Longitude:-147.9
Datum:NAD83
Sample Type 1:Tephra Fall
Field Lithology:Rhyolite
Text Description:
Semi-lithified tephra located in the basal part of the Gold Hill Loess, 11 m above the Cripple Gravel. It has been deformed by solifluction into pods, up to 5 cm thick and 38 cm long, that are spread out vertically over a 20-25 cm interval and interbedded with massive, grey (2.5Y6/3) and oxidized (2.5Y6/4) silt. All contacts with the surrounding loess are sharp in most places and wispy in a few. There is often a darker pink rim, a few mm to less than a mm thick, along the silt-tephra contact of the pods. In some places, the tephra has been oxidized and is rusty along the silt-tephra contact. The larger pods are sometimes separated into smaller pods by wisps or mm thick silt layers, and some of the pods have very convoluted outlines while others are more regular ovals. It can be traced continuously from stations Gold_Hill_II to Gold_Hill_IV. Sample contains aggregates of fine-grained, colourless and brown glass shards poorly cemented by silica. Highly vesicular pumice is common with elongate vesicles, however, poorly vesicular pumice and bubblewall glass shards also common. Mineral component includes feldspar and FeTi oxides with accessory amounts of clinopyroxene, orthopyroxene, hornblende, and apatite.

References:
Tephrostratigraphy of the late Cenozoic Gold Hill loess, Fairbanks area, Alaska
Tephrochronology of late Cenozoic loess at Fairbanks, central Alaska
The Dawson Cut Forest Bed in the Fairbanks area, Alaska, is about two million years old
Late Pliocene Dawson Cut forest bed and new tephrochronological findings in the Gold Hill Loess, east-central Alaska
The Palisades is a key reference site for the middle Pleistocene of eastern Beringia: new evidence from paleomagnetics and regional tephrostratigraphy
Update on the late Cenozoic tephrochronology of the Gold Hill loess at Fairbanks, Alaska, and correlation with the Klondike goldfields in the Yukon
A 3-my record of Pliocene-Pleistocene loess in interior Alaska

GEOCHEM DATA
StationIDLatitudeLongitudeGeologistDateVisitedAge InfoVolcanoEruptionLocation DescriptionText DescriptionSample IDSample Type 1Sample Type 2Final UnitMaterialCoeffSiO2TiO2Al2O3FeOTMnOMgOCaONa2OK2OP2O5Total-majorsREF majorsMETH majorsFe2O3/Fe203T origFeO/FeOT origVolatiles csvMETH volatilesCsRbBaSrLaCePrNdSmEuGdTbDyHoErTmYbLuYZrNbHfTaPbThUScVCrFeCoNiCuZnGaMoAsNaKRef trace1METH trace1RbBaSrLaCeNdSmEuGdDyErYbLuYZrNbPbThUScTiVCrNiCuZnGaRef trace2METH trace2Light csvHalogen csvother major csvother lile csvother ree csvother hfse csvother hpe csvother tm csvother misc csv
Gold_Hill_II64.9-147.9Preece, S. J. 2020000 ± 140000 glass - FT; 996; Age is approximate. Weighted mean average of two dates obtained on sample UT497. See Preece and others (1999) for methods.Trench dug down to the cliff face on the north side of the Gold Hill mining cut, Fairbanks, Alaska; located approximately 400 m to the northeast of station Preece_1999_Gold_Hill_I. Location imprecisely georeferenced from Figure 4 in Preece et al. (1999). Semi-lithified tephra located in the basal part of the Gold Hill Loess, 11 m above the Cripple Gravel. It has been deformed by solifluction into pods, up to 5 cm thick and 38 cm long, that are spread out vertically over a 20-25 cm interval and interbedded with massive, grey (2.5Y6/3) and oxidized (2.5Y6/4) silt. All contacts with the surrounding loess are sharp in most places and wispy in a few. There is often a darker pink rim, a few mm to less than a mm thick, along the silt-tephra contact of the pods. In some places, the tephra has been oxidized and is rusty along the silt-tephra contact. The larger pods are sometimes separated into smaller pods by wisps or mm thick silt layers, and some of the pods have very convoluted outlines while others are more regular ovals. It can be traced continuously from stations Gold_Hill_II to Gold_Hill_IV. Sample contains aggregates of fine-grained, colourless and brown glass shards poorly cemented by silica. Highly vesicular pumice is common with elongate vesicles, however, poorly vesicular pumice and bubblewall glass shards also common. Mineral component includes feldspar and FeTi oxides with accessory amounts of clinopyroxene, orthopyroxene, hornblende, and apatite.UT497Tephra FallCumulateGlass 74.36 0.37 12.96 2.33Reported analytical value of zero. Reported standard deviation value of zero. 0 0.26 1.43 3.53 4.36 93.3356EMP2.33Cl=0.6EMP 4.18 138 1629 299 33.65 73.8 33.6 6.91 1.05 0.87 3.02 0.53 8.31 1.09 14.61 4.97 5.34 3.78 72 56INAA
Gold_Hill_II64.9-147.9Preece, S. J. 2020000 ± 140000 glass - FT; 996; Age is approximate. Weighted mean average of two dates obtained on sample UT497. See Preece and others (1999) for methods.Trench dug down to the cliff face on the north side of the Gold Hill mining cut, Fairbanks, Alaska; located approximately 400 m to the northeast of station Preece_1999_Gold_Hill_I. Location imprecisely georeferenced from Figure 4 in Preece et al. (1999). Semi-lithified tephra located in the basal part of the Gold Hill Loess, 11 m above the Cripple Gravel. It has been deformed by solifluction into pods, up to 5 cm thick and 38 cm long, that are spread out vertically over a 20-25 cm interval and interbedded with massive, grey (2.5Y6/3) and oxidized (2.5Y6/4) silt. All contacts with the surrounding loess are sharp in most places and wispy in a few. There is often a darker pink rim, a few mm to less than a mm thick, along the silt-tephra contact of the pods. In some places, the tephra has been oxidized and is rusty along the silt-tephra contact. The larger pods are sometimes separated into smaller pods by wisps or mm thick silt layers, and some of the pods have very convoluted outlines while others are more regular ovals. It can be traced continuously from stations Gold_Hill_II to Gold_Hill_IV. Sample contains aggregates of fine-grained, colourless and brown glass shards poorly cemented by silica. Highly vesicular pumice is common with elongate vesicles, however, poorly vesicular pumice and bubblewall glass shards also common. Mineral component includes feldspar and FeTi oxides with accessory amounts of clinopyroxene, orthopyroxene, hornblende, and apatite.UT497Tephra FallCumulateGlass 74.1 0.37 12.92 2.32Reported standard deviation of zero 0.06Reported standard deviation of zero 0.34 1.42 3.52 4.35 3621EMP2.32Cl=0.6; H2O=6.34EMP 4.18 1630 33.65 73.8 33.6 6.91 1.05 0.87 3.02 0.53 8.31 1.09 14.61 4.97 5.34 70 996INAA
Gold_Hill_II64.9-147.9Preece, S. J. 2020000 ± 140000 glass - FT; 996; Age is approximate. Weighted mean average of two dates obtained on sample UT497. See Preece and others (1999) for methods.Trench dug down to the cliff face on the north side of the Gold Hill mining cut, Fairbanks, Alaska; located approximately 400 m to the northeast of station Preece_1999_Gold_Hill_I. Location imprecisely georeferenced from Figure 4 in Preece et al. (1999). Semi-lithified tephra located in the basal part of the Gold Hill Loess, 11 m above the Cripple Gravel. It has been deformed by solifluction into pods, up to 5 cm thick and 38 cm long, that are spread out vertically over a 20-25 cm interval and interbedded with massive, grey (2.5Y6/3) and oxidized (2.5Y6/4) silt. All contacts with the surrounding loess are sharp in most places and wispy in a few. There is often a darker pink rim, a few mm to less than a mm thick, along the silt-tephra contact of the pods. In some places, the tephra has been oxidized and is rusty along the silt-tephra contact. The larger pods are sometimes separated into smaller pods by wisps or mm thick silt layers, and some of the pods have very convoluted outlines while others are more regular ovals. It can be traced continuously from stations Gold_Hill_II to Gold_Hill_IV. Sample contains aggregates of fine-grained, colourless and brown glass shards poorly cemented by silica. Highly vesicular pumice is common with elongate vesicles, however, poorly vesicular pumice and bubblewall glass shards also common. Mineral component includes feldspar and FeTi oxides with accessory amounts of clinopyroxene, orthopyroxene, hornblende, and apatite.UT497Tephra FallCumulateGlass 73.04 0.37 13.02 2.25 0.06 0.33 1.5 3.61 5.12 4792EMP2.25Cl=0.7; H2O=4.13EMP

SAMPLE LOCATION

Contact AVO Privacy Accessibility Information Quality FOIA
URL: avo.alaska.edu/samples/sample_info.php
Page modified: August 1, 2017 15:29
Contact Information: AVO Web Team

twitter @alaska_avo
facebook alaska.avo
email Receive volcano updates by email: USGS VNS

This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G19AC00060 and G19AC00171.

Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.