Timing of ore-related magmatism in the western Alaska Range, southwestern Alaska

2014 ◽  
Author(s):  
Ryan D. Taylor ◽  
Garth E. Graham ◽  
Eric D. Anderson ◽  
David Selby
Keyword(s):  
Alaska Range ◽  
Southwestern Alaska

scholarly journals Mass concentration and origin of black carbon in spring snow on glaciers in the Alaska Range

Polar Science ◽  
2020 ◽  
pp. 100572
Author(s):  
Keiko Konya ◽  
Masahiro Yamaguchi ◽  
Masayuki Takigawa ◽  
Takuma Miyakawa ◽  
Shad O'Neel
Keyword(s):  
Black Carbon ◽  
Mass Concentration ◽  
Alaska Range

Flake Dispersal Experiments: Noncultural Transformation of the Archaeological Record

1983 ◽  
Vol 48 (3) ◽  
pp. 553-572 ◽  
Author(s):  
Peter M. Bowers ◽  
Robson Bonnichsen ◽  
David M. Hoch
Keyword(s):  
Human Activity ◽  
Time Lapse ◽  
Primary Factor ◽  
Frost Heave ◽  
The Arctic ◽  
Archaeological Sites ◽  
Archaeological Record ◽  
Alaska Range ◽  
Natural Processes ◽  
Present Test

Time lapse studies of frost action effects on arctic and subarctic surficial archaeological sites have been conducted from 1973 to the present. Test plots of experimentally produced flakes were constructed in 1973 in the Tangle Lakes Region of the Central Alaska Range and subsequently remapped and photographed in 1974, 1976, and 1980. Similar test plots were laid out in the arctic foothills province of the Brooks Range. Observations made during the study period include: (1) flake displacements of as much as 20 cm/yr; (2) average minimum movement is 4 cm/yr; and (3) upslope movements were observed, suggesting that slope is not the primary factor in flake displacements. Frost heave, needle ice and, possibly, wind appear to be the dominant forces responsible for dispersals. It is argued that these and other natural processes can restructure the archaeological record into patterns that easily can be mistaken for those produced by human activity.

X-Ray and Optical Data for a Rare Earth–Poor Eudialyte from the North–Central Alaska Range

1990 ◽  
Vol 5 (2) ◽  
pp. 89-92 ◽  
Author(s):  
Neil E. Johnson ◽  
Mickey E. Gunter ◽  
Diana N. Solie ◽  
Charles R. Knowles
Keyword(s):  
Rare Earth ◽  
Powder Diffraction ◽  
Weight Percent ◽  
Optical Data ◽  
Alaska Range ◽  
North Central ◽  
X Ray ◽  
The North ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

AbstractPowder X-ray and optical data have been recorded for a sample of exceptionally rare earth-poor eudialyte (Na12(Ca, REE)6(Fe2+,Mn,Mg)3Zr3(Zr,Nb)x[Si9O27−y(OH)y]2[Si3O9]2(C1,F)z, with x = 0. 1–0.9, y = 1–3 and z = 0.7–1.4) from a pegmatitic vein associated with the peralkaline Windy Fork granite in the north–central Alaska range. The eudialyte is uniaxial positive with ω= 1.6062(2), ε= 1.6138 (3) and microprobe analyses indicate that the sum of REE + Yis less than 0.1 weight percent. Refined unit cell dimensions are: a = 14.2572(4), c = 30.1338(27), Dx= 2.67, F30= 128 (0.006, 42), M20= 76. An indexed powder diffraction pattern is given.

scholarly journals Melt regimes, stratigraphy, flow dynamics and glaciochemistry of three glaciers in the Alaska Range

2012 ◽  
Vol 58 (207) ◽  
pp. 99-109 ◽  
Author(s):  
Seth Campbell ◽  
Karl Kreutz ◽  
Erich Osterberg ◽  
Steven Arcone ◽  
Cameron Wake ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Ice Core ◽  
Chemical Diffusion ◽  
Flow Dynamics ◽  
Alaska Range ◽  
Ice Volume ◽  
Glacier Ice ◽  
Age Model ◽  
Ground Penetrating ◽  
Climate Studies

AbstractWe used ground-penetrating radar (GPR), GPS and glaciochemistry to evaluate melt regimes and ice depths, important variables for mass-balance and ice-volume studies, of Upper Yentna Glacier, Upper Kahiltna Glacier and the Mount Hunter ice divide, Alaska. We show the wet, percolation and dry snow zones located below ~2700ma.s.l., at ~2700 to 3900ma.s.l. and above 3900ma.s.l., respectively. We successfully imaged glacier ice depths upwards of 480 m using 40-100 MHz GPR frequencies. This depth is nearly double previous depth measurements reached using mid-frequency GPR systems on temperate glaciers. Few Holocene-length climate records are available in Alaska, hence we also assess stratigraphy and flow dynamics at each study site as a potential ice-core location. Ice layers in shallow firn cores and attenuated glaciochemical signals or lacking strata in GPR profiles collected on Upper Yentna Glacier suggest that regions below 2800ma.s.l. are inappropriate for paleoclimate studies because of chemical diffusion, through melt. Flow complexities on Kahiltna Glacier preclude ice-core climate studies. Minimal signs of melt or deformation, and depth-age model estimates suggesting ~4815 years of ice on the Mount Hunter ice divide (3912ma.s.l.) make it a suitable Holocene-age ice-core location.

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