Only present at Site B of Chester Bluff. At Site B, Woodchopper Creek (WC) tephra forms a white bed up to 0.3 cm thick that is continuous over 4m. It has diffuse contacts with surrounding massive loess and is faulted downward over 1m. Contaminated by detrital material but also appear to be dominated by green amphibole and some ortho-pyroxene. The composition reported was calculated from analyses of four samples: UA1098, UA1212, UA1213, UA1214.
An extensive middle to late Pleistocene tephrochronologic record from east-central Alaska
Tephrochronology of middle to late Pleistocene loess in east-central Alaska
|StationID||Latitude||Longitude||Geologist||DateVisited||Age Info||Volcano||Eruption||Location Description||Text Description||Sample ID||Sample Type 1||Sample Type 2||Final Unit||Material||Coeff||SiO2||TiO2||Al2O3||FeOT||MnO||MgO||CaO||Na2O||K2O||P2O5||Total-majors||REF majors||METH majors||Fe2O3/Fe203T orig||FeO/FeOT orig||Volatiles csv||METH volatiles||Cs||Rb||Ba||Sr||La||Ce||Pr||Nd||Sm||Eu||Gd||Tb||Dy||Ho||Er||Tm||Yb||Lu||Y||Zr||Nb||Hf||Ta||Pb||Th||U||Sc||V||Cr||Fe||Co||Ni||Cu||Zn||Ga||Mo||As||Na||K||Ref trace1||METH trace1||Rb||Ba||Sr||La||Ce||Nd||Sm||Eu||Gd||Dy||Er||Yb||Lu||Y||Zr||Nb||Pb||Th||U||Sc||Ti||V||Cr||Ni||Cu||Zn||Ga||Ref trace2||METH trace2||Light csv||Halogen csv||other major csv||other lile csv||other ree csv||other hfse csv||other hpe csv||other tm csv||other misc csv|
|Jensen_2008_Chester_Bluff||65.38||-142.66997||Jensen, B. J. L.||< 780000 stratigraphy; 10291; Age based on magnetic polarity of the sediments.||Chester Bluff is located in Yukon Charley Rivers National Preserve (YCNP) in east-central Alaska, on the northwest bank of the Yukon River directly upstream from its confluence with the Charley River. It is a terrace comprising a series of individual bluffs dissected by gullies that extend laterally for about 3 km. The south-facing bluffs are dry and substantial excavation (>2m) is needed to reach frozen sediments. Chester Bluff can be broadly differentiated into four units. The base of the bluff is a bedrock terrace exposed up to ~10 m above river level, composed of argillite, part of the Cretaceous Biederman Formation. Deposited on the terrace are 8-10 m of paleo-Yukon River gravel, which are overlain by 5-10 m of sand and silt rhythmites with minor gravel and planar-bedded sand. Up to 40 m of silt, interpreted as loess and interbedded with multiple organic horizons and tephra beds, cap the sequence. Sites A through C were visited in the area and were found to host 19 distinct tephra beds. A near vertical slope at Site A prevented trench completion. Two trenches were excavated on either side of Site A to examine the lateral continuity of tephra beds. Site B was successfully logged from the top of the bluff to the upper-most sand unit associated with the flood deposits. Thick colluvium at Site C prevented completion of the trench at this site. No coordinates provided; location imprecisely georeferenced from Figure 1 in Jensen et al. (2008).||Only present at Site B of Chester Bluff. At Site B, Woodchopper Creek (WC) tephra forms a white bed up to 0.3 cm thick that is continuous over 4m. It has diffuse contacts with surrounding massive loess and is faulted downward over 1m. Contaminated by detrital material but also appear to be dominated by green amphibole and some ortho-pyroxene. The composition reported was calculated from analyses of four samples: UA1098, UA1212, UA1213, UA1214.||Jensen_2008_Chester_Bluff_Woodchopper_Creek_tephra||Tephra Fall||Cumulate||Glass||73.8||0.19||15.12||1.38||0.04||0.5||2.04||4.28||2.63||6162||EMP||1.38||Cl=0.03; H2O=5.22||EMP|
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