Alaska Volcano Observatory - Tephrochronology of late Cenozoic loess at Fairbanks, central Alaska

TEPHROCHRONOLOGY OF LATE CENOZOIC LOESS AT FAIRBANKS, CENTRAL ALASKA

Preece, S. J., Westgate, J. A., Stemper, B. A., and Pewe, T. L., 1999, Tephrochronology of late Cenozoic loess at Fairbanks, central Alaska: Geological Society of America Bulletin, v. 111, n. 1, p. 71-90.

DATA TABLES *Not all tables in a publication may be listed. Not all tables from a publication have data entered in the database.

3601: Average major-element composition of glass shards of type I tephra beds in Gold Hill Loess, Fairbanks, Alaska

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* Notes: Analyses of UT1100 series samples done on a Cameca SX-50 wave-length dispersive electron microprobe operating at 15 kev accelerating voltage, 20 micron beam diameter, and 10 nAmp beam current. All other analyses done on an ETEC energy dispersive microprobe operating at 20 kev accelerating voltage, 1-2 micron beam diameter and 50-60 nAmp beam current. Standardization achieved by use of mineral and glass standards. Analyses recast to 100% on a water-free basis. All samples are rhyolites, with the exception of VT-1, which has a dacitic composition (International Union of Geological Sciences [IUGS] classification, Le Bas et al. 1986). n = number of analyses; FeOt = total iron oxide as FeO; H2O* = water, by difference; N.D. = not detected; average composition of TiO2, MnO, MgO, and Cl only include non-zero values. Individual shard analyses are listed in GSA Data Repository item 9903 (see footnote 1). Average composition in wt% based on the following samples: GI (UT788), EAB (UA743), VT (UT822, UT869, UT870, UT872, UT895), DAB (UT745), HH (UT816, UT817, UT825, UT826), PA (UA355, UT497), OC (UT815, UT896, UT897, UT898, UT899, UT900, UT901, UT828), NT (UT1104), and LW (UT887). *

3611: Average major-element composition of glass shards of type II and other tephra beds in Gold Hill Loess, Fairbanks, Alaska

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* Notes: N.D. = not detected; operating conditions (from footnote of Table 1 in Preece et al. 1999): Analyses of UT1100 series samples done on a Cameca SX-50 wave-length dispersive electron microprobe operating at 15 kev accelerating voltage, 20 micron beam diameter, and 10 nAmp beam current. All other analyses done on an ETEC energy dispersive microprobe operating at 20 kev accelerating voltage, 1-2 micron beam diameter and 50-60 nAmp beam current. Standardization achieved by use of mineral and glass standards. Analyses recast to 100% on a water-free basis. All Type II tephra beds are rhyolites; HP and SD-2 tephra beds are rhyolitic, AT-2 and SD-1 are dacitic and AT-1 is andesitic in composition. Average composition in wt% based on the following samples: SC (UT491, UT734, UT746, UT845), CF (UT791), WP (UT738), MF (UT792), SP (UT790, UT889), PH (UT819), PT (UT873), HP (UT861, UT1101), AT (UT892, UT1098, UT1100), and SD (UT743). *

5651: Average trace-element composition of glass shards in tephra beds of the Gold Hill Loess, Fairbanks, Alaska

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