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Data Supporting The Geochemical Atlas of Alaska, 2016

June 13, 2016

A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska, and there are significant opportunities for applying this information. To maximize the spatial density and extent of data coverage for statewide mapping of element distributions, we compiled and integrated analyses of more than 175,000 sediment and soil samples from three major,
separate sources: the U.S. Geological Survey, the National Uranium Resource Evaluation program, and the Alaska Division of Geological & Geophysical Surveys geochemical databases. Various types of heterogeneity and deficiencies in these data presented major challenges to our development of coherently integrated datasets for modeling and mapping of element distributions. Researchers from many different organizations and disparate scientific studies collected samples that were analyzed using highly variable methods throughout a time period of more than 50 years, during which many changes in analytical techniques were developed and applied. Despite these challenges, the U.S. Geological Survey has produced a new systematically integrated compilation of sediment and soil geochemical data with an average sample site density of approximately 1 locality per 10 square kilometers (km2) for the entire state of Alaska, although density varies considerably among different areas. From that compilation, we have modeled and mapped the
distributions of 68 elements, thus creating an updated geochemical atlas for the State. Our results suggest that careful treatment of legacy data may provide significant and revealing geochemical maps that can be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas.