Title: The Geochemical Atlas of Alaska, 2016 By Gregory K. Lee, Douglas B. Yager, Jeffrey L. Mauk, Matthew Granitto, Paul D. Denning, Bronwen Wang, and Melanie B. Werdon 2016 U.S. Geological Survey Data Series 908 ABSTRACT: A rich legacy of geochemical data produced since the early 1960s covers the great expanse of Alaska, and there are significant opportunities for applying that 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 those 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 with 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, we have systematically produced a new 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, 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 of Alaska. Our results suggest that careful treatment of legacy data can provide significant and revealing geochemical maps that can be used for landscape geochemistry, mineral resource exploration, and geoenvironmental investigations over large areas. DISCLAIMERS: This database, identified as DS 908, has been approved for release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty, expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey. Although this information product, for the most part, is in the public domain, it also may contain copyrighted material as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. ------------------------------------------------------------------------------- FILES: The pamphlet and its accompanying files can be downloaded via the Web from http://dx.doi.org/10.3133/ds908. ScienceBase data release for this report at: http://dx.doi.org/10.5066/F7GF0RK5 List of files: Textual files ds908_readme.txt DS908.pdf -- pamphlet that accompanies this report ds908_metadata.zip ds908_geochem_data.xml/txt (ds908_metadata folder, for the Publications Warehouse, or the DVD as indicated) ds908_WBD_means.xml/txt (ds908_metadata folder, for the Publications Warehouse, or the DVD as indicated) Figure files (ds908_full_size_figures folder) ds908_figure_1_USGS_seds_soils.pdf -- U.S. Geological Survey (USGS) sediment and soil sample localities in Alaska ds908_figure_2_AK_NURE_seds.pdf -- National Uranium Resource Evaluation (NURE)–Stream Sediment Reconnaissance (HSSR) sediment sample localities in Alaska. ds908_figure_3_ADGGS_Seds.pdf -- Alaska Division of Geological and Geophysical Surveys (ADGGS) sediment sample localities. ds908_figure_4_AK_sed_HUC_dens.pdf -- Sediment samples within 12-digit (subwatershed) hydrologic units in Alaska. ds908_figure_5_AK_Physiography.pdf -- Physiographic provinces of Alaska. ds908_figure_6_AK_Bsmt_domains.pdf -- Basement domain map of Alaska showing major tectonostratigraphic domains. ds908_figure_7_AK_Land_Status.pdf -- General land status map of Alaska. ds908_figure_8_AK_gravity.pdf -- Gravity anomalies in Alaska. ds908_figure_9_AK_magnetics.pdf -- Magnetic anomalies in Alaska. ds908_figure_10_AK_Rad_K.pdf -- Aeroradiometric measurement values of potassium in Alaska. ds908_figure_11_AK_Rad_U.pdf -- Aeroradiometric measurement values of uranium in Alaska. ds908_figure_12_AK_Rad_Th.pdf -- Aeroradiometric measurement values of thorium in Alaska. Data files (ds908_datafiles folder) ds908_AK_atlas_geochem.gdb.zip (archived Esri geodatabase) AK_geochem_data -- point feature classes within the feature dataset AK_WBD_means -- The hydrologic unit-based concentration means that were used to produce map sheets 1B–68B are provided as polygon feature classes within a feature dataset ds908_AK_geochem_data.xlsx -- The geochemical data compilation of best values ds908_AK_geochem_data.zip (archived shapefile format) AK_geochem_data.shp (.CPG/.dbf/.prj/.sbn/.sbx/.shx.xml/.shx) ds908_AK_WBD_means.zip (archived shapefile format) AK_WBD_means.shp (.CPG/.dbf/.prj/.sbn/.sbx/.shx.xml/.shx) ds908_table1.xlsx -- Replacement values used for censored data for the Geochemical Atlas of Alaska, 2016. ds908_table2.xlsx -- Map sheets for the Geochemical Atlas of Alaska, 2016 Element files (in folders ds908_elements_Aluminum-Lanthanum, disk 1; ds908_elements_Lead-Zirconium, disk 2 on the DVD set, and in the ds908_elements folder online) The individual folders contain the following files for each of the 68 elements in this report: DS908_element_#A.pdf/.img/.tif DS908_element_#B.pdf/.tif DS908_element_#C.pdf/.tif/.img DS908_element_#D.pdf/.img/.tif 1.Aluminum Al, 2.Antimony Sb, 3.Arsenic As, 4.Barium Ba, 5.Beryllium Be, 6.Bismuth Bi, 7.Boron B, 8.Cadmium Cd, 9.Calcium Ca, 10.Carbon C, 11.Cerium Ce, 12. Cesium Cs, 13.Chlorine Cl, 14.Chromium Cr, 15.Cobalt Co, 16.Copper Cu, 17.Dysprosium Dy, 18.Erbium Er, 19.Europium Eu, 20.Fluorine F, 21.Gadolinium Gd, 22.Gallium Ga, 23.Germanium Ge, 24.Gold Au, 25.Hafnium Hf, 26.Holmium Ho, 27.Indium In, 28.Iron Fe, 29.Lanthanum La, 30.Lead Pb, 31.Lithium Li, 32.Lutetium Lu, 33.Magnesium Mg, 34.Manganese Mn, 35.Mercury Hg, 36.Molybdenum Mo, 37.Neodymium Nd, 38.Nickel Ni, 39.Niobium Nb, 40.Palladium Pd, 41.Phosphorous P, 42.Platinum Pt, 43.Potassium K, 44.Praseodymium Pr, 45.Rubidium Rb, 46.Samarium Sm, 47.Scandium Sc, 48.Selenium Se, 49.Silicon Si, 50.Silver Ag, 51.Sodium Na, 52.Strontium Sr, 53.Sulfur S, 54.Tantalum Ta, 55.Tellurium Te, 56.Terbium Tb, 57.Thallium Tl, 58.Thorium Th, 59.Thulium Tm, 60.Tin Sn, 61.Titanium Ti, 62.Tungsten W, 63.Uranium U, 64.Vanadium V, 65.Ytterbium Yb, 66.Yttrium Y, 67.Zinc Zn, 68.Zirconium Zr --------------------------------------------------------------------------------- NOTE: datafiles in other formats may be available in the ScienceBase data release for this report at: http://dx.doi.org/10.5066/F7GF0RK5 and will be described in the ScienceBase metadata for this report that resides the ScienceBase website. --------------------------------------------------------------------------------- HOW TO OBTAIN THE DIGITAL FILES: The digital files constituting the geologic map database of this report can be obtained via the Internet from the U.S. Geological Survey publications website. Go to the web page at http://dx.doi.org/10.3133/ds908/ and follow the directions to download the files. A USGS ScienceBase Data Release also accompanies this report, and may be found at: http://dx.doi.org/10.5066/F7GF0RK5 This report is also presented as a 2-disk set of dual-layer DVDs, available from the USGS Geological Survey at http://store.usgs.gov/ or contact the USGS at: 1-888-ASK_USGS (1-888-275-8747) --------------------------------------------------------------------------------- The products in this report are Portable Document Format (.pdf) maps, which require Adobe Acrobat for viewing. Acrobat software runs on a variety of systems, and is available for download free of charge from Adobe at http://www.adobe.com. ArcReader may be downloaded free of charge from http://www.esri.com/software/arcgis/arcreader/download for viewing additional files included in this report. Excel Viewer may be downloaded free of charge from http://www.microsoft.com/en-us/download/details.aspx?id=10 for viewing the tables included in this report.