4fbd1afa-c8c8-46ca-8a53-d131c4a34f84_source eng; USA utf8 dataset Simone Montayne Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays pointOfContact 2023-12-06 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) Geologic map of Okmok Volcano 2023-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Larsen, J.F. originator Neal, C.A. originator Schaefer, J.R. originator Nye, C.J. originator https://doi.org/10.14509/31015 CSV Report of Investigation RI 2023-1 63 p., 4 sheets Geologic map of Okmok Volcano, Report of Investigation 2023-1, provides 40Ar/39Ar and radiocarbon geochronology data from Okmok Volcano and its eruptive products. Okmok Volcano is one of 54 historically active volcanoes in the Alaska-Aleutian volcanic arc that stretches across southern mainland Alaska and the Aleutian Islands. Okmok Volcano dominates the northeastern portion of Umnak Island, which is 100 km southwest of Unalaska/Dutch Harbor and 1,400 km southwest of Anchorage. Okmok Volcano is one of the most frequently active volcanoes in the Aleutian volcanic arc. In 1998, the Alaska Volcano Observatory (AVO) began a multi-year effort to expand geophysical monitoring in the central Aleutians Islands, including at Okmok Volcano. These data support the development of a modern geologic map of Okmok Volcano and related investigation of its eruptive history and hazards. The analytical data tables associated with this report are provided in digital format as comma-separated value (CSV) files. They are available from the DGGS website: http://doi.org/10.14509/31015. This data describes the nature and character of samples from a past eruption to aid in the discussion of spatial and temporal patterns of Alaska volcanism. In addition, the work supports improvements to eruption scenario forecasts and hazard response. Geophysical Institute and the Alaska Division of Geological & Geophysical Surveys, currently Cooperative Agreement G19AC00171, and by USGS Volcano Hazards Program funding to the Alaska Volcano Observatory. We thank many geologists and geophysicists who provided their time, insights, and camaraderie at Fort Glenn in all kinds of weather, including Jim Beget, Deb Bergfeld, Alain Burgisser, Michelle Coombs, Cheryl Cameron, John Eichelberger, Jeff Freymueller, Rick Hazlett, Alexander Max Kaufman, David Lescinsky, Taryn Lopez, Doerte Mann, Steve McNutt, Michael Ort, and Guy Tytgat. Former undergraduate and graduate students who participated in the geology fieldwork at Okmok Volcano include a cohort from Pomona College and the University of Alaska Fairbanks: Leslie Almberg, Matt Patrick, Ben Finney, Delanora Grey, Ken Papp, Joel Unema, and Lily Wong. Reviews by Tim Orr, Julie Nolan, and Drew Downs provided helpful insight and are much appreciated. Bering Pacific Ranches Ltd. supported this work through lodging and logistics support. Access to Umnak Island was by charter flights or boat from the Port of Dutch Harbor. We thank Cliff Gill (Airborne Scientific), Don Graves (Miss Peppers), and Jimmer MacDonald (Miss Alyssa) for safe transport to Umnak Island in often challenging sea conditions. Maritime Helicopters and pilots Bill Springer, Rick Farrish, and Jon Combs made our work possible, providing efficient, safe, and professional transportation in the field area. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. completed Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. pointOfContact notPlanned 40Ar/39Ar Ashfall Caldera DGGS Fumarole Chemistry Geochemical Data Geochemistry Geochronology Geologic Geologic Hazards Geologic Map Geology Gis Glacial Hazards Helicopter Survey Lava Flow Moraines Outcrop Samples Pumice Radiocarbon Ages Radiocarbon Dating Rhyolite Rock Glaciers Scoria Subduction Volcanic Volcanic Arc Volcanic Ash Volcanic Eruption Volcanic Rocks Volcaniclastic Deposits Volcaniclastics Volcanoes theme Alaska Division of Geological & Geophysical Surveys Aleutian Islands Bering Sea Colorado Creek Crater Creek Dutch Harbor Jag Peak Mount Recheshnoi Mount Vsevidof Okmok Okmok Caldera Okmok Hot Springs Okmok Volcano Okmok, Mount Pacific Ocean Reindeer Creek Tulik Umnak Island place Alaska Division of Geological & Geophysical Surveys Crater Creek Basalt stratum Alaska Division of Geological & Geophysical Surveys Holocene Pleistocene temporal Walker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of America The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. otherRestrictions Use Constraints: Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. otherRestrictions Access Constraints: This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below). Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska 2005-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Beget, J.E. originator Larsen, J.F. originator Neal, C.A. originator Nye, C.J. originator Schaefer, J.R. originator https://doi.org/10.14509/7042 Report of Investigation RI 2004-3 32 p., 1 sheet, scale 1:150,000 crossReference Alaska Volcano Observatory geochemical database, version 2 2019-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Cameron, C.E. originator Mulliken, K.M. originator Crass, S.W. originator Schaefer, J.R. originator Wallace, K.L. originator https://doi.org/10.14509/30058 Digital Data Series DDS 8 v. 2 22 p crossReference The 2008 phreatomagmatic eruption of Okmok Volcano, Aleutian Islands, Alaska: Chronology, deposits, and landform changes 2015-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Larsen, J.F. originator Neal, C.A. originator Schaefer, J.R. originator Kaufman, A.M. originator Lu, Zhong originator https://doi.org/10.14509/29405 Report of Investigation RI 2015-2 53 p crossReference Electron probe microanalytical data of minerals and glass from rock samples from Okmok volcano, Alaska 2022-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Larsen, J.F. originator Schaefer, J.R. originator Cameron, C.E. originator https://doi.org/10.14509/30853 Raw Data File RDF 2022-6 13 p crossReference Geochemistry of some quaternary lavas from the Aleutian Arc and Mt. Wrangell 2018-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Nye, C.J. originator Beget, J.E. originator Layer, P.W. originator Mangan, M.T. originator McConnell, V.S. originator McGimsey, R.G. originator Miller, T.P. originator Moore, R.B. originator Stelling, P.L. originator https://doi.org/10.14509/29843 Raw Data File RDF 2018-1 29 p crossReference 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska 2005-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Schaefer, J.R. originator https://doi.org/10.14509/7041 Raw Data File RDF 2005-1 crossReference Digital elevation model (DEM) and shaded relief image of Okmok Caldera, 2010 2012-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Schaefer, J.R. originator Larsen, J.F. originator Unema, J.A. originator https://doi.org/10.14509/23223 Raw Data File RDF 2011-6 crossReference vector eng; USA geoscientificInformation -168.399980 -167.753160 53.280010 53.562390 1998-01-01 2023-01-01 >Appendix A 40Ar/39Ar Ages of Okmok lavas: Field station locations and 40Ar/39Ar ages of Okmok lavas >Appendix B Radiocarbon ages: Field station locations and radiocarbon ages used to interpret Okmok Volcano geologic map units >Appendix C Stations and samples: Field station locations of samples discussed in this report true csv unknown Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. distributor Contact DGGS for current pricing Free download https://doi.org/10.14509/31015 csv table information dataset Horizontal Positional Accuracy Report AVO staff used handheld GPS units to acquire location coordinates. Positional uncertainty reported by the GPS units was not recorded. This data releaase is complete. This data releaase is complete. Not applicable This lineage was generated by the FGDC CSDGM to 19139 transformation Sample collection - A team of five geologists from AVO (UAF/GI and USGS partner agencies) conducted summer geologic fieldwork throughout Umnak Island from July 1998 to 2016. 2016-01-01T00:00:00 40Ar/39Ar Analytical Techniques - Rocks were submitted for 40Ar/39Ar age dating to the geochronology laboratories at the University of Alaska Fairbanks (UAF) and the USGS in Menlo Park. For 40Ar/39Ar analysis at UAF, 12 samples were dated, with the data yielding the isochron ages provided in the digital data; all ages are quoted to the +/-1-sigma level and calculated using the decay constants of Steiger and Jager (1977). The USGS Menlo Park geochronology lab analyzed 17 groundmass samples separated by crushing, sieving, and magnetic techniques, with 14 samples yielding interpretable results. Uncertainties in 40Ar/39Ar ages are also reported at the one-sigma level unless otherwise noted and include propagated uncertainties in counting statistics and J values. Lab methods and age interpretation calculations are described in detail in the accompanying report. 2017-01-01T00:00:00 Radiocarbon Analytical Techniques - Radiocarbon dating (conventional and Accelerator Mass Spectrometer [AMS]) of organic material to constrain eruption ages was carried out using Beta Analytic and Geochron Laboratories. Datable material was found typically in soils beneath tephra fall or pyroclastic density current deposits on the lower flanks of the volcano. Dating of wood and carbonized vegetation found within surge deposits was also possible in several cases. All samples were hand-cleaned thoroughly to remove modern plant material before submission to the lab. Soil samples were treated before analysis in the lab by dispersion in water, and isolating organic matter using agitation and ultrasound. Modern rootlets were screened with a nylon filter, and the remaining clay and organic fraction were subject to both acid and alkali washes. The humic acid fraction was precipitated, filtered, dried, and combusted in O2 to produce CO2 for analysis. The ages of the two caldera-forming eruptions are well constrained by this method. A compilation of dates and laboratories is provided in the digital data. 2017-01-01T00:00:00 otherRestrictions Metadata Use Constraints: If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys. unknown This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2019-08-12T11:11:00 version of the FGDC CSDGM to ISO 19139 transform. Simone Montayne Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays pointOfContact