Identification_Information: Citation: Citation_Information: Originator: Browne, B.L. Originator: Neal, C.A. Originator: Bacon, C.R. Publication_Date: 2022 Title: The ~400 yr B.P. eruption of Half Cone, a post-caldera composite cone within Aniakchak caldera, Alaska Peninsula Geospatial_Data_Presentation_Form: table Series_Information: Series_Name: Professional Report Issue_Identification: PR 126 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 60 p. Online_Linkage: https://doi.org/10.14509/30839 Description: Abstract: DGGS Professional Report 126, The ~400 yr B.P. eruption of Half Cone, a post-caldera composite cone within Aniakchak caldera, Alaska Peninsula, presents an investigation of the ~400 yr B.P. Half Cone eruption. This eruption is the largest post-caldera eruption yet identified from the Aniakchak volcano. Our goals for this study are to (1) describe the dispersal and volume of the ~400 yr B.P. Half Cone eruption based on stratigraphic characteristics of the resulting deposits, (2) evaluate the pre-eruption storage conditions of magmas expelled during the ~400 yr B.P. Half Cone eruption based on both whole-rock geochemical analyses of juvenile material and in situ geochemical analyses of mineral and glass regions of deposits, and (3) synthesize stratigraphic and geochemical observations into a chronology for the ~400 yr B.P. eruption. All files are available from the DGGS website: http://doi.org/10.14509/30839. Purpose: Aniakchak volcano continues to show episodic signs of unrest, suggesting that eruptions will occur in the future. This research describes the nature and character of a significant 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. Supplemental_Information: >Appendix A: Sample metadata with locations and descriptions of pyroclastic samples >Appendix B: Sample metadata with locations, descriptions, and thicknesses of pyroclastic samples >Appendix C: Locations, descriptions, and whole-rock geochemistry values from rock samples >Appendix D: Locations, descriptions, and electron microprobe analyses of plagioclase from rock samples >Appendix E: Locations, descriptions, and electron microprobe analyses of pyroxene from rock samples >Appendix F: Locations, descriptions, and electron microprobe analyses of magnetite and ilmenite from rock samples >Appendix G: Locations, descriptions, and electron microprobe analyses of matrix glass from pyroclastic samples Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2002 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -158.226500 East_Bounding_Coordinate: -155.785900 North_Bounding_Coordinate: 58.933900 South_Bounding_Coordinate: 56.801500 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Active Volcanoes Theme_Keyword: Aleutian Arc Theme_Keyword: Analyses and Sampling Theme_Keyword: Analytical Lab Results Theme_Keyword: Analytical Results Theme_Keyword: Ash Cloud Theme_Keyword: Ashfall Theme_Keyword: Coastal Theme_Keyword: Coastal and River Theme_Keyword: DGGS Theme_Keyword: Dome Theme_Keyword: Earthquake Theme_Keyword: Ecology Theme_Keyword: Erosion Theme_Keyword: Fan Theme_Keyword: Feldspar Theme_Keyword: Felsic Theme_Keyword: Gas Theme_Keyword: Geobarometry Theme_Keyword: Geochemistry Theme_Keyword: Geologic Theme_Keyword: Geologic Hazards Theme_Keyword: Geological Process Theme_Keyword: Geology Theme_Keyword: Geomorphology Theme_Keyword: Geothermometry Theme_Keyword: Glacial Theme_Keyword: Glass Theme_Keyword: Groundwater Theme_Keyword: Hazards Theme_Keyword: Ice Theme_Keyword: Igneous Theme_Keyword: Interpretation Theme_Keyword: Iron Theme_Keyword: Landslide Theme_Keyword: Levees Theme_Keyword: Magnetite Theme_Keyword: Methods Theme_Keyword: Mineralogy Theme_Keyword: Minerals Theme_Keyword: Mountain Theme_Keyword: Obsidian Theme_Keyword: Petrographic Theme_Keyword: Petrography Theme_Keyword: Petrology Theme_Keyword: Plagioclase Theme_Keyword: Pumice Theme_Keyword: Pyroclastic Density Current Theme_Keyword: Pyroclastic Fall Theme_Keyword: Pyroclastic Flow Theme_Keyword: Pyroclastic Surge Theme_Keyword: Pyroclastics Theme_Keyword: Rhyodacite Theme_Keyword: Rocks Theme_Keyword: Surface Theme_Keyword: Surficial Theme_Keyword: Talus Theme_Keyword: Tephra Theme_Keyword: Tephrochronology Theme_Keyword: Till Theme_Keyword: Tuff Theme_Keyword: Volcanic Theme_Keyword: Volcanoes Theme_Keyword: Volcanology Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Alaska Peninsula Place_Keyword: Aniakchak River Place_Keyword: Brooks Camp Place_Keyword: Brooks River Place_Keyword: Cape Menshikof Place_Keyword: Cinder River Place_Keyword: Cub Creek Place_Keyword: Half Cone Place_Keyword: High Creek Place_Keyword: King Salmon River Place_Keyword: Lava Creek Place_Keyword: Mud Creek Place_Keyword: Painter Creek Place_Keyword: Rainbow Creek Place_Keyword: Surprise Lake Place_Keyword: Vent Mountain Place_Keyword: Wiggly Creek Place_Keyword: Wind Creek 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). 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: 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. Data_Set_Credit: The region we investigated for this study is the original homeland of the Alutiiq/Sugpiaq people who have inhabited the coastal environments of southcentral Alaska for over 7,000 years (Ringsmuth, 2007). We acknowledge the complex history and rich culture of the Alutiiq/Sugpiaq people and honor the families and tribal members still connected to this land. In particular, we are grateful to the people of Port Heiden for their generosity in sharing their insights and memories of Aniakchak volcano and for allowing us to base our field campaigns in their community. Fieldwork was supported by the Alaska Volcano Observatory, the U.S. Geological Survey, and the University of Alaska Fairbanks Department of Geosciences and Geophysical Institute. This work was also partially supported by the U.S. Geological Survey under Cooperative Agreement No. G19AC00171. We especially thank Game McGimsey and Tom Miller for sharing their knowledge of Aniakchak volcano's geology, and pilots Howard Reed (Maritime Helicopters, Homer, Alaska) and Sam Egli (Egli Air Haul, King Salmon, Alaska) for safe transport during fieldwork. We also appreciate assistance from Game McGimsey, Rob Nicholson, James Gardner, and Tom Miller during field campaigns. We thank several colleagues for their scientific discussions, analytical assistance, and assistance with sample preparation, including Pavel Izbekov, Ken Severin, Frank Kyte, Kristi Wallace, Fiona Eberhardt, Manny Nathenson, Jessica Larsen, Chris Nye, Cheryl Cameron, Kate Bull, and Matthew Loewen. Brandon Browne also thanks Patricia Ekberg, John Perreault, Kristen Janssen, Simone Montayne, and Dennis Hojna. Thoughtful and constructive reviews by Tim Orr (USGS/Alaska Volcano Observatory), Nathan Andersen (USGS/Cascades Volcano Observatory), Ellen Daley, and Janet Schaefer (DGGS/Alaska Volcano Observatory) improved the report. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the State of Alaska or the U.S. Government. Cross_Reference: Citation_Information: Originator: Cameron, C.E. Originator: Mulliken, K.M. Originator: Crass, S.W. Originator: Schaefer, J.R. Originator: Wallace, K.L. Publication_Date: 2019 Title: Alaska Volcano Observatory geochemical database, version 2 Series_Information: Series_Name: Digital Data Series Issue_Identification: DDS 8 v. 2 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 22 p Online_Linkage: https://doi.org/10.14509/30058 Cross_Reference: Citation_Information: Originator: Cameron, C.E. Originator: Nye, C.J. Publication_Date: 2014 Title: Preliminary database of Quaternary vents in Alaska Series_Information: Series_Name: Miscellaneous Publication Issue_Identification: MP 153 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 11 p Online_Linkage: https://doi.org/10.14509/27357 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: This data collection provides a compilation of detailed geochemical summary data used to support the observations and interpretations presented in the accompanying report. Uncertainties and attribute accuracy vary according to the data product. We encourage users to review the report and accompanying method documentation to better understand the methods and limitations of the source data and analytical results. Logical_Consistency_Report: Not applicable Completeness_Report: This data release is complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Location data were collected using handheld recreational grade Garmin GPS units. These devices have a typical reported error of 9 to 21 feet. However, the actual location accuracy of the sample coordinates varies according to the observer's sampling context and recording conventions. Lineage: Process_Step: Process_Description: Field data collection - Geological investigations were conducted in the field during the summers of 1992-1994, 1997, and 2002. Field sites were located within Aniakchak caldera and beyond the caldera rim, mostly to the north and northeast of the volcano. The goal of this study was to use field and analytical observations of deposits from the ~400 yr B.P. Half Cone eruption to reconstruct the eruption chronology, estimate the volume and dispersal characteristics of tephra, and gain insight into pre-eruptive magma storage conditions. Process_Date: 2002 Process_Step: Process_Description: Geochemistry and petrography - Samples were examined in thin section and analyzed using whole-rock geochemistry and electron probe microanalysis to determine elemental abundances and petrographic characteristics. Users are encouraged to review the accompanying report for further discussion of methods and outcomes. Process_Date: 2003 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: .0000001 Longitude_Resolution: .0000001 Geographic_Coordinate_Units: decimal degrees Geodetic_Model: Horizontal_Datum_Name: NAD83 Ellipsoid_Name: GRS 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222101000025 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_a_sample_descript_data.csv, pr126-appendix_a_sample_descript_data_dictionary.csv Entity_Type_Definition: Sample metadata with locations and descriptions of pyroclastic samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix A Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_b_sample_thickness_data.csv, pr126-appendix_b_sample_thickness_data_dictionary.csv Entity_Type_Definition: Sample metadata with locations, descriptions, and thicknesses of pyroclastic samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix B Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_c_whole-rock_gx_data.csv, pr126-appendix_c_whole-rock_gx_data_dictionary.csv Entity_Type_Definition: Locations, descriptions, and whole-rock geochemistry values from rock samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix C Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_d_plagioclase_data_data.csv, pr126-appendix_d_plagioclase_data_dictionary.csv Entity_Type_Definition: Locations, descriptions, and electron microprobe analyses of plagioclase from rock samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix D Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_e_pyroxene_data.csv, pr126-appendix_e_pyroxene_data_dictionary.csv Entity_Type_Definition: Locations, descriptions, and electron microprobe analyses of pyroxene from rock samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix E Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_f_FeTi_oxides_data.csv, pr126-appendix_f_FeTi_oxides_data_dictionary.csv Entity_Type_Definition: Locations, descriptions, and electron microprobe analyses of magnetite and ilmenite from rock samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix F Detailed_Description: Entity_Type: Entity_Type_Label: pr126-appendix_g_tephra_glass_data.csv, pr126-appendix_g_tephra_glass_data_dictionary.csv Entity_Type_Definition: Locations, descriptions, and electron microprobe analyses of matrix glass from pyroclastic samples Entity_Type_Definition_Source: AVO Entity_Attribute_Layer_Name: Appendix G Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: 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. Resource_Description: PR 126 Distribution_Liability: 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. Standard_Order_Process: Non-digital_Form: DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount. Fees: Contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: table Format_Version_Date: 20220412 Format_Information_Content: tabular data Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/30839 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20220414 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Person: Simone Montayne Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907)451-5020 Contact_Facsimile_Telephone: (907)451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 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. Metadata_Extensions: Online_Linkage: https://dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions