Title: Geologic Map of the North Half of the Lake Walcott 30'×60' Quadrangle, Idaho By Mel A. Kuntz, Duane E. Champion, Brent R. Turrin, Phillip B. Gans, Harry R. Covington, and D. Paco VanSistine Prepared in cooperation with the National Park Service and the U.S. Bureau of Land Management U.S. Geological Survey Scientific Investigations Report 3405 U.S. Geological Survey data release https://doi.org/10.5066/F7VQ30VZ ABSTRACT The geologic map of the northern half of the Lake Walcott 30'×60' quadrangle shows the volcanic geology of the southern part of the Craters of the Moon lava field, the complex geologic features of the Holocene Kings Bowl and Wapi lava fields, and the southern part of the Great Rift volcanic rift zone. The long extent and distribution of skylights in lava-tube systems of the Horse Butte and Wapi Park lava fields are depicted on this map. 40Ar/39Ar and K/Ar age determinations give detail to the Holocene, late Pleistocene, and late middle Pleistocene volcanic lava fields in this quadrangle. Most of the younger basalt eruptions (less than 150 thousand years [ka]) have occurred along the Great Rift volcanic rift zone, but two of the younger lava fields are located in the western part of the quadrangle. Kimama Butte, a shield volcano, is 87±11 ka, and Shale Butte is dated at 11±6 ka. Paleomagnetic studies have shown that the Horse Butte-Inferno Chasm eruptive fissure system has at least five paleomagnetic-correlative lava fields, the Claasen vent complex consists of at least seven correlative lava fields, and the Streifling-Flat Top vent complex includes at least four correlative lava fields. This map provides geologic, geochronologic, and paleomagnetic data for Holocene lava fields along the southern part of the Great Rift, and for late Pleistocene and late middle Pleistocene lava fields in the central and western parts of the quadrangle. These data can contribute to wise management and preservation of the Craters of the Moon National Monument and for broad-scale understanding of the basaltic-volcanic evolution of the eastern Snake River Plain. DISCLAIMERS Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. This database, identified as SIM 3405, 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 (USGS), 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 any 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. ------------------------------------------------------------------------------- REPORT FILES The map, pamphlet, and its accompanying text files can be downloaded via the Web at http://dx.doi.org/10.3133/sim3405 and follow the directions to download the files. List of Files sim3405_Readme.txt sim3405.pdf (pamphlet that accompanies the map sheet) sim3405_sheet_georeferenced.pdf (georegistered map sheet with shaded relief) The manuscript product is a Portable Document Format (.pdf) report, which requires 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 Suggested citation: Kuntz, M.A., Champion, D.E., Turrin, B.R., Gans, P.B., Covington, H.R., and VanSistine, D.P., 2018, Geologic map of the north half of the Lake Walcott 30'×60' quadrangle, Idaho: U.S. Geological Survey Scientific Investigations Report 3405, pamphlet 25 p., scale 1:100,000, https://doi.org/x10.3133/sim3405. ------------------------------------------------------------------------------- DATA RELEASE GIS AND OTHER FILES ScienceBase GIS data release for this report can be downloaded at: https://doi.org/10.5066/F7VQ30VZ List of Files lakewalcott_north.gdb.zip Geology lakewalcott_n_flowline lakewalcott_n_label lakewalcott_n_line lakewalcott_n_misc_pts lakewalcott_n_poly lakewalcott_n_sample_pts Contour_10 Topo_100k lakewalcott_n_shapefiles.zip lakewalcott_n_flowline.shp (cpg./dbf./prj./sbn./shp.xml./shx./) lakewalcott_n_label.shp (cpg./dbf./prj./sbn./shp.xml./shx./) lakewalcott_n_line.shp (cpg./dbf./prj./sbn./shp.xml./shx./) lakewalcott_n_misc_pts.shp (cpg./dbf./prj./sbn./shp.xml./shx./) lakewalcott_n_poly.shp (cpg./dbf./prj./sbn./shp.xml./shx./) lakewalcott_n_sample_pts.shp (cpg./dbf./prj./sbn./shp.xml./shx./) HOW TO OBTAIN THE DIGITAL GIS FILES: The ScienceBase data release 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 ScienceBase web page at http://dx.doi.org/10.5066/F7VQ30VZ ArcReader may be downloaded free of charge from http://www.esri.com/software/arcgis/arcreader/download.htm for viewing additional files included in this report. Suggested citation: VanSistine, D.P., 2018, Data release of the geologic map of the north half of the Lake Walcott 30'×60' quadrangle, Idaho: U.S. Geological Survey data release, https://doi.org/10.5066/F7VQ30VZ.