U.S. Geological Survey 2003 tabular digital data Bear Lake is a tectonic lake that has existed for at least several hundred thousand years. The lake basin is a relatively simple half graben, a spoon-shaped depression tilted toward the main fault on the east side of the lake. The U.S. Geological Survey, in cooperation with researchers from several universities, has been studying the sediments of Bear Lake since 1996. The general purpose of this effort is to reconstruct past limnological conditions and regional climate on a range of timescales, from hundreds of years to hundreds of thousands of years. This research relates to a variety of human concerns, including water usage in the Bear River basin. Past work has included several coring operations, a seismic-reflection survey, sediment-trap deployments, a barge-mounted drilling operation with the GLAD800 drill rig, and a variety of other studies. The objectives of the September, 2002 operations, preliminarily reported here, were (1) to compile a detailed bathymetric map of the lake using swath-mapping techniques, in order to provide baseline data for a variety of applications and studies, and (2) to complete a sidescan-sonar survey of the lake, providing a nearly complete acoustic image of the lake floor. Limited amounts of subbottom acoustic-reflection data (CHIRP) were also collected, along with samples of lake-floor sediments representative of different kinds of backscatter patterns. These surveys followed an earlier subbottom acoustic-reflection survey (1997), using boomer and 3.5 kHz systems (S. M. Colman, unpublished data). Sound velocity profiles were collected in order to map the sound velocity profile of the water column. The interferometric sonar systems acquires high-resolution bathymetric measurements in a swath. However, changes in the sound velocity profile with depth will affect the acousit ray path. The acoustic ray path must be accurately modeled in order to calculate accurate depth and position of individual soundings. 20020904 20020916 Ground Condition Complete none planned -111.5 -111.17 42.2 41.08 none Sound Velocity Profiles CTD salinity water temperature conductivity U.S. Geological Survey USGS Coastal and Marine Geology Program CMGP Woods Hole Field Center none Bear Lake Utah Idaho North America United States none The USGS asks to be referenced in any use of these data. U.S. Geological Survey Jane F. Denny Geologist, Seafloor Mapping Group mailing and physical address

384 Woods Hole Road

Woods Hole MA 012543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov Monday-Friday, 8am-5pm, Eastern Standard Time Attribute data are location data. These locations are accurate within 3 meters (recorded WAAS horizontal accuracy). These data were all acquired with a Applied Microsystems Sound Velocity Profiler deployed off of the same platform. These data were collected throughout the survey area. These data are known to be complete. WAAS is assumed to be accurate within 1-2 meters. Standard GPS is assumed accurate within 5-10 meters. All data were recorded using the WAAS (Wide Area Augmentation System) navigation. All WAAS data are referenced to WGS84. All sample locations are assumed to be accurate to +/- 3 meters. Sound Velocity profiles were collected throughout the study area to map the velocity structure of the water column. Changes in the speed of sound throughout the water column will affect the swath bathymetric data; outer beams will experience refraction. The SVP was deployed and sent to the lake floor. Upon retrieval, data were downloaded and placed into a Mircosoft Excel spreadsheet. The data were exported from the Excel spreadsheet to a text file. The USGS Mapgen PROJ command was used to convert latitude and longitude values to eastings and northings (UTM Zone 12, WGS84 ellipsoid). This file was imported into ArcView as a table. The table was then converted to a shapefile. 2003 Jane F. Denny U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov Vector point 0.000089992 0.000089992 Decimal degrees WGS84 WGS84 6378137.0000000 298.26 svp.shp Arcview shapefile ESRI Shape Feature geometry. ESRI point feature geometry name Arcview Longitude x coordinate of feature ESRI -111.5 -111.17 decimal degrees Latitude location of y coordinate ESRI 42.2 41 decimal degrees Easting location of X coordinate in UTM space ESRI 450000 490000 meters Northing location of Y coordinate in UTM space ESRI 4500000 4700000 meters cast Sample Identification USGS Cast USGS Date Date sample was collected Calendar Date Date Time Time the sample was collected USGS time Depth Water depth at sample location Fathometer 5 meters 65 meters Jane F. Denny U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov JPG Images of Grab Samples Altough this data set and its lineage have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or it's related materials. The act of distribution shall not constitute any such warranty, and no resposibility is assumed by the USGS in the use of these data or related items. Users must assume resposibility for the proper use of this data. This data should not be used at resolutions for which it is not intended. This data has no been reviewed for conformity with U.S. Geological Survey editorial standards, or the North American Strigraphic code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government. 20030425 2003 Jane F. Denny U.S. Geological Survey Geologist mailing and physical address

384 Woods Hole Road

Woods Hole MA 02543 USA 508-457-2311 508-457-2310 jdenny@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 None None