Identification_Information: Citation: Citation_Information: Originator: David C. Twichell Originator: VeeAnn A. Cross Publication_Date: 2003 Title: Chirp Seismic Shotpoint Navigation every 100 shots in Geographic Coordinates - Lake Mead Survey 2001 Geospatial_Data_Presentation_Form: vector digital data Online_Linkage: Larger_Work_Citation: Citation_Information: Originator: David C. Twichell Originator: VeeAnn A. Cross Originator: Stephen D. Belew Publication_Date: 2003 Title: Mapping the floor of Lake Mead (Nevada and Arizona): Preliminary discussion and GIS data release Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 03-320 Publication_Information: Publication_Place: Woods Hole Field Center, Woods Hole, MA Publisher: U.S. Geological Survey Description: Abstract: Lake Mead is a large interstate reservoir located in the Mojave Desert of southeastern Nevada and northwestern Arizona. It was impounded in 1935 by the construction of Hoover Dam and is one of a series of multi-purpose reservoirs on the Colorado River. The lake extends 183 km from the mouth of the Grand Canyon to Black Canyon, the site of Hoover Dam, and provides water for residential, commercial, industrial, recreational, and other non-agricultural users in communities across the southwestern United States. Extensive research has been conducted on Lake Mead, but a majority of the studies have involved determining levels of anthropogenic contaminants such as synthetic organic compounds, heavy metals and dissolved ions, furans/dioxins, and nutrient loading in lake water, sediment, and biota (Preissler, et al., 1998; Bevans et al, 1996; Bevans et al., 1998; Covay and Leiker, 1998; LaBounty and Horn, 1997; Paulson, 1981). By contrast, little work has focused on the sediments in the lake and the processes of deposition (Gould, 1951). To address these questions, sidescan-sonar imagery and high-resolution seismic-reflection profiles were collected throughout Lake Mead by the USGS in cooperation with researchers from University of Nevada Las Vegas (UNLV). These data allow a detailed mapping of the surficial geology and the distribution and thickness of sediment that has accumulated in the lake since the completion of Hoover Dam. Results indicate that the accumulation of post-impoundment sediment is primarily restricted to former river and stream beds that are now submerged below the lake while the margins of the lake appear to be devoid of post-impoundment sediment. The sediment cover along the original Colorado River bed is continuous and is typically greater than 10 m thick through much of its length. Sediment thickness in some areas exceeds 35 m while the smaller tributary valleys typically are filled with less than 4 m of sediment. Away from the river beds that are now covered with post-impoundment sediment, pre-impoundment alluvial deposits and rock outcrops are still exposed on the lake floor. Purpose: This ArcView shapefile is used to enable correlation between the seismic-reflection profiles and the sidescan-sonar imagery, geologic interpretation, and other features represented on the lake floor. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20010401 Ending_Date: 20010416 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -114.756065 East_Bounding_Coordinate: -114.024584 North_Bounding_Coordinate: 36.484177 South_Bounding_Coordinate: 36.014389 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: seismic Theme_Keyword: shotpoint Theme_Keyword: navigation Theme_Keyword: subbottom Theme_Keyword: seismic reflection Theme_Keyword: chirp Theme_Keyword: SIS-1000 Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Woods Hole Field Center Theme_Keyword: Open-File Report Theme_Keyword: OFR03-320 Theme_Keyword: cruise serial number 01007 Place: Place_Keyword_Thesaurus: General Place_Keyword: Nevada Place_Keyword: Lake Mead Place_Keyword: Hoover Dam Place_Keyword: Boulder Basin Place_Keyword: Virgin Basin Place_Keyword: Gregg Basin Place_Keyword: Overton Arm Place_Keyword: Mojave Desert Place_Keyword: United States Place_Keyword: North America Access_Constraints: none Use_Constraints: The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David C. Twichell Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2266 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: dtwichell@usgs.gov Native_Data_Set_Environment: Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 8.2.0.700 Cross_Reference: Citation_Information: Originator: H.E. Bevans Originator: S.L. Goodbred Originator: J.F. Miesner Originator: S.A. Watkins Originator: T.S. Gross Originator: N.D. Denslow Originator: T. Choeb Publication_Date: 1996 Title: Synthetic organic compounds and carp endrocrinology and histology, Las Vegas Wash and Las Vegas and Callville bays of Lake Mead Nevada Series_Information: Series_Name: Water-Resources Investigations Issue_Identification: 96-4266 Publication_Information: Publisher: U.S. Geological Survey Cross_Reference: Citation_Information: Originator: H.E. Bevans Originator: M.S. Lico Originator: S.J. Lawrence Publication_Date: 1998 Title: Water quality in the Las Vegas Valley area and the Carson and Truckee River basins, Nevada and California, 1992-1996 Series_Information: Series_Name: Circular Issue_Identification: 1170 Publication_Information: Publisher: U.S. Geological Survey Cross_Reference: Citation_Information: Originator: K.J. Couvay Originator: T.J. Leiker Publication_Date: 1998 Title: Synthetic organic compounds in water and bottom sediment from streams, detention basins, and sewage-treatment plant outfalls in Las Vegas Valley, Nevada, 1997 Series_Information: Series_Name: Open-File Report Issue_Identification: 98-633 Publication_Information: Publisher: U.S. Geological Survey Cross_Reference: Citation_Information: Originator: V.A. Cross Originator: D.C. Twichell Publication_Date: 2003 Title: Archive of Seismic-Reflection Data Collected During USGS Cruise Lake Mead 01007 in Lake Mead - Nevada and Arizona, 1-28 April, 2001 Series_Information: Series_Name: Open-File Report Issue_Identification: 02-478 Publication_Information: Publisher: U.S. Geological Survey Cross_Reference: Citation_Information: Originator: H.R. Gould Publication_Date: 1951 Title: Some quantitative aspects of Lake Mead turbidity currents Series_Information: Series_Name: SEPM Special Publication Issue_Identification: No. 2 Publication_Information: Publisher: Society of Economic Paleontologists and Mineralogists Cross_Reference: Citation_Information: Originator: J.F. LaBounty Originator: M.J. Horn Publication_Date: 1997 Title: The influence of drainage from the Las Vegas Valley on the limnology of Boulder Basin, Lake Mead, Arizona-Nevada Series_Information: Series_Name: Journal of Lake and Reservoir Management Issue_Identification: v. 13 Cross_Reference: Citation_Information: Originator: L.J. Paulson Publication_Date: 1981 Title: Nutrient management with hydroelectric dams on the Colorado River Series_Information: Series_Name: Technical Report Issue_Identification: #8 Publication_Information: Publication_Place: Department of Biological Sciences, University of Nevada, Las Vegas, Nevada Publisher: Lake Mead Limnological Research Center Cross_Reference: Citation_Information: Originator: A.M. Preissler Originator: G.A. Roach Originator: K.A. Thomas Originator: J.W. Wilson Publication_Date: 1998 Title: Water resources data, Nevada, water year 1998 Series_Information: Series_Name: Water Resources Data Nevada Issue_Identification: NV-98-1 Publication_Information: Publisher: U.S. Geological Survey Data_Quality_Information: Logical_Consistency_Report: These data have been checked to remove obviously erroneous data points. Completeness_Report: These data represent shotpoint navigation for all the seismic lines collected on this cruise. Positional_Accuracy: Horizontal_Positional_Accuracy: Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 20 m Horizontal_Positional_Accuracy_Explanation: The navigation was collected with a P-CODE GPS receiver with an assumed accuracy of approximately 10m. Additional error is introduced by undertainty as to the positional relationship between the acquisition system and the navigation antenna. Lineage: Process_Step: Process_Description: This particular seismic data was acquired with an SIS-1000 chirp subbottom system with the digital data stored on a Triton-QMIPS datalogger. Navigation is updated approximately every 10 seconds and sent to this data logging system. Once the seismic SEG-Y data is separated from the raw data files, the unique navigation points and the shotpoints associated with them are pulled from the header of these seg-y data files. These navigation points reflect the best known position of the acquisition system. In other words, the layback of the instrument is taken into account for the positional fix. Process_Step: Process_Description: The shot point navigation for each line of seismic data was combined into a single file and then resampled using DigiRule's GeoCad program to a shot interval of 100. The beginning and ending shot of each line was maintained. Process_Step: Process_Description: These points were then imported into ArcView and saved as a shapefile. Process_Step: Process_Description: Since the original navigation was stored in the SEG-Y header in UTM, zone 11, NAD 83 meters, the file was then reprojected to the Geographic Coordinate system using ArcToolbox in ArcGIS 8.1 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 6759 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000000 Longitude_Resolution: 0.000000 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: lm01_100sht Entity_Type_Definition: ArcView shapefile attribute table Entity_Type_Definition_Source: ESRI Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: LINENUM Attribute_Definition: Line number assigned to the seismic line along which the shotpoint navigation point falls. Attribute_Definition_Source: Data processor Attribute_Domain_Values: Unrepresentable_Domain: character set Attribute: Attribute_Label: SHOT Attribute_Definition: The seismic shot number corresponding to that point. Attribute_Definition_Source: Software computed. Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 17143 Attribute: Attribute_Label: EASTING Attribute_Definition: The UTM easting position of the shot point. Attribute_Definition_Source: Software generated. Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 702048 Range_Domain_Maximum: 767566 Attribute: Attribute_Label: NORTHING Attribute_Definition: The UTM northing position of the shot point. Attribute_Definition_Source: Software computed. Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 3989078 Range_Domain_Maximum: 4040949 Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: David C. Twichell Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2266 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: dtwichell@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: These data were prepared by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this publication have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 0.495 Metadata_Reference_Information: Metadata_Date: 20031006 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: VeeAnn A. Cross Contact_Organization: U.S. Geological Survey Contact_Position: Marine Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Rd. City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Access_Constraints: none Metadata_Use_Constraints: none Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile