Identification_Information: Citation: Citation_Information: Originator: David C. Twichell Publication_Date: 2005 Title: Interpretation of the Surficial Geology in the Pulley Ridge Study Area Geospatial_Data_Presentation_Form: vector digital data Online_Linkage: http://pubs.usgs.gov/of/2005/1089/data/interpretation/pulley_interp.zip Larger_Work_Citation: Citation_Information: Originator: VeeAnn A. Cross Originator: David C. Twichell Originator: Robert B. Halley Originator: Kate T. Ciembronowicz Originator: Bret D. Jarrett Originator: Erika S. Hammar-Klose Originator: Al C. Hine Originator: Stan D. Locker Originator: Dave F. Naar Publication_Date: 2005 Title: GIS Compilation of Data Collected from the Pulley Ridge Deep Coral Reef Region Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1089 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2005/1089 Description: Abstract: Pulley Ridge is a series of drowned barrier islands that extends almost 200 km in 60-100 m water depths. This drowned ridge is located on the Florida Platform in the southeastern Gulf of Mexico about 250 km west of Cape Sable, Florida. This barrier island chain formed during the initial stage of the Holocene marine transgression. These islands were then submerged and left abandoned near the outer edge of the Florida Platform. The southern portion of Pulley Ridge hosts zooxanthellate scleractinian corals, green, red and brown macro algae, and a mix of deep and typically shallow-water tropical fishes. This reef community is in unusually deep water, and its extent and the controls on its distribution were unknown. To address these questions scientists from the U.S. Geological Survey Coastal and Marine Geology Program in cooperation with scientists from the University of South Florida Department of Marine Sciences have completed a detailed mapping of the southernmost 35 km of Pulley Ridge. The area was mapped using multibeam bathymetry, sidescan-sonar imagery, and high-resolution seismic-reflection profiling to define the geologic framework on which the reef is established. Submersible dives, remotely operated vehicle (ROV) transects, and transects of bottom photographs and video were collected to identify the corals and to map their distribution. This extensive suite of data has been compiled and preliminary analysis of the data suggests that the reefs are not tied to the ridge system, but instead are more broadly distributed. Whether reef distribution is controlled by oceanographic conditions or by subtle differences in the substrate that overlies the barrier island system is unclear, and are topics of continued research. Purpose: Polygon shapefile indicating the interpretation of the sidescan-sonar mosaic. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2004 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -83.768420 East_Bounding_Coordinate: -83.599513 North_Bounding_Coordinate: 24.996035 South_Bounding_Coordinate: 24.665195 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: CMGP Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: coral Theme_Keyword: coral reef Theme_Keyword: geologic map Theme_Keyword: geology Theme_Keyword: OF 2005-1089 Theme_Keyword: Open-File Report Theme_Keyword: polygon Theme_Keyword: shapefile Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Woods Hole Science Center Place: Place_Keyword_Thesaurus: General Place_Keyword: Florida Place_Keyword: Florida Shelf Place_Keyword: Gulf of Mexico Place_Keyword: North America Place_Keyword: Pulley Ridge Place_Keyword: United States 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 XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 Data_Quality_Information: Lineage: Process_Step: Process_Description: Sidescan-sonar image mosaics were enhanced within PCI Geomatics software, using a linear stretch mapping the values between 80 and 140 across the entire 8-bit range (0-255). In addition, a 7x7 average filter was applied to smooth the images. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: G-polygon Point_and_Vector_Object_Count: 41 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: pulley_interp 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: ID Attribute_Definition: Computer generated polygon ID number. Attribute_Definition_Source: Software. Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: 0 Attribute: Attribute_Label: INTERP Attribute_Definition: Interpretation of the seafloor based on the sidescan-sonar mosaic. Attribute_Definition_Source: Scientist - David C. Twichell Attribute_Domain_Values: Unrepresentable_Domain: character set Overview_Description: Entity_and_Attribute_Overview: The Interp attribute definitions are as follows: terraces: Alternating linear bands of high and low backscatter on the sidescan-sonar imagery. The high-backscatter stripes are interpreted to be reflections off rock surfaces while the low-backscatter stripes are either shadows cast by the terraces or areas where fine-grained sediment has covered parts of the terraces. The bathymetry shows that the terraces occur along the flanks of the narrow ridge that marks the crest of the ridge. Video observations show outcrops of hardgrounds in these areas. high-backscatter: The sidescan-sonar images were smoothed in PCI with a 7x7 average filter, and the areas with values mostly between 117 and 225 were mapped as areas of high backscatter. video observations indicate that these areas are a mix of exposed hardgrounds, carbonate rubble, and deep-water coral. broad lines: The sidescan sonar image shows subtle variations in backscatter intensity that coincide with low-relief ridges on the multibeam bathymetry. depression-large: Sub-circular depressions show on the multibeam bathymetry that have 30-200 m diameters and are less than 3 m deeper than the surrounding seafloor. Many of these depressions have low-backscatter floors on the sidescan-sonar imagery. Video observations indicate that the floors of these depressions are fine sand. mottled-mod: The sidescan-sonar image shows a mottled seafloor of moderate and low-backscatter patches that have dimensions of 50-200 m. The average backscatter values on the filtered image for these areas are mostly 110-120. mod-backscatter: More uniform in backscatter intensity than the mottled-moderate backscatter regions. These areas occur mostly around the edges of the ridge where the seafloor is smoother than it is on the ridge itself. Video observations from these areas show a sandy seafloor with some carbonate cobbles, but the cobbles are not as concentrated as they are on the ridge. mottled-low: Low backscatter areas that are interrupted by sub-circular moderate backscatter patches that are 20-100 m in diameter. The moderate backscatter patches commonly have a pit or mound near their centers. The background in these areas mostly has a DN value less than 100. The multibeam bathymetry shows that the seafloor in these areas is smooth, and video observations indicate that the seafloor is somewhat sandier than other parts of the study area. low-backscatter: Areas with a smooth seafloor with a low-backscatter (DN less than 105) appearance. the only part of the study area with this appearance is in the southernmost part of the area beyond the shelf on the uppermost slope. 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 report 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: Format_Name: Shapefile Transfer_Size: 0.040 Metadata_Reference_Information: Metadata_Date: 20050512 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_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile