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National Geophysical Data Center

Eastern Gulf of Mexico
Marine Habitat Study

BLM Data Set No. AA551-CT8-22

Data Announcement 79-MGG-000

Geological and geophysical data are now available for locations in the Eastern Gulf of Mexico associated with Lease Sale No. 65 (see figure below). The Bureau of Land Management (BLM) contracted with Woodward-Clyde Consultants in 1978 to collect and interpret these data in order to identify and delineate areas of potential constraints to oil and gas development. The BLM has provided these data to the National Geophysical Data Center (NGDC) for public dissemination.

The primary objective of the Eastern Gulf of Mexico Marine Habitat Study was to identify and delineate marine habitat areas in 49 of the proposed lease blocks included in OCS Sale No. 65. The lease blocks are located offshore Florida in the Gulf of MExico. The 49 blocks were divided into 10 noncontiguous map aras for the purposes of discussion and data presentation.

location map showing study areas.
Figure 1

High-resolution geophysical surveys and underwater television and camera ground truth surveys were conducted in support of the survey objectives. Over 1,930 km of geophysical data were collected from the following systems: depth sounders, a 3.5-kHz subbottom profiler, a sidescan sonar, and a high-resolution seismic reflection profiler. These data, along with data previously collected for the U.S. Geological Survey and the BLM, were used to produce maps of the bathymetry and seafloor sediment characteristics (see figure below) and a geologic cross section for each of the map areas (see table 1).

Upon completion of the geophysical survey, the geophysical data and preliminary interpretation maps were reviewed by scientists from Woodward-Clyde Consultants, TerEco Corporation, and the BLM. Based upon this review, 23 transects in six map areas were selected for the ground-truth survey using underwater television and a 35-mm underwater camera. Approximately 33 hr of videotape and 2,500 color transparencies were collected along the 23 transects. Descriptions of bottom features and associated macro-benthic assemblages were produced for each transect.

Table 1. Eastern Gulf of Mexico Marine Habitat Study Survey Areas

Sample plot of bathymetry and seafloor sediment characteristics.
Figure 2. Bathymetry and seafloor sediment characteristics

Availability of Data:

The BLM Data Set No. AA 557-CT8-22 consists of the following raw data and documentation:

The Final Report

Volume 1 is the technical report, which is divided into 19 sections and 2 appendices. Section 2 describes the geophysical and biological surveys that were previously conducted in Lease Area 65. Field operations with this survey are discussed in Sections 3 and 4. Sections 5, 6, and 7 describe the basic procedures for data handling, analysis, mapping, and presentation of the data from this study. Sections 8 through 17 present descriptions of the results of this survey in the 10 survey areas. Section 18 presents recommendations for areas which may require further studies to accurately assess the impact of offshore petroleum operations in these areas. References to previous studies are listed in Seition 19. Formats available: paper copy or microfiche.

Volume 2 contains the maps and geologic cross sections produced for each of the 10 study areas. These include 11 navigation and survey plots, 10 bathymetry and seafloor sediment characteristics maps, and 3 geologic cross sections (a total of 24 sheets). Formats available: Blackline (paper base), Sepia (paper base), Super Sepia (polyester base).

Volume 3 is the Operation Reports. The Operation Reports contain operations and instrumentation logs and are intended for use only by those scientists who will be utilizing the original field data. Formats available: paper copy or microfiche.

Geophysical Data

Subbottom profiles (3.5 kHz), bathymetry records, sidescan sonar records, and high-resolution seismic reflections. Formats available: 10 reels of 35-mm microfilm.

Color Slides (35-mm) of bottom features and associated macro-benthic assemblages. Formats available: 100 slides.

Total set (includes discount). Total Set includes Items 1 through 3, is available in three options based upon the chosen format for the maps and sections. Formats available: Blackline, Sepia, Super Sepia.