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Bonnie A. McGregor

Publications and source records attributed to Bonnie A. McGregor.

7 recordsLinked to original sources
USGS1991

Depositional patterns of the Mississippi Fan surface: Evidence from GLORIA II and high-resolution seismic profiles

GLORIA long-range side-scan sonar imagery and 3.5-kHz seismic-reflection profiles depict a series of nine elongate deposits with generally high-backscatter surfaces covering most of the latest fanlobe sequence of the Mississippi Fan in the eastern Gulf of Mexico. The youngest deposit is a “slump” that covers a 250 by 100 km area of the middle and upper fan. The remaining mapped deposits, termed depositional lobes, are long (as much as 200 km) and relatively thin (less than 35 m thick) bodies. Small channels and lineations on the surface of many of these depositional lobes radiate from a single, larger main channel that is the conduit through which sediment has been supplied to these surficial deposits on the fan. The 3.5-kHz profiles show that adjacent depositional lobes overlap one another rather than interfingering, indicating that only one lobe was an active site of deposition at a time. Shifting of the depositional sites appears to be caused by both aggradation and avulsion. The chronology developed from the overlapping relations indicates the oldest of the mapped depositional lobes are on the lowermost fan, and the youngest are further up the fan. Depositional lobes on the lower fan consist of a series of smaller, elongate features with high-backscatter surfaces (540 km in length) located at the ends of previously unrecognized small channels (< 5 m deep). These small channels extend as much as 120 km from the main channel. Small channelized turbidity currents and/or debris flows, sand flows, or mud flows appear to be the dominant transport process constructing these depositional lobes. Channelized flow is an important mechanism for transporting sediment away from the main channel on this fan and the resulting facies created by these small flows are laterally discontinuous.

Mississippi↗
USGS1985

Mapping and research in the exclusive economic zone

By proclamation of the President on March 10, 1983, the United States claimed sovereign rights and jurisdiction within an Exclusive Economic Zone (EEZ). The United States is responsible for wisely developing and managing the EEZ and its marine resources and for protecting its environment. The U.S. Exclusive Economic Zone is a region that extends seaward 200 nautical miles from the coast and brings within the national domain over 3 million square nautical miles of submarine lands. The EEZ contains vital natural resources, both living and nonliving, of the seabed, subsoil, and overlying water. Because most of the EEZ has not been explored, its resources and their potential remain undefined

Report↗
USGS1984

RECOMMENDATIONS FROM THE DEPARTMENT OF THE INTERIOR - EEZ SYMPOSIUM.

The Presidential proclamation on March 10, 1983, of a 200-nautical-mile-wide Exclusive Economic Zone (EEZ) focuses attention on the mineral resources of a vast submarine area. The hard-mineral resources in the EEZ include shallow-water placer deposits, polymetallic sulfide deposits, and cobalt-enriched manganese crusts in deeper water. The petroleum resource potential of basins within the EEZ is of importance especially in the deep water of the continental slope and rise. In order to formulate a national program to assess the resources in the EEZ, a symposium on 'A National Program for the Assessment and Development of the Mineral Resources of the United States Exclusive Economic Zone', was held at the National Center of the US Geological Survey. The symposium covered resource evaluation, engineering development needs, and the legal framework for management of the assessment and development of this vast area. Recommendations resulting from the symposium are discussed as well as the initial steps for implementing those recommendations and formulating an effective national program.

Conference Paper↗