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GEOHORIZONS |
1 U.S. Geological Survey, Mail Stop 964, Box 25046, Denver, Colorado 80225; saltus{at}usgs.gov
2 U.S. Geological Survey, Mail Stop 939, Box 25046, Denver, Colorado 80225; cpotter{at}usgs.gov
3 U.S. Geological Survey, Mail Stop 964, Box 25046, Denver, Colorado 80225; jeff{at}usgs.gov
Rick Saltus has worked since 1980 as a geophysicist for the U.S. Geological Survey. His work primarily involves the application of gravity and magnetic methods to geologic, tectonic, and resource assessment studies. He graduated from Stanford University (M.S., 1988; Ph.D., 1991). He has contributed to the U.S. Geological Survey energy assessments of northern and central Alaska.
Chris Potter, a structural geologist, has been employed at the U.S. Geological Survey since 1989. Chris received graduate degrees from Brown University (M.S., 1976) and the University of Washington (Ph.D., 1983), before spending several years as a research associate at Cornell University and assistant professor at Lafayette College. Most of his research involved regional studies in the North American Cordillera and central United States, commonly integrating field geologic studies with seismic reflection and other geophysical data. He has been working on structural interpretations and hydrocarbon assessments on the North Slope of Alaska for the past 10 years.
Jeff Phillips has worked as a research geophysicist with the U.S. Geological Survey since 1975, specializing in potential-field theory and its application to geologic problems, including water, mineral, and energy resources. He received his graduate degrees from Stanford University (M.S., 1973; Ph.D., 1975). He has participated in U.S. Geological Survey energy assessment studies of northern and central Alaska.
Aeromagnetic and gravity data are processed and interpreted to reveal deep and shallow information about the crustal structure of the central North Slope, Alaska. Regional aeromagnetic anomalies primarily reflect deep crustal features. Regional gravity anomalies are more complex and require detailed analysis. We constrain our geophysical models with seismic data and interpretations along two transects including the Trans-Alaska Crustal Transect. Combined geophysical analysis reveals a remarkable heterogeneity of the pre-Mississippian basement. In the central North Slope, pre-Mississippian basement consists of two distinct geophysical domains. To the southwest, the basement is dense and highly magnetic; this basement is likely mafic and mechanically strong, possibly acting as a buttress to basement involvement in Brooks Range thrusting. To the northeast, the central North Slope basement consists of lower density, moderately magnetic rocks with several discrete regions (intrusions?) of more magnetic rocks. A conjugate set of geophysical trends, northwest-southeast and southwest-northeast, may be a factor in the crustal response to tectonic compression in this domain. High-resolution gravity and aeromagnetic data, where available, reflect details of shallow fault and fold structure. The maps and profile models in this report should provide useful guidelines and complementary information for regional structural studies, particularly in combination with detailed seismic reflection interpretations. Future challenges include collection of high-resolution gravity and aeromagnetic data for the entire North Slope as well as additional deep crustal information from seismic, drilling, and other complementary methods.
This article has been cited by other articles:
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  R. W. Saltus and T. L. Hudson Regional magnetic anomalies, crustal strength, and the location of the northern Cordilleran fold-and-thrust belt Geology, June 1, 2007; 35(6): 567 - 570. [Abstract] [Full Text] [PDF]
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