Robert P. Kucks

High resolution aeromagnetic survey of Lake Superior

A 57,000 line kilometer, high-resolution aeromagnetic survey was flown in 1987 as a contribution to the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE). Existing aeromagnetic data from the United States and Canada were combined with the new data to produce a composite map and gridded data base of the Lake Superior region (Figure 1). Analysis of the new data permits more accurate definition of faults and contacts within the Midcontinent Rift system (MCR). The aeromagnetic map provides important information supplemental to the seismic profiles acquired under the GLIMPCE program in 1986, allowing lateral extension of the seismic interpretation. In particular, modeling of the data provides an independent assessment of a reflection seismic model derived along line A (Figure 2). The profile and gridded digital data are available to geoscientists through the Geophysical Data Centre of the Geological Survey of Canada (GSC), while the gridded data are available from the USGS-EROS Data Center. GLIMPCE was established in 1985 to study the nature and genesis of the crust in the Great Lakes region. Program participants include the GSC, the U.S. Geological Survey (USGS), provincial and state surveys, and Canadian and American universities. In the Lake Superior area, a major objective of the program is to develop thermal, tectonic, and petrogenetic models for the evolution of the MCR and to evaluate these in the broader context of the tectonic evolution of the North American continent. Pre-1982 geological and geophysical knowledge of the MCR in the Lake Superior region has been summarized by Wold and Hinze [1982]. The Lake Superior region provides a unique window on this Proterozoic rift system, exposing igneous rock of the Keweenawan Supergroup that disappears under Paleozoic cover to the southwest.

Upgraded gravity anomaly base of the United States

A concerted effort to compile an upgraded digital gravity anomaly database, grid, and map for the United States by the end of 2002 is under way. This joint effort by the geophysics groups at the University of Texas at El Paso (UTEP), U.S. Geological Survey (USGS), and National Oceanic and Atmospheric Administration (NOAA) (with support from the National Imagery and Mapping Agency [NIMA]), is an outgrowth of the new geoscientific community initiative called Geoinformatics (www.geoinformaticsnetwork.org). This dominantly geospatial initiative reflects the realization by Earth scientists that existing information systems and techniques are inadequate to address the complex scientific and societal issues that we must confront. Currently, the lack of standardization and chaotic distribution of available geoscience data, a lack of documentation about them, and the lack of easy-to-use access tools and computer codes for their analysis are major obstacles for scientists, government agencies, and educators alike. ...