Geoelectric constraints on the Precambrian assembly and architecture of southern Laurentia

By: , and 



Using images from an updated and expanded three-dimensional electrical conductivity synthesis model for the contiguous United States (CONUS), we highlight the key continent-scale geoelectric structures that are associated with the Precambrian assembly of southern Laurentia. Conductivity anomalies are associated with the Trans-Hudson orogen, the Penokean suture, the ca. 1.8–1.7 Ga Cheyenne belt and Spirit Lake tectonic zone, and the Grenville suture zone; the geophysical characteristics of these structures indicate that the associated accretionary events involved the closure of ancient ocean basins along discrete, large-scale structures. In contrast, we observe no large-scale conductivity anomalies through the portion of southern Laurentia that is generally viewed as composed of late Paleoproterozoic–early Mesoproterozoic accretionary crust. The lack of through-going conductors places constraints on the structure, petrology, and geodynamic history of crustal growth in southern Laurentia during that time period. Overall, our model highlights the enigmatic nature of the concealed Precambrian basement of much of southern Laurentia, as it in some places supports and in other places challenges prevailing models of Laurentian assembly. The revised CONUS electrical conductivity model thus provides important constraints for testing new models of Precambrian tectonism in this region.

Study Area

Publication type Book chapter
Publication Subtype Book Chapter
Title Geoelectric constraints on the Precambrian assembly and architecture of southern Laurentia
DOI 10.1130/2022.1220(13)
Volume 220
Year Published 2022
Language English
Publisher Geological Society of America
Contributing office(s) Geologic Hazards Science Center, Geology, Geophysics, and Geochemistry Science Center
Description 18 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Laurentia: Turning points in the evolution of a continent
Country United States
Other Geospatial continental United States
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