Compiler: R. C. Speed
Published as part of the Geological Society of America’s Decade of North American Geology (DNAG) project, this display presents 23 cross sections at scale 1:1,000,000 without vertical exaggeration across ocean-continent transitions of North America (Canada, Mexico, USA). The sections depict tectonostratigraphic relations and are color-coded by the tectonic affiliation of units, not by the age of units. The sections extend from oceanic lithosphere well into the modern morphologic North American continent and, in most, to the craton. The sections extend down to the Moho. The objectives of the display are several: 1) to provide a comparative view of the Phanerozoic structure around North American margins, using a new and standardized graphics format; 2) to portray the nature and sequence of events in the tectonic evolution of the margins with a newly conceived tectonic coding scheme; and 3) to show in continuity the structure from onland to offshore realms. The 3 sections are from published and unpublished contributions of a group of about 200 geologists and geophysicists who participated in the North American Continent-Ocean Transects Program through the 1980s.