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Paleomagnetic and 40Ar/39Ar geochronologic data from late Proterozoic mafic dikes and sills, Montana and Wyoming

August 1, 1997

Paleomagnetic and 40Ar/39Ar results from mafic dikes and sills in northwestern Wyoming and western Montana yield similar virtual geomagnetic poles and isotopic dates. In combination with paleomagnetic and geochronologic data from elsewhere in the western Cordillera, these data provide evidence for a regional mafic magnetic event at 780 to 770 Ma that affected a large area of western North America.

Publication Year 1997
Title Paleomagnetic and 40Ar/39Ar geochronologic data from late Proterozoic mafic dikes and sills, Montana and Wyoming
DOI 10.3133/pp1580
Authors Stephen S. Harlan, John William Geissman, Lawrence W. Snee
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Professional Paper
Series Number 1580
Index ID pp1580
Record Source USGS Publications Warehouse