PETROLOGY AND GEOCHEMISTRY OF PRECAMBRIAN BASEMENT ROCKS IN WALSH COUNTY, NORTH DAKOTA

In 1977, thirty-two legacy cores were drilled in eastern North Dakota and western Minnesota along the Red River of the North, for the purpose of evaluating uranium potential. That project was funded by the Department of Energy and overseen by Bendix Corporation. For this study, three of the cores were sampled at the North Dakota Geological Survey Drill Core Library, in Grand Forks. Samples were taken from drill cores RRVD #17, RRVD #18, and RRVD #19A to focus the study to Walsh County, ND. The basement rocks are Archean gneiss, buried under younger layers in Eastern North Dakota. They are part of the Superior Province that covers parts of southern Canada, MN, WI, and MI. The Red River Valley drill cores show rock and mineral age and compositions similar to those of the Western Superior Province. The Western Wabigoon terrane contains volcanic (granitic) and metasedimentary rocks and similar dates to our sampled drill cores. Petrography and whole rock major element geochemical analyses were carried out, and we are currently researching geochemistry and mineralogy of the processes which produced a paleoweathered zone which overlies the less weathered basement. This paleoweathering process may suggest uplift and reburial consistent with those that affected the Superior Province.