Mark Severson, Research Fellow

Position and Focus

The main emphasis of work at the NRRI has been related to studies of Cu-Ni-Platinum Group Elements and Fe-Ti-V deposits at the base of the Mesoproterozoic mafic intrusive Duluth Complex. Work has involved logging drill core (950,000 feet) and establishing igneous stratigraphic sections for several intrusive bodies within the Duluth Complex. Mineralization trends were then reinterpreted in regard to stratigraphic and structural controls. Additional research activities that have been conducted include:

1. geologic mapping at various scales including four published 7.5 quadrangle-size maps and a 1:200,000 map of the entire Duluth Complex - all were produced in cooperation with the Minnesota Geological Survey;
2. petrographic studies;
3. geochemical studies of both mineralized and unmineralized rock; and 4. microprobe analyses of sulfides and oxides.

The second main emphasis has been related to establishing the stratigraphy of the Biwabik Iron Formation on the Mesabi Range. A clearer picture of the stratigraphy has lead to a better understanding of how taconite ore zones correlate between and within each of the mines, and has helped outline waste rock zones with aggregate material potential.

Other research projects while at the NRRI have included drill core logging and mapping of Paleoproterozoic rocks of Minnesota in regard to:

1. the stratigraphy of additional iron-formations of the Cuyuna and Emily districts;
2. waste characterization studies of the Virginia Formation; and
3. SEDEX potential in the Animikie Basin and Fold-and-Thrust Belt of central Minnesota.

Lastly, underground geologic mapping of Archean supracrustal rocks was carried out at the Tower-Soudan Mine. Seven geologic maps have been produced in cooperation with the Minnesota Geological Survey.

Background

M.S., Geology, University of Minnesota, Duluth, 1979
B.S., Geology, Western Illinois University, Macomb, IL, 1975