Troctolite. Includes the Boulder Lake, Tuscarora (~1,099 Ma), Partridge River (~1,098 Ma), South Kawishiwi, and part of the Western Margin intrusions.
State Minnesota
Name Troctolite
Geologic age Mesoproterozoic
Lithologic constituents
Igneous > Plutonic > Gabbroic > Gabbro > Troctolite
Comments Part of the Duluth Complex - layered series. Part of the Keweenawan Supergroup and Midcontinent Rift Intrusive Supersuite.

Jirsa, Mark A., Boerboom, Terrence J., Chandler, Val W., Mossler, John H., Runkel, Anthony C., and Setterholm, Dale R., 2011, S-21 Geologic Map of Minnesota-Bedrock Geology; Minnesota Geological Survey, State Map Series S-21. Scale 1:500,000.

NGMDB product
Counties Cook - Lake - Saint Louis