Lower sequence, primarily basalt

Lower sequence, primarily basalt. Includes the Ely's Peak and Grand Portage basalts and Hovland lavas (~1,108 Ma).
State Minnesota
Name Lower sequence, primarily basalt
Geologic age Mesoproterozoic
Lithologic constituents
Major
Igneous > Volcanic > Mafic-volcanic > Basalt (Flow)
Comments Part of the North Shore Volcanic Group - lower sequence, reversed and unknown polarity. Part of the Keweenawan Supergroup and Midcontinent Rift Intrusive Supersuite.
References

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 - Saint Louis