Michigan’s bedrock tells a quieter volcanic story than the Pacific Rim, but the state’s ancient lava flows and volcanic deposits are key to understanding its deep past. From shoreline basalts to buried volcanic centers, these features mark episodes of rifting and island-arc activity that shaped the Upper Peninsula and parts of the Lower Peninsula long before human settlement.
There are 8 Volcanoes in Michigan, ranging from Copper Harbor lavas to Portage Lake Volcanics. For each, you’ll find below the data organized as Location (county or nearest town), Coordinates (lat, long), Age (Ma); you’ll find below a concise table summarizing those fields for every entry.
Are any of these volcanoes potentially active or hazardous today?
No — Michigan’s volcanic units are ancient (typically hundreds of millions of years old) and show no signs of modern magmatic activity; the hazards today are geological inheritance (rock types, mineralization) rather than eruptions.
How reliable are the ages and locations listed for these volcanic units?
Ages come from radiometric dating and regional stratigraphic correlation and are generally reliable within published error ranges; locations are based on mapped outcrops and borehole data, so the table gives the best-available coordinates for each mapped unit.
Volcanoes in Michigan
| Name | Location (county or nearest town) | Coordinates (lat, long) | Age (Ma) |
|---|---|---|---|
| Midcontinent Rift (Michigan segment) | Keweenaw Peninsula & Upper Peninsula | 47.30,-88.60 | 1,100 |
| Keweenaw Volcanics | Houghton County (Keweenaw Peninsula) | 47.12,-88.56 | 1,100 |
| Portage Lake Volcanics | Houghton County (near Houghton/Hancock) | 47.15,-88.57 | 1,100 |
| Isle Royale Volcanics | Isle Royale National Park (Keweenaw County) | 48.03,-88.67 | 1,100 |
| Porcupine Mountains volcanics | Ontonagon County (Porcupine Mountains State Park) | 46.82,-89.97 | 1,100 |
| Marquette Volcanics | Marquette County (Marquette area) | 46.55,-87.40 | 1,100 |
| Ontonagon Volcanics | Ontonagon County (near Ontonagon) | 46.90,-89.30 | 1,100 |
| Copper Harbor lavas | Keweenaw County (Copper Harbor) | 47.48,-88.16 | 1,100 |
Images and Descriptions
Midcontinent Rift (Michigan segment)
A vast Proterozoic rift-related volcanic belt of flood basalts and related volcanics exposed across Michigan’s UP. Formed ~1,100 Ma, source of native copper and dramatic Lake Superior cliffs; many outcrops are roadside or in parks and visitable.
Keweenaw Volcanics
Thick sequences of Proterozoic basaltic lava flows and volcaniclastics that host native copper. Key exposures around Houghton and Eagle Harbor form cliffs and quarries; accessible via Keweenaw National Historical Park and scenic drives.
Portage Lake Volcanics
A stacked series of basaltic flows and intercalated volcanic rocks that built much of central Keweenaw topography. Important for copper mineralization with visible outcrops at old mine sites and trails; many are visitable with guided tours.
Isle Royale Volcanics
Well-preserved Proterozoic lava flows, pillow basalts and volcanic fragments on Isle Royale. These scenic island outcrops show submarine to subaerial volcanism; reachable by ferry or boat, with hikes to classic exposures and cliffs.
Porcupine Mountains volcanics
Ancient basaltic and andesitic flow sequences and volcaniclastic beds form the Porcupine Mountains’ rugged ridges and Lake of the Clouds cliffs. Part of the Lake Superior volcanic province and readily visitable on park trails and overlooks.
Marquette Volcanics
Metavolcanic flow and fragmental rocks of the Marquette Range, part of the same rift-related volcanic episode. These rocks underlie local highlands and host iron-bearing units; roadcut and shoreline exposures are accessible around Marquette.
Ontonagon Volcanics
Volcaniclastic sequences and basaltic flows of the Lake Superior province exposed in the Ontonagon area. Important for regional geology and copper-mineral context; river valleys and roadside exposures make them visitable.
Copper Harbor lavas
Basaltic lava cliffs and flow tops visible around Copper Harbor with columnar jointing in places. Classic shoreline exposures of Keweenaw volcanics offering interpretive stops, hiking, and scenic overlooks for visitors.
