r/u_sickabouteverything
I moved to the St. Croix Falls area and began painting the basalt rocks along the river, surrounded by white pine and mixed hardwood bluff country. At first I was just trying to capture the mood of the place: dark volcanic cliffs, glacial potholes, pine-covered ridges, and the St. Croix cutting through it all.
But the more I read the park placards, talked with rangers, and researched online, the more I realized I was painting the exposed edge of a billion-year-old volcanic story.
The Midwest is often treated like a flat, quiet place, but geologically it is anything but quiet. Around 1.1 billion years ago, the continent began to tear apart along what is now called the Midcontinent Rift. Lava poured through the cracks and built enormous fields of basalt around the Lake Superior and Upper Midwest region. The rift failed before it became a new ocean, but the scar is still there.
Later, ancient highlands and mountain belts wore down. Some of this erosion happened before forests and deep-rooted land plants existed, so rivers and floods could move sediment across wide open landscapes without trees stabilizing the ground. Over time, the weaker minerals broke down, while durable quartz survived. That quartz became clean sand, gathered into beaches, dunes, river channels, and shallow marine deposits.
Then shallow seas covered parts of the Midwest. Sand became sandstone. Marine sediments became limestone and dolostone. In places, harder limestone capped softer sandstone, creating the conditions for dramatic cliffs, bluffs, caves, and retreating waterfalls.
The Ice Age opened the story back up. Glaciers and glacial meltwater carved valleys, drilled potholes into basalt, stripped away softer layers, and exposed the older rocks beneath. Around St. Paul, a massive glacial waterfall once tore through limestone and sandstone, part of the same erosional story that left the Mississippi River gorge and St. Anthony Falls behind.
That is why places like St. Croix Falls, Chimney Rock, Red Wing, and the bluffs along the Mississippi feel so strange and powerful. They are not just scenic overlooks. They are exposed pages of deep time: fire, erosion, sand, sea, limestone, ice, floodwater, and modern rivers all stacked into one landscape.
Even the silica mining story comes from this same history. The clean quartz sand now mined in parts of the Upper Midwest is not ordinary sand. It is the durable residue of vanished mountains, ancient shorelines, buried seas, and millions of years of sorting by water, wind, and time.
This is the geological history of the Midwest: a quiet-looking region built from volcanoes, lost mountains, tropical seas, Ice Age floods, sandstone towers, limestone caps, and silica pure enough to become part of the modern world.
Continue reading the full article below.
u/sickabouteverything — 11 days ago