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Who knew? Fault line connects Pattison and Amnicon state parks

There has not been an earthquake here in, oh say, 500 million years. But a major fault line runs right through Douglas County, between Pattison and Amnicon State Parks. When the fault line was active, the area was rocked by many earthquakes as th...

Pattison falls

There has not been an earthquake here in, oh say, 500 million years.

But a major fault line runs right through Douglas County, between Pattison and Amnicon State Parks.

When the fault line was active, the area was rocked by many earthquakes as the two sides of the fault pushed up against one another. Over thousands of years the force of the earthquakes created the ridge that runs through Amnicon Falls State Park and Pattison State Park. "That whole hill, as you look south from Superior, is a result of the fault," said Jim Haasis, a volunteer with "Friends of Pattison and Amnicon Falls State Parks."

The Douglas Fault runs all the way from the Ashland area to the Twin Cities. Haasis, who gives geological tours of Pattison Park every summer, says learning about the existence of a fault line in northern Wisconsin raises eyebrows among many visitors to the park. "Most are surprised about the fault," Haasis said. "Usually I get some questions about that." Haasis has a degree in geology and enjoys teaching visitors to the park about the geology of the area. "I try to impress on them the geological history of the park," he said. "It goes back 2 billion years when the basalt was laid down."

Basalt is the bedrock that Pattison Park sits on. At one point oceans covered this area. When the water drained, after millions of years, a layer of sand was left behind which eventually was compressed into a layer of sandstone on top of the basalt. When the Douglas Fault was active, about 500 million years ago, the shift in land left behind unmistakable clues. Gradually the sandstone south of the fault was pushed up over the sandstone on the north side and eroded away, exposing the basalt. But on the north side of the fault line, the sandstone is still there. "That's how you can tell where the fault is," Haasis said. "If you look down the Black River you can see sandstone on one side and basalt on the other side."

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In Pattison Park, the fault line is covered by the Black River and debris from steep banks. But in Amnicon Falls State Park visitors have a rare opportunity to see and touch the fault line. "Station one is down by the covered bridge," Haasis said. "Walk down the steps, turn your back to the river, look at the bank, and you're looking right at the fault." Haasis says it is a rare opportunity to see a fault line up close. Most fault lines in this country are covered by vegetation or rock debris and far less evident.

Volunteers like Haasis and intern naturalists give geology hikes through the park, pointing out evidence of lava flows that occurred about 1 billion years before the earthquakes on the Douglas Fault line, showing the contrast between the basalt and sandstone on either side of the fault, and talking about the glaciers that came later. "I try to give them a sense of the times and the history they're looking at," Haasis said. "A lot of things happened."

One of the most popular attractions at Pattison Park is the Big Manitou Falls, a 165-foot high waterfall, the highest in the state and the fourth highest east of the Rocky Mountains. Campgrounds, trails and a nature center surround the falls. But besides the popular waterfalls - Big Manitou Falls and Little Manitou Falls-- the 1,500-acre park is also provides miles of wilderness experiences. Only a small percentage of the park is developed. "I don't think many people know a lot about the wilderness areas that are here," said Dan Kephart, park ranger. "A lot of people don't see the back country area. It's really pretty neat."

There's an old growth forest in the southern part of the park with some really old pine trees that were originally part of Martin Pattison's logging camp. Hikers will come across old growth white pines that are four or five feet in diameter, Kephart said. Remains of the logging camp can still be seen along the Logging Camp Trail.

Whether it's lava flows and fault lines, or powerful waterfalls and natural hiking trails, Pattison Park has a variety of experiences for nature-lovers.

Related Topics: DOUGLAS COUNTY
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