1 Comment

About the Route – Classic XXXII Day 3

The first of two layovers and we invite you to choose your own adventure – you’ve earned it! Follow your fancy wherever it leads you. You can take a short out and back ride, go on a 60-mile excursion, head down a spectacular gravel road, go off on a fossil-finding hike, help the local Fossilites with a community project, or just take ‘er easy and figure it out as you go. The options are limitless and there’s no wrong way to do Day 3.

Day 3: Fossil, Oregon

Main Route: 38.8 miles / 4,085’ elevation

Main Route with Gravel: 43.1 miles / 4,164’ elevation

Long Route with Gravel: 59.3 / 6,599’ elevation

Layover days are a great opportunity to enjoy a break from riding and take in some sights around the area. But this series is called “About the Route” and that means riding so let’s get on course!

We’ve prepared three course options for the day and since they’re built on component pieces you can go longer or shorter and still share many of the same experiences. Our Main Route is the full distance of the easternmost spur of the Painted Hills Scenic Bikeway which is an out-and-back from Fossil to the Clarno Unit of the John Day Fossil Beds. Three hiking trails here, Clarno Arch Trail (1/4 mile roundtrip), Trail of Fossils (1/4 mile loop), and Geologic Time Trail (1/4 out-and-back) take you up to 54 million years back in time with glimpses of fossilized plants in the cliff walls. Climbing south out of Fossil on the Shaniko-Fossil Highway the route turns west at Morris Canyon and rolls downhill to the turnaround. Expect one last little kicker climb before the rest stop at the turnaround and then roll back the way you came. Oh yeah, that means you finish the day on a zesty downhill cruise!

If you enjoyed some crunchy snacks at the rest stop and your bike wants some, the Main Route with GRAVEL adds a little mixed-surface treat to the day. Riding back you’ll continue east but turn at the fork in the road onto Pine Creek Road where you’ll parallel its namesake as you ride through Perin, Wright, Jordan and Huntley Canyons. The creek ends where the road turns northward and becomes Cottonwood Creek Road; this is the final push to the highest point of the day at over 3800’. From here’s it’s a 50/50 ride home – gravel through Schoolhouse Canyon and back to the Shaniko-Fossil Highway for a downhill cruise through Juniper Canyon and back into town.

Want to do it all? The Long Route with GRAVEL rolls west past the Clarno Unit into the town of Clarno where you’ll ride over the John Day River on the Clarno Bridge. Did you know the John Day River is the longest undammed river in Oregon and  one of the longest free-flowing rivers in the continental United States? A miniature steamboat, The John day Queen, ferried people across the river until a timber-plank bridge was built in 1908. The current steel bridge replaced the original bridge in 1975.

It was definitely worth the ride!

Geology Rocks! by Ian Madin

Ian Madin worked as a geologist with the Oregon Department of Geology and Mineral Industries for 32 years and has ridden with Cycle Oregon for over a decade now. Here, he gives us a look at the the cool and sometimes hidden geology of the regions through which we ride. His nightly presentations at Classic are always fun and informative so grab a cold beverage or dessert (maybe both!) and grab a seat when we get him on the mic.

Be sure to read Ian’s Classic XXXII Geology Rocks! preview feature first. You can find it on our blog here.

About the Route Classic XXXII Day 1 is here.

About the Route Classic XXXII Day 2 is here.

View all Classic XXXII routes on Ride with GPS here

Dikes, Nuts and Slides – If you have some time to spare on your Fossil layover day, be sure to check out the Oregon Paleo Lands Institute Center in town (https://www.oregonpaleolandscenter.com/).  This local non-profit organization is dedicated to educating the public about the fascinating geology, fossils, landscape and culture of the Painted Hills region.

As you start your ride towards the John Day River at Clarno, you will be passing through more John Day rocks as you climb toward the pass into the Pine Creek basin.  Here the John Day ash and sediment are mixed in with lava flows and dikes of basalt, andesite and rhyolite that are part of the Clarno Formation.  The Clarno and John Day rocks were formed by eruptions that overlapped in time and location, but have been mapped and studied separately based on the type of rock.  The John Day rocks are the result of ash erupted from large volcanoes that blanketed the entire region, while the Clarno rocks were erupted from more numerous local vents and did not travel very far.  The distinction between basalt, andesite and rhyolite lava and dikes is based on the chemical composition.  Basalt is relatively low in silica, while rhyolite is silica rich, and andesite is in between.  As you ride through this mixed landscape, John Day rocks form smooth slopes with little outcropping, and may show patches of bright colors.  The Clarno rocks tend to form dark grey and brown blocky outcrops and rugged slopes littered with boulders.  Two miles into our descent into the Pine Creek basin, you will pass a large landslide on your right, that extends almost 1.4 miles from the ridgeline all the way to the valley bottom, where the creek and road both skirt the landslide toe.  Large landslides like this are common in areas where thick dense volcanic rock like basalt and andesite are interlayered with clay-rich sedimentary rocks like the ash layers of the John Day. 

Areas with steep slopes and dense lava sitting on top of weaker clay rich rocks often have large landslides like this one, 2 miles below the pass into the Pine Creek Basin.

Shortly after the first snack stop you will pass a nicely exposed basalt dike on your right.  In the lidar image below, you can see the rough outcrop of rock slicing across the landscape on the right side of the road. This steeply inclined layer of hard rock formed as an injection of molten basalt magma into the surrounding John Day rocks thousands of feet beneath the ancient land surface.  The dike probably fed a small volcano at the surface, which has been removed by erosion.

About 0.7 miles west of the first rest stop you will pass a well exposed basalt dike on your right.

Around mile 14, you will start to see a cliff of hard rock that forms a bold cliff partly up the slopes on your right. This is a layer of volcanic rock called a lahar that is part of the Clarno rocks.  A lahar, also known as a volcanic mudflow, forms in an eruption on a large volcano that is covered in ice and snow. The hot lava melts the snow, and mixes with the water to form a hot slurry of boulders and mud which flows down the volcano and into adjacent valleys, burying everything in its path. When the lahar comes to rest, it solidifies into a hard rock like concrete.  Anything that was in the way, like soil, vegetation or wildlife gets jumbled into the moving mass and then frozen in place in the hardened rock. 

In this 3D lidar view, you can see prominent cliffs formed by erosion resistant lahar layers.  Those at the left side of the image are at the Clarno day use area.

This is the environment for the famous Clarno nut beds, which are found in the JDFBNM Clarno day use area at mile 16.4. Here the cliffs of lahar you saw earlier are down at road level, and these bouldery palisades contain a wide range of plant and animal fossils. Take a moment to stop and read some of the interpretive signs which are located right along the highway.  If you look carefully, you can find fossil leaves, maybe even a walnut or ancient banana!

The bold cliffs at the Clarno day use area are composed of volcanic lahars.

When you leave the Clarno interpretive area you will pass tantalizingly close to the John Day River and then climb a low ridge climb before finally descending to the bridge over the river at Clarno.  The ridge is composed of layers of John Day ash and sediment that have been tilted to the west.  You will see more brightly colored rock as you toil up the hill and then coast down to the river.  The river crossing at Clarno is the take out for river float trips that start from Service Creek, and the put in for trips that go on down to Cottonwood Canyon State Park, nearly 70 miles away.

The final climb to reach the John Day River at Clarno is over a ridge of tilted John Day rocks, some with bright red paleosols. In the background of this image, the yellow line marks the unconformity between the John Day/Clarno rocks and the overlying Columbia River Basalt.

For those who are continuing on across the river for the long option, the geology gets pretty simple. Everything from the river to the turnaround point is a giant landslide.  Once again, the combination of heavy volcanic rocks lying on top of the weak and slippery clay soils and sediments of the John Day rocks has caused the entire mountainside to give way and slide towards the river. A slide this large, 5 miles wide and 10 miles long, has probably been intermittently active for tens of thousands of years.  What you will notice as you ride across it is irregular topography and scattered areas of broken rock.

Leave a Reply

Your email address will not be published. Required fields are marked *

1 Comment

  1. Malcolm Hutchinson says:

    This is the day I would like to be with you but that’s not possible. My maternal grandfather originated from Fossil Oregon. I’m now 77 and not available this year. Otherwise I’d love to join the ride.

    Have fun folks!

    Malcolm H