GC1KHEM Boulder Creek
Type: Earth | Size: Not chosen | Difficulty: | Terrain:
By: squatchmeb,eaglescout5 @ | Hide Date: 01/06/2009 | Status: Available
Country: United States | State: Colorado
Coordinates: N40° 00.364 W105° 25.631 | Last updated: 08/30/2019 | Fav points: 0

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This an earthcache with multiple stops. It will show the finder the significance of Boulder Creek to the city of Boulder, Colorado. Second stage at N 40° 00.633 W 105° 18.200. A possible midpoint of interest is N 40° 00.338 W 105° 24.399.

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The primary water source for the city of Boulder, Colorado is Boulder Creek. The creek was named well ahead of the city's founding, for all of the large granite boulders that have cascaded into the creek over the eons. It is from Boulder Creek that Boulder City and hence Boulder is believed to have taken its name. Boulder Creek has significant water flow, derived primarily from snow melt and minor springs west of the city. The creek is a tributary of the South Platte River.

The oldest rocks in the Boulder area are Precambrian in age, and have been dated at about 1.7 billion years before present time (BP), as measured from the decay of radioactive elements. The Precambrian rocks consist of granitic and metamorphic rocks. The oldest Precambrian rocks in the Boulder area are metamorphic rocks, which means they were transformed by heat, pressure, and chemical reactions from older rocks into their present form. The Precambrian rocks were most likely originally laid down as sediments, such as sand and mud, in an ancient sea. These rocks were deeply buried beneath younger strata, and the metamorphic transformation occurred deep in the earth. The most common types of Precambrian metamorphic rocks west of Boulder are schist, gneiss, and quartzite and are found in the foothills and mountains west of the Boulder area.

On at least two occasions, mountains were formed from these rocks and they were uplifted by great forces from below. Hot molten magma was injected into the rocks, forming granitic rocks. The rocks have been uplifted and exposed to the surface by tectonic processes and erosion. The predominant Precambrian granitic rock in the Boulder Canyon area is the Boulder Creek granodiorite, and it makes up the walls of Boulder Canyon.

At the beginning of the Paleozoic Era, about 600 million years ago, ocean water gradually flooded across the old eroded surface of the Precambrian rocks. Sands were deposited along beaches, and lime mud was precipitated in the deeper waters of the ocean as it covered Colorado. The sands and lime mud were buried under great thicknesses of younger strata and were transformed into sandstone and limestone.

For most of the next 300 million years, a gentle pattern was repeated over most of Colorado, with intervals of gradual flooding by the sea and deposition of sediments, followed by slight uplifts and erosion. None of the rocks deposited during this time period are found near Boulder; they were either not deposited because the land was slightly above sea level, or they have since been eroded away.

During the early part of the Pennsylvanian Period, about 300 million years ago, two mountain ranges were pushed up in central and western Colorado. These ranges are known as the Ancestral Rockies. This event pushed Precambrian rocks well above the land surface and exposed them to weathering. Erosion cut into these rocks and carried floods of loose debris away to the east and west. This debris was deposited as a mixture of coarse and fine fragments, forming the sandstones and shales that make up the Fountain Formation. The Fountain Formation has a deep red color because of oxidation of iron in the minerals, and contains well-developed layering or bedding. The Formation was originally laid down flat, but was steeply tilted during fairly recent mountain forming. The Flatirons, directly west of Boulder, where Boulder Creek flows, is composed of Fountain Formation.

It is here at the beginning of this earthcache journey that you see these mountainous beginnings.

Boulder is an attraction for tourists and a geological feature close to Boulder is visited by many each year: Boulder Falls, located at N 40° 00.338 W 105° 24.399. This would make a nice rest stop, and interesting on your way between the start and end points.

During the present great interval of geologic time - the Quaternary Period -the Boulder area has seen erosional effects of glaciation. At least four times during the past million years or so, vast sheets of ice have moved southward out of the Arctic to cover much of Canada and the northern United States. There were many active glaciers in the mountains west of Boulder, but none of the glaciers seemed to have extended below the 8000 foot level of elevation, so there are no deposits of glacial debris near Boulder. Geologists recognize at least three distinct periods during which the mountain glaciers grew and gouged their way down the valleys from the continental divide. Floods of meltwater from the ice hastened the erosion. Glacial deposits and erosional features can be seen near the towns of Nederland and Eldora.

This lack of glacial action at the lower altitudes contributes to the fact that the contours of the land nearer Boulder are different than Nederland/Eldora. Near Boulder the land is flatter and mesas are in evidence.


To claim this earthcache, please email:
1) the altitudes of the starting and ending points mentioned above and your reasoning why the difference is important in the health of the Boulder area.

2) name the geological formations you see at each point

3) take and post with your log a picture of your group at each location

08/28/2018 By Libertarian Lad
We attempted to do this one, but 0.3 miles from the first spot, the road was private with large no trespassing and keep out signs. So we abandoned the search. Maybe there is another approach.

10/09/2016 By Killian33
I found this one with Nickgatt and Barasaur. We needed to find an earthcache for International Eathcache Day. An email with the answers will be sent to the owner. Thanks for the earthcache.

10/09/2016 By nickgatt
Found an Earthcache for International Earthcache Day! TFTec

10/09/2016 By Barasaur
I was able to meet up with nickgatt and Killian33 for a day of hiking and caching in the Boulder Canyon. It took us a few different tries to get to this cache's starting point. After many tries we found a way there but we still had to cross what seemed to be a lot of private property. I am glad to be able to claim this cache with some great friends.

(7054)

05/29/2016 By benji55545
This was one of the most physically demanding earthcaches I've ever done. I guess a couple of the ECs on mountain summits were harder ( GC3RQEW, Sierra Nevada Mountain Range Geomorphology comes to mind) but this one takes the cake for unexpected difficulty. I'm not entirely convinced the coords are correct, especially for the second stage. The first stage might actually be easier than I made it, assuming that you end up on the north side of the creek when you drive down Dream Canyon Rd. The last house on the street seems to be on the South Side of the creek, though. In any case, there are signs that say 'PRIVATE ROAD KEEP OUT' and 'PRIVATE PROPERTY NO TRESPASSING' attached to the dead end sign. They're in all caps so you know they are serious. Or are they? I stopped to take a picture of the signs and some wild turkeys that were running around and a homeowner waved at me as they drove onto Dream Canyon Rd. Hard to say if it really is a private road. In any case, I decided to respect their privacy and drove a little north on Switzerland Park Rd. to a point where the road intersected Forest Service land, at least according to my topo map. This dropped me right on top of a cool old mine, so I was already happy with my decision.

After climbing up and over the hill, I traversed the hillside for a bit in order to stay on public land. The slope is too steep to make this a very enjoyable experience. I finally made it to GZ and jotted down the necessary information, duly noting the house (and presumably... road) glaring at me directly across the creek. I took a slightly different path back that would require a little less traversing on steep terrain and got some nice views of the whole area.

After finding a few more caches, plus stopping for some beer and pizza in Ned (for energy, of course) I approached waypoint 2. I think I took the same path as uciphd. The landslide has stabilized a bit, so it was kind of useful to have the exposed rock to hold on to while climbing this slope. Really, you want me to go up there?! I'm still not convinced this is the right spot, but the cross-country trek allowed me to discover a variety of spring wildflowers I wouldn't have seen otherwise. Once I was at GZ, I noticed some faint paths, but I'm not sure where they lead. I think they are probably deer paths. There was a decent view from waypoint 2 that gave me a good sense of the extent of Boulder Valley that relies on Boulder Creek for water. I also got a view of the Boulder Red Rocks that I haven't gotten before. I don't think they are visible from Flagstaff. Thanks for the Earthcache. It gave me a new appreciation of the importance of Boulder Creek, and perhaps even more so, its effect on the area's terrain.

08/09/2014 By uciphd
I found myself on Switzerland Park Road early this morning to find the nearby D1/T4.5 and D5/T5 caches, so I thought this would be a fine time to tackle this earthcache. In the past, I’ve fished, hiked, and otherwise spent many hours alongside Boulder Creek, so it seemed like an interesting and appropriate adventure. My research told me the second stage would be a doozy, and that it most definitely was (those aforementioned T4.5 and T5 caches have nothing on that part of this earthcache!). Maybe that’s why so few have completed this one...

Accessing the posted coords was a little odd, as I had to force myself to ignore the “Dead End – Do Not Enter” sign and proceed forward like I lived there. And people do live there, so I guess it’s OK to ignore the sign. Just before it looked like I was going to drive into someone’s front yard, I pulled over and secretly made my way to the WP1 coords at Boulder Creek and the impressive rock formations.

From there, I wended my way back down to the canyon floor and parked off Rte. 119 at the nearest place I could to WP2. After playing a dangerous game of Frogger across the highway, I found myself on the Boulder Creek trail, a mere 600 feet from WP2. Not too bad, right? Well, consider that from there it’s a 33-degree angle hike up what’s basically an avalanche chute of dirt and loose boulders. Now THAT’s some serious terrain. The devastating evidence from last year’s floods was a constant reminder for me to watch my footing very, very, VERY carefully. Every so often I needed to pause to catch my breath, but in time I made it to the WP2 coordinates and took in the sweeping views. Coming back the way I came, I proceeded with even more caution lest I wanted to end up part of an avalanche of boulders careening toward the canyon floor.

Thanks squatchmeb for a very satisfying earthcache in which I came to appreciate the origins of Boulder Creek and it’s impact on the town of Boulder.