This EarthCache was placed under the guidelines of the National Park Service and is on public property. No physical cache has been placed. This is a US Fee Area so to access this area you are expected to pay that fee or be a holder of a park pass. A side note – this earthcache is found along the Going-to-the-Sun Road. This road is closed typically from mid-October to early July, but that changes from year to year depending on snowfall, plowing, and weather conditions. Please check the conditions of the park and for any closures or postings at Current Conditions - Glacier National Park (U.S. National Park Service) (nps.gov) or Road, Trail & Campground Status - Glacier National Park (U.S. National Park Service) (nps.gov) for the most up to date information. In no way are individuals permitted into closed areas to access this geocache.
Please be advised that besides the geocache being located inside a fee area, during peak months there may be other requirements for entrance, like vehicle reservations.
This earthcache is at the Oberlin Bend – the last bend in the road when approaching Logan Pass from the west side, or the first bend after crossing Logan Pass from the east. There are several parking spots here, including accessible parking. There are stairs and a ramp up to a viewpoint. Ground zero is located at the furthest view down a short flight of stairs, but this cache can easily be accomplished at the viewpoint prior to the stairs.
Glaciation
The impressive mountains and valleys within Waterton-Glacier International Peace Park are the result of approximately 1.6 billion years of earth history and a variety of geological processes. Among these processes, glaciation played a particularly transformative role. Beginning with a global cooling trend about 2 million years ago, the onset of the Pleistocene Ice Age marked the start of extensive glaciation. During this epoch, large ice sheets advanced and retreated across North America, including what is now Glacier National Park. By the last major glaciation, around 20,000 years ago, the park was completely enveloped by glaciers. At this time, the Continental Divide, where the Logan Pass Visitor Center stands today, served as a boundary between the Cordilleran and Laurentide ice sheets.
The Cordilleran Ice Sheet, a major glacial mass, extended from British Columbia and South Central Alaska in the north to Olympia in Washington, Spokane, the Idaho Panhandle, and much of Western Montana in the south. It merged with the Laurentide Ice Sheet at the Continental Divide. Covering millions of square miles, the Laurentide Ice Sheet spread across most of Canada and a significant portion of the Northern United States. Its last advance, occurring between approximately 95,000 and 20,000 years ago, enveloped much of northern North America.
As the massive Cordilleran and Laurentide ice sheets retreated from Glacier National Park, they left behind glaciers, or "rivers of ice," that filled the lower valleys and sculpted the mountains and valleys into diverse landforms. These glaciers continued to shape the landscape through their powerful alpine and valley glacial action until they eventually melted completely around 12,000 years ago, leaving behind the rugged and picturesque terrain that defines the park today.
Even though the Pleistocene Ice Age glaciers are gone, the results of their passing are evident on the landscape. Massive u-shaped valleys, numerous cirque lakes or tarns, horns, cols, moraines, and aretes are but a few of the glacially carved landforms that contribute to the beauty of Waterton-Glacier International Peace Park.
Arêtes and the Garden Wall
At ground zero, you are standing at the head of a deep U-shaped valley cut by the glacier that flowed from Logan Pass to Lake McDonald and beyond. Mount Oberlin is to the left as you look down the valley. The imposing cliff to the right and across from ground zero is the Garden Wall, crowned by Bishops Cap. It might be hard to believe, but the Garden Wall is even steeper and more precipitous on its other side, where Grinnell Glacier is sheltered by its towering headwall.
The Garden Wall is a nearly 15-mile-long, steep alpine mountainside in Waterton-Glacier International Peace Park. It acts as a natural barrier between the Many Glacier region and Lake McDonald Valley. Known for its diverse range of flowering plants and shrubs that bloom in late spring and summer, the Garden Wall is situated on the west side of the Continental Divide and extends northward from Logan Pass. This area provides a notable example of an arête, a type of sharp, ridge-like geological formation created by glacial erosion.
An arête is a narrow, jagged ridge of rock that forms between two adjacent glaciers as they carve into the landscape. This distinctive landform typically emerges in regions where two glaciers erode parallel U-shaped valleys or where two glacial cirques cut back toward each other. As the glaciers move, they erode the rock on either side of the ridge through processes such as plucking and abrasion, creating a steep and sharp-edged crest. The continual grinding action of the glaciers makes the ridge narrower and the sides steeper. Over time, freeze-thaw weathering sculpts the ridge's top into a sharp, serrated peak. These serrated ridgelines often resemble saw blades or knife edges, with their rugged, craggy appearance. The low points along this serrated crest are called cols, which are saddle-shaped depressions that serve as spillways for the glacial ice and represent areas where the glacier action has sufficiently eroded the rock.
Questions:
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In your own words, describe how an arête is formed.
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Are the glaciers which formed the Garden Wall still in the park today? Why or why not?
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Which of the two ice sheets do you is more likely responsible for the glaciers that created the Garden Wall, and why?
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Your best guess: How many “teeth” and/or cols are there in the Garden Wall arête?
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Optional: Take a photo of yourself or a “stand-in” (hat, GPS, etc.) in front of the Garden Wall
Bibliography:
“Garden Wall.” In Wikipedia. Accessed August 24, 2024. https://en.wikipedia.org/wiki/Garden_Wall
National Park Service. "Glacier National Park Montana Geology." National Park Service. Last modified June 6, 2023. Accessed July 19, 2024. https://www.nps.gov/glac/learn/education/geology.htm.
National Park Service. "Glacier National Park Montana Glacial Geology." National Park Service. Last modified August 7, 2020. Accessed July 19, 2024. https://www.nps.gov/glac/learn/nature/glacial-geology.htm.
National Park Service. "Waterton-Glacier International Peace Park: World Heritage Site." National Park Service. Last modified March 29, 2021. Accessed July 24, 2024. https://www.nps.gov/articles/000/waterton-glacier-international-peace-park-world-heritage-site.htm.
Rains, Tim. GTSR- NPS100. Photograph. Flickr. October 26, 2016. Accessed July 19, 2024.
https://www.flickr.com/photos/glaciernps/30467160742/in/album-72157657446658275/.
Raup, Omer B., et al. Geology along Going-to-the-Sun Road, Glacier National Park, Montana. 2nd ed., Tucson, AZ, Glacier National Park Conservancy, 2018.
"The formation of glaciated upland features." Video, 1:00. BBC Bitesize. Accessed July 19, 2024. https://www.bbc.co.uk/bitesize/guides/zgndmp3/revision/2.
U.S. Geological Survey. "Geology of Glacier National Park." USGS. U.S. Geological Survey. Accessed August 24, 2024. https://www.usgs.gov/geology-and-ecology-of-national-parks/geology-glacier-national-park.