About the KMTA GeoTrail:
Welcome to a geocaching trail exploring Alaska’s only National Heritage Area. In 2009, Congress designated the Kenai Mountains-Turnagain Arm (KMTA) region of Southcentral Alaska as a National Heritage Area (NHA). This designation formally recognizes the history of an area that has deeply shaped the legacy of Alaska and the nation. It is the history of the Alutiiq, Sugpiaq, and Dena’ina people—the original stewards and inhabitants of the Kenai Peninsula. It’s that of the Iditarod National Historic Trail, Alaska Railroad, Gold Rush, Seward Highway, and local industries that give KMTA its character. KMTA’s geographic footprint bridges Cook Inlet and Prince William Sound via mountains, glacial valleys, and productive rivers. Throughout this landscape are communities and stories that connect us to our past and future. It includes the small and vibrant communities of Bird, Indian, Girdwood, Whittier, Hope, Cooper Landing, Moose Pass, and Seward, and all the wilderness between them. As Alaska’s only National Heritage Area, KMTA aims to enhance, preserve, and share the region’s natural and cultural resources— in essence its heritage. Above all else, KMTA strives to foster pride of place and an enduring stewardship ethic for this special place. As you travel through the Heritage Area to complete this GeoTrail, we encourage to keep that stewardship ethic front of mind as you learn about and enjoy the richness of the region.
As you search for the geocaches making up this GeoTrail, you’ll be asked to complete a passport that qualifies you to purchase the KMTA GeoTrail Geocoin. For more information on the Passport and GeoTrail, please visit KMTA-GeoTrail.GCAK.org
KMTA field guide link: https://kmtacorridor.org/field-trip-guide/
The unique code word for this cache is found as described in the cache listing Hint.
**Cell coverage warning: this location may have limited cell phone coverage (at least for data). It would be wise to download the cache information before arriving at GZ.**
KMTA GeoTrail #3: Turnagain Pass: Interpreting Glacial Moraine Evidence
Please email/message the answers to questions below to the CO. Do not include these answers in your log.
A. Please add the text “Turnagain Pass: Interpreting Glacial Moraine Evidence” to your message.
B. What type of valley do you think you are you in?
C. In your opinion, how was this valley created?
D. Based on your view of the area, what types of moraines were here?
E. There are debris cones in the area. What direction do you see debris cones, if any?
F. Using the information sign at ground zero, what are three activities enjoyed in the surrounding area relating to the cache content?
Optional request: please include responses in your log as conversational pieces:
G. What other valleys have you seen while visiting Alaska, or if none, in your travels elsewhere? Any famous ones, such as the Grand Canyon (United States), San Joaquin Valley (United States), The Valley of Flowers (India), Jiuzhaigou Valley (China), etc.?
H. Please provide a photo of yourself or a personal item that proves that you have visited this site in your log. Do NOT include the informational signs at the posted coordinates in your photo.
Turnagain Pass has a complex story shown through a series of glaciations. The valley was originally dredged out during past glaciations and the glaciations widened the broad valley of Turnagain Pass eventually becoming the thoroughfare for the Seward Highway. A view of the south wall of the valley adds to the story not only of the bygone era but the thickness of the ice. Travelers have had to deal avalanches, past and present. This may mean delays when avalanches close the highway or caution when recreating in the back country. Travelers bygone were offered easier travel in winter through the alders and over marshes, but the threat of an avalanche was very real. And very deadly. Not far from this valley, at the Lynx Creek mine, six men were buried (five perished) at the turn of the century when a slide ripped through the camp. Read on for a lot of good information to draw an educated conclusion!
Some simple definitions to help form an opinion:
- Debris Cone: debris deposited in a conical shape with a surface slope greater than 10 degrees usually transported by small streams or snow avalanches.
- Erosion: the gradual wearing away of Earth’s surfaces through the action of wind and/or water.
- Glaciation: the process, condition, or result of being covered by glaciers or ice sheets.
- Moraine: an accumulation of earth and stones carried and finally deposited by a glacier.
- Sediment: naturally occurring material that is broken down by processes of weathering and erosion.
- Valley: an elongate depression of the Earth’s surface usually between ranges of hills or mountains.
Different types of moraines:
- Ground moraines form under the glacier because tiny streams under the glacier build sediment up due to the sediment hitting hills and valleys under the glacier and is commonly referred to as till plain. Ground moraine is a term used to describe the uneven blanket of till left behind in the grassy or vegetative areas between more prominent moraine ridges.
- Lateral moraines form along the glacier side and consist of debris that falls or slumps from the valley wall or flows directly from the glacier surface. Where the rate of debris supply is high, lateral moraines can reach heights of more than 328 feet. Lateral moraines are usually found in matching ridges on either side of the glacier. Since the glacier pushes the rock and dirt up the sides of the valley about the same time, lateral moraines usually have about the same heights.
- Medial moraines form where lateral moraines meet at the middle of two valley glaciers, or where debris contained in the ice is exposed at the surface due to melting in the ablation zone. The ablation zone is simply more melting of the glacier ice than the accumulation of snow over the course of many years. Medial moraines are debris ridges at the glacier surface running parallel to the direction of ice flow.
- Supraglacial moraines can be lateral or medial moraines and both. Supraglacial moraines are made up of rocks and earth that fell on the glacier from the all around the area. One of the easiest ways this happens is through dust and dirt left by wind and rain.
- Recessional moraines sometimes form on a yearly basis and are known as annual moraines because of winter glacier advances. Recessional moraines can be found behind a terminal moraine limit and form during short-lived phases of glacier advance or standstill that interrupt a pattern of glacier retreat.
- Terminal moraines form at the glacier terminus, sometimes called an end moraine. The moraine ridge marks the maximum limit of the glacier's advance. They mirror the shape of the ice margin at the time of deposition. The largest terminal moraines are formed by major continental ice sheets and can be over 328 feet in height and over 62 miles long.
Different types of valleys:
- V Shaped Valleys, also called river valleys, are usually described as having steep sloped sides that create the visual of the V shape. V shaped valleys are most often formed from erosion and can be found near river sources because of the availability of steeper banks. They can also be formed downstream. The river will pick up rocks, dirt, and debris. The water’s force against the rock and debris grinds into the river bed to create the valley. After a period of time, if the erosion continues, it can get very deep and a canyon will form.
- U Shaped Valleys, called glacial valleys, are described as having steep sloped sides that curve in at the base of the valley wall. They are created by a melting glacier and gravity. Glacial ice takes years to make with an accumulation of more snow than melt. With the assistance of gravity, the weighted glacier moves. It weathers away, and leaves a carving much like trough. Because of the glacier’s weight, having been created in a previous V shaped valley, when the ice melt eroded the valley sides, it forever changed the shape of the valley from a V to a U with a broader valley floor.
- Flat Floored Valleys, similar to V shaped valleys, are born from flowing streams. These valleys are the most common on Earth and makes the most sense to be the most common because they are generally the oldest in existence. Flat floored valleys tend to be more conspicuous. After a long duration, they get wider by the stream slowly eroding the walls or sides of the valley then the banks of its channels. Streams that flood will carry eroded materials down, dispersing the materials across the flood plain, creating the flat valley visual that is so familiar.
References:
- www.definitions.net/glaciation
- www.merrium-webster.com
- www.kmtacorridor.org/field-trip-guide/
- Jacob Bendle. Web. 22 June 2020. https://www.antarcticglaciers.org/glacial-geology/glacial-landforms/glacial-depositional-landforms/moraine-types/
- Kim Rutledge, Melissa McDaniel, Santani Teng, Hilary Hall, Tara Ramroop, Erin Sprout, Jeff Hunt, Diane Boudreau, Hilary Costa. Web. 15 July 2022. https://education.nationalgeographic.org/resource/moraine
- https://eartheclipse.com/science/geology/valley-landform-formation-types.html
- Victor R. Baker, Web. https://www.britannica.com/science/valley
Please only used established pathways and trails. Practice Leave No Trace Guidelines:
- Plan ahead & prepare
- Travel & camp on durable surfaces
- Dispose of waste properly
- Leave what you find
- Minimize campfire impacts
- Respect wildlife
- Be considerate of others
This cache is maintained by local Alaskan geocacher hyfolks26.
Please contact her with any questions or maintenance requests.
