The Borderline EarthCache
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This is the third of 6 earthcaches that highlight the landscape of Denali National Park and Preserve.
Welcome to Denali Geo-Ventures, a set of virtual earthcaches that highlight the amazing landscape that is Denali National Park and Preserve. These activities are offered through the Murie Science and Learning Center, a consortium of partners working with the National Park Service to support research and education efforts in Alaska’s northern parks. This set of earthcaches was created by Alaska Geographic, a non-profit organization dedicated to connecting people with our public lands.
These Denali Geo-Ventures take you behind the scenery; to investigating why the land at Denali’s entrance is so spectacular, and how it came to be. To ensure you have a positive experience and help us protect the park, please read through all of the ‘Before You Go’ information at the bottom of this page.
We usually think of change as a gradual process, with landscapes, plants, and animals changing almost imperceptibly over the course of many human generations. However, change can also be sudden: huge chunks of earth shift; natural disasters occur; disease spreads through and wipes out entire populations. To truly understand the complex processes of the natural world, we have to come to an understanding that includes both slow and rapid change.
The scene before you is a perfect example of this concept. How can there be such a difference in the ages of these rock formations even though they’re located so close to each other? The place where you’re standing is an old tectonic fault, a boundary that separates very distinct sections of rock where different chunks of the earth’s crust have been sliding against each other. This fault is called the Hines Creek Fault, so named because of the creek you are currently standing next to, which carves through this long, low valley that was created in part by the tectonic activity from this fault.
The Hines Creek Fault is an offshoot of the Denali fault system, a major continental translocation that can be traced clear across the state of Alaska. The Hines Creek Fault follows somewhat the same path through Denali National Park and Preserve as the park road. During the uplifting that created the mountains to the north of you, the earth fractured and the Hines Creek Fault appeared. While the Hines Creek Fault hasn’t been active for a long time, it draws a definite line in the kinds of geology you’ll find here. As a general rule, north of the Hines Creek Fault are the old rocks of the Yukon-Tanana Crystalline Sequence. But south of the Hines Creek Fault you’ll find the rocks of the Upper and Lower Cantwell Formations, and many other igneous, sedimentary, and metamorphic rock types, all of which are younger than the Yukon-Tanana Crystalline Sequence.
To Get To This Cache: Hike the McKinley Station Trail. The trailhead can be found behind the Denali Visitor Center or at the other end of the trail, at the Riley Creek Mercantile.
To Log This Cache: Just upstream from the footbridge, on the opposite of Hines Creek you'll see a prominent volcanic outcrop of the upper Cantwell formation. What are the predominant colors of this tall rock outcrop (about 2 stories high)? Email your answer to us at courses@alaskageographic.org. Use ‘Denali Geo-Venture - The Borderline’ in the subject line of your email.
Before You Go Information!!!
1. All of the Denali Geo-Venture sites are located on established park trails or roads and are within the first 15 miles of the park road. There is no need to go off these durable surfaces to find your site. Help us protect the park by avoiding the trampling of the fragile subarctic plants. Also, please abide by the Leave No Trace ethics for your entire stay in Denali.
2. Denali Geo-Ventures do not involve any physical caches to be found. You will be required to look for a clue at each cache and email your answer to courses@alaskageographic.org.
3. The completion of these Denali Geo-Ventures is easiest in the summer when the Park Road is open beyond Park Headquarters. In the winter months access to some of the caches can be done on a day hike, yet may require travel through snow and challenging conditions. For information about visiting Denali and weather conditions call the Denali Visitor Information line at (907) 683-9532.
4. Summer visitors with or without personal vehicles can participate in the Denali Geo-Ventures. If visiting without your own vehicle, you may need to make use of the free Savage River Shuttle bus to reach some of the Denali Geo-Venture sites. Consult a Shuttle Bus Schedule for hours of operation.
5. As with all visitors to Denali National Park and Preserve, you are required to pay the park entrance fee at the Denali Visitor Center or the Wilderness Access Center. Entrance fees are $10 per individual or $20 per vehicle. Several park passes are available and may be used in lieu of the park entrance fee.
6. For the east-end Park Visitor Center hours of operation visit this page of the Denali National Park and Preserve website.
7. Denali is a wilderness that is home to many species of wildlife, large and small. To ensure your safety while in this wilderness please remember to Keep Wildlife Wild and review our Bear and Wildlife Safety information.
Additional Hints
(No hints available.)