Grand Teton National Park's Jenny Lake and Black Dike

Geologically speaking, there are three basic and interrelated activities that have shaped the landscape of North America: continental plate movements, glacial movements, and volcanic eruptions. Although Grand Teton National Park in Wyoming is, in itself, evidence of a convergence of the three geological activities, the park's Jenny Lake and the Black Dike display the evidence in a relatively small area. Jenny Lake testifies, in particular, to glacial activity, while the Black Dike testifies to the influence of volcanic activity. The mountain setting, formed by the movement of the continental plates, ties it all together.

You can enjoy the lake and the dike for their beauty and/or mystery, but your appreciation can be deepened when you understand why the two exist in the first place. Assuming the presence of the mountains as the backdrop for Jenny Lake and the Black Dike, let's begin with Jenny Lake.

Jenny Lake is a favorite spot for my wife and me. We have visited Grand Teton National Park several times, and we always take the time to stop at Jenny Lake to take each other's picture in front of the lake. Usually there is someone else nearby who is willing to take a picture of both of us together. On the shoreline is a tree with a curved trunk that my wife refers to as "our tree." That tree and the lake are among our special memories of Grand Teton National Park.

A helpful website says that Jenny Lake was named for Jenny, a Shoshone Indian, who was married to a trapper name Beaver Dick. Dick was a guide for the U. S. Territorial Survey Expedition which explored and mapped the area in 1872.

According to Wikipedia, the lake itself was formed thousands of years ago through a combination of running water, glacial movements, the rocks carried by the glaciers, and the water from melting glaciers, all of which produced the present-day Jenny Lake. The lake covers 226 acres and is an estimated 260 feet deep at its deepest point. On its west side, the lake butts up against the Teton Mountain range.

Looking at the Teton Mountains from Lake Jenny, a visitor can see another geological feature: the Black Dike on Mount Moran. A website that specializes in pictures of volcanic formations defines dikes as "bodies of magma that cut through and across...adjacent rocks." Dikes are formed when magma (basically volcanic lava) pushes through a crack in existing rock and then solidifies. If the color of the hardened lava is different from the surrounding rock, the dike will easily be visible.

The Black Dike is not only different in color from its surroundings, it is also large, being 150 feet thick. The Black Dike has become a reference point or landmark for mountain climbers.

Together, Jenny Lake and the Black Dike add to the beauty of the area and are enduring witnesses to the unbelievable power of natural events to bring about the beautiful area known today as Grand Teton National Park. As you go through the park and as you encounter places like Jenny Lake and the Black Dike, give yourself permission to be overwhelmed by the beauty and in awe of the tremendous power that shaped the landscape of a continent.

Note: The pictures that accompany this article are too small to clearly show the Black Dike. For a better view, go to the website that describes one man's climbing trip in the Grand Teton National Park and click to the fourth page/picture.

Sources:

www.unearthedoutdoors.net/parks/141/9
en.wikipedia.org/wiki/Jenny_Lake
volcano-pictures.info/glossary/dike.html
http://home.comcast.net/~wyomtns/grand/trip.html