Note: This is an Earthcache. There is no physical cache to find. Logging this Earthcache requires that you undertake an educational task relating to the specific Earth Science at the site.
Prior to logging this cache, click on Message this owner, or send an email with answers to the following questions:
- What color is the diabase dike?
- Do you think diabase is harder or softer than shale?
- Do you think the gorge is likely to get deeper or shallower?
- Required to log this cache: Please provide a photo of yourself or a personal item in the picture to prove you visited the site. Upload the photo with your log.
High Falls
High Falls is located in Grand Portage State Park. In fact, it’s one of the reasons for Grand Portage. This is the first of 20 miles of impediments on the Pigeon River that prevented the Indians, and later the Europeans, from paddling up from, or down to Lake Superior. The Ojibwe Indians created a nine-mile trail from Lake Superior to bypass the falls. The North West Company and their Voyageurs used this trail in the fur trade and transportation of goods.
The massive rock face of the waterfall is an erosion-resistant diabase dike. This formed about 1.1 billion years ago, when superheated magma pushed up from more than 50 miles below the surface, into vertical cracks in the upper sandstone/shale layer. The magma cooled into a hardened, erosion-resistant rock known as diabase. In the gorge you can see shale rock, which is softer and erodes easily. Erosion from the falling water continues to reshape the gorge. Geologists are still debating on whether the gorge was there before the glaciers or if it was formed by the melting glacial waters.
There is an excellent 1/2 mile (each way) paved trail that leads to several different viewing platforms.
