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. Please stay on the trail, this area is rocky and falls could be fatal. This cache is in the backcountry and grizzly bears frequent this area, it is advisable to bring bear spray. In order to log a find on this EarthCache read the cache page and send me the answers to the question below. This location is a several miles round trip hike with moderate elevation gain. It is suitable and safe for children as long as you heed the NPS trail advice. Best to check with the ranger station at Many Glacier about trail conditions.
The geology of the Rocky Mountains is an interesting one and Glacier National Park is part of that story. During the Proterozoic era, a shallow sea extending from the Arctic Ocean southward as far as southern California and Arizona, covering area from much of Idaho, Western Montana, Wyoming, Utah, Arizona and parts of California, Colorado, New Mexico and Texas. The large shallow sea-filled area that had sank is known as a geosyncline. This belt formation built up thousands of feet of sediment during this era, the Grinnell Formations being one of them. With time and pressure these layers changed to sedimentary rock and in some cases metamorphic rock. There are some igneous rock found in the park but these formations are after this period (geologists think this was magma intrusion of the layers during the Cretaceous period). Towards the end of the Cretaceous period, driven by tectonic plate action the geosyncline was uplifted along a line from Mexico to Alaska where two continental plates collided. This plate action is much like we see today in the Himalayas where India is colliding with Asia and the mountains continue to grow. Locally, this belt is called The Lewis Overthrust. During this subduction plate action (one plate forced over another plate), older layers are above younger layers of the plate forced down. The energy from this can also create metamorphic rocks from sedimentary rocks as we see throughout the park. Erosion then shaped the layers of stacked rocks, exposing layers from different eras and water and ice (glaciers) moved those around which brings us to the ice age when the Grinnell Formation (one of those layers) was exposed and moved.
In the Many Glacier area of the park, some nice exposures of the Grinnell Formation exist and can be identified by the dominantly red color, which gave the falls their name. This is due to the iron oxides that is abundant in this formation. It was created while this area was an inland sea and this mud and sand mixture was compressed. Some places this formation can be 3000 feet thing. At Waypoint 2, look for the thin white layers of quartzite, former sandstone that has been converted by pressure to metamorphic rock (see Quartzite Layer image at the bottom of this cache (below 'For Online Maps')).
The falls were created by the Swiftcurrent Glacier that pushed layers of this Grinnell Formation to the terminal moraine, that was breached Switfcurrent creek where the falls exist today that lead into Redrock Lake. The terminal moraine can best be seen from Swiftcurrent trail when it reaches Redrock Lake (waypoint 1). The Swiftcurrent Glacier has been receding since the end of the ‘little ice age’, about 1850 and is now below the 25 acer threshold that is normally used to be considered an active glacier.
* Congradulations to caverdon for a hard earned FTF!
In order to log this EarthCache, please complete the following and email your answer. Armchair logs will be deleted without notice.
* additional images are available in the Cache Images section for your reference.
1. As you proceed to Red Rock Falls (main Earth Cache quadrantes) from Waypoint 2 start looking for evidence of the Grinnell Formation rocks (red in color). When do you start seeing these red rocks at least boulder size?
* In geology, a boulder is a rock fragment with size greater than 25.6 centimeters (10.1 in) in diameter.
2. Why do you think you stop seeing bolder size pieces of the Grinnell Formation at the location noted in question 1?
3. If you are physically able to continue up the trail to the top of the falls, continue on the Waypoint 2 and locate the white layer of quartzite, how think is that layer?
4. Please include a picture of yourself at the location, we always like to see people enjoying this EarthCache!
Option: You can post some personal item at the GZ if you prefer not to include a picture of self.
Bibliography
The Geologic Story of Glacier National Park, by James L. Dyson
1953 published by Glacier Natural History Assoc, transcribed in 2019 to e-book format
Geology – A Complete Introduction by Dr David Rothery
5th Revision (2015) published by Hodder & Stoughton
Retreating Glaciers in Glacier National Park. Published by USGS (accessed in 19Aug2019)
link: https://www.usgs.gov/centers/norock/science/retreat-glaciers-glacier-national-park?qt-science_center_objects=0#qt-science_center_objects
Glacier margin time series (1966, 1998, 2005, 2015) of the named glaciers of Glacier National Park, MT, USA. Published by USGS (accessed on 19Aug2019)
Link: https://www.sciencebase.gov/catalog/item/58af7022e4b01ccd54f9f542