This cache has been placed for
the CARMH2 event.. The cache should not be located prior to 7 p.m.
Friday July 22nd. The caches for the CARMH2 event are released
early so that the geocaching community has an opportunity to plan
their routes prior to the event start.
To log this cache, email us your
answers to the following questions. Please do not post them in your
log!
1. How many clinker bed formations are visible?
2. What is the approximate size (height X width) of the largest
formation?
3. What mineral gives the clinker its reddish color? HINT: Google
it!
4. Post a photo of yourself or your GPS with the largest clinker in
the background. (This request is optional and is not required to
log the cache.)
Upon arriving at the Echodale viewpoint, you will be met with
interesting reddish layers and brick-like masses of baked and fused
clay, shale, and sandstone that color and shape the landscape.
These baked materials, known as clinker formed in areas where seams
of lignite coal burned, producing heat that baked the nearby
sediments to a form of natural brick. Clinker beds typically range
from a few feet to 50 feet or so thick.
How they formed:
Clinker develops when coal burns
from the surface into a hill, where it cooks, fuses, and melts the
adjacent rock, forming new, completely different types of rocks.
Sandstone is baked to a brick-like rock. Shale may be fused like a
ceramic in a kiln. Other rock may melt to look like hardened lava.
Clinker beds are porous allowing water to infiltrate into them
rather than run off. The infiltration recharges the groundwater and
protects the underlying rock from erosion, producing hills with red
clinker caps. Before a coal bed can ignite and burn it must be dry
and exposed to air.
In the process, coal beds are
left above the water table where water can drain out of them and
the coal is exposed to oxygen. Lightning, spontaneous combustion,
chemical reactions, and range fires ignite the coal. Burning trees
rooted in coal beds can also start the fires. As the fire burns
into the hill, the overlying rock breaks up and collapses, this
allows air deeper into the hill and keeps the coal burning
underground. Eventually, too much overlying rock collapses to allow
air to enter, and the fire goes out.1
GeoFacts:
• The ceramic-like rock
produced from welded shale is called clinker. Similar to pottery,
it has sharp edges when broken. For thousands of years, in
Montana’s red cliffs, Native Americans made tools from it,
such as hide scrapers, knives, and arrowheads.
• The open spaces within
beds of clinker make the layers permeable to water. The baked
character of the rocks makes the rocks less soluble than typical
coal or sandstone beds. Therefore, clinker beds are important in
the production of less mineralized ground water in south-eastern
and far eastern Montana.1
(1) As details are limited on the red cliffs in
Echodale, and surrounding areas, the above information was
researched from various informational material on red cliffs
located in Montana and North Dakota.
References:
North Dakota's Clinker