The posted coordinates will be your first stop of this two stop EarthCache. Parking coordinates are also provided for the main trailhead. Dogs are allowed but must be on a leash. This area is kid friendly, but watch them closely when they are near any ledges. Bears and Mountain Lions live in the area and I was even face-to-face with a Bear in this Open Space. Please stay on the trail. I also added pictures in the gallery from our adventure while researching the area. Some great things can be found here!
Geological Map of the immediate area (larger view can be found using the link under sources):
The area this EarthCache will focus on includes the Tertiary and Cretaceous Periods, namely, the Paleocene and Upper Cretaceous Periods.
The Upper part of the Dawson Formation (TKda1) is known as Facies Unit One. "Cliff-forming, white to light-gray, cross-bedded or massive, very coarse arkosic sandstone, pebbly arkose, or conglomerate; beds of massive, light-gray to light-brownish-gray, very thick-bedded, homogeneous clayey sandstone; and lesser amounts of white to light-tan, crossbedded, poorly-sorted, fine- to medium-grained feldspathic sandstone. Occasional interbeds of thin to very-thin bedded gray claystone and sandy claystone or dark-brown to brownish-gray organ-rich siltstone to coarse sandstone containing abundant plant fragments. The upper part, in the northwestern part of the quadrangle, contains numerous interbeds of 1- to 6-foot thick, light- to dark-red paleosol. Unoxidized outcrops contain abundant iron sulfide as disseminations, nodules, and concretions. Weathering of the iron sulfides produces large slabs and layers of iron-oxide-cemented sandstone that protect columns and monument-like (hoodoo) erosion forms. Thickness varies from about 400 feet in the southeastern part of the quadrangle to about 1,200 feet in the western part."
The Lower part of the Dawson Formation (Kda) is "Greenish-gray to olive-brown, crossbedded or massive, very thick beds of sandstone containing andesite (fine-grained volcanic rock) pebbles up to 3 inches in diameter; interbedded with grayish-green to dark-green and brown to brownish-gray silstone and sandy claystone. Local lenses of chert pebble conglomerate and medium- to coarse-grained, cross-bedded, white to light-gray sandstone at the base. Thickness varies from 0, where unit has been removed by erosion, to 240 feet."
So what does all this mean? I am a visual and hands-on learner, so let's go on a little field trip. At Waypoint One (posted coordinates), you can see what I am referring to.
Notice the dark line running horizontally at this location? Is this an example of the Upper or the Lower Dawson Formation? How wide is it at its Northernmost point (in inches) and what is the widest it gets before completely eroding away?
Don't be afraid to get up close and personal with these formations. Feel them, notice the texture and colors. Please do not carve your name or other things into the sandstone! The higher you go up, the coarser it gets. We'll discuss this more at Waypoint Two. Feel free to post a picture of yourself holding your GPS at this location or on top.
Closer look. I love the color changes, so definite!
After you're done exploring this area, head on over to Waypoint Two so we can take a closer look at the layering and erosion of this area. If you find another location with Hoodoos you like better, go for it. Just send me those coordinates in your e-mail.
Hoodoos at Waypoint Two
The erosion of the hoodoos gives us a great peek at the composition of this area. You can explore the geology here with your eyes and with your hands. As discussed earlier, the upper part of these formations is the hardest part, and protects the lower layers. Wind erosion is doing some damage and in the photo gallery, you will find one that is balancing on some pretty thin sandstone.
Let's take a closer look at these layers...
A: The bottom layer is very light and fragile.
B: As you go up the structure, it gets darker and more coarse.
C: Again, coarser and darker.
D: Weathering of the iron sulfides produces large slabs and layers of iron-oxide-cemented sandstone that protect the column.
Let's look at it as a whole...
Please also post a picture of yourself with your GPS at WP2 (optional) and e-mail the answers to all the questions for WP1 and WP2 (not optional). Do not post answers in your log or it will be deleted. Failure to e-mail answers will also result in deletion. Thanks for visiting!
Without causing noticeable damage on the hoodoo you chose, feel each section on the formation. For A-D, answer these questions.
How easily does this section erode?
How big are the pebbles, if any, in this section?
Describe the coloring as you move up and are there any irregularities? (Example: while exploring, we found a Hoodoo with deep red spots at the base)
Finally, on the Hoodoo you chose, measure (in inches) how tall each section is.
SOURCES: Shout out to jp66 for her help creating this cache. "Geologic Map of the Pikeview Quadrangle, El Paso County, Colorado" by Jon P. Thorson, Christopher J. Carroll, and Matthew L. Morgan 2001 - Image provided by Colorado Geological Survey. CSMS Geology Post Blog by Mike. Permission via City of Colorado Springs Parks, Recreation & Cultural Services Department.
Online Resource: Geologic Map of the Pikeview Quadrangle, El Paso County, Colorado
FTF goes to hartsdale