KEEP YOU EYES ON THE GROUND: CHIPPING SITES

Rocks of the Laramie Formation crop out in Ute Valley Open Space and Popes Valley.

It is “back in saddle” II.  After two months of fighting with my internet provider (no signal to load photos) and several months of camping, often with a unproductive laptop, I am back with my trusty desktop!  My camping trip involved five weeks in Wyoming, South Dakota, Minnesota, Wisconsin, Iowa, Missouri, and Kansas.  I was able to observe some fantastic geology and pick up some neat specimens.  Much of my time was spent on “blue highways” (back roads), a feat that is always exciting for me.  I hope to detail the trip in an article(s) for the Rocky Mountain Federation of Mineralogical Societies Newsletter (www.rmfms.org) and the CSMS Pick & Pack (www.csms.us).

I leave fairly close to Ute Valley Open Space, a park-like open space of several hundred acres in northwest Colorado Springs.  The bluffs and valley walls present numerous well-exposed outcrops of the Upper Cretaceous Laramie Formation (Fig. 1) including abandoned coal mines, rock quarries, upturned hogbacks, and an area perfect for hiking, bird watching, and plant identification.  Rocks of the Laramie Formation, so well exposed in the open space, represent the final regression of the vast Western Interior Seaway that flooded what is now Colorado during much of the Cretaceous Period (~144 to ~65 million years ago).  As the rocks weather, unconsolidated sand is produced along with tightly cemented ironstone concretions that often blanket the surface.  In addition, pebble and cobbles of the nearby Pikes Peak “granite” (Precambrian in age, ~1.05 Ga), along with component pieces of quartz and feldspar, are scattered over the surface.  The granite, quartz, and feldspar were deposited by streams coming down from the nearby mountains post-deposition of the Laramie (probably Pleistocene). 

 Ironstone and sandstone concretions often blanket the unconsolidated sand in Ute Valley Open Space.

 Most days I take my daily hike through the rocks and trees and always see “something” new and exciting.  Geologists have a habit of walking with their eyes on the ground looking for interesting objects; I am no exception.  Recently, I spotted an accumulation of small rocks/minerals that seemed rather “out of place” among the ironstone and sandstone cobbles blanketing the surface.  Upon closer observation, I noticed several fragments of brightly colored red jasper, beautiful dark amber chalcedony, and various other pieces of microcrystalline quartz.  These fragments are not “local”, at least I do not recognize their provenance.  I have seen similar minerals out in the Colorado Plateau but it would be a stretch to assign these fragments to that area.

 Fragments of microcrystalline quartz may represent a Native American chipping site.Small knife for scale.

 I am not an archaeologist but it is my guess these fragments represent a chipping site for a group of Native Americans, perhaps Utes, but that is a personal assumption.  It is interesting to note the fragments were in a small deflation basin where wind has blown the unconsolidated sand “away”.  That is most likely the reason why an earlier discovery was not made.  I took a few pictures and then gently covered up the site with sand as regulations prohibit the collection of such items on land managed by the City of Colorado Springs.

So, keep your eyes on the ground (the road if you are a Doors fan, as in Roadhouse Blues) and observe something new everyday!