Daniel's Park
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DANIEL'S PARK - STOP #1
8/10/2002, 10:15 am

Daniel's Park is located south of Denver & Highlands Ranch, Colorado.  From this location we could see a great panoramic from the south-southeast to the west (see below).  See the footnotes to the picture for an explanation of the geology.
GPS Coordinates:

N 39o 28.343'
W 104o 55.370'
Elev: 6590 ft

PANORAMIC (actual full-color view - scroll right to see all)

  1. The buttes seen along the horizon tell a story of the ancient landscape.
  2. The sandstone in the foreground at far right of image (scroll right) were the vantage point for this picture.  They contain clues of paleocurrent flow direction (see further down this page).
  3. Castle Pines golf course, home of the PGA International tournament can be seen in the foreground.

SCHEMATIC VIEW

 

  1. This is a schematic view of the Daniel's Park overlook that is more representative of "paper" field book.
  2. This view shows the valley that resulted from the Plum Creek drainage.  The remaining buttes withstood erosional forces because of their "caps" of rhyolite (and some sandstone & granite).
  3. Flood of 1965 resulted in Denver building Chatfield reservoir dam to protect against future floods.
  4. Image created by tracing landscape with solid black line, then using "bucket fill" feature to change the color details to white.  Some color added afterwards to accent geological features.

VIEW OF LANDSCAPE WITH ANCIENT LAVA FLOW


 

  1. Volcanic flow from an extinct volcano near Mt. Princeton flowed downward to the east.  At this time the area shown in the Daniel's Park overlook was flat.  The ORANGE line shows the lava flow that once existed.  It is important to note that for this lava flow to occur and a level line, the plum creek drainage and rift valley further west could not have existed.
  2. Over time, the forces of erosion (likely from the Plum Creek drainage) eroded away much of the landscape.
  3. However, some buttes here remained because the formations underneath the rhyolite were compacted and held in place while other eroded away.
  4. Of particular interest is Castle Rock because it does not have a rhyolite cap on top of the butte.  Instead, it is composed of very large rhyolite blocks in smaller granite cobbles and sandstone.  This seems to indicate that a massive flood occurred which moved these large rhyolite blocks downstream where they were deposited in the other granite and sand.  There are close-up images of the castle rock conglomorate which tops the Castle Rock butte.  See the field trip page titled Castle Rock.
  5. Some buttes closer to the town of Castle Rock were mined long ago for their rhyolite.  This was used as building material for some of the old buildings in downtown Denver.

SANDSTONE AT DANIEL'S PARK

This coarse sandstone, or conglomorate, tops Daniel's park and provided the vantage point for the pictures above.  It contains of quartz, feldspar, mica, etc.  Feldspar contains lots of potassium and is sometimes referred to as "K-spar" by geologists.  Sometimes a rare Amazonite can be found in this sandstone.  Amazonite is a bright blue/green color and is much sought after by gemologists.

To determine the "provinance" (or origin) of the sandstone, we looked for clues.  It is a fluvial (river deposited sandstone) formation.  Trough crossbeds can be found in the sandstone.  To determine age, the lower trough crossbeds are the older.  Looking down on the crossbeds, we found the typical "smile" patterns present.  To determine the direction of geocurrent flow, we combined the knowledge of lower is older and "smile" direction.  At the time of these deposits, the river was flowing nearly due north (about 350 deg).

Simple reminder for "smiles" and geocurrent direction:
 
If you see a smile, you are looking downstream in the ancient riverbed.  (In a river, it makes you smile to go downstream.)
If you see a frown, you are looking upstream.  (It makes you frown to go upstream.)
 

This sandstone is part of the D2 formation and is 55 million years old.
 
 
Bob Raynolds describing trough crossbeds and direction of paleocurrent flow
 
 
Schematic example showing "smiles" in trough crossbeds.

Schematic example showing trough crossbeds (looking west).

A "rose" diagram can be  used to plot the polar coordinates and counts of each observation.  These are useful in understand general current flow at a given time and location.  Although we didn't take many samples of the paleocurrent direction, a rose diagram of this area would like look something like this.  This indicates that at this location and time (55 mya), the paleocurrent was flowing almost directly NORTH.  Based on more data and research, one would come to the known conclusion that the water flowed out of the mountains and followed the Rockies north.  Then, it slowly began curving eastward before curving south and heading for the Gulf of Mexico.
 


Rose diagram showing expected paleocurrent at Daniel's Park sandstone.