2016 Mtns & Mesas with covers

page 40
Mountains & Mesas
Pass Creek Pass divides geologic eras
Once you’re in Gardner, start looking off to your
left for Co Rd 550. Be aware that this is a dirt road
heading up into the mountains with no real amenities
along it, so excercise caution. Once on Co Rd 550,
drive for about five miles, then turn left onto Co Rd
570. Stay on that road for about 3.6 miles, it will turn
into Cross Creek Road. Stay on that, turn slightly left,
onto Co Rd 572, and you will be on Pass Creek Road.
Follow Pass Creek Road through the mountains for
stunning views of the 25 million year old intrusions
on the east side, and 1.7 billion year old mountains
on the west side. As you come down over the pass,
hang a left at the fork in the road (should be about 17
miles on the Pass Creek Road) and keep driving until
you reach Highway 160. Turn left again, heading
east, and follow the highway back to Walsenburg. If
Oldies rock
tours
by Ruth Orr
Okay, so maybe there aren’t any guitars, keyboards,
or crazy haired men in tight leather, but the
rock tours outlined here are worth screaming for anyway.
We are lucky to live in an incredibly geologically
diverse and historically rich area of the country.
From the tops of our mountains and mesas to the bottoms
of our valleys, we can read the history of our
land in the rocks. Now, with the help of these trips,
you can travel through
time and see the
processes that
made our
counties what
they are today.
Rock On-
Gneiss guitar,
man
Red remnants of a long gone range
The geologic history of the area is ancient. Between
one and two billion years ago, huge beds of
granite formed all over the area. A range of mountains
known as the Ancestral Rockies uplifted in the
same place the current Rocky Mountains are today.
As they eroded, huge amounts of sediments were
dropped in the low areas near the mountains. As
they hardened, they formed the thick beds of red rock
that gave Colorado its name. You can see these rocks
if you drive along Highway 69 from Walsenburg to
Gardner and look right, at the base of Greenhorn
Mountain. They are also visible if you want to get
out of the car and hike a bit. (For more info see the Red
Rocks on the Cucharas Trip. )
As you drive along Highway 69, keep an eye out
for the Gardner Butte on the right hand side of the
road before you reach Gardner. About 27 million
years ago, the Sangre de Cristo mountains were
thrust upward, and the faulting caused breaks and
cracks in the surrounding rock. Bubbles of magma
pushed up, but failed to reach the surface. They
slowly hardened into the Spanish Peaks, Mount
Maestas, Silver Mountain, and the Sheep Mountains.
Around the same time, smaller cracks in the rock allowed
for Gardner Butte, Huerfano Butte, and the
world-famous dikes around the new mountain systems.
All the buttes are volcanic pugs, essentially
magma blocks that hardned underground before
they could successfully explode out onto the surface.
The softer rock around them slowly eroded away, finally
exposing the rock to the surface.