GPCirque

Guanella Pass Cirque

To Get There: Guanella Pass can be reached in one of two ways. From the south, you take the small road (Park County Road 62) out of Grant north off 285. From the north, you take FR381 south from Georgetown. My preference, simply because of where I live is to drive up via Grant. The road varies considerably from relatively good paved to half washed out/landslide damaged dirt. Depending on the time of year and whether the road crews have been out, the road can be an easy drive to one needing (or at least wanting some) 4-wheel help. Generally its fine.
	At the pass, which is 11,669', you are faced with the dilemma of whether to walk over to east toward Mt. Bierstadt and several other interesting peaks or west to the cirque. On this occasion we will go west.
The trail (South Park Trail) is a fairly easy walk unless you are not use to the elevation. It is rocky in some places, moderately steep in a few, but doable for most everyone. Walking toward the cirque, you go past lots of wildflowers (depending on the time of year), scattered rocks (metamorphics and pegmatites), and occasionally some wildlife.

Two small ponds about 1 mile back. Occasionally they may dry up as the one on the right did.	Several large rock slides are present as you get near the cirque.
Depending on the time of year, snow may be present and make finding the trail or staying on it difficult as you can see.	Where is the trail? It was here a second ago!
As you approach the cirque, you will find two good size lakes referred to on the topographic maps are Square-Top Lakes. These lakes were formed as the glacier which occupied this cirque retreated. This "chain" of lakes (hey, two can make a chain) are referred to as pater noster lakes.	Upper Lake
Lower Lake	Its hard to tell whether these rocks which "block" the flow of water which created the lakes are loose material (till) or in situ. Foliation of the metamorphics above are vertical and seem to be fairly uniform across this area suggesting that the rocks are in place.
Lower lake as seen from the upper lake.
The cirque is pretty classic. Bowl-shaped, steep walled depression carved out of rock by glacial action. No obvious scouring of the rocks were noted, however, the glacier may not have been very large. As you can see, there was still quite a bit of snow present even in June when these pictures were taken. We passed some skiers (perhaps crazier people than geologists) who were skiing down these snow fields stopping just short of the very, very cold water in the lake.	These "dams" that hold back the water to form these lakes are moraines (deposits of till left by the receding glacier).
porphyry	schist
June 29, 2001