Draining the southern slopes of the “Fourteener” Mt. Princeton, Chalk Creek tumbles over a high ledge of rock known as quartz monzonite, to form this beautiful little waterfall. The bright gray-white color of the mountain’s dominant rock formation, especially on sunlit cliffs seen from a distance, superficially resembles the sedimentary limestone type known as chalk. That gave the creek its geologically incorrect name. Both rocks contain a lot of calcium (calcite deposited by hot mineral water, in this instance), but they formed vastly differently! Mt. Princeton instead is an exposed pluton, a large mass that started as molten, igneous rock, then cooled and solidified underground about 35 million years ago, before faulting and erosion lifted and exposed it. A little more than three years after this shot, a massive rockfall, containing boulders the size of cars, killed five hikers on this trail.
8 WSW Nathrop CO (21 Jul 10) Looking NE
38.72, -106.2348Agnes Vaille Falls
Draining the southern slopes of the “Fourteener” Mt. Princeton, Chalk Creek tumbles over a high ledge of rock known as quartz monzonite, to form this beautiful little waterfall. The bright gray-white color of the mountain’s dominant rock formation, especially on sunlit cliffs seen from a distance, superficially resembles the sedimentary limestone type known as chalk. That gave the creek its geologically incorrect name. Both rocks contain a lot of calcium (calcite deposited by hot mineral water, in this instance), but they formed vastly differently! Mt. Princeton instead is an exposed pluton, a large mass that started as molten, igneous rock, then cooled and solidified underground about 35 million years ago, before faulting and erosion lifted and exposed it. A little more than three years after this shot, a massive rockfall, containing boulders the size of cars, killed five hikers on this trail.
8 WSW Nathrop CO (21 Jul 10) Looking NE
38.72, -106.2348