Yosemite granites cooled miles beneath
the earth's surface as early as 100 million years ago. As
tectonic forces uplifted the Sierra Nevada, powerful rivers
and creeks cut Yosemite's canyons and valleys, carving the
landscape into V-shaped canyons.
(10 to 3 million years ago) |
As the climate cooled, a series of
glaciers entered river-carved valleys-plucking, polishing,
and transporting rocks. The largest glaciers filled Yosemite
Valley almost to the top of Half Dome.
(3 million to 20,000 years ago) |
Repeated glaciations eroded valleys,
steepened granite walls, and sculpted many of the dramatic
landforms we see today.
(3 million to 20,000
years ago) |
As the last major glacier melted and
receded, Yosemite Valley filled with water and sediment,
turning the Valley floor into a shallow lake. The lake
eventually filled with sediment, creating a flat valley
floor.
(20,000 to 10,000 years
ago) |
The
extensive work of glaciers is visible throughout the park.
Waterfalls leap from hanging valleys, Rockfalls from the
glacially-steepened cliffs widen the Valley.
(10,000 years ago to
present) |