geology

Home » Climate Change » Yosemite Glaciers


Glaciers in Yosemite: Lyell Glacier and Maclure Glacier




Ice Age Glaciation of Yosemite Valley



Glaciers played a major role in determining the landscape and features of Yosemite National Park. During the Great Ice Age portions of the Park were covered by glacial advances at least three times. These glaciers, along with stream erosion and mechanical weathering, deepened Yosemite Valley, widened it and produced the extremely steep valley walls.


Hanging Valleys and Waterfalls



During the time of maximum glacial advance a large trunk glacier filled Yosemite Valley. Smaller tributary glaciers flowed down adjacent valleys and merged into the trunk. When the glaciers retreated the trunk glacier had cut a much deeper valley than the tributary glaciers, forming hanging valleys where the tributary glaciers joined the trunk. Today waterfalls such as Yosemite Falls and Bridalveil Falls mark the mouths of these hanging valleys.


Moraines and Lake Yosemite



The glacial retreat also left a terminal moraine that created a dam across Yosemite Valley. A large lake known as Lake Yosemite formed behind that dam. Meltwater washed millions of tons of rock, sand and mud into the lake, filling it in some places with over 1000 feet of glacial sediment. Today those sediments underlie the flat floor of Yosemite Valley.


Smaller Glacial Features



Today in the higher portions of Yosemite National Park small-scale evidence of Ice Age glaciers can still be seen. Groves and scratches in the Valley's bedrock, known as "striations" are evidence that glaciers scoured and gouged their way through the valley. And, rocks different from the Yosemite bedrock can be found. These out-of-place rocks, known as "erratics," were transported by glacial ice from areas outside the park but they are now left as evidence that a glacier passed through.

Video:   Rockfall Hazards in Yosemite

Two Glaciers Remain



Today, at the highest elevations in the Park (over 12,000 feet above sea level), two glaciers, Lyell Glacier and Maclure Glacier, are still active. These glaciers are small and slowly retreating as climate change warms their environment. They are expected to last just a few more decades.

Very few visitors see Lyell and Maclure Glaciers because long strenuous hikes are required to reach their high elevations. Crevasses, boulder fields and slippery ice make them dangerous places to visit. However, you can visit these glaciers easily today by viewing the video at the top right column of this page.

Contributor:

Photos:   Spectacular Photos of a Yosemite Rockfall



Find it on Geology.com




More from Geology.com


Sea Level Rise Map
Sea Level Rise Map: A Google map that shows where flooding will occur as sea level rises.
Diamonds from Coal
Biggest Misconception: Lots of people think that diamonds form from coal. Not True!
Great Rift Valley
The East Africa Rift System: Learn about the complex East Africa Rift Valley system.
Diamonds
Diamonds: Learn about the properties of diamond, its many uses and diamond discoveries.
Gemstones
Gemstones: Fantastic images and articles about colored stones and diamonds.
Expansive Soil
Expansive Soil: Causes more damage than floods, hurricanes & tornadoes combined.
Meteorites
Meteorites - Rocks that were once parts of planets or large asteroids.
Frac Sand
Frac Sand: The amount of frac sand produced in the USA is up by over 300% since 2009.


Visit Lyell and Maclure Glaciers, located at the highest points in Yosemite National Park. These glaciers are still active but slowly retreating as climate change warms their environment. They are expected to last a few more decades until they melt away completely. Video supplied by the Yosemite Conservancy and Yosemite National Park.




Yosemite glaciers
Topographic map of the area surrounding Lyell and Maclure Glaciers in Yosemite National Park. Map provided by MyTopo.com. Larger Printable Map


Diamonds Don't Form From Coal
Largest Oil Spills Map
San Andreas Fault
Igneous, Metamorphic, and Sedimentary Rocks
The Only Diamond Mine in the USA
Marcellus Shale
What is Geology?
Articles About Volcanoes



© 2005-2016 Geology.com. All Rights Reserved.
Images, code, and content on this website are property of Geology.com and are protected by copyright law.
Geology.com does not grant permission for any use, republication, or redistribution.
Images, code and content owned by others are marked on the pages where they appear.