One of nature's most powerful and influential forces is also one of nature's coldest and slowest processes. These great icy rivers are called glaciers and have formed some of the most beautiful scenery on this planet. These enormous frozen bodies of water are often thousands of feet wide and deep and many miles long. They cover millions of acres of land and drastically change the land into beautiful mountains with many amazing features. One of the areas where glaciers have been most influential is in Yosemite National Park in California. Here almost every glacial feature is shown. However, before this information about glaciers in Yosemite was clear, there was the Yosemite Controversy with
In the 1920’s, geologist J. Harlen Bretz challenged the current concept of how various geological formations happened. At the time, geologists believed in uniformitarianism, which meant that geologic change in the past resulted from the same slow, steady processes at work today.
As this river of ice moved slowly over the hidden rocks, the base of the glacier grazed millions of sediments in the Earth. The after math composed of soil, pebbles, cobbles and boulders that pushed forward, smashing rocks into glacial dust. Then the climate began to warm. Melted water from the glaciers carried the soils and rocks away from the dissolving glacier, depositing its leftovers throughout the landscape. This combination of soils and rocks deposited. Then low hills, or moraines, were created across the state. Michigan's glacial drift averages 200 to 300 feet. The scraping of boulders created particles. The heaviest pieces formed ridges, which made the stream's flow in a certain direction. Lighter materials were carried further, dropping on the way as the flowing water slowed. These materials dried forming enormous, flat colored areas of sand, silt, clay creating a mixture called the outwash plains. The weight of the glacier over the Michigan basin was dropping, and the Earth began to recoil, like a sponge coming back to its original shape. The Michigan landscape began to appear. Plants began to approach on the shriveled landscape. Individual plants found a suitable growing environment near each other, which created a suitable home for
Glacier National Park, located in Northwestern Montana, is an astounding spectacle of history and beauty. Not simply just the history of the Native Americans and European-descended settlers that call the area their home, but also the geologic history of the Earth. The region is known for the beautiful scenery that can be seen from anywhere in the park. Large, steep mountains rise out of deep, lake-filled valleys and thick conifer forests open up into grassy, flower filled meadows. The park is also home to a wide variety of plants and animals. Grizzly bears and mountain goats wander through the forests and rocky cliffs while beargrass flowers light up meadows and evergreens rise high above the valleys below. It is for this beauty and scenery that the region was designated a national park for people to enjoy.
Till is a mixture of many different sediment sizes all mashed together. Till is usually located on the sides and the end of a glacier. If a glacier makes enough till it can be called a moraine. A moraine is a large ridge of till that could stretch counties to states long. One common moraine is the Mille Lacs/Right/Cromwell/Highland moraine. Another feature made from till is a drumlin, a drumlin is a hill of till that faces the direction that a glacier came. Two drumlin fields are the Pierz and Toimi drumlins. When glaciers melt they leave behind kettle lakes. The kettle lakes are often formed in the depressions that the glacier made and then melted in. The kettle lakes are most common in northwestern Minnesota.
Erosion is a process where natural forces like water, wind, ice, and gravity wear away rocks and soil. Erosion occurs at the Earth’s surface, and has no effect on the Earth’s mantle and core. Water erosion is the removal of soil particles by heavy rainfall or running water. “While the causes of erosion by water are generally natural, water erosion is usually caused by rainfall and runoff on a slope” (GEI Works Erosion Pollution). “The process of water erosion usually occurs on stream and river banks, sea shores and seaside cliffs” (Reference.com).
Glaciers also left us many moraines in the state of Michigan. Moraines are land masses where debris, carried by glaciers has formed ridges or mounds. Moraines can be an indicator of the end of a large glacial retreat. Moraines are created by the wasting ice sheet and are composed of glacial till. Glacial till (unsorted glacial sediment) is laid down quickly as the glacier moves and is composed of various sediments with many rocks and stones. In Michigan there are many famous moraines. As the lucky residents of Marquette we can look out our windows and see evidence of glaciers because of all of our rolling hills. Rolling landforms are a typifying aspect of a moraine.
Roughly 2.4 million years ago, the Ice Age began on Earth. Over time, the thick snowpack that had accumulated in the Sierra Nevada due to cooled temperatures compacted into giant sheets of ice. These ice sheets became glaciers when they were set into motion due to the pressure of their own weight. The glaciers cleared everything that came in their path including boulders, soil, and trees; everything but the bedrock, which was instead smoothed out, was completely stripped. As global temperatures fluctuated over the years, the glaciers have advanced and retreated multiple
Much of Michigan’s landforms can be traced to the Pleistocene period, which lasted until around 10,000 years ago. Of the four periods of glacial movements in the Pleistocene period, the Nebraskan, Kansan, Illinoian and Wisconsin, the Wisconsin Glaciation is the most prominent cause of the current Michigan landscape in the Upper Peninsula and Lower Peninsula (Damery, 2001). The Wisconsin Glaciation occurred about 100,000 years ago. The climate cooled, and the Laurentide Ice Sheet was spread across the continent. About 31,500 years ago, this glacier began to approach Wisconsin. The Laurentide Ice Sheet expanded in the area that today is Wisconsin and Michigan, for 13,500 years before the ice began to melt and retreat. As this ice sheet moved south, valleys were filled in, the drainage systems of rivers were blocked, and major basins that are now the Great Lakes were gouged. The graphic below shows the land that the Laurentide glacier
Although it may not feel like it, we are currently in an ice age today. An ice age is just a period of time when the Earth’s climate faces a constant and drastic decrease in temperature. Periods of colder temperature during an ice age have been called "glaciations" because they result in something being covered by glaciers or ice sheets. Shorter-term, irregular intervals of warmer temperatures have been called "interglacials", which is what we are currently living in today. However, some scientists believe that the climate may dramatically decrease in the near future, and we could see glaciers return again like we did in the last glacial period. This last glacial period is referred to as “The Ice Age.” It was the most recent glacial period within our current ice age occurring in the
One major way Connecticut got its shape was from glaciation. For example, glaciation formed Jobs Pond. Jobs Pond is a giant kettle hole, which is a depression caused by the impact of a massive chunk of ice, or a glacier. According to The Mystery Of Jobs Pond, geologists and hydrologists the water level rises and falls with the groundwater level in the area, because porous sand and gravel make up the bottom of the pond. A kettle hole is formed by a glacier, so glaciation formed Jobs Pond. Another landscape formed by glaciation is recessional moraines. A recessional moraine is a pile of rocks left behind when a glacier recedes, or moves back. As a glacier moves, it picks up rocks in a process called plucking. Then, as the glacier starts to melt, it recedes. As it does this it drops off rocks, forming a recessional moraine. Recessional moraines, formed from glaciation, are found all along the Connecticut shoreline.
and come apart and allow for countless sheets of lava to be transferred out over the land (Hay, 1992). Through time the ice caps frequently collected and spread over enormous extents in North America. In this timeframe, movements to the south would occur making the ice push and relocate expansive quantities of soils and rocks. This movement effected how the great glacial streams would flow (Hay, 1992). With the extremely large rains and glacial ice melting valleys and flooding played a great role in the Pleistocene.
Earth has experienced many episodes of dramatic climate changes with different periods in earth history. There have been periods during which the entire planet has been covered in ice and at another time it has been scorchingly hot and dry. In this regards, earth has experienced at least three major periods of long- term frigid climate and ice ages interspersed with periods of warm climate. The last glacial period which current glaciers are the result of it, occurring during the last years of Pleistocene, from approximately 110,000 to 10,000 years age (Clayton, 1997). Indeed, glaciers present sensitive indicators of climate change and global warming and by estimating and monitoring the dynamic evolution of these ice masses, several
Glaciers are one of the most fundamental phenomenon on the planet, and much of their purpose and impact on earth has been well documented and published. Ice sheets, Ice Caps and Glaciers trap nearly 90% of the world's fresh water, and are replenished by snowfall each year. Their existence on this planet dates back 650,000,000 years and yet they are always moving, always shifting and always melting. Before, human existence and even during the brief era of humans, ice dominated all of the earth's landmass and have regulated, created and altered many of the landscapes around the world.