scioly
Here’s the combined set of flashcards, incorporating all the details and definitions:
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Flashcard 1
**Q:** How do glaciers affect climate?
A: Glaciers reflect sunlight due to their high albedo (the amount of sunlight reflected by a surface), cooling the Earth. When glaciers melt, less sunlight is reflected, leading to warming. Example: The melting of the Arctic ice cap reduces albedo, contributing to global warming and altering weather patterns.
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Flashcard 2
**Q:** What are the key phases of glaciers?
A:
1. Accumulation Phase: Glacier gains mass from snowfall. Example: The Greenland Ice Sheet grows during cold periods.
2. Ablation Phase: Glacier loses mass through melting, sublimation (the process where ice changes directly into vapor), and calving (when chunks of ice break off into the ocean). Example: Glacier National Park's glaciers have been shrinking due to increased ablation.
3. Advance and Retreat: Depending on the balance, glaciers either advance or retreat. Example: The Hubbard Glacier in Alaska is currently advancing.
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Flashcard 3
**Q:** What are isostatic effects on the lithosphere?
A: The lithosphere (the rigid outer layer of the Earth) sinks under the weight of growing glaciers (**isostatic depression**) and rises when glaciers melt (**isostatic rebound**), affecting landscape features like raised beaches and sea levels. Example: The land in Scandinavia is still rising today after the last Ice Age due to isostatic rebound.
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Flashcard 4
**Q:** What are the types of glaciers?
A:
1. Alpine (Valley) Glaciers: Found in mountains, flow down valleys. Example: The Franz Josef Glacier in New Zealand.
2. Ice Sheets: Massive, continent-sized glaciers (e.g., Antarctica). Example: The Antarctic Ice Sheet, covering 98% of the continent.
3. Ice Caps: Dome-shaped, smaller than ice sheets, cover mountain regions. Example: The Vatnajökull Ice Cap in Iceland.
4. Piedmont Glaciers: Spread out onto plains at the base of mountains. Example: The Malaspina Glacier in Alaska.
5. Tidewater Glaciers: Flow into the ocean, often forming icebergs. Example: The Columbia Glacier in Alaska.
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Flashcard 5
**Q:** How can you analyze USGS topographical maps?
A: By interpreting contour lines (lines on a map that connect points of equal elevation), elevation, and symbols to identify glacial features like moraines (ridges of debris left by glaciers), U-shaped valleys, and drumlins (elongated hills formed by glacial movement). Example: A USGS topographical map of Yosemite National Park shows U-shaped valleys formed by glaciers.
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Flashcard 6
**Q:** What theories explain the advancement and retreat of glaciers?
A:
1. Milankovitch Cycles: Changes in Earth's orbit and tilt. Example: The timing of Ice Ages has been linked to these cycles.
- Eccentricity: Changes in the shape of Earth's orbit (100,000-year cycle).
- Obliquity: Changes in the tilt of Earth's axis (41,000-year cycle).
- Precession: Wobble in Earth's axis (26,000-year cycle).
2. Atmospheric Composition: Variations in greenhouse gases (gases that trap heat in the atmosphere, like CO2). Example: High levels of CO2 are associated with warmer interglacial periods.
3. Volcanic Activity: Large eruptions can cause short-term cooling, leading to glacial advance. Example: The eruption of Mount Tambora in 1815 led to "The Year Without a Summer," contributing to glacier advance.
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Flashcard 7
**Q:** What is glacial history?
A: The study of past glaciations (periods when large areas were covered by glaciers), such as the Last Glacial Maximum (~20,000 years ago), using geological evidence to understand glacial impacts and predict future changes. Example: The study of the Laurentide Ice Sheet that once covered much of North America provides insights into glacial history.
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Flashcard 8
**Q:** How do glaciers shape the landscape?
A:
1. Erosional Features: Create U-shaped valleys, fjords, cirques (amphitheater-like hollows carved by glaciers). Example: Yosemite Valley in California is a U-shaped valley formed by glacial erosion.
2. Depositional Features: Form moraines, drumlins, eskers (long, winding ridges formed by streams under glaciers). Example: Long Island in New York is made up of terminal moraines.
3. Glacial Lakes: Formed by retreating glaciers leaving depressions that fill with water. Example: The Great Lakes in North America were formed by glacial activity.
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Flashcard 9
**Q:** What are kettle lakes** and how do they form?**
**A:** Kettle lakes are formed when blocks of ice left behind by a retreating glacier melt, leaving depressions that fill with water. Example: Walden Pond in Massachusetts is a kettle lake.
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Flashcard 10
**Q:** What are eskers** and how are they formed?**
**A:** Eskers are long, winding ridges formed by streams of meltwater flowing beneath a glacier, depositing sediment in a pattern that persists even after the glacier has retreated.
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Flashcard 11
**Q:** What are drumlins** and how are they formed?**
**A:** Drumlins are streamlined, elongated hills formed beneath glaciers. Their shape and orientation indicate the direction of the glacier's movement.
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Flashcard 12
**Q:** What is sublimation** and in what context does it occur with glaciers?**
**A:** Sublimation is the process where ice changes directly into vapor without first becoming liquid water. It occurs in glaciers, especially in arid or windy conditions. Calving refers to chunks of ice breaking off from the edge of a glacier and falling into the water, forming icebergs. Both processes contribute to ablation (loss of glacier mass).
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Flashcard 13
**Q:** What is albedo** and how does it affect climate?**
**A:** Albedo refers to the amount of sunlight reflected by a surface. Glaciers have high albedo, meaning they reflect a lot of sunlight. As glaciers melt due to climate change, less sunlight is reflected, leading to increased warming of the planet.
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Flashcard 14
**Q:** What are moraines** and how are they formed?**
**A:** Moraines are ridges of debris and sediment left behind by glaciers as they move and transport rock and other materials. These ridges form at the edges or along the path of the glacier.
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Flashcard 15
**Q:** What are U-shaped valleys** and how are they formed?**
**A:** U-shaped valleys are valleys with a distinct U-shape caused by glaciers carving the valleys through erosion.
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Feel free to ask for more details or additional questions if you need further clarification!