Podcast
Questions and Answers
What natural event is particularly associated with Larsen B ice shelf's instability?
What significant change occurred to Larsen B between January 31 and March 7, 2002?
Which factor contributed to the collapse of Larsen B ice shelf?
What would be the potential impact of a complete melt of the Greenland Ice Sheet?
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Which part of the Antarctic Ice Sheets is known to contain the majority of the world's ice?
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How did the presence of meltwater affect the Larsen B ice shelf?
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What characterizes a niche glacier?
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What is the relationship between the North and South Patagonian Ice Fields during the Last Glacial Period?
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What is diamictite primarily composed of?
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Which process primarily creates features associated with glacial landscapes?
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What is the average thickness of the Greenland Ice Sheet?
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What distinguishes a drumlin from other glacial formations?
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How are dropstones formed?
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What term refers to all sedimentary deposits of glacial origin?
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What do glacial erratics indicate?
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What type of sedimentary rock forms from till or moraines in glacial contexts?
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What primarily characterizes an outwash plain?
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What distinguishes a U-shaped valley from a V-shaped valley?
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What are striations in the context of glacial activity?
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Which of the following best describes a roche moutonnée?
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What is the primary method of sediment transport in ice rafting?
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Which process involves the glacier freezing onto valley sides and pulling away rock?
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What does the term 'entrainment' refer to in glacial processes?
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How are whalebacks similar to roche moutonnée?
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What characterizes ice streams within ice caps and ice sheets?
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Which of the following best describes a tidewater glacier?
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What is the main distinction between ice caps and ice sheets?
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What role do ice shelves play in relation to outlet glaciers?
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What distinguishes a distributary glacier from a tributary glacier?
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Which of the following statements is true regarding hanging glaciers?
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What common feature is associated with tidewater glaciers?
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What happens to an ice shelf that undergoes significant melting?
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What event is associated with the initiation of the Huronian glaciation?
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Which gas was primarily oxidized after the Great Oxygenation Event, contributing to a cooler climate?
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What is one proposed cause for the end of the Huronian glaciation?
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Which type of climate condition is more likely to have occurred during the Marinoan glaciation?
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What phenomenon is described by the term 'Snowball Earth'?
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What contributes to the cyclical nature of glaciation periods during the Huronian glaciation?
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How did the Great Oxygenation Event affect life forms on Earth at the time?
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Which glaciation is more likely considered less extensive despite lasting longer?
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Study Notes
Glacial Events and Phenomena
- Jökulhlaups are glacial outburst floods triggered by volcanic activity.
- Larsen B, an ice shelf previously stable for millennia, collapsed between January and March 2002, losing approximately 3,250 square kilometers of ice.
- Post-collapse, parts of Larsen B rapidly vanished due to warm water currents eroding its underside, making it unstable since at least 1995.
- The 2002 collapse was exacerbated by meltwater pooling in cracks, which further advanced the disintegration.
Ice Fields and Sheets
- The North and South Patagonian Ice Fields are among the largest globally, situated in the Andes of Argentina and Chile; the South Patagonian is larger.
- During the Last Glacial Period, the two ice fields merged, covering almost all of southern Chile.
- Greenland Ice Sheet, covering about 80% of Greenland, is the second largest after Antarctic Ice Sheet; a complete melt could raise sea levels by 7-8 meters.
- The East Antarctic Ice Sheet contains about 4/5ths of the world's ice and is nine times larger than the West Antarctic Ice Sheet.
Glacier Types
- Ice sheets (>50,000 sq.km) and ice caps are both classified as continental glaciers.
- Ice streams exhibit increased flow rates (500-1000 meters/year), crucial for the mass balance of glaciers.
- Tidewater glaciers terminate in water, calving into icebergs; ice tongues rapidly extend into the sea.
- Ice shelves form from glaciers flowing into oceans, influencing the stability and mass balance of outlet glaciers.
Glacial Geology
- Glacial deposition creates unique geological features through processes including erosion and sediment transport.
- Diamictite is a sedimentary rock made from unsorted particles, commonly formed from glacial till.
- Drift encompasses all glacially-originated sediment, while dropstones result from icebergs depositing larger sediments into marine environments.
- Drumlins are streamlined hills formed by glacial movement, indicating the direction of flow.
Specific Features and Processes
- Roche moutonnée is a smooth hill formed by glacier action, often marked by striations that indicate glacial movement.
- U-shaped valleys, resulting from glacial erosion, contrast with V-shaped valleys formed by water.
- Entrainment describes the process of glaciers picking up loose material through basal ice freezing and ice rafting.
Historical Glaciation Events
- The Great Oxygenation Event led to significant glaciation, linked to the appearance of photosynthesizing cyanobacteria.
- The Huronian glaciation involved cyclical glacial and interglacial periods, likely influenced by volcanic activity.
- Cryogenian Snowball Earths were major glaciations where icy conditions covered most of the planet, with debate over the extent of glaciation during these periods.
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Description
This quiz explores the phenomenon of jökulhlaups, or glacial outburst floods, especially in the context of volcanic activity in Iceland. It also covers the significant events surrounding the collapse of the Larsen B ice shelf in Antarctica in 2002. Test your knowledge on these critical environmental changes and their implications.