Fluvioglacial Landscapes Flashcards
List 3 facts about fluvioglacial processes?
• Meltwater flows subglacially, englacially, or supraglacially.
• High-pressure meltwater can erode channels under the ice.
• Meltwater carries large amounts of sediment, often appearing cloudy.
How do glacial and fluvioglacial deposits differ in 4 ways?? (Mention 3 things)
- Glacial deposits = unstratified (un-layered) / fluvioglacial = stratified (layered).
- Glacial deposits = poorly sorted (into different particle sizes) / fluvioglacial deposits = well-sorted.
- Glacial deposits = random long-axis alignment / fluvioglacial deposits = dominant directions of alignment.
- Glacial deposits = little sign of grading (deposition by size - larger particles first) / fluvioglacial deposits = well-graded, with sediment being smaller with distance from the glacier.
What are eskers?
When subglacial, englacial or supraglacial river channels get filled with sediment.
What are kames and kame terraces?
• Kames: features produced at the edges of a glacier or ice sheet.
• Kame terraces: Where lots of kames occur together, they create ‘benches’ of deposits on valley sides
What are meltwater channels, and how do they form?
• Channels that follow the slope of the land and are often wide and braided.
• Meltwater channels are eroded by streams draining away from the ice margin.
What are kettle holes?
• small, often circular, lakes formed by the melting of ice blocks left by the retreating glacier.
What are proglacial lakes?
Lakes formed in front of an ice mass from meltwater.
What is a sandhur?
Large areas of sandy and pebbly material washed out of the ice by meltwater streams.
How do eskers form in 5 steps?
- Meltwater streams flow within or beneath glaciers, carrying sand and gravel.
- These streams deposit material in tunnels inside or under the ice.
- When the glacier melts, the sediment-filled tunnels are left behind as long, winding ridges — called eskers.
- Eskers can be over 100 m high and stretch for many kilometres.
- Supraglacial/englacial eskers are often flattened (beaded), while subglacial eskers tend to be more peaked.
How are kames formed in 4 steps?
- Meltwater streams on or beside a melting glacier carry sand and gravel.
- As the ice melts, this material is deposited in heaps along the glacier’s edge or surface.
- When the glacier fully melts away, it leaves behind irregular mounds of sediment.
- These mounds are called kames, and they often appear in groups, looking like cones or deltas.
How does a Sandhur form in 5 steps?
- Meltwater streams flow from the glacier’s snout, carrying sand, gravel, and silt.
- These streams braid and spread across the land, creating a wide, flat plain.
- Larger sediments are dropped near the glacier, while finer particles are carried further away.
- Deposits build up in layers, often with coarser material each spring due to increased meltwater.
- This forms a layered outwash plain called a sandur.
How are kettle holes formed in 3 steps?
- As a glacier retreats, it sometimes leaves behind isolated blocks of ice buried in outwash material.
- These ice blocks slowly melt, creating depressions in the ground.
- The depressions can fill with water, forming small, circular lakes called kettle holes.
