Global Perspectives and Local Landscapes · 6th Year · The Dynamic Earth: Rocks and Mountains · Autumn Term

Glacial Landforms: Valleys and Drumlins

Studying specific landforms created by glacial erosion and deposition, such as U-shaped valleys, corries, and drumlins.

• NCCA Curriculum Specifications
• NCCA: Primary - Natural Environments
• NCCA: Primary - Local Studies

About This Topic

Glacial landforms reveal the dramatic impact of ice ages on Earth's surface. Erosion by glaciers produces U-shaped valleys through abrasion and plucking, creating wide, flat floors and steep sides, while corries form as ice hollows out cirque basins on mountainsides. Deposition occurs when melting ice drops debris, forming drumlins, which are elongated, teardrop-shaped hills aligned with former ice flow. In Ireland, these features dominate landscapes, from the U-shaped valleys of Gap of Dunloe in Kerry to drumlins across the midlands.

This topic fits the Dynamic Earth unit by linking rock cycles, plate tectonics, and surface processes. Students differentiate erosion from deposition, analyze Irish topography using maps and photos, and construct models to show ice movement. Key questions guide inquiry: how did glaciers shape local valleys and hills? Such study fosters geological time scales and evidence-based reasoning, essential for NCCA Natural Environments and Local Studies standards.

Active learning suits this topic well. Hands-on modeling with clay or ice trays lets students manipulate variables like ice pressure, making invisible past processes visible. Field sketches or virtual tours of Irish sites connect abstract concepts to familiar places, boosting retention and spatial skills through collaboration.

Key Questions

1. Differentiate between landforms created by glacial erosion and those created by deposition.
2. Analyze how the movement of ice shaped the valleys and hills of Ireland.
3. Construct a model illustrating the formation of a specific glacial landform.

Learning Objectives

• Compare and contrast landforms created by glacial erosion (e.g., U-shaped valleys, corries) with those created by glacial deposition (e.g., drumlins).
• Analyze aerial photographs and topographical maps of Irish landscapes to identify and explain the formation of specific glacial features.
• Construct a physical or digital model that accurately illustrates the process of drumlin formation, including key elements like ice flow direction and till deposition.
• Explain how the immense power and movement of past glaciers significantly shaped the topography of Ireland, referencing specific examples.

Before You Start

Earth's Internal Structure and Plate Tectonics

Why: Understanding how geological forces shape the Earth's surface provides context for the large-scale processes that create mountains where glaciers form.

Weathering and Erosion

Why: Students need a foundational understanding of how natural forces break down and transport rock and soil to differentiate glacial erosion from other forms.

Introduction to Rocks and Minerals

Why: Knowledge of different rock types helps students understand the materials glaciers erode and transport, and the composition of glacial deposits.

Key Vocabulary

Glacial Erosion	The process by which glaciers wear away rock and land through scraping (abrasion) and picking up rock fragments (plucking).
Glacial Deposition	The process by which glaciers drop or deposit the sediment and rock they have carried, often forming distinct landforms.
U-shaped Valley	A long, wide valley with steep sides and a flat floor, carved by the erosive action of a glacier moving through a pre-existing river valley.
Corrie	A bowl-shaped hollow or basin, often found on the side of mountains, formed by glacial erosion and the freeze-thaw action of ice.
Drumlin	An elongated, teardrop-shaped hill formed by glacial deposition, with the steeper, blunter end facing the direction from which the ice advanced.
Till	Unsorted glacial sediment deposited directly by melting ice, often containing a mixture of clay, sand, gravel, and boulders.

Watch Out for These Misconceptions

Common Misconception

All U-shaped valleys form from rivers.

What to Teach Instead

Rivers create V-shaped valleys through downcutting, but glaciers widen and deepen to U-shapes via side abrasion. Model-building activities let students test both processes side-by-side, revealing shape differences through direct comparison and measurement.

Common Misconception

Drumlins are natural hills unrelated to ice.

What to Teach Instead

Drumlins form from glacial till molded by moving ice, showing streamlined shapes. Map mapping in groups helps students trace alignments to ice flow, correcting random hill ideas via pattern recognition.

Common Misconception

Glaciers erode uniformly without direction.

What to Teach Instead

Erosion follows ice flow, plucking upstream and abrading downstream. Simulations with directed ice blocks demonstrate this, as peer observation clarifies directional effects missed in static diagrams.

Active Learning Ideas

Modeling Station: U-Shaped Valley Formation

Provide trays with sand and plasticine for valley bases. Students push wooden blocks wrapped in sandpaper to simulate glacial abrasion, observing valley widening. Compare to river models using water flow, then sketch changes.

45 min·Small Groups

Map Analysis: Irish Drumlins

Distribute OS maps of County Monaghan drumlin fields. Pairs identify shapes, orientations, and flow directions using keys. Discuss deposition evidence in small groups, creating annotated overlays.

30 min·Pairs

Whole Class: Corrie Diorama Build

Project images of Irish corries like Corrie na Cró in Donegal. Class divides into teams to build layered dioramas with foil for ice and clay for rock. Present formation sequences.

50 min·Small Groups

Individual: Erosion vs Deposition Sort

Prepare cards with landform images and processes. Students sort into erosion or deposition categories, justify with notes from readings. Share in plenary.

20 min·Individual

Real-World Connections

• Geologists and geomorphologists study glacial landforms to understand past climate change and predict future landscape evolution. For example, they analyze features in the Wicklow Mountains to reconstruct glacial history and inform conservation efforts.
• Tourism operators in areas like Killarney National Park utilize the dramatic glacial landscapes, such as U-shaped valleys and corries, to attract visitors interested in hiking and scenic beauty, directly linking geological features to economic activity.
• Civil engineers consider the presence of glacial deposits, like till, when planning infrastructure projects such as roads and buildings in areas like the Irish midlands, as the material's stability and water-holding capacity affect construction methods.

Assessment Ideas

Exit Ticket

Provide students with two images: one of a U-shaped valley and one of a drumlin. Ask them to write one sentence explaining whether each landform was primarily created by erosion or deposition, and one key characteristic of each.

Quick Check

Display a topographical map of a region in Ireland known for glacial features. Ask students to identify at least two potential glacial landforms (e.g., a valley that appears U-shaped, a cluster of drumlins) and briefly justify their choices based on map symbols and contours.

Discussion Prompt

Pose the question: 'Imagine you are explaining drumlins to someone who has never seen one. How would you describe their shape, how they formed, and their relationship to the ice that created them?' Facilitate a class discussion where students share their explanations, encouraging peer feedback on clarity and accuracy.

Frequently Asked Questions

How do Irish landscapes show glacial landforms?

Ireland's last ice age left clear traces: U-shaped valleys in Kerry's Reeks, corries in Wicklow, and drumlin swarms in the midlands like Lough Neagh basin. Use Ordnance Survey maps and Google Earth for students to trace ice flow paths, linking local studies to global ice ages. This builds pride in Ireland's geology.

What is the difference between glacial erosion and deposition?

Erosion carves landforms like U-valleys and corries by abrasion and plucking; deposition builds drumlins and moraines from dropped till. Teach via dual models: erode clay with tools, then pile debris. Students grasp contrasts through tactile creation and side-by-side analysis.

How can active learning help teach glacial landforms?

Active methods like building ice-push models or mapping local sites make ancient processes concrete. Students in small groups experiment with variables, discuss observations, and refine models, deepening understanding over passive reading. Irish field sketches connect global concepts to home, enhancing engagement and memory.

What models work best for drumlins?

Use wet sand or dough pushed by a board to form teardrop shapes, mimicking subglacial flow. Students measure lengths, note orientations, and compare to Irish photos. This 20-minute individual or pair task clarifies deposition dynamics, with class shares reinforcing evidence links.