Worksheet on glacial landforms including cirques, arêtes, and pyramidal peaks.

Let's solve the task step by step based on the image you've provided.

---

Aim:

To describe and explain how erosion by glaciers creates Corries, Arêtes, and Pyramidal Peaks.

---

Starter Task:

You are asked to:
1. Define the key glacial mountain features.
2. Label them on the photograph.

We’ll go through both parts.

---

## 🔹 Step 1: Definitions (Complete the Worksheet)

Based on the information in the blue box:

✔ Arête

An arête is a knife-edge ridge formed when two neighbouring corries erode back-to-back. The glacier plucks and abrades the rock, leaving a sharp, narrow ridge between two corries.

> *Definition:* A sharp, narrow ridge of rock formed between two adjacent corries.

---

✔ Corrie (Cirque)

A corrie is a rounded, armchair-shaped hollow with a steep back wall on the side of a mountain. It forms when ice accumulates in a hollow and erodes the surrounding rock through freeze-thaw weathering and plucking.

> *Definition:* A bowl-shaped hollow on the side of a mountain, formed by glacial erosion, often containing a tarn.

---

✔ Pyramidal Peak

A pyramidal peak (also called a horns) is formed where three or more corries meet. As each corrie erodes its side, they converge at the top, creating a sharp, pyramid-like peak.

> *Definition:* A sharp, pointed mountain peak formed where three or more corries have eroded into a central point.

---

✔ Tarn

A tarn is a lake that forms in the bottom of a corrie after the glacier melts. It fills the depression left behind by glacial erosion.

> *Definition:* A small mountain lake located in the basin of a corrie.

---

## 🔹 Step 2: Label the Photograph

Now, let’s identify and label the features on the photo using the definitions.

From the image:

- Top right corner: This is likely an arête – a sharp ridge separating two corries.
- Left and right sides of the mountain: These are corries – bowl-shaped depressions with steep back walls.
- Center-top of the mountain: The pyramidal peak – the sharp summit formed by multiple corries.
- At the bottom of one corrie: A tarn – a small lake in the hollow.

📌 Labels:

1. Top right ridge → Arête
2. Left and right hollows → Corrie
3. Central peak → Pyramidal Peak
4. Lake in the bottom of a corrie → Tarn

---

## 🔹 How Glaciers Create These Features

🌍 Process of Glacial Erosion:

Glaciers move slowly downhill, carrying rocks and debris. They erode the landscape through:
- Plucking: Ice freezes into cracks, pulling out rock fragments.
- Abrasion: Rocks embedded in ice scrape against the bedrock.

---

🔹 Formation of Corries:

1. Snow accumulates in a hollow on a mountain side.
2. It compresses into ice, forming a glacier.
3. The glacier erodes the base and back wall via plucking and abrasion.
4. Freeze-thaw cycles weaken the rock.
5. Over time, the hollow deepens and becomes a corrie.
6. When the glacier melts, a tarn may form in the basin.

---

🔹 Formation of Arêtes:

1. Two corries develop on opposite sides of a ridge.
2. Each erodes back toward the center.
3. The remaining ridge becomes narrow and sharp → arête.

---

🔹 Formation of Pyramidal Peaks:

1. Three or more corries form around a central point.
2. Each erodes the mountain from different directions.
3. The convergence of these erosional processes creates a sharp, pyramid-shaped peak.
4. Famous examples: Mountaineer's Horn (e.g., the Matterhorn).

---

## ✔ Summary Table:

| Feature | Description | How it Forms |
|----------------|-----------------------------------------------------------------------------|------------------------------------------------------------------------------|
| Corrie | Bowl-shaped hollow with steep back wall | Glacier erodes snow-filled hollow; forms tarn when ice melts |
| Arête | Knife-edge ridge between two corries | Two corries erode back-to-back, leaving a sharp ridge |
| Pyramidal Peak | Sharp, pointed mountain peak | Three or more corries erode into a central point |
| Tarn | Lake in the bottom of a corrie | Melting glacier fills the eroded hollow |

---

## 🧩 Final Answer for Worksheet:

Definitions:

- Arête: A sharp, narrow ridge formed between two corries.
- Corrie: A bowl-shaped hollow on a mountain side, formed by glacial erosion.
- Pyramidal Peak: A sharp, pyramid-like peak formed where three or more corries meet.
- Tarn: A lake found in the bottom of a corrie.

Labels on Photo:

- Top ridge: Arête
- Hollows on sides: Corries
- Top peak: Pyramidal Peak
- Lake below: Tarn

---

✔ You’ve now completed the worksheet! This understanding helps explain how powerful glacial erosion shapes dramatic mountain landscapes.