What is Tarn?
You must have noticed or seen some lakes in the mountains which have been formed because of the melting of the glaciers. Lakes are generally found in any type of environment and all parts of the world. Here, in this article, we will be talking about a type of lake that is considered a small mountain lake or tarn. It is also known as Corrie loch. This article will help you to understand one of the types of lakes or one of the important geographical features. It will be helpful in Geography, Earth Sciences, Geology, Geomorphology and Physical Geography.
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Introduction
A body of water that is surrounded by land is called a lake. It is not a part of the ocean. Most of the lakes are browsed and drained by the rivers and streams. There are many lakes which are found in the world. They are found on every continent and in every type of environment. They are generally found in mountains, deserts, on plains, and near seashores. The still bodies of water are lake as compared to the river where the water flows. Lakes are generally deeper than ponds and have a large surface area. They can contain salt and freshwater. They are larger than the ponds.
There are different kinds of lakes found in the world. It is classified on the basis of its origin and mode of formation. The different kinds of lakes are organic lakes, volcanic lakes, glacial lakes, Tectonic lakes, fluvial lakes, Landslide lakes, Solution Lakes, Aeolian lakes, Shoreline lakes, Anthropogenic lakes, Meteorite lakes. Out of these, we came to know about the " Tarn" which is a type of glacial lake.
Formation of Lake
The lakes are formed by erosion. When the glaciers melted, water-filled the hollows, which formed the lake. Glaciers carved deep valleys and deposited high amounts of earth, pebbles and boulders as they melted. These materials sometimes formed dams that have water and formed more lakes.
Tarn Meaning
Tarn means a small mountain lake in a hollow area surrounded by steep slopes formed by a glacier. The word tarn comes from the old Norse tjorn which means "small mountain lake with no tributaries." It is a proglacial mountain lake which is formed in a cirque excavated by a glacier. It is found in corries which are the result of erosion of glaciers. After the glaciers have melted, it leaves behind circular hollows in the heads of the valleys up in the mountains. Such hollows are arm chaired shaped cirques and corries. The water collects on the floor of the cirques to form the tarn lakes. Both corries and tarns are typically located in higher topographies to match their glacial origins.
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Definition
The word tarn is derived from the old Norse word tjorn which means a small mountain lake with no tributaries. Tarn is a small mountain lake which is set in a glaciated steep-walled amphitheatre known as a cirque. A cirque is formed by ice and indicates the head of a glacier. Some of the cirques are so furbished that a lake formed in the base of the cirque after the ice has melted. These are called tarn.
"It is a small steep-banked mountain lake or pool." - Merriam-Webster
"It is a small mountain lake in a hollow area surrounded by steep slopes formed by a glacier." - Cambridge dictionary.
"A tarn is a small lake in an area of mountains." - Collins dictionary.
Features
There are some features of the tarn
Tarn is lakes that are formed in glacially carved cirques.
They are obstructed by moraines below a tarn.
Tarns are often full of tiny, glacially-ground sediment that pass the light and make the watercolour.
They are found in mountainous areas.
The highest tarns of the world are found in Snowdonia, Lake District and Scotland.
Examples
Some of the famous examples of tarn are mentioned below:
Lake Tear of the Clouds, Adirondack Mountains, New York.
Veľké Hincovo, a tarn in Slovakia
Lousy Lake (tarn) in North Cascades National Park, Washington, USA
Lakes of the Clouds, below Mount Washington in the White Mountains
Banderishka Chukar seen from the Banderishka Lakes (tarns), Pirin Mountain, Bulgaria
Gergiysko lake (tarn), Pirin Mountain, Bulgaria
The Dreadful Lake (tarn), Rila Mountain, Bulgaria
The Seven Rila Lakes (tarns), Rila Mountain, Bulgaria
Marichini lakes (tarns), Rila Mountain, Bulgaria
Sea Lion Tarn on Livingston Island in Antarctica
Conclusion
To conclude, we can say that tarn is nothing but a type of small mountain lake which is surrounded by steep slopes that are formed by a glacier. The word tarn comes from the old Norse tjorn which means "small mountain lake with no tributaries." It is a proglacial mountain which is formed in a circle and excavated by glaciers. A bowl-shaped feature in the centre of the glacier is called cirque which is formed by ice and indicates the head of the mountains. Here, we have learned tarn meaning, definition, basics of lakes or formation of lakes, famous examples of the tarn, etc. All these things will help you to learn one of the important geographical features of the Earth.
FAQs on Tarn
1. What exactly is a tarn in the context of geography?
In geography, a tarn is a specific type of mountain lake that forms in a cirque, which is an amphitheatre-shaped basin excavated at the head of a glacial valley. These lakes are direct results of glacial erosion and are typically found at high altitudes where glaciers once existed or still exist.
2. How is a tarn formed through glacial action?
A tarn is formed in a multi-step process driven by glaciers:
- Plucking and Abrasion: A glacier at the head of a valley erodes a bowl-shaped depression called a cirque (or corrie) through processes of plucking (freezing onto rock and pulling it away) and abrasion (scraping the bedrock).
- Deepening of the Basin: The rotational movement of the glacier often deepens this basin.
- Melting and Filling: When the climate warms and the glacier melts and retreats, the meltwater gets trapped in the over-deepened cirque basin, forming a small, deep, and often circular lake—the tarn.
- Moraine Dam: Sometimes, a ridge of glacial debris (a moraine) deposited at the lip of the cirque can act as a natural dam, helping to hold the water in.
3. What is the main difference between a tarn and a regular lake?
The primary difference lies in their origin and location. A tarn is specifically a glacial lake that forms in a cirque in a mountainous area. In contrast, the term 'lake' is much more general and can describe any large body of inland water, formed by various geological processes such as tectonic activity, volcanic action, or river systems, and can be found at any elevation, not just in mountains.
4. How is the formation of a tarn directly related to a cirque?
A tarn cannot exist without a cirque. The cirque is the landform that provides the basin for the tarn to form in. Think of the cirque as the container and the tarn as the water it holds. The powerful erosional forces of the glacier that create the hollowed-out cirque are the essential first step. Without this bowl-shaped depression carved into the mountainside, there would be no place for meltwater to accumulate and form a tarn.
5. Why are tarns usually found only in high-altitude, mountainous regions?
Tarns are exclusively found in high-altitude mountains because their formation is dependent on alpine glaciers. These glaciers only form in environments where the temperature is low enough for snow to accumulate over many years and compact into ice. Such conditions—high snowfall and low temperatures—are characteristic of high-altitude mountain ranges. Therefore, the landforms created by these glaciers, including cirques and tarns, are signatures of past or present glaciated mountain environments.
6. Can you provide some examples of tarns in the Indian Himalayas?
Yes, the Indian Himalayas are home to numerous tarns, which are often significant pilgrimage sites or popular trekking destinations. Some well-known examples include:
- Roopkund Lake in Uttarakhand, famous for the human skeletons found at its bottom.
- Suraj Tal in Himachal Pradesh, located near the Baralacha La pass.
- Chandratal Lake in the Spiti Valley of Himachal Pradesh.
- Gadsar Lake in Kashmir, part of the Kashmir Great Lakes Trek.
7. What happens to a tarn over a long geological period?
Over thousands of years, a tarn will gradually evolve and may eventually disappear. This happens through a process called sedimentation. Streams flowing into the tarn carry silt, sand, and organic matter, which slowly fill the basin from the bottom up. Eventually, the tarn can transform into a marsh, a bog, or a flat, grassy meadow known as a cirque meadow. This natural aging process illustrates that landforms, even lakes, are not permanent features but are constantly changing.
