What is the primary definition of a valley as a physical-geographic term?

A valley is defined as an elongated low area, typically situated between hills or mountains, which usually contains a river or stream flowing from one end to the other. This geological feature is characterized by its elongated shape and its position relative to surrounding higher terrain.

How are the majority of valleys formed according to the provided text?

Most valleys are formed through the process of erosion, specifically by rivers or streams gradually wearing away the land surface over very long periods. This continuous action of flowing water shapes the landscape, creating the characteristic low-lying areas we recognize as valleys.

Besides river erosion, what other natural process can form valleys?

Valleys can also be formed by the erosive power of glacial ice. These glacial valleys may still contain glaciers in high mountain or polar regions, or they may be ice-free remnants from past ice ages, now occupied by streams or rivers.

What are rift valleys and what is their primary cause?

Rift valleys are a distinct type of valley that primarily arises from tectonic activity, specifically the expansion or stretching of the Earth's crust. Unlike valleys formed by erosion, rift valleys are a direct result of geological earth movements.

What is the short description provided for a valley?

The article provides a concise description of a valley as a low area situated between hills, often containing a river running through it.

What are the three main processes that can contribute to the development of a valley over geological time?

The three primary processes contributing to valley formation are erosion by moving water (forming river valleys), erosion by glaciers (forming glacial valleys), and tectonic processes such as rifting. Often, these processes can interact and contribute to a valley's development over vast geological timescales.

What is the typical cross-sectional shape of a river valley compared to a glacial valley?

River valleys, formed by water erosion, typically exhibit a V-shaped cross-section. In contrast, valleys eroded by glaciers, known as glacial troughs, usually have a U-shaped cross-section with steeper sides.

What is referred to as the valley floor, and what may it contain?

The valley floor is the flat or relatively flat portion of a valley situated between its sides. This area is typically formed by sediments deposited by rivers and may feature fluvial terraces, which are remnants of former river levels.

What factors influence the development of a river valley?

The development of a river valley is influenced by several factors, including the type of bedrock the river flows over, the difference in elevation between the river's source and its mouth, and the prevailing climate conditions.

How does the river's flow and gradient change from its upper course to its lower course?

Typically, the flow of a river increases downstream, while the gradient, or steepness, decreases. This change affects the river's erosive power and sediment transport capabilities along its course.

What is corrasion, and what type of valley does it help create?

Corrasion is the process by which a stream erodes its bed, often by using rock material carried within the water. This process, particularly effective in the upper reaches of a river, helps to produce steep-sided, V-shaped valleys.

What geological features can influence a stream's course, leading to a winding path with interlocking spurs?

The course of a stream can be determined by resistant bands of rock, geological faults, fractures, and folds. These features can cause the river to take a twisting path, creating interlocking spurs that are later truncated by glacial erosion.

What processes occur in the middle section of a river's course, and what is a characteristic outcome?

In the middle valley, as numerous tributaries join the main river, the valley typically widens, and the water flow slows down. Both erosion and deposition occur, with lateral erosion on the outside of river bends and deposition on the inside, leading to the river developing a meandering pattern.

What characterizes the lower valley section of a river, and which process dominates?

The lower valley section is characterized by the lowest gradients and often much broader meanders, resulting in a wider floodplain. In this section, deposition of sediment generally dominates over erosion.

What is a drainage basin, and how does it relate to river valleys?

A drainage basin, also known as a river basin, is the area of land where all surface water converges to a single point, such as a river mouth or a lake. A typical drainage basin encompasses various types of valleys, from small tributary valleys to larger main valleys.

What terms are used to describe river valleys that have been incised very deeply?

When a river incises its course vertically to such an extent that the valley becomes extremely deep and narrow, it may be described as a gorge, ravine, or canyon.

What can cause rapid down-cutting in river valleys, leading to features like river terraces?

Rapid down-cutting in river valleys can be caused by localized uplift of the land surface or by the rejuvenation of the watercourse. Rejuvenation can occur, for example, due to a drop in global sea level during an ice age, which lowers the base level to which the river erodes.

What are true glacial valleys also known as, and what is their characteristic shape?

True glacial valleys are also referred to as glacial troughs. They are characteristically shaped by glaciers and typically possess a U-shaped cross-section, often with steep or even vertical sides and a relatively flat bottom.

What are cirques, and how do they relate to the formation of glacial valleys?

Cirques are armchair-shaped hollows found at the uppermost part of glacial valleys. They are excavated by the rotational movement of cirque glaciers, which are the initial formation points for glaciers that then extend downhill, shaping the larger valleys.

How did glaciers widen and deepen valleys during ice ages to create the characteristic U-shape?

During ice ages, glaciers widened and deepened valleys through abrasion. Rock material embedded within the moving glacial ice scraped against the valley sides and floor, carving out the distinctive U-shaped or trough-like form.

What are truncated spurs, and how do they relate to glacial valley formation?

Truncated spurs are remnants of interlocking spurs, which are features formed by river valleys. In glaciated mountain landscapes, glaciers erode these interlocking spurs, cutting them off and creating truncated spurs, which are characteristic of these environments.

What can form in glacial valleys due to differing erosion rates, and what might these features become?

Valley steps, also known as rock steps, can form in glacial valleys as a result of variations in the bedrock's hardness and the ice's erosive power. In some locations, these steps can lead to the excavation of rock basins, which may later fill with water to form ribbon lakes or become filled with sediment.

What is a misfit stream in the context of a glacial valley?

A misfit stream is a river or stream found within a glacial valley that appears smaller than would be expected given the size of the valley it occupies. This often occurs when a glacial valley, carved by a large glacier, is later occupied by a much smaller stream.

What are tunnel valleys, and how are they formed?

Tunnel valleys are large, long, U-shaped valleys that were originally cut beneath the ice near the margins of continental ice sheets. They were formed by subglacial water erosion, acting as pathways for large volumes of meltwater.

What are Urstromtälern, and how did they form in northern Central Europe?

Urstromtälern, or 'glacial meltwater valleys', are huge, flat valleys formed in northern Central Europe. They were created by glacial meltwaters flowing parallel to the ice margin during ice ages, as the Scandinavian ice sheet advanced against the natural lie of the land.

What is a valley shoulder, and how does it relate to valley width?

A valley shoulder refers to the upper part of a valley's slope. Generally, the broader a mountain valley is, the lower its shoulders are located, meaning the slopes are less steep relative to the valley floor.

What is a hanging valley, and why does it appear to 'hang' above the main valley?

A hanging valley is a tributary valley whose floor is at a higher elevation than the main valley it joins. This occurs because the main glacier, typically larger, erodes a deeper valley than the tributary glacier, making the tributary valley appear to hang above the main one.

Where else can hanging valleys be found besides mountainous regions, and what is an example related to fjords?

Hanging valleys can also be found underwater in fjord systems. For instance, branches of Norway's Sognefjord are significantly shallower than the main fjord, indicating they are hanging valleys, with Fjærlandsfjord being about 400 meters deep while the nearby main fjord is 1,200 meters deep.

What are trough-shaped valleys, and in what types of climates are they commonly found?

Trough-shaped valleys are characterized by gently sloping valley sides with an unclear transition to the bottom, differing from glacial U-shaped valleys due to less downward and sideways erosion. They are primarily found in periglacial regions and in tropical climates with variable wetness, both of which experience heavy denudation.

What are the defining characteristics of box valleys?

Box valleys are distinguished by their wide, relatively level floors and steep sides. They are commonly observed in periglacial areas but can also be found in tropical and arid regions.

What is a cove, and where is it typically found?

A cove is a small valley, often closed at one or both ends, commonly found in the central or southern Appalachian Mountains. It can sometimes result from the erosion of a geologic window.

What is a dry valley, and how does it differ from a typical river valley?

A dry valley is a valley that was not formed by sustained surface water flow. In areas of limestone bedrock, dry valleys can occur because the water drainage has shifted underground, rather than remaining at the surface.

What is a hollow, and in which regions is this term commonly used for a valley?

A hollow is a term used regionally to describe a small valley surrounded by mountains or ridges. It is particularly common in Ireland, New England, Appalachia, and the Ozarks, where it can refer to a small valley or a dry stream bed, sometimes called a 'holler'.

What is a longitudinal valley?

A longitudinal valley is an elongated valley that is situated between two nearly parallel mountain chains, following the general trend of the mountain ranges.

What are steephead valleys characterized by?

Steephead valleys are described as deep, narrow, flat-bottomed valleys that end abruptly.

What is a strike valley?

A strike valley is a valley that typically develops parallel to a cuesta, which is a ridge with a gentle slope on one side and a steep slope on the other. These valleys form in strata that are more easily eroded.

What is a structural valley?

A structural valley is a valley formed not by erosion, but by geological events such as the creation of drop faults or the uplift of highlands.

What are some British regional terms for valleys, and what do they signify?

British regional terms for valleys include 'strath', which signifies a wide valley between hills with a level or gently sloping floor; 'glen', which is a steeper and narrower river valley than a strath; and 'corrie', which is a basin-shaped hollow in a mountain, often used synonymously with the glacial term 'cirque'. The Welsh term 'cwm' is also used similarly to 'cirque'.

What does the term 'dale' typically refer to in place names, and where is it commonly found?

The term 'dale' is widely used in place names, particularly in the north of England and southern Scotland. As a generic term for a valley, it usually refers to a wide valley, although smaller stream valleys also bear this name in areas like the Yorkshire Dales.

What is a 'clough' in British regional terminology?

In northern England, 'clough' is a commonly used word to describe a narrow valley with steep sides.

What does the term 'gill' describe in specific regions of England?

In Cumbria and the Pennines, 'gill' is used to describe a ravine that contains a mountain stream.

What does the term 'combe' signify, and where is it frequently encountered?

The term 'combe', also spelled 'coombe', is widespread in southern England and describes a short valley that is set into a hillside.

What does the term 'vale' describe in England and Wales, and what geological process often leads to their formation?

In England and Wales, 'vale' is used to describe a wide river valley, often featuring a particularly broad floodplain or flat valley bottom. These vales commonly form between outcrops of different rock types, where less resistant rock, such as claystone, has been eroded.

Where did some of the earliest human complex societies originate, and what role did river valleys play?

Some of the first human complex societies originated in river valleys, such as those of the Nile, Tigris-Euphrates, and Indus rivers. These valleys provided essential resources like fresh water, food, and facilitated agriculture through irrigation, while also moderating temperature extremes.

What factors influence the location of human settlements within valleys?

The siting of settlements within valleys is influenced by several factors, including the necessity to avoid flooding and the strategic importance of river crossing points.

What are the extraterrestrial equivalents of terrestrial valleys, and what are their names?

Elongated depressions found on planets like Mars and Venus, as well as on the Moon, are known as 'valles' (singular: 'vallis'). Deeper valleys with steeper sides are called 'chasmata' (singular: 'chasma'), and long, narrow depressions are referred to as 'fossae' (singular: 'fossa').

What do the Latin terms 'vallis', 'chasma', and 'fossa' mean in the context of planetary geology?

In planetary geology, 'vallis' is the Latin term for 'valley', 'chasma' refers to a 'gorge', and 'fossa' signifies a 'ditch' or trench.

What is a canyon, as mentioned in the 'See also' section?

A canyon is described as a deep chasm situated between cliffs.

What is a paleovalley?

A paleovalley is an inactive river or stream channel that has subsequently been filled or buried by sediment.

What is a stream channel?

A stream channel is defined as a narrow body of water through which a stream flows.

What is the purpose of the 'Authority control databases' section at the end of the article?

The 'Authority control databases' section provides links to various national and international databases (like GND, LoC, BnF, NDL, NKC, NLI) that catalog and manage information about the subject 'Valley', helping to standardize and organize data related to it.

Valley Wiki: Valley Dynamics: A Geomorphic Exploration

Dive in with Flashcard Learning!

When you are ready...
🎮 Play the Wiki2Web Clarity Challenge Game🎮

Defining the Valley

Geomorphic Description

A valley is fundamentally an elongated, low-lying area situated between elevated landforms such as hills or mountains. Typically, these depressions are characterized by a river or stream flowing from one end to the other, shaping the landscape over extended geological periods.

Primary Formation Processes

The genesis of most valleys is attributed to the persistent action of erosion. Moving water, in the form of rivers and streams, gradually carves into the land surface. In colder climates or higher altitudes, glacial ice also plays a significant role in excavating and widening valleys, often resulting in distinct U-shaped profiles.

Tectonic Influence

Beyond erosional forces, tectonic activity can also be a primary driver in valley formation. Rift valleys, for instance, are created by the stretching and thinning of the Earth's crust, leading to significant depressions formed by faulting and subsidence.

Mechanisms of Formation

River Valleys

The development of river valleys is a dynamic process influenced by bedrock characteristics, elevation differences, and climate. In upper reaches, rivers typically exhibit vigorous erosive power, carving steep-sided, V-shaped valleys through processes like corrasion. As rivers mature, they develop broader floodplains, meandering courses, and depositional features, with erosion and deposition often in equilibrium.

Key characteristics include:

V-shaped profiles: Common in upper valleys due to vertical erosion.
Interlocking spurs: Protrusions of higher land that a river must wind around.
Floodplains: Broad, flat areas adjacent to rivers, formed by deposition during floods.
Meanders: Sinuous bends in a river's course, formed by lateral erosion and deposition.
Gorges/Canyons: Deep, narrow valleys formed by rapid down-cutting, often due to uplift or lowered base levels.

Glacial Valleys

Glaciers are powerful agents of erosion, carving distinct landforms. Glacial valleys, or troughs, are typically U-shaped in cross-section, with steep, often smoothed sides and a broad, flat floor. This shape is a result of the immense erosive power of ice, which plucks and abrades bedrock.

Characteristic glacial valley features include:

U-shaped cross-section: Distinct from the V-shape of river valleys.
Cirques: Armchair-shaped hollows at the head of glacial valleys, where glaciers originate.
Truncated spurs: The remnants of interlocking spurs that have been eroded by the main glacier.
Hanging valleys: Tributary valleys that are higher than the main valley floor, often featuring waterfalls.
Fjords: Glacial valleys that have been flooded by the sea.
Tunnel valleys: Large, U-shaped valleys formed by subglacial meltwater erosion.

Tectonic Valleys

Valleys can also be formed by large-scale movements within the Earth's crust. Rift valleys are a prime example, created by the pulling apart of tectonic plates. This process causes the crust to stretch, thin, and subside, forming elongated depressions bounded by faults.

Key aspects of tectonic valley formation:

Rifting: The process of crustal extension and thinning.
Faulting: The breaking and displacement of rock layers, creating steep valley walls.
Subsidence: The sinking of land blocks between faults.
Examples include the Great Rift Valley in Africa and the Jordan Rift Valley.

Diverse Valley Forms

Transition and Box Valleys

Valleys exhibit a range of forms influenced by topography, rock type, and climate. Transition valleys bridge characteristics of different types, while box valleys are defined by wide, relatively level floors and steep sides, often found in periglacial or tropical regions.

Hanging Valleys

A hanging valley is a tributary valley that terminates abruptly at a higher elevation than the main valley floor. This geomorphic feature is typically associated with glacial erosion, where a smaller glacier's valley is left 'hanging' above the deeply incised valley of a larger glacier.

These can also occur due to differential erosion rates in non-glacial environments, where tributary valleys are composed of more resistant rock than the main valley.

Often marked by waterfalls at their mouths.
Common in fjord systems and mountainous regions.

Trough-Shaped Valleys

Trough-shaped valleys are characterized by gently sloping sides and less distinct transitions to the valley bottom. They are primarily found in regions with significant denudation, particularly in periglacial and tropical climates where weathering and mass wasting are dominant processes.

Regional Terminology

British Isles

The British Isles utilize a rich lexicon for valleys, often derived from Celtic languages. Terms like 'glen' (steep, narrow valley) and 'strath' (wide valley) are common in Scotland, while 'dale' signifies a wide valley, particularly in Northern England. 'Combe' denotes a short valley in Southern England, and 'clough' refers to a narrow, steep-sided valley in the North.

Corrie/Cwm: A basin-shaped hollow, often glacial.
Glen: Steep, narrow river valley.
Strath: Wide, gently sloping valley.
Dale: Wide valley, common in Northern England.
Clough: Narrow valley with steep sides.
Gill: Ravine with a mountain stream.
Combe: Short valley set into a hillside.
Vale: Wide river valley, often with a broad floodplain.

Global & General Terms

Beyond specific regional terms, various general descriptors exist. 'Canyon' and 'gorge' denote deep, steep-sided valleys. 'Dry valleys' are those without sustained surface flow, often due to underground drainage. 'Hollow' or 'dell' can refer to small, secluded valleys. 'Strike valleys' form parallel to geological features like cuestas.

Canyon/Gorge: Deep, steep-sided valleys.
Dry Valley: Lacking permanent surface water.
Hollow/Dell: Small, secluded valley.
Strike Valley: Parallel to geological strike.
Structural Valley: Formed by tectonic activity (e.g., faulting).

Valleys and Human Habitation

Cradle of Civilization

Many of the earliest complex human societies emerged within river valleys. These locations provided essential resources: reliable freshwater, fertile alluvial soils for agriculture, sustenance from aquatic life, and moderated temperatures. The proximity to water facilitated irrigation, supporting the growth of early civilizations.

Agricultural Hubs

The flat, fertile floodplains characteristic of mature river valleys proved ideal for the development of agriculture. These areas allowed for systematic cultivation and supported larger populations, leading to the establishment of permanent settlements and the subsequent rise of complex societies and urban centers.

Settlement Patterns

The siting of settlements within valleys is influenced by numerous factors. Avoiding flood-prone areas, accessing reliable water sources, and utilizing natural transportation routes are critical considerations. The valley's topography also dictates access points and potential defensive positions.

Notable Valley Examples

Africa & Asia

Africa features the Great Rift Valley and the Nile Valley, crucial for ancient civilizations. Asia hosts diverse valleys like the Beqaa Valley in Lebanon, the Kathmandu Valley in Nepal, and the historically significant river valleys of China (e.g., Yangtze, Yellow River).

Africa: Albertine Rift, East African Rift, Nile Valley, Valley of the Kings.
Asia: Beqaa Valley (Lebanon), Jordan Rift Valley, Kathmandu Valley (Nepal), Panjshir Valley (Afghanistan), Valleys of China (e.g., Jiuzhaigou).

Europe & Oceania

Europe boasts iconic valleys such as the Loire Valley (France) with its chateaux, the Danube Valley, and numerous glacial valleys in Norway (e.g., Gudbrandsdalen, Romsdalen) and Switzerland (Lauterbrunnen Valley). Oceania includes notable valleys like the Barossa Valley and Hunter Valley in Australia, and the Hutt Valley in New Zealand.

Europe: Loire Valley (France), Gudbrandsdalen (Norway), Romsdalen (Norway), Lauterbrunnen Valley (Switzerland), Great Glen (Scotland).
Oceania: Barossa Valley (Australia), Hunter Valley (Australia), Hutt Valley (New Zealand), Strath Taieri (New Zealand).

North & South America

North America is renowned for its dramatic valleys, including the Grand Canyon, Yosemite Valley, and the Hudson Valley. South America features significant valleys like the Aburra Valley (Colombia) and the Calchaquí Valleys (Argentina).

North America: Grand Canyon (USA), Yosemite Valley (USA), Hudson Valley (USA), Fraser Valley (Canada), Shenandoah Valley (USA).
South America: Aburra Valley (Colombia), Cauca Valley (Colombia), Calchaquí Valleys (Argentina).

Extraterrestrial Valleys

Martian Depressions

The surfaces of other celestial bodies also exhibit valley-like features. Mars, for instance, possesses extensive systems of elongate depressions known as 'valles', akin to canyons, such as the vast Valles Marineris. These features provide insights into the geological history and potential past hydrological processes on other planets.

Lunar and Venusian Features

The Moon features formations termed 'rimae' or 'rima', which are cleft-like depressions. Venus displays 'chasmata', deep gorges, and 'fossae', long narrow depressions. These extraterrestrial valleys are studied using remote sensing data to understand planetary geomorphology.

Related Concepts

Landforms

Valleys are closely related to other geomorphic features shaped by similar processes. Canyons and gorges represent deeply incised valleys. Gullies are smaller erosional features. Paleovalleys are ancient, often buried, valley systems.

Water Features

The presence of water is central to valley formation and definition. Stream channels, riverbeds, and floodplains are integral components of river valleys. Features like waterfalls are often found in hanging valleys, highlighting the interplay between water and topography.

Academic Resources

Flashcards

Enhance your understanding with interactive flashcards covering key terminology, formation processes, and valley types.

Test Your Knowledge

Assessment Module

Challenge your comprehension of valley geomorphology with our curated quiz.

Cited Sources

Reference List

Consult the foundational sources used in compiling this educational overview.

Teacher's Corner

Edit and Print this course in the Wiki2Web Teacher Studio

Edit and Print Materials from this study in the wiki2web studio

Click here to open the "Valley" Wiki2Web Studio curriculum kit

Use the free Wiki2web Studio to generate printable flashcards, worksheets, exams, and export your materials as a web page or an interactive game.

True or False?

Test Your Knowledge!

Gamer's Corner

Are you ready for the Wiki2Web Clarity Challenge?

Learn about valley while playing the wiki2web Clarity Challenge game.

Unlock the mystery image and prove your knowledge by earning trophies. This simple game is addictively fun and is a great way to learn!

Play now

Explore More Topics

Discover other topics to study!

References

Nesje, A., & Whillans, I. M. (1994). Erosion of Sognefjord, Norway. Geomorphology, 9(1), 33-45.

A full list of references for this article are available at the Valley Wikipedia page

Feedback & Support

To report an issue with this page, or to find out ways to support the mission, please click here.

Important Disclaimer

Notice Regarding Content

This document was generated by an AI and is intended for educational and informational purposes only. While efforts have been made to ensure accuracy based on available data, it may not be exhaustive or entirely up-to-date.

This is not professional geological or geographical advice. The information provided should not substitute consultation with qualified experts for specific applications or research. Always verify critical information with primary sources and academic professionals.

The creators assume no liability for any errors, omissions, or actions taken based on the information presented herein.

Valley Dynamics

💡 Dive in with Flashcard Learning! 💡

Defining the Valley 🏞️

📏 Geomorphic Description

⏳ Primary Formation Processes

tectonic Tectonic Influence

Mechanisms of Formation ⚙️

💧 River Valleys

🧊 Glacial Valleys

🌍 Tectonic Valleys

Diverse Valley Forms ⛰️

↔️ Transition and Box Valleys

⬆️ Hanging Valleys

🕳️ Trough-Shaped Valleys

Regional Terminology 🗣️

🇬🇧 British Isles

🌐 Global & General Terms

Valleys and Human Habitation 🏠

🏛️ Cradle of Civilization

🌱 Agricultural Hubs

🗺️ Settlement Patterns

Notable Valley Examples 📍

🌍 Africa & Asia

🏞️ Europe & Oceania

🇺🇸 North & South America

Extraterrestrial Valleys 🌌

🪐 Martian Depressions

🌕 Lunar and Venusian Features

Related Concepts 🔗

⛰️ Landforms

💧 Water Features

Academic Resources 🎓

🃏 Flashcards

Test Your Knowledge ❓

📝 Assessment Module

Cited Sources 📚

📜 Reference List

Teacher's Corner 🧑‍🏫

Edit and Print this course in the Wiki2Web Teacher Studio

True or False? 🤔

❓ Test Your Knowledge! ❓

Gamer's Corner 🎮

Are you ready for the Wiki2Web Clarity Challenge?

Explore More Topics

📜 Discover other topics to study!

References

📜 References

Feedback & Support 👍

To report an issue with this page, or to find out ways to support the mission, please click here.

Important Disclaimer ⚠️

📜 Notice Regarding Content

Dive in with Flashcard Learning!

Defining the Valley

Geomorphic Description

Primary Formation Processes

Tectonic Influence

Mechanisms of Formation

River Valleys

Glacial Valleys

Tectonic Valleys

Diverse Valley Forms

Transition and Box Valleys

Hanging Valleys

Trough-Shaped Valleys

Regional Terminology

British Isles

Global & General Terms

Valleys and Human Habitation

Cradle of Civilization

Agricultural Hubs

Settlement Patterns

Notable Valley Examples

Africa & Asia

Europe & Oceania

North & South America

Extraterrestrial Valleys

Martian Depressions

Lunar and Venusian Features

Related Concepts

Landforms

Water Features

Academic Resources

Flashcards

Test Your Knowledge

Assessment Module

Cited Sources

Reference List

Teacher's Corner

True or False?

Test Your Knowledge!

Gamer's Corner

Discover other topics to study!

References

Feedback & Support

Important Disclaimer

Notice Regarding Content