Category: Geography Notes PPT

The coastal plains of India lie on both sides of peninsular India. The eastern coastal plains of India are along the Arabian Sea and the western coastal plains of India are along the Bay of Bengal. The eastern coastal plains extend from West Bengal to the southernmost point of Kanyakumari and the western coastal plains extend from the Rann of Kutch in Gujarat to the southernmost point of Kanyakumari. As it is clear the coastal plains of India meet at the peninsular tip at Kanyakumari, also the southernmost tip of the Indian mainland. The coastal plains of India exist in-between the long-range mountain ranges and the water bodies on each side. The eastern coastal plains exist in-between the Eastern Ghats and the Bay of Bengal and the western coastal plains exist between the Western Ghats and the Arabian Sea. 

 

In India, the coastal regions are known for trade, agriculture, tourist centers, industrial centers, salt making, and fishing. They offer crucial hinterlands for the large ports. Different parts of the Indian coastal plains own fertile and rich soil where apart from the tice several other crops can be grown. 

 

A coastal plain is called a low-lying and flat land that is adjacent to the sea coast. The coastal plains in India lay on either side of the Deccan Plateau with the eastern and western coast of India. The total extension of these two is 6150 km from the Rann of Kutch from the west to West Bengal.

 

What is a Coastal Plain?

A coastal plain is a flat low-lying area of land, which is adjacent to the sea coast. Geographically speaking, a coastal plain is a low-relief landmass that is surrounded by the sea or an ocean on one side and the highlands on the other. Thus, they are bounded seaward because of the shoreline and landward because of the highlands. As one follows from the sea to the highlands, there is a gradual increase in the elevation of the land area rising gently in a series of flat-land terraces separated by scraps or hills with altitudes reaching 100m-300m.

 

Western Coastal Plains 

The western coastal plain is sandwiched between the Arabian sea and Western ghats. It is called a narrow plain. It comprises a three-section, Konkan (Mumbai Goa) is the northern part of India. Kannad Plain is the central stretch while the Malabar coast is known as the Southern Stretch.

 

Eastern Coastal Plains

The eastern coastal plain with the Bay of Bengal is leveled and wide. In the northern part, this is called the Northern Circar while the southern part is called the Coromandel Coast. The large rivers like Mahanadi, the Krishna, the Godavari and the Kaveri have also built enormous deltas on the coast. Chilika lake is a crucial feature of the eastern coast.

 

This is an overview of these two types of coastal plains, you will get the detailed definition of these two prepared by the experts below.

 

Coastal Plains of India and How are they Formed?

The story of the coastal plains of India and how they are formed is an interesting one from the viewpoint of geography. The Indian subcontinent was part of a supercontinent called the Gondwanaland about 140 million years ago. As the supercontinent split, the Indian tectonic landmass got isolated and over millions of years traveled towards the Eurasian plate and eventually combined with it. Thus, the regular and quite straight coastline of India is the result of the breaking up of the Gondwanaland during the Cretaceous period. Because of this breaking, it not only gave rise to the coast-line in the south but with it the coastal plains of India also came into existence. 

 

As is already known the coastal plains of India are divided into the following two coastal plains:

• Eastern Coastal Plains

• Western Coastal Plains

 

Both the coastal plains together form a coastline of 7516.6km. This coastline includes the Indian mainland coastline with a length of 6100km and the shorelines of the Lakshadweep and Andaman-Nicobar islands. The coastal plains of India are a part of 13 state and union territories of India. Altogether the coastal plains is a result of a beautiful formation of landmass because of the location of the three huge water bodies surrounding the Indian subcontinent. 

 

Both the eastern coastal plains and western coastal plains are shown in the given figure:

Both the coastal plains are further explained below:

 

Eastern Coastal Plains

The eastern coastal plains stretch from West Bengal in the north to the southern tip of Kanyakumari in Tamil Nadu, in the south. The coastal plains also include the states of Andhra Pradesh and Orissa. As mentioned above they lie between the Eastern Ghats and the Bay of Bengal. The region covers deltas formed by the rivers of Mahanadi, Krishna, Godavari, and Kaveri spread throughout the southeast peninsula. These deltas of the eastern coastal plains are very fertile. An example of this is the delta of the river Krishna which is known as the ‘Granary of South India’. 

 

The eastern coastal plains can be further subdivided into the following three coasts:

• The Utkal Coast: They extend from Chilka Lake to the Kollur Lake covering a very wide area. It is the recipient of heavy rainfall owing to the Eastern Ghats. Rice, coconut, and banana are some of the major crops for cultivation. 

• Andhra Coast: It extends from Kollur Lake in the north to Pulicat Lake in the south. It covers the basin area of the Krishna and Godavari rivers. 

• Coromandel Coast: It falls in between Pulicat Lake and Kanyakumari. It also received high rainfall because of the northeast monsoon, especially during the winter season. 

 

When asked to name the states union territories forming the eastern coastline the answer can be given from above as West Bengal, Orissa, Andhra Pradesh, Tamil Nadu, Pondicherry, and the Andaman and Nicobar Islands.

 

Western Coastal Plains

The western coastal plains extend from Gujarat in the north to the state of Kerala in the South. In-between it covers the states of Maharashtra, Goa, and Karnataka. Although it covers a length of 1500 km, the western coastal plains are very narrow as compared to their counterpart in the east with a width of 10 km to 25 km. The Bombay Coast is the widest area of the western coastal plains. Significant features of these coastal plains include oil-rich areas and beautiful lagoons in the Malabar Coast which are attractive tourist destinations. Even they receive heavy rainfall due to the Western Ghats during the southwest monsoon.

 

The western coastal plains can be further divided into the following areas:

• Kachchh and Kathiawar Coast: Kachchh formed from the silt deposition by the Indus is covered with shallow water during the monsoon season. It is divided into the Great Rann of Kutch and the Little Rann of Kutch in the east. Located to the south of Kutch comes the Kathiawar coast.

• Konkan Coast: It extends from Daman union territory in the north to the state of Goa in the south. The major crops that grow in these coastal areas are rice and cashew nuts. 

• Kanada Coast: An iron-rich area this region lies in-between the Marmagaon and Mangalore regions. 

• Malabar Coast: Extending between Mangalore and Kanyakumari it is a relatively broad area and is well-known for the lagoons running parallel to the southern coast in Kerala.

 

In India, coastal plains do not offer many port areas but host many attractive sites for tourist destinations. Along with that, they are recipients of high rainfall and thus are centers of many economical, agricultural, and pisciculture activities. A very brief description of the coastal plains of India is given in this article which also offers an insight into the peculiarities of the Indian landmass. 

 

Several crops depend on the coastal regions in India, so their importance must be well-known by each citizen. As discussed above, different regions support the cultivation of different crops, so a fair idea about it could help students gain better marks in their examination. The aim of experts is not only to help the students gain better marks, but they also gain knowledge about the different parts of the country.

It is a secondary mineral that forms under the oxidized zone of copper sulfide deposits. The cuprite mineral frequently occurs in association with native copper, malachite, tenorite, azurite, chrysocolla, and a variety of iron oxide minerals. 

Cuprite was first discovered by Wilhelm Karl Ritter Von Hadingier in 1845 and its name is derived from the Latin cuprum because of its copper content.

The mineral is found in Atrial Mountain, Urai Mountain, and Sardinia and in more isolated locations in France, Chile, Bolivia, Cornwall, Arizona, and Namibia.

The table given below shows the physical properties of cuprite.

Cuprite Properties

Cuprite Chemical Formula

The cuprite chemical formula is CU₂O.

Cuprite Healing Properties

• The high copper content in copper makes this stone wonderful for the brain.

• The crystal eases the anxiety and worries of a person and supports him in the stage of emotional turmoil.

• Cuprite strengthens meditation and helps to deliver the spiritual message of both the human being and the divine to each other.

• It liberates oxidative stress and enhances analytical abilities.

• It is an excellent stone to help with females’ reproductive problems and provide regulating and balancing activities.

• Cuprite has been proved in curating the disease related to the skeletal system, tissues, dizziness, alcoholism, addictive habit, vitamin assimilation, oxygenation of the blood, cramps, etc.

• Cuprite maintains the energy level, stamina, enthusiasm, and vigour of the body.

Cuprite Uses

• Cuprite is widely used as a colourant to produce red ruby glass since the first and second Milena BCE.

• Cuprite is very seldom used for jewellery because of its brittle nature. It is generally used for cabochons or ornamental cravings.

• In meditation, cuprite may be used to ground through the root chakra into the deeper energies of Earth.

• Cuprite has proved to be a wonderful tool for those who want to connect deeper with the energies of the Earth on which we live on.

Crycholla Cuprite

Crycholla cuprite is a hydrated copper phyllosilicate mineral and mineraloid with chemical formula (CU, Al₂)H₂Si₂O₅(OH)₄.nH₂O. The name Crycholla is derived from the Greek word “ Chrysos” meaning gold and kola meaning glue, together means kola glue. Deposits of Crycholla are widely occurring in the massive form, rather than in crystals. The colour of the crystal ranges from medium greenish blue to light turquoise blue, green, and blue-green. 

The crystal is found in Zimbabwe, the Congo, Russia, Czech Republic, Spain, Britain, Zaire, Australia, Indonesia, Mexico, Chile, Peru, Israel, USA, and the Czech Republic,

Crycholla Cuprite is quite a supportive energy stone that inspires verbal expression. It helps both men and women to communicate most lovingly. It is the powerful stone that encourages the person to speak out about those things that are quite essential. It was historically used by American Indian people to bring a strengthening and calming energy.

As Crycholla Cuprite is a copper-based stone, it forms when copper oxidizes.

Cuprite Malachite  

Cuprite Malachite is a green copper carbonate hydroxide mineral with the chemical formula CU₂CO₃(OH)₂. It is formed by the surface weathering process of copper ore and is generally not used for copper extraction due to its insignificant resource and inadequate metallurgical recovery.

The mineral occurs in different parts of the world including Congo, Gabon, Zambia, Namibia, Mexico, Australia, and with the largest deposit/mine in the Urals region, Russia. It is used as a mineral pigment in green paints since antiquity, for decorative purposes, ornamental stone, and gemstone. 

Azurite Cuprite 

Azurite Cuprite, also known as chessylite is a soft deep blue copper mineral produced by the weathering of copper ore deposits. It is a mineral with the chemical formula Cu₃(CO₃)₂(OH)₂. It is known widely for its deep blue to violet-blue colour. The Azurite Cuprite is not a common and abundant mineral but its beautiful colour grabs attention.  Azurite is naturally occurring in Sinai and the Eastern Desert of Egypt.

Azurite is often used as a bead, and as jewellery, and also as an ornamental stone.

Did You Know?

• Cuprite was named by Wilhelm Karl von Haidinger in 1845 from the Latin term cuprum, meaning copper. 

• Cuprite often occurs mixed with copper-bearing minerals such as cuprite malachite, chrysocolla cuprite, and azurite cuprite.

• Cuprite is also known as Ruby copper, or red copper because of its beautiful red colour.

• Despite its nice colour, it is rarely used in jewellery due to its low Mohs hardness of 3.5-4.

• Cuprite often pseudomorphs into malachite, which implies its composition changes to malachite while retaining cuprite’s external crystal form.

• In 1970, the finest and gem quality cuprite was mined in Organza, Southwest Africa.

• An excellent stone combining cuprite and chrysocolla comes from the Sonora valley in Northern Mexico and is referred to as Sonoran Sunset or Sonora Sunrise stone.

The basic meaning that the word environment conveys is surroundings. Whatever we see in our surroundings is a part of our environment and contributes to its formation. Environmental science is a budding aspect of science and higher studies that deals with the study of interactions between different species of flora and fauna that exist in nature. The flora comprises all the species of plant life found on the earth whereas fauna consists of all the animal species you’d see in your surroundings. Together, flora and fauna make our environment. 

What is Natural Environment? 

The natural environment comprises all the living and nonliving things that occur naturally In the environment. Natural in this context means “anything that isn’t man-made or artificial”. The basic sense that the term natural environment conveys is “anything related to the earth”, anything which occurs in nature without any manufacturing process in a factory! 

What is Our Natural Environment Made of? 

As iterated earlier, the natural environment includes any component which occurs naturally in the environment without any processing by humans. Our natural environment consists of:

• All the ecological units of an ecosystem. All these units have been unaffected by human civilization and its advancement. This includes all the species of bizarre animals found in nooks and corners of the earth and any vegetation that grows in any part of the world. Any living organisms including even the smallest microorganism found in any part of the world. 

• The other component of the environment is the non-living component. This includes every single non-living component that exists naturally in nature. Like the stones, water, air. Anything non-living has existed in the same state for a long time and continues to occur in nature.

Natural Environment Examples 

Still, confused about what the natural environment exactly is? Well, here’s a list of natural environment elements, this will give you a better idea about. The given list includes objects you see in your surroundings every day, all these objects are an integral part of our natural environment.

The examples given above are a few examples of the parts of our natural environment. 

Types of Natural Environment

Our natural environment could further be divided into domains. These domains are 

• Lithosphere

• Atmosphere

• Biosphere

• Hydrosphere

All these domains together make up the environment. 

The lithosphere consists of the earth’s crust. All the rocks, different layers of soil, and minerals found in the earth’s crust are a part of the lithosphere. This domain facilitates the lives of forests and trees, and hence they’re interdependent. 

The hydrosphere is the domain that comprises water bodies. Hydra means water in Latin. Hydrosphere hence includes all the forms of water bodies you can find on earth. The rivers, lakes, oceans, seas, and ponds. All of them come under the hydrosphere. 

The Atmosphere refers to the thin blanket of air that surrounds our planet. This thin blanket of air is held together by the gravitational force and is responsible for protecting us from harmful UV radiation. The atmosphere holds several gases in a specific ratio. Few of the major gases found in the atmosphere are oxygen, nitrogen, and carbon dioxide. 

The biosphere refers to all the living organisms found on mother earth. Ranging from tiny insects to the giant blue whale, all of these are a part of the biosphere. The biosphere is dependent on all the other domains since no organism on earth can survive without air, water, or soil. Hence, these domains are interdependent. 

What is a Manmade Environment? 

Man-made, the word is self-explanatory. Man-made means anything which is produced due to human kind’s efforts. Anything which isn’t found in the surroundings naturally is termed as man-made. The world, in which all of us live is a blend of both the natural environment and the man-made environment. 

Examples of Artificial Environment

When you look around yourself, you’d find various objects in your home. Objects have been made out of naturally existing objects but human beings modified these objects according to their convenience. For instance, consider a door. A door is generally made out of wood. Wood comes from trees which are a part of the biosphere, however, human beings have modified the wood and transformed it into a door. This is how the artificial or man-made environment came into being. Given below are a few other man-made environment examples that would help you to get a better understanding. 

Our man-made environment consists of electronic elements. If you look around the house, you will find several electronic devices such as a television, fan, air conditioner, to name a few. All these electronic devices are made by human beings to make our lives more convenient. Electricity is the basic source for all these electronic devices and the electricity is produced by natural sources like wind, coal, solar. Hence artificial or man-made environment is derived from the natural environment to improve the quality of our life. 

The deposits of minerals have different  shapes, which depend on how they were deposited. The most common shape of mineral deposition is mostly the tabular form. The mineral deposit in the form of a filling is mostly situated in layers of rock that are parallelly placed. The orientation of this ore body is to be marked by its dip (this is the angle which it makes with the horizontal structure) and this strike (the position which it takes in regard to the four points of the compass). The Rock that is lying above the ore body is known as the hanging wall and the rock which is lying below the ore body is called the footwall.  

Analysis of Footwall Morphology

Under the U.S Geological Survey National Elevation Dataset that is elevation data, we will analyze footwall morphology along each fault, with a horizon of 30 m resolution. The data is very much coarse and have particularly the accurate delineation of the catchments draining of the Stone Creek and Sweetwater footwalls. Higher‐resolution (that is 10 m) data is utilized only as a part of the study area, hence we use the same 30 m data to make comparison results from all the different kinds of footwalls. For each of these faults, we need to extract the footwall catchments which is >0.05 km2 in area and the drain across the map that is traced is the active fault (the darker shaded areas). 

In the first attempt at quantifying the footwall morphology, we are required to calculate the simplest possible measures of these catchments that is their area, relief, and their mean slope.

To assess further along with the strike variations in footwall relief, we need to project the extracted footwall catchments which are onto a fault parallel to the profile. At each of the positions along the profile we then calculate the maximum, mean, and minimum elevations in the fault‐normal direction. The footwall relief at each point is the difference between the maximum elevations and minimum elevations. This method is quite sensitive to the small‐scale variations in which the plan‐view catchment shape is not the true measure of an individual catchment which has relief because of the catchments that got widened away from the fault. In these places, the swath is not exact to the fault parallel. However, this method allows us to derive a continuous type footwall relief profile and then eliminate the issues that are inherent in the arbitrary selection along with the striking profile. As a check, we also need to calculate the relief in the individual catchments as a function of the outlet position along strike; and the overall patterns and length scales that are very much similar to those which are derived from this profiling method.

For the suspect that relief in these tectonically active footwalls may be strengthened the limited, implying a relationship between the topographic slope and the relief, we also are required to calculate the average catchment slopes within these extracted regions. 

We then determine the mean topographic slope for each of the catchments, using the slope values which are measured over a 3 × 3 cell (90 × 90 m) size window. The slope will be estimated using the 30 m resolution digital elevation model which will significantly underestimate the true meter‐scale that the slope values, while these estimates and will provide a useful means to compare the slopes which are averaged over the scale of individual hillslopes, that is present along the strike and between the different footwalls.

Catchment Patterns

For both that is the Stone Creek and the Sweetwater faults, there are cuts across a smooth and low‐relief surface which developed on the Archean gneiss. It is being tilted to the southeast by Miocene which is faulting of the Ruby Range block. These faults define the small range fronts which are quite steep and is linear near the fault and the strike centers and they become more diffused and difficult to separate from the inherited topography that is on the Ruby Range block near the fault tips. Both these footwalls represent asymmetric map‐view catchment patterns where the smallest catchments may occur near the fault strike center, which we need to infer the displacement maxima. The Catchment areas also increase and progressively advance towards the fault tips. The location of the smallest catchments near this strike center is close to the inferred displacement maximum, which is somewhat counterintuitive. Everything being the same, higher displacements near these faults in the midpoint should also lead to higher rates of footwall incision, and therefore larger the structure, the more widely spaced catchments will be. Both the footwalls are then composed only with Archean gneiss. This is done so that lithology swill is not a significant control on the catchment size.

The Blacktail and the Red Rock footwalls also show a greater variation in the along‐strike distribution of catchment areas which is single‐segmented. The largest catchments, which are the Beaver head River and the Blacktail Deer Creek located in the Blacktail footwall and the Big Sheep and Little Sheep Creeks which is located in the Red Rock footwall, are the antecedent to these faults’ structures. They are based on their regional extent and their continuity across several footwall blocks. The catchments which are being developed in response to this fault displacement have no distinct pattern that emerges. We are required to interpret this as to take due action in part of the fault tip propagation into these areas of significant and pre-faulting topography system. 

Glaciers are present on the Earth in the form of ice sheets in the polar regions which are known as continental glaciers but that does not mean glaciers are only present in the polar regions. They are found in all other parts of the world except the continent of Australia. These are great sources of fresh water on earth that are present in the form of dense ice. In this article, we will be talking about this landform. In this, we will learn about the meaning or definition of the glacier, their distribution, benefits, and other related concepts. This article will help you to understand the very important landform of the Earth and helps you in your studies.

Glacier Meaning and Definition

It is a body of dense ice that moves slowly. It is a perennial structure that forms because of the accumulation of recrystallization of ice, snow, rock, sediments, or any other form which originates on land. They exist where the average annual temperature is closer to the freezing point and precipitation in winters have to snow and especially exist in those areas where temperatures of the current year do not affect the snow accumulation of the last whole year. This continuous accumulation of ice leads to the formation of glaciers. These glaciers look like mountains or peaks and also termed sometimes as mount glacier or glacier mountain.

Mendenhall Glacier in Alaska is a type of mountain glacier as well as a temperate glacier which also consists of a glacial lake and glacial caves. Glacier ridge can be seen in various mountain ranges as well.

According to the Oxford Learner Dictionary, “ glacier means a large mass of ice, formed by snow on mountains, that moves very slowly down a valley.”

According to the Cambridge Dictionary, “ glacier means a large mass of ice that moves slowly.”

Types of Glacier

Glaciers can be majorly divided into two classifications based on geographic locations such as

The glacier mountain finds in the tropical regions are known as tropical glaciers. For example, glaciers present in India and Pakistan which are tropical countries.

The glacier mountain or range or sheets present in the temperate regions are known as temperate glaciers. For example, the Fox glacier in Newzealand or Mendenhall glacier in Alaska are considered temperate glaciers.

Other Types of Glacier Mountain are Classified as Under:

These are massive thick glaciers that covered most of the planet during the ice age. They are present on the gentle terrain and sometimes they are so thick that they cover the underlying features as well. From a central accumulation zone, these sheets move in all directions outwards. For example, the Antarctic ice sheets.

The floating parts of ice sheets are known as ice shelves. For example, there are a lot of such ice shelves in Greenland and Ellesmere Island.

These are restricted to mountain plateaus and are smaller ice sheets. For example, on Baffin Island the presence of the Penny Ice Cap.

These are formed inside or near the mountains in a bowl-like depression. Mostly due to avalanches, the ice or snow accumulation occurs here from the surrounding slopes. For example, Lower Curtis glacier in Washington.

They are formed on the walls of the glacial valley and found in the regions where there are steep mountains. For example, in the Alps mountains, they are common.

These are the glacier rock that finds their ways to reach the oceans and are insensitive to climate change.

Distribution 

They are found on all the continents of the earth except Australia. The distribution in different continents and regions of the world is mentioned below in the table:

Climate

• The climate and temperature of the glaciers vary with locations and time. 

• Somewhere the entire region is under the melting point and sometimes it is only under the melting point in the sole. 

• In some regions, it can have a combination of both such as the base layer is at the melting point but the upper layer is below the melting point. 

• The temperature of 0 degrees celsius can be seen in the temperate glaciers. 

• The temperature of -40 degrees celsius to -60 degrees celsius can be seen in the upper layers of the Antarctic region.

• If the temperature reaches up to the pressure melting point, it can lead to glacier erosion.

Vegetation and Wildlife

These regions do have harsh conditions but still provide some favourable conditions for various species.

• Animals found here such as bear, snow leopard, wolverine, etc.

• Vegetation like algae, fungus, lichens, mosses, mushrooms, liverworts, etc.

• Tundra and alpine vegetation are found in temperate regions.

Benefits

• They are a great source of fresh water in the form of glacier lake and glacier streams.

• They are useful for the production of hydroelectric power.

• Glacier peak or mount glacier also serve as tourist attractions and a source of great revenue for the state.

• They maintain the ecological balance of the planet.

• They maintain global temperature.

Did You Know?

• If the entire glaciers or ice sheets of Antarctica melts then the sea level will almost rise by 65m which means London will be submerged underwater along with several other similar places.

• Antarctica and Greenland combined hold more than 99% of the glaciers of the Earth.

• Glaciers move very slowly. The Kutiah glacier of Pakistan has moved about more than 12km in only 3 months and it is the fastest glacier surge ever recorded.

• Lambert – Fisher Glacier present in Antarctica is one of the largest glaciers in the world.

• Fox glacier which is present in Newzealand is one of the most accessible glaciers and also the most attractive tourist destination with 1000 tourists daily visits.

Conclusion:

Thus, in this article, we have covered one important landform i.e. glacier. We have learned the meaning and definition of glaciers, their various types along with their distribution around the world. We have seen its various benefits and have learned what will happen to Earth if glaciers melt. These are dense and huge mass of ice sheets that move very slowly and are a great source of freshwater and maintains the global temperature of the planet. These notes will help the students of Class 8 as well as the students of higher classes. 

We have read about the glacier and its related concepts. Let us have a look at the FAQs.

Horst Meaning- A horst is a raised fault block bounded by natural faults in physical geography and geology. A horst is a raised block of the Earth’s crust that has lifted or stayed stationary while the land around it (graben) has sunk.

Horst and Graben are found together in an extensional environment. The graben is the block that has been downthrown, while the horst is the block that has been upthrown next to the graben.

What is the Meaning of Horst?

Horst meaning: Horst is a Dutch and German word that means heap and is similar to the English word “Hurst.”

What is the Meaning of Graben?

A graben is a fault block that has been lowered relative to the blocks on each side without significant interference or tilting. Bordering faults, or fault zones, are usually of near-parallel strike and steeply dipping, with nearly equal vertical displacement. The relative movement of the blocks that define a graben Both of the blocks may have rotated according to their initial positions, but the middle block may have subsided further than the outer two. As a result, a true graben in its original surface shape is a linear structural depression. The scale of grabens varies widely, but the superiority of a long fault trough is a distinguishing feature.

Geomorphology of Horst

The cross-sections of horsts may be symmetrical or asymmetrical. The horst is likely to be symmetrical and approximately flat on top of the usual faults on either side have identical geometry and are moving at the same rate. The top of the horst would most likely be inclined and the entire profile would be asymmetrical if the faults on each side have different rates of vertical motion. In cross-section, erosion has a big influence on how symmetrical a horst looks.

Horst and Graben Formation

Horst and graben are formed when opposite-dip natural faults with parallel strike lines occur in pairs. They are inextricably linked. Horsts and grabens may be as small as a few centimetres wide or as large as tens of kilometres wide, with vertical movement of several thousand feet. They’re bordered on both sides by steeply dipping regular faults, which have virtually equivalent movement, resulting in blocks that are barely tilted. The faults that form horsts tend to dip away from each other, while those that form grabens tend to dip against each other. Two or more horsts and grabens can be found close together.

They’re thought to be caused by lateral stress, which could be caused by regional uplift or salt dome formation; they’re most common on dome crests or anticlines.

Hydrocarbon Exploration and Horsts

The vast majority of discovered hydrocarbons in many rift basins around the world are located in traditional traps associated with horsts.  Most of the petroleum discovered in Libya’s Sirte Basin (tens of billions of barrels of reserves) is located on large horst blocks like the Zelten Platform and the Dahra Platform, as well as smaller horsts like the Giallo High and the Bu-Attifel Ridge.

Examples of Horst and Graben Formation

Wallonia’s Condroz and Ardennes regions are strong examples of horst and graben succession.

The Satpura Range is a horst in India, flanked to the north by the Narmada Graben and to the south by the much smaller but parallel Tapi Graben.

The Vosges Mountains in France and the Black Forest in Germany are examples of horsts, as are the Table, Jura, Dole Mountains, and the Rila – Rhodope Massif, which includes the well-defined horsts of Belasitsa (linear horst), Rila mountain (vaulted domed shaped horst), and Pirin mountain (a horst forming a large anticline situated between the complex graben valleys of Struma and that of Mesta.