Category: Geography Notes PPT

We usually see the Earth from the outside. We see different types of landscape structures, plains, plateaus, grasslands, deserts, beaches, islands, forests or wildlife, etc. but have you ever wondered what can be found inside the Earth? All the things we see outside or use in our daily lives are formed because of the internal processes of the earth along with external factors. Here, we will be focusing on the inside of our Earth. We will learn about the rocks and minerals found inside our Earth, their uses, the classification of rocks, and various other related concepts. 

These rocks and minerals are very useful for us and are used in various processes and products. These notes will serve the needs of students who are looking for Class 7 Geography Chapter 3 notes. 

Rocks and Minerals

These are said to be building blocks of Earth which forms various kinds of landscapes on Earth as well as provide a number of resources as well. Rocks consist of minerals and these rocks are mined to extract minerals because these have Important properties and commercial value. There is no specific structure or chemical composition of rocks but minerals do have definite structure or other properties. Each rock can consist of one or more minerals. Rocks can be formed because of various geological processes and during these processes, various minerals get collected in one rock. When rocks are mined, these are called ores and the remaining rock after extraction of minerals is called tailing.

Uses of Rocks and Minerals

• These are used in everyday life around us.

• Rocks are used for making roads, buildings, and other construction purposes.

• Some rocks which are precious are used as gemstones and some small rocks are also used in games as well.

• Minerals are used for energy purposes such as coal, petroleum, etc. whereas others like fluorite, copper, talc, kaolinite, zinc, gold, diamond, etc. are used for making different kinds of products in the manufacturing industries from paper to jewellery products, minerals are used.

Difference Between Rocks and Minerals

Classification of Rocks

The various types of rocks are mentioned below. 

Igneous Rocks

The rocks formed because of the solidification or cooling of the lava from the volcano are known as Igneous rocks. These are said to be the first and earliest rocks to be formed and other rocks are made from these rocks, thus these are also known as the primary rocks. These rocks are also considered magmatic rocks because of their formation from the magma or also called volcanic rocks because of the relationship with a volcano. These can be divided into the following two types:

These are those rocks that solidify under the crust of the Earth along with the presence of other existing rocks and it cools slowly and rocks become coarse-grained. The rocks which form deep in the crust and are coarse-grained are termed plutonic or abyssal rocks whereas the rocks which form under the crust but near the surface and are medium-grained are termed subvolcanic rocks or hypabyssal rocks.

The types of rocks which solidify above the crust of the Earth or on the surface outside are called extrusive Igneous rocks. Here, the process of cooking is not slow as compared to the intrusive one. They follow a quick solidification process because of the outside temperature present in the region thus, they are of fine quality and glassy texture.

Examples of Igneous Rocks

The first image is of Basalt which is an example of extrusive Igneous rocks and is dark in colour and finely grained whereas the other image is of coarse-grained rock i.e Diorite which is an example of intrusive igneous rocks. Other examples are Dacite, Diabase, Gabbro, Obsidian, Granite, Peridotite, etc.

Sedimentary Rocks

These are the rocks that formed on or near the surface of the Earth because of geological processes such as erosion, weathering, dissolution, precipitation or lithification, etc. And usually have distinctive layers of bedding. They can be divided into three types:

These sediments are carried in rivers or deposited in oceans or lakes and with time when the water disappears, the rock forms. Examples: sandstone, limestone, shale, etc.

• Clastic Sedimentary Rocks

They are made up of clasts of the pre-existing rocks and the names of such rocks depend upon the size of the clast or grain.

• Biologic Sedimentary Rocks

When a large number of living species die then such kinds of rocks form. Chert or limestone are formed in this way.

Examples of Sedimentary Rocks

 

The first image is of limestone and another black one shale. Breccia, Chalk, Caliche, Chert, Conglomerate, Coal, Diatomite, Flint, limestone, etc. Are the other examples.

Metamorphic Rocks

These are the rocks that are formed from igneous or sedimentary rocks or even earlier metamorphic rocks which are formed due to high pressure, high heat, or other factors. The metamorphism process leads to the transformation of the existing rocks into another form. They are of three types:

These include phyllite, schist, gneiss, quartzite, or marble.

• Foliated Metamorphic Rocks

These are the rocks formed because of the parallel arrangement of certain minerals under pressure and are of platy or sheet-like structure.

• Non- Foliated Metamorphic Rocks

They do not have platy or sheet-like structure and grains do not align even after having so much pressure.

Examples of Metamorphic Rocks

The first image is of Gneiss and the other one is Anthracite. Other examples are Amphibolite, Hornfels, Marble, Lapis Lazuli, Novaculite, Quartzite, Soapstone, etc.

Rock Cycle

It is a cycle of various processes that lead to the formation and transformation of various types of rocks inside or outside the crust of the Earth. The three types of rocks which are formed are called igneous, sedimentary, and metamorphic due to various geological factors such as melting, cooling, heat or pressure, erosion, weathering, compacting and cementing, etc. When the heat and temperature inside the crust of the Earthrise, the magma forms which comes on the surface in the form of lava. When this lava hardened inside or outside the surface of the Earth becomes igneous rocks and when these igneous rocks erode into sediments because of various processes leads to the formation of sedimentary rocks and when these two rocks go under extreme pressure or other processes lead to the formation of metamorphic rocks which eventually are a transformation of already existing rocks.  These metamorphic rocks can be eroded further to form sedimentary rocks or can be melted into magma. Thus this cycle continues and these rocks go on the interchange from one type of rock to another. Our earth has several favourable conditions which lead to the formation or interchangeability of these rocks such as wind, water, tectonic plates, and their movements, heat or pressure, subduction, etc.

So, now we have covered the facts about Earth and have seen what does happen inside it. 

Conclusion

Thus, here in this article, we have covered Chapter 3 of Class 7 Geography i.e. Inside our Earth. These notes will be useful for those who are in Class 7 or even the students of upper classes to understand the basic concepts. These will be helpful for those who find it difficult to read the chapter in the book and make notes out of it. has eased your work by providing you with these crisp as well as comprehensive notes which will surely help you to understand the concepts properly as well as in revising the whole chapter quickly. You can check out notes of all other chapters or topics and other subjects as well on our website. These are created and prepared by the subject matter experts of after thorough research to help you in your studies. We believe that these notes will surely help you to grow.

A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body. The terrain landscape formed due to the landform is topography. The characteristic physical attributes like slope, stratification, elevation, orientation, rock exposure, and soil type categorize landforms. Landform includes hills, mounds, ridges, berms, cliffs, rivers, valleys, volcanoes, peninsulas, and various other structures. Minor landforms include canyons, valleys, basins, and buttes, whereas major landforms are hills, mountains, plateaux, and plains. 

Coastal Landforms Definition

Coastal landforms mean any of the relief features remaining on the coast because of the combination of processes, sediments, and the geology of the coast itself. The development and persistence of landforms are the results of a combination of processes acting on sediments and rocks present on the coast. The power and current of waves play a major role in these processes. 

Beach, delta, coastal dune, wave-cut platform, a sea stack, sea cliff, and sea arch are some of the famous coastal landforms.

Erosional and Depositional Landforms 

There are two major types of coastal landforms – erosion and deposition. The erosional and depositional landforms, though they contain some similar features, show distinct different types of landforms. Erosional landforms show high relief and rugged topography. They can be seen on the leading edge of lithospheric plates, the west coasts of North and South America. The erosional coasts also occur due to glacial activity, which is seen in New England and the Scandinavian countries.

The erosional features are dominated by exposed bedrocks with steep slopes and high elevations near the shore. The bedrocks resist the erosion leading to its slow rate of shoreline retreat. The type of rocks and their lithification play a major role in the rate of erosion.

 

Features of Sea Erosion  

Seacliff Formation

The sea bedrock cliffs range from a few meters to hundreds of meters above sea level. The sea cliff landforms are the most widespread of erosion coasts. The wave-induced erosion near sea level and collapse of rocks at higher elevation lead to vertical nature. One can observe a notch in cliffs when they are extended to the shoreline where waves batter the bedrock.

At the base of the sea cliffs, one can find many veneers of sediment that form a beach. The sediment might be of sand, but it is more of cobbles or boulders, a coarse material. These types of beaches might get demolished with the strong waves during the stormy seasons as they are made in low wave-energy conditions. Some beaches of California and Oregon are its example. 

Coastal erosion means breaking down and carrying away materials by the sea, and deposition means the material carried away by sea is deposited or left behind on the coast. Coastal erosion happens due to ‘destructive waves’. We know that in the stormy season, the waves are very powerful and can destroy material into pieces. The strong backwash of waves pulls the material away in the sea.

Destructive Waves  

Erodes through four main processes as –

It is a force against the coastline that leads to dislodging and carrying the material away by the sea.

This can be seen in rocky areas when the water burst against the crack of rocks. These cracks keep on spreading as the air gets compressed and decompressed because of the waves crashes. The creation of caves is the result of compression as the rocks go on breaking off.

Abrasion means when the material is thrown to the coast with the swashes, they tend to break and spread, and this leads to more material backwashing into the sea. 

Attrition means the crashing of rocks and stones against each other while they are carried away by the sea. The attrition gives result formation of sand and rounded pebbles on the beach. 

When the cracks in the rock at the base are eroded and expanded by the continuous crashing of waves, the sea caves are formed. It is the result of constant compression and hydraulic action.

Sea arch is formed when the headland is broken through while waves continue to erode and expand to cut through.

Sea stack means the sea arch is no more capable of supporting till the root and falls broken in the sea. The remaining pillar-like rock is called a sea stack.

The sea stump means a broken pillar is remaining just above sea level. It is a sea stuck almost completely eroded.

Constructive Waves  

Are of low energy and high swashes. Swashes mean the waves deposit or drop the material on the coast. They have stronger swashes than backwashes. This leads to a build-up of material washed away during backwashes. This results in the formation of beaches. 

Magma is described as the extremely hot liquid or the semi-liquid rock which is situated under the Earth’s surface. This magma can easily push through the holes or the cracks in the crust surface which causes a volcanic eruption. When the magma flows or it erupts onto the Earth’s surface, this is given a new name called lava. Like a solid rock that has many constituents, magma is also a mixture of many minerals.

Magma, the word has originated from ancient Greek which means ‘thick unguent’. This is a molten or semi-molten material that is of course naturally produced. They also form the igneous rocks in this process. In another study, it is proved that the magma which is found underneath the earth’s surface has magmatism that is similar to be found on other terrestrial planets and other natural satellites. Apart from molten rock, this magma may also contain suspended crystals and gas bubbles. 

Magma Rock 

Magma is molten or half molten rock that also forms igneous rocks. These magma rocks consist of silicate liquid. The magma tricks at the depth of the earth’s surface which is afterwards ejected in the form of lava. The suspended crystals and the fragments of unmelted rock may also be transported in the magma; this is also dissolved and with high volatility may get separated as bubbles and some liquid may also get crystallized during this movement. Other such intertwined physical properties are also responsible to determine the characteristics of magma. This will also lead to describe the chemical composition of the magma, viscosity of the magma, the dissolved gases in the magma, and its temperature.  

Molten Magma

Molten Magma mostly exists in the lower part of the Earth’s crust and also in the upper portion of the mantle. So, the mantle and the crust are solid, and hence the presence of magma is quite crucial to the understanding of the geology and the morphology of the mantle. 

Magma here forms from the partial melting of the mantle rocks. As these rocks move upward (or they have water as added to them), they begin to melt a little bit. These then melt and migrate upward and form larger volumes that continue to swim upward. They also may collect in the magma chamber. Also, they might just come straight up. 

While they rise, the molecules of gas present in the magma come out of this solution and form bubbles and as these bubbles rise, they gradually expand. After which the pressure of bubbles becomes stronger than the surrounding solid rock and then this surrounding rock fractures, which allows the magma to get to the surface of it. 

Magma and Lava 

We use the term ‘magma’ which means underground molten rock and we also use the term ‘lava’ for the molten rock which breaks through the Earth’s surface.

The accurate distinction between magma and lava is about its location. When we refer to magma, we indicate the molten rock which is being trapped underground. While, when the molten rock comes up to the surface this keeps flowing like a liquid, and then this is called the lava.

Magma is hotter than lava. The hotness actually depends on when the lava has reached the surface and also if the magma and the lava emit from the same magma chamber.

Basaltic Magma 

Basaltic lava, also known as the mafic lava, is the molten rock that is enriched in iron and magnesium with depleted in silica. The basaltic magmas are formed by exceeding the melting point of the mantle that is either by adding the heat or changing its composition or by decreasing its pressure.

Basaltic magma is also formed through the dry partial melting of the mantle. The mantle lies quite below the crust of the earth. The Basalts also make up most of the crust of the ocean, thus the basaltic magma is generally found in the oceanic volcanoes.

Types of Magma 

There are three types of magma: basaltic, andesitic, and rhyolitic. All of these has a different mineral composition. All this type of magma has a significant percentage of silicon dioxide. 

• Basaltic magma is high in iron, magnesium, and calcium but it has deficient or it is low in potassium and sodium. 

• Andesitic magma has adequate amounts of all these minerals.

• Rhyolitic magma is high in potassium and sodium while it is low in iron, magnesium, and calcium. 

Andesitic Magma 

Andesitic magma has moderate amounts of minerals, with a rising temperature that ranges from about 800oC to 1000oC. The Rhyolitic magma is quite high in potassium and sodium but it is low in iron, magnesium, and calcium. 

Magma Volcano 

These are the molten rock inside the earth, they are deeper in the Earth’s surface are hot rocks that slowly melt and this becomes a thick flowing substance which is called magma. Since this is lighter than the solid rock that is around it the magma rises and then collects in magma chambers. Thus, in this process, some of the magma pushes through vents and fissures coming down to the Earth’s surface.

The microclimate or miniature climate is the local or small-scale environmental conditions that influence plant growth and development, such as evapotranspiration and wind. This term is often used as an equivalent for a macroclimate, the seasonal or large-scale climate. As a result of the plant effect, we can observe different types of microclimates. 

A microclimate is more localized than the weather or local climate and is therefore generally much easier to understand and predict. Weather conditions, on the other hand, have a larger projection and, as a result, are more difficult to predict.

Factors that influence Microclimate

The microclimate is affected by the weather, and the weather is affected by the wind, temperature, relative humidity, precipitation, and atmospheric pressure. There is a clear relationship between wind and temperature: the temperature is cooler in an area with light wind and warmer in an area with heavier wind. 

This concept of microclimate is very important, as it plays an important role in the growth of plants. In a greenhouse, there are two types of microclimates:

• A sheltered microclimate is present in the greenhouse. This microclimate results from the greenhouse itself, which may protect the plant from the sun. 

• A natural microclimate is that which is present outdoors. The temperature of the soil is affected by the amount of shade cast by the surrounding vegetation and by the presence or absence of water. Air movement caused by the wind may also be important. This can also contribute to increased humidity. Plant growth is related to microclimates that support high levels of light and heat.

Microclimates play a critical role in how people experience various climate zones in different seasons.

There are a lot of factors that determine what a microclimate is and in fact, the term.

“microclimate” itself is a misnomer because there are really many different climate zones and microclimates, which can vary greatly.

But to get to the point, what is the temperature of the microclimate?

This is a critical aspect of climate zones because as the microclimate temperature approaches the dew point, the temperature of the airdrops and dew forms at the same time, the winds start to be warmer and that means the air is starting to be loaded with water vapor.

What you are seeing is the combination of temperature and humidity dropping and the air becoming heavy with water vapor, which explains why the air becomes heavy and becomes more prone to precipitation. This occurs most visibly in fog, but it also occurs in clouds, and when the air gets heavy with water vapor, it is able to produce precipitation.

A microclimate is a small region, such as a square meter or a meter-cube, that has its own environmental conditions, with its own conditions of heat and cold, light, and humidity.

For example, many of the plants in a small garden can have their own unique microclimates with particular conditions such as soil moisture, air humidity, and wind direction. A specific plant can be placed in a certain place in order to obtain the desired microclimate. For example, a potted plant can be kept in a location that is shaded most of the day. In a greenhouse, the microclimate can be used to regulate the relative humidity, temperature, and airflow.

In some of the literature, the microclimate is also called a site environment or a local environmental condition.

Causes

In a microclimate, the sun is closer to the ground (more direct sunlight) than it is to an observer, usually resulting in lower temperatures for that observer. This situation can be created by different types of vegetation. For example, tall trees shade smaller plants. However, in dense forests, the canopy shade is a secondary factor as the foliage is too dense to permit sunlight to reach the ground.

For a greenhouse or other structure that receives direct sunlight throughout the day, the effect of canopy shading is more important.

The intensity of direct sunlight in a given microclimate is a function of a number of factors: 

• The difference in elevation between the microclimate and an observer

• The tilt of the solar path relative to the surface

• The angle of the solar surface is relative to the vertical. In an example, the direct sunlight of noon is 10 percent of that of noon. This factor may be used to estimate the solar exposure of a microclimate.

Some types of plants, such as vines and deciduous trees, reduce the temperature of their leaves by evapotranspiration. Leaves are evaporative surfaces, and evaporative cooling reduces the temperature of the leaves. However, in the case of most vines, their water-conserving behavior is a function of soil moisture, while evaporative cooling occurs when soil moisture is greater than the plants’ root zone capacity. The water-conserving behavior is a function of soil moisture that allows the plants to maximize the quantity of water that is available to the plant. Evaporative cooling is a function of both leaf and soil moisture.

Light intensity is also an important factor. A shade tree can be planted in a sunnier location to provide shade for the rest of the garden. A structure can be built to collect the light and redirect it. The building can be located on a different day from the light that reaches the ground, or it can be located at a different time of day.

The wind pattern affects the shape and distribution of a greenhouse, and it affects the distribution of light and air humidity. The effect of wind on the air inside a greenhouse is often called a wind shadow. Many different forms of wind, such as the wind gusts, the wind direction, and the wind speed, are significant factors in the design of a greenhouse. The microclimate is sometimes used synonymously with the microclimate of a plant.

Uses

A microclimate can be used for the following:

• Plant phenology: the observation of growth, flowering, fruiting, and the death of a plant

• Water balance: the calculation of the evaporation and transpiration of water from plants

• Climatic studies: the comparison of a microclimate with the seasonal climate of a region

• Plant selection: the placement of plants that have specific needs for microclimate

• Design: the specification of a structure in terms of space usage

• Air quality and air pollution: the reduction of harmful gasses, like carbon dioxide and nitrous oxide

The microclimate is the aggregate of environment variables, including temperature, humidity, radiations, and to which plant is exposed. It is the climate near the Earth’s surface and it is distinct from the local climate or weather projection microclimate because of the earth effects and, most importantly, the presence of vegetation.

Microclimates occur, for example near the water bodies, which may cool the atmosphere, or in heavily urban areas where brick, concrete and asphalt absorb the sun’s energy, heat up and radiate that heat to the ambient air then the resulting urban heat island is a kind of microclimate.

The term “microclimate” is first introduced in publications such as “Climates in Miniature”: A Study of Microclimate Environment (Thomas Bedford, Franklin).

Microclimatology

The term microclimatology is defined as the scientific investigation of microclimate, and it’s concerned with the atmospheric layer that extends from the Earth surface to a height where the consequences of the features of the supporting surface can no longer be differentiated from the local climate (American Meteorological, 2000).

Urban Microclimate

Urban microclimate can be defined as the local climate observed in the urban areas, which differs from the climate of the surrounding rural areas. Several factors are responsible for creating an unhealthy urban microclimate.

Human-generated heat is the biggest factor and much of it is caused by internal combustion by car engines that use fossil fuels. Cars also cause pollution and moisture to the air. All the heat- retaining covered surface required for cars makes the climate more unhealthy. Other factors that are responsible for creating unhealthy urban microclimates are poor building constructions and designs, inferior insulating materials, and inefficient building management practices. 

Microclimate Parameters

Two microclimate parameters that define microclimate within a certain area are temperature and humidity. 

Macro and Micro Climate

A microclimate is defined as the variations in localized climate around a building, whereas a microclimate is the climate of larger areas such as a region or country. The macro and microclimate have a crucial effect on both the energy and atmospheric performance of buildings during the summer season.

The construction site affects exposure to the prevailing wind, the solar radiation the building receives, pollution level, temperature and rain penetration.

Factors Affecting Microclimate And Microclimate

The factors that adversely affect macroclimate and microclimate are discussed below.

Macroclimate is Affected By the following factors:

A microclimate is Affected by the following factors:

Outsiders Designer Control

• Area and local climate

• Site surrounding

• Site shape

• Topography features

• Surrounding Buildings

Within Designer’s Remit

• Location of open areas

• Spacing and orientation of buildings

• Form and height of a building

• Fenestration

• Tree covers

• Windbreak

• Ground Profiling

• Surrounding Surface (paving grass etc.)

 

Climate and Microclimate

Weather is defined as the atmospheric condition at a certain point in time or a short period of time. It is characterized by distinct methodological events such as air velocity, temperature, air pressure, and their interactions. On the other hand, climate can be defined as the average state of the atmosphere and related characteristics of the underlying water or land in a particular region for a long duration. The term microclimate can be used to describe an indoor climate, i.e., the condition of the area in a certain closed space. 

Difference between the Climate and Microclimate

The difference between climate and microclimate is that the climate is an area of the Earth’s surface between two parallels of latitude, whereas microclimate is a small, local region retaining a unique pattern of weather or weather effects that differs from the local climate. 

Did You Know?

• North California above the Bay Area is renowned for microclimate with significant temperature differences.

• San Francisco is a city with microclimate and sub microclimates.

• The Chesapeake Bay is also known for its subtropical climates.

• The wind microclimate around buildings is the result of the layout of the building.

• A microclimate is advantageous for gardeners who carefully choose and position their plants.

• Tall buildings in urban areas create their own microclimate both by overshadowing larger areas and by channelizing strong wind to ground level.

• Halixa, Nova Scotia has varied microclimates.

If you ever see ice sheets, you must have observed some peaks or rocks above the ice sheet which are higher in elevation than the surrounding ice. Different types of landforms can be seen on the surface of the Earth and it is also one of them. If we talk about an island, it is a mountain body that is exposed above and surrounded by the water. Similarly, Nunatak is a kind of glacial island that is exposed above and surrounded by ice. In this article, we will talk about Nunatak. We will learn nunatak’s meaning, its features, examples of nunatak glaciers in the world, etc. 

Nunatak Meaning

Nunatak is derived from the Inuit term “nunataq” which means lonely mountain in this American indigenous language. Nunatak is a rock or mountain that stands above the surrounding land of the ice sheet which is being glaciated. This kind of landform can be observed in the areas where a permanent ice sheet is there and nunataks are seen above the ice sheet. These are also known as “Glacial islands”.

Features

Some of the Features of the Nunatak Glacier are Given below:

• Some of the Nunataks are isolated mountains or rocks whereas some are found in clusters as well. For example, Queen Lousie Land, Greenland.

• They present reference points in ice caps or glaciers which can be identifiable.

• In ice sheets, these are the only regions where vegetation can be observed.

• Lifeforms here present unique habitats surrounded by ice sheets or glaciers.

• These generally are angular in shape along with rough & spiky points because of these features accumulation of ice on the tops are hampered ( although snow accumulation can happen on them ).

• It forms when the majority of the area is covered by the ice sheets or glacier which leaves the nunataks exposed above.

• The height of nunataks can be 20 feet or even more i.e. hundreds of feet. In Antarctica, the height of nunataks may be over 1000 feet. 

• They are found in the mountain regions where glaciers are there and these are found above the ice flows. They are also found where some former glacial activity has occurred in the mountain regions. Rocks & peaks with jagged surfaces can be found there along some of the areas below with smooth surfaces can also be found. 

Nunatak Definitions

Some of the Standard Definitions are Mentioned Below:

• “It is a hill or mountain completely surrounded by glacial ice.” – Merriam-Webster

• “It is a rock or a mountain that sticks up above the level of an area of ice or snow.” – Cambridge dictionary.

• “It is an isolated mountain peak projecting through the surface of surrounding glacial ice and supporting a distinct fauna and flora after the recession of the ice.” Or “a hill or mountain that has been completely encircled by a glacier.” Or “In Geology, it is an isolated mountain peak protruding through glacial ice.”  – Collins dictionary.

• “It is a rocky summit or mountain range that stands above a surrounding ice sheet in an area that is currently being glaciated.” – Oxford Reference.

Examples

• In Antarctica, some of the examples are Cook Nunataks, Andersson Nunatak, Lincoln Nunatak, Bergen Nunatak, Olander Nunatak, Bruna Nunatak, Bradley Nunatak, etc.

• In North America, some of the examples are Anoritooq Nunatak, Borgtinderne, C. H. Ostenfeld Nunatak, Crown Prince Frederick Range, Graah Mountains, Lille Renland, Peary Nunatak, Packsaddle Island, etc.

• In Eurasia, some of the examples are Lodalskåpa, Gora Severny Nunatak, Canisp, Stac Pollaidh, Suilven, etc.

Famous Nunataks

• Suilven is one of the famous Nunataks found in Scotland which looks like a mountain when we see it from land whereas it looks like a pillar when we see it from the sea. 

• Stac Pollaidh is also found in Scotland which is a mountain in the form of a ridge with smooth mountainsides that was carved out by glacial activity.

• Svarthamaren is one of the large Nunataks found in Antarctica which is famous because of home to one million birds i.e Antarctic Petrel during the breeding season.

Conclusion

Thus, to sum up, in the end, we can say that nunataks are a kind of landforms that can be found where glaciers are there and observed above the ice sheets. These are considered the only place where vegetation, as well as life, can be observed in the ice sheets. They form like an island in the ice sheets and where glacial activity has occurred earlier which leads to the formation of nunataks. These can rise from 20 feet to hundreds of feet and also over 100 feet as well. In this article, we learned about nunatak glacier, nunatak meaning and definitions, its features and examples, etc. This article will help you to understand new kinds of landforms found in the mountain/ glacier regions.

Mineral phases whose structures only produce oxide or hydroxide anions. Oxide and hydroxide minerals make up a small percentage of the Earth’s crust by volume. Their geochemical and petrologic significance, on the other hand, cannot be overstated. Metal ores such as iron, aluminium, titanium, uranium, and manganese depend heavily on oxy and hydroxide minerals. Oxide and hydroxide minerals can be found in any geological environment. Some form as primary minerals in igneous rocks, while others form as secondary phases as silicate and sulphide minerals weather and alter. Some minerals, such as oxides and hydroxides, are biogenic. For example, iron(III) and manganese(IV) hydroxides and oxides often result from bacterial oxidation of dissolved Fe₂⁺ and Mn₂⁺in low-temperature aqueous solutions.

Here we will learn about different mineral chemical compound oxides and hydroxides and iron oxides and hydroxides.

Mineral Chemical Compound Oxides and Hydroxides

Positively charged ions of metals or transition elements bind to negatively charged oxygen in oxide minerals, which are inorganic compounds,O₂^–. Oxide minerals are differentiated from other oxygen-bearing minerals such as silicates, sulphates, borates, phosphates, and carbonates by their classification into simple and complex oxides. Minerals with a hydroxyl group are known as hydroxyl minerals (OH^-1) instead of O₂^– , and oxyhydroxides, which comprise both hydroxyl group and oxygen, are often included in the group of oxide minerals.

The world we live in is based on the technological advancements made possible by oxides and their hydroxide counterparts.

On a molecular level, arrangements of closely knit oxygen atoms with metal or semimetal atoms woven in the spaces between can be found in the oxide family of minerals. Simple oxides are those that have only one form of metal or semimetal attached to them, and complex oxides are those that have several metals incorporated into their molecular structure. The hydroxides, on the other hand, are made up of metals attached to a highly reactive hydroxide ion (OH). Hydroxide minerals are lighter and less compact than oxide minerals since they form at lower temperatures.

While the crowned heads of royal dignitaries are adorned with rubies and sapphires (both colour varieties of the corundum mineral species), spinel, and chrysoberyl, minerals such as chromite (the most important ore of chromium), ilmenite (titanium oxide), and hematite (iron oxide) have provided us with some of the greatest innovations ever made. Iron oxides have played an important role in the cultural, technological, and industrial growth of ancient and modern civilizations, from cave paintings to satellites.

The world we live in is based on the technological advancements made possible by oxides and their hydroxide counterparts. They’re also abundant, making up the second most common component of the Earth’s crust.

Iron Oxides and Hydroxides

Simple oxides and multiple oxides are the two primary forms of oxides. Simple oxides are made up of a single metal and oxygen in one of many metal combinations: oxygen proportions (X:O): XO,X₂O, X₂O₃, etc. Ice, H₂O, is a simple oxide of the X₂O type that incorporates hydrogen like the cation. We know that SiO₂(quartz and its polymorphs) is the most commonly occurring oxide.

Oxides are found in small quantities in igneous and metamorphic rocks, as well as in sedimentary rocks as preexisting grains. The main ores of iron (hematite and magnetite), chromium (chromite), manganese (pyrolusite, as well as the hydroxides magnitude and romanechite), tin, and uranium all have significant economic value.

The spinel-group minerals have type XY₂O₄ and contain oxygen atoms in approximate cubic closest packing. Cubic packing of MgAl₂O₄ is shown below.

We would find structures of closely knit oxygen atoms with metal or semimetal atoms woven in the spaces between if we could peer into the oxide family of minerals on a molecular scale. Simple oxides are those that have only one form of metal or semimetal attached to them, and complex oxides are those that have several metals incorporated into their molecular structure. The hydroxides, on the other hand, are made up of metals attached to a highly reactive hydroxide ion (OH). Hydroxide minerals are lighter and less compact than oxide minerals since they form at lower temperatures.

While the crowned heads of royal dignitaries are adorned with rubies and sapphires (both colour varieties of the corundum mineral species), spinel, and chrysoberyl, also minerals such as chromite ilmenite (titanium oxide), and hematite (iron oxide) have provided us with some of the greatest innovations ever made. Iron oxides, in particular, have played an important role in the cultural, technological, and industrial growth of ancient and modern civilizations, from cave paintings to satellites.

The most common and most significant sources of iron known to us is hematite (Fe₂O₃). It’s a basic oxide with two iron cations and three oxygen anions in its structure. Hematite is a mineral that occurs under a variety of geologic conditions and can be found in a wide range of rock types. Other minerals, such as magnetite (another basic iron oxide) and quartz, may often mix with it.

Another significant hematite deposit is represented by banded iron formations. About two billion years ago, when cyanobacteria in Earth’s early oceans started to produce oxygen, a reaction occurred between their oxygen byproduct and iron in the oceans. The ocean floor was left with layers of dark magnetite and crimson, hematite-stained chert, a constant reminder of a planet only starting to exhale.

Hematite is used in a wide range of shapes and sizes. It has a flaky or massive structure, a metallic or earthy lustre, and a dark grey to silver or reddish-brown hue. It may take the shape of a kidney stone, which is a botryoidal form. Roses are flower-like clusters formed by flat hematite crystals. Hematite is distinguished by a distinct reddish-brown streak that occurs when the mineral is struck across a ceramic plate, regardless of its type.

Hematite gets its name from the Greek word for blood, and its dark red powder can be used to stain anything from bricks to make-up when crushed. Prehistoric pigments created from this crushed iron oxide—also known as red ochre in the art world—adorn the walls of sites like France’s Chauvet Cave. The use of red ochre evolved along with art and culture. Painters and other artists have been using tubes of the pigment to demonstrate their ideas for decades.

Despite the fact that humans have been mining hematite and other iron oxides for millennia, modern applications have only emerged in the last few decades. Many household products, such as mattress springs, vacuum cleaners, and dishwashers, are made with iron oxides. The manufacture of steel (an alloy of iron and carbon) is perhaps the most significant use of iron oxides today; approximately 98 percent of the iron ore mined in the United States is used in steel production.

Chemical Properties of Oxides

A chemical compound with at least one oxygen atom and one other element in its chemical formula is known as an oxide. An anion of oxygen in the oxidation state of 2 is commonly found in metal oxides. The majority of the Earth’s crust is made up of solid oxides, which are formed when elements are oxidised by oxygen in air or water. Carbon monoxide (CO) and carbon dioxide (CO₂) are the two main carbon oxides produced by hydrocarbon combustion (CO₂). Also materials that are thought to be pure elements may produce an oxide layer. Aluminum foil, for example, produces a thin layer of Al₂O₃ (known as a passivation layer) that protects it from further corrosion.

Diagram of oxide is shown below