Category: Geography Notes PPT

Grasslands are defined as areas where grasses predominate over large shrubs or trees. Mountains rose in western North America during the Miocene and Pliocene Epochs, which lasted about 25 million years and created a continental climate favourable to Grasslands. Ancient forests dwindled, and Grasslands proliferated. Following the Pleistocene Ice Ages, Grasslands spread across the globe as hotter and drier climates prevailed. Grasslands can be called multiple names, for example Grasslands in the USA midwest known as “prairies’ ‘. In South America, they are called “Pampas”. 

Grasslands are found on all the continents except for Antarctica as the land there is covered with thick snow, leaving no scope for any vegetation to break out from the soil. Human beings alter the natural vegetation and give birth to artificial vegetation of crops and pastures.

Grasslands are Classified into Two Types:

1. Savannas or Tropical Grasslands

2. Temperate Grasslands

Examples of tropical grassland include the hot savannas of sub-Saharan Africa and northern Australia.

 

Savanna Tropical Grassland

Savanna is Grassland with a few scattered trees. Savannas of one kind or another cover nearly half of Africa’s surface (about five million square miles, mostly in central Africa) as well as large areas of Australia, South America, and India. 

Savanna is a mix of different trees and grass, their proportion depends directly on the rain in that area. Some may range below 0.3 m while some can outgrow this and grow upto 2.1 m that is approximately 7 feet. It is also spelled as “Savannah”. 

 

Tropical Grassland Climate

• The most important factor in the formation of a savanna is the Climate. 

• Savannas are always found in warm or hot climates with annual rainfall ranging from 50.8 to 127 cm (20-50 inches). 

• It is critical that rainfall be concentrated in six to eight months of the year, followed by a long period of drought during which fires can occur. Many of these areas would become Tropical forests if rain fell evenly throughout the year.

• Climatic savannas are savannas formed as a result of climatic conditions. 

• Edaphic savannas are savannas that are caused by soil conditions and are not entirely maintained by fire. These can occur on steep hills or ridges with shallow soil, or in valleys with clay soils that become waterlogged in wet weather. 

• People clearing forest land for cultivation creates a third type of savanna, known as derived savanna. 

• Farmers cut down a forest, burn the dead trees, and plant crops in the ashes for as long as the soil is fertile. The field is then abandoned, and, while forest trees may recolonize, grass (succession) takes over on the bare ground, becoming luxuriant enough to burn within a year or so. 

• In Africa, elephants have created a savanna by eating leaves and twigs and breaking off branches, smashing trunks, and stripping the bark of trees in protected parkland. Elephants can quickly transform dense woodland into open grassland. Annual fires keep the area as a savanna.

 

Rainfall/Season:

• The average annual Rainfall in savannas is 76.2-101.6 cm (30-40 inches).

• The savanna has both a dry and wet Season. Seasonal fires are critical to the biodiversity of the savanna. 

• The start of the dry Season is signalled in October by a series of violent thunderstorms followed by a strong drying wind. 

• During the dry Season, fires are common around January. Poachers who want to clear away dead grass to make it easier to see their prey often start fires in savannas. The fires do not completely destroy the community. The majority of the animals killed in the fires are insects with short lives. 

• Some animals, such as birds, come to fire sites to eat grasshoppers, stick insects, beetles, mice, and lizards that are killed or driven away.

• Small creatures can find refuge in underground holes and crevices. 

• Larger animals can usually run fast enough to avoid the fire. Although fire consumes the dry stems and leaves of grasses, the grasses’ deep roots are unharmed. When the soil becomes moisture, these roots, with all of their starch reserves, are ready to send up new growth. 

• The scattered shrubs can also survive on food reserves stored in their roots until the time comes for them to rise above the soil again. 

• Trees, unlike grasses and shrubs, can withstand fire by retaining moisture in all of their above-ground parts throughout the dry season.

 

Tropical Grasslands Location

• Tropical Grasslands of the world near the equator produce plants that can withstand hot weather for the majority of the year, as well as drought and fires. 

• The African savannas are probably the most well-known, but Tropical Grasslands can also be found in South America, India, and Australia. 

• There are llanos in Colombia and Venezuela, Campos in the Brazilian highlands, Pantanals in Upper Paraguay, plains in Australia, and India’s Deccan Plateau. 

• Even though they are all hot, the annual rainfall varies. The Australian plains may only receive 18 inches (45.72 centimetres) of rain per year, but African savannas receive more than 50 inches (127 centimetres). 

• South America’s llanos and Pantanal are frequently flooded during a portion of the year.

 

Tropical Grassland Animals

• Although it may appear that Animal life is scarce on the savanna, it is actually thriving. Elephants, zebras, wildebeest, giraffes, and other browsers eat the grasses on Africa’s savannas, which are then eaten by cheetahs, lions, and other predators. 

• Emus and other foragers in Australia rely on hot Grasslands. Insects, on the other hand, constitute the majority of Animal life in the savannas. There are billions of locusts, termites, and flies here. 

• Zebras prefer fibrous grass, whereas hartebeest eat plant stalks left by previous foragers. Giraffes and elephants eat the trees, and carnivorous Animals hide in the tall grasses before pouncing.

 

Tropical Grassland Vegetation

The natural vegetation of Tropical Grasslands

• The savanna soil is porous, allowing water to drain quickly.

• It only has a thin layer of humus (the organic portion of the soil formed by the partial decomposition of plant or animal matter), which provides nutrients to vegetation. Savannas are sometimes referred to as forests. 

• Grass and forbs are the most common types of vegetation (small broad-leaved plants that grow with grasses). Because of differences in rainfall and soil conditions, different savannas support different grasses. 

• Because the savanna supports so many species competing for living space, only one or a few types of grass are usually more successful than the others in a given area.

• For example, in drier savannas such as the Serengeti plains or Kenya’s Laikipia plateau, the dominant grasses on well-drained soils are Rhodes grass and red oat grass; star grasses are dominant throughout East African savannas, and lemon grasses are common in many western Uganda savannas. The open landscape is dotted with deciduous trees and shrubs. 

• One type of savanna, known as grouped-tree grassland, is found in southwestern Kenya, Tanzania, and Uganda, and features trees that grow only on termite mounds, with the intervening soil being too thin or poorly drained to support tree growth at all. 

• Frequent fires and large grazing mammals kill seedlings, keeping tree and shrub density low. 

Threats to Savanna Grassland – 

• Fire – managing fire is very typical because it can be very dangerous and fatal to the lives of every breathing being. Fire in a forest is way more troublesome than compared to the cities and villages. Though everything is connected and closely attached, even a small spark can turn the whole forest in ashes very quickly. Savannas are known for fire occurring on a regular basis. 

• Animal grazing – animals don’t graze on closely structured forest as the trees and grass doesn’t provide much opportunity to them to even enter in them. Savanna on the other hand is open structured and considered as a hub for the grazing animals to enter and graze on the vast fields. Animal grazing affects the soil because when these animals graze, they disturb the soil with their tongue. 

• Change in the climate – there is evidently said by the researchers that Savanna is expanding its range in reaction to the visible variation in the climate there and it is possible that the Grasslands are shifting dramatically and the distribution of vegetation changing. 

• Clearing of trees – the Savannas of Australia and South America are clear of trees now and still going on in a continuous manner. The vegetation in these areas are disturbed by the process of thinning down the trees.  There are many techniques used in clearing or cutting down woody plants. Heavy machinery was also used for this process. 

Volcanic Ashfall can be defined as the minerals, rock fragments and glasses that are exposed violently during a volcanic eruption in the form of ashes into the atmosphere.

The force created by the gases present in the magma propels the ashes to solidify in the atmosphere in the form of volcanic rock fragments and glass. On this page, students will get an idea about the formation and properties of volcanic ashes. We have also provided information about different types of Valcano.

These ashes also commonly known as tephra includes all the erupted volcanic particles, even the one larger than 2 mm in size. The explosion of this ash in the air has a negative impact on the health of humans as well as animals. As the disruption takes place in a wider aspect, it also greatly affects the infrastructures, buildings, industries, vegetations and cultivations of the nearby areas. 

Formation of Volcanic Ash Falls 

The formation of volcanic ashes or ashfall is an outcome of a volcanic eruption that takes place due to the expansion of the magma. Magma is the hot molten form of rocks present under the Earth’s surface. On exertion of high pressure, these magma comes out violently in the form of hot bubbling lava which leads to a volcanic eruption. On coming in contact with the air, the magma solidifies in the form of rock fragments and glass known as volcanic ashes. These ashes are minute particle-like which have a diameter less than 2 millimetres.

As a result, the volcanic ash in the air can be carried to a larger area by the winds and falls eventually on the ground creating a layer of a thick dust-like particle around the area of eruption. 

The formation of volcanic ashes also occurs as a result of phreatomagmatic eruptions. This kind of eruption takes place due to the contact of the magma with the water bodies, or even snow. This, as a result, forms an insulating vapour film as the boiling point of magma is higher than that of water. The reaction of cold water with hot magma increases the amount of heat transferred, thus, leading to expansion of water and fragmentation of the magma, which later comes out violently through the vents of the Volcano. 

Unlike burnt wood ashes, these volcanic ashfalls can be dangerous as they have sharp edges containing very small particles of glass and hardened rocks. There are several harmful effects of volcanic ashes on humans as well as animals. It can lead to breathing problems and irritation of the eyes, lungs and nose. 

Composition of Volcanic Ashfalls

Volcanic ashfalls are the hardened form of magma in the form of rock fragments and volcanic glasses after coming in contact with the exposed air. The elements found in the volcanic ashes depends upon the thickness of the ashes along with the chemistry of the erupted magma. But as per the reports, the abundantly found elements in these volcanic ashes includes silicon and oxygen. The dark coloured ashes formed after eruptions mainly consist of 45-55% of silica. This silica is rich in iron (Fe) and magnesium (Mg) content. These ashes are sharp-edged particles that have a thickness ranging from 1-5mm which even goes up to 100-300 mm in adverse conditions. 

Apart from the volcanic ashes, volcanic eruption also releases harmful gases into the atmosphere which causes severe breathing problems and irritation to the human eyes and nose. These gases are mainly sulfur dioxide, carbon monoxide and dioxide, hydrogen, hydrogen sulfide and hydrogen chloride. 

Effects of Volcano Ashfalls 

The effects caused by the ashfalls depends upon the thickness of the volcanic ashes. The thickness of the ashes may range from 1-5 millimetres and in adverse conditions it may be over 100-300 millimetres. Since volcanic eruptions cover a wider area, it greatly affects the nearby area. 

Some of the Impacts of Volcanic Ashfalls on the Ecosystem are Given Below:

• Volcanic Ashfalls can greatly affect the crop fields and can cause damage to the crops and vegetation. 

• They also contaminate the nearby water bodies, which as a result affects the marine ecosystem.

• Due to its expansion in a large area, it causes damage to the infrastructure including roads, buildings and breakage of telephone and electric polls, thus affecting the normal living of human beings.

• As volcanic eruptions release harmful gases such as carbon dioxide, sulfur dioxide and hydrogen sulfide into the atmosphere, it gives rise to breathing inability and irritation of the skin, eyes and nose.

• Ashfalls of higher thickness ranging from 100-300 millimetres can lead to collapsing of building, the burial of low plants and severe damage to plantation and trees.

• Livestock and other animals are killed every year due to this complete burial of land and soil horizon.

White Mica Powder is a pearlescent powder pigment that yields a satin white colour, ideal for backgrounds and seascapes. We can also use a little amount of mica powder in order to lighten darker micas. Mica Powder in different forms is acquired by grinding and exfoliating mica flakes, which is a slow, expensive and extremely complicated process. The process of mica powder formation is tough mainly because it is having a plate-like structure and delamination of flakes.

           

Facts About Mica Powder

Mica powders are:

• Composed from muscovite flakes coated with ultramarines, iron oxides and organic dyes

• Cosmetic grade natural mineral pigments that contain a wonderful shimmer and metallic-like appearance.

• Completely non-toxic, ethically sourced, vegan ( NO crushed beetles) and are cruelty-free,

• Contains millions of light-reflecting particles that form appealing shiny effects in all kinds of arts, crafts and cosmetics.

• Pure white mica powder is free from “fillers” and thus have pure pearly colour

• Is also available in delicate pastels to vibrant and bold shades

• Is a raw material which is perfectly safe to use in cosmetics (skin, lips, eyes)

What is a White Mica?

White mica is a finely-grained (coarse) version of any of the silicate minerals i.e.— muscovite, paragonite, or talc. White mica denotes a group of dioctahedral sheet silicates that are usually formed in low-grade metamorphic and hydrothermally reworked rocks. This substitution results in white mica in addition to compositions transitional from muscovite to celadonite, which is often referred to as phengite or phengitic white mica.

Top Tips To Use Mica Powder

• Intermix: With mica powders, you can create any colour under the sun

• Quantity in Resin: Mica powder being inert allows you to pretty much use as much as you like. It doesn’t affect the chemicals that induce resin and hardener to cure.

• Dust into Moulds: Use a soft-bristled craft brush in order to dust mica powder inside silicone moulds before making resin candles and castings. This will provide a more balanced shimmer effect.

• Soap & Bath: The mineral is just perfect for CP & M&P soap makers. However it is not soluble in water, therefore to make bath bombs you will need to add Polysorbate 80.

Refer to the table below for complete information on mica and white mica powder.

Physical and Chemical Composition and Properties of White Mica

Mica Reserves in India

India is the foremost supplier of mica mineral to the world with major reserves in:-

• Andhra Pradesh (41%)

• Rajasthan (21%)

• Odisha (20%)

• Maharashtra (15%)

• Bihar (2%)

• Jharkhand (Below 1%)

Mica Production and Distribution in India

India bears a near monopoly when it comes to the production of mica [60 % of the world’s total] With

• Andhra Pradesh (1st in production [93 %]).

• Rajasthan (2nd in production [6.3 %]).

• Jharkhand (3rd in production).

Mica Exports

India is by far the largest exporter of mica. Certain grades of Indian mica are and will continue to be vital to the world’s electrical industries. Major exports of white mica are executed through Kolkata and Visakhapatnam ports.

Fun Facts

• White mica and most Mica have a high refractive index (higher than sparkle) and even excellent chemical, mechanical and thermal stability.

• Made from natural minerals, mica powder contains a small micron size (giving great cover and diffusion, and the all-significant shimmer)

• you only require a little amount of mica powder in order to create lustrous effects.

• Can be used in art, resin, nail polish, car paint card-making, calligraphy, body butter/wax, oil, face products and cosmetics such as eye shadow, blushers and lip products.

• You can mix micas to create new shades

• India is one of the top suppliers of mica to the world.

• Mica-carrying igneous rocks form in Maharashtra, Andhra Pradesh, Bihar, Jharkhand, and Rajasthan.

• Significant imports of Indian mica are Japan (19%), United States (17%), and the United Kingdom etc.

Everything that takes up space is classified as matter. Air is unavoidable for our existence. The atmosphere is a blanket of air that covers the world. It is among the most vital elements for the existence of life since no life can survive for a single pulse of time without it. It is necessary for all creatures to survive. Let us learn about “what is air made of” and air composition. Also, air influences abiotic environmental components such as wind, rain, and climate.

The atmosphere, usually known as air, is a combination of different gases. When we think of air, the first thing that comes to mind is oxygen, which is necessary for life on earth to survive. However, oxygen is not the only important gas present in the air. Other gases are equally crucial in the maintenance of life. Let’s take a closer look at the composition of the air that allows life to exist on earth.

Air Composition in Atmosphere

The atmosphere of the Earth is made up of a combination of gases called air. These gases are colourless and odourless. In the atmosphere, these gases combine to form a mixture of gases. It is made up of 78 % nitrogen, 21% oxygen, and 1 % other gases and water vapour. As we move up through the levels of the atmosphere, the composition of the air does not change. The number of molecules present in the air is what changes. The number of air molecules decreases and becomes smaller, as we go up. The moisture content varies from location to location. As compared to wetlands, arid places have less moisture content. The amount of water vapour or moisture in the air fluctuates. Air’s maximum moisture carrying capacity is primarily determined by temperature. Until you reach a height of around 10,000 m, the composition of the air remains unchanged.

()

Percentage of Gases in Air

Nitrogen is the most abundant naturally occurring gas, accounting for approximately 78% of air. With a prevalence of roughly 21%, oxygen is the second most abundant gas in the air. Argon, an inert gas, accounts for 0.93 % of the total composition. The atmosphere contains trace amounts of carbon dioxide, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, iodine, carbon monoxide, water vapours, and ammonia. Now, let us talk about how these gases are produced and their various roles in our environment.

• Nitrogen: Nitrogen makes up 78% of the air in the atmosphere. The nitrogen cycle transfers nitrogen to plants, animals, and the environment.

• Nitrous Oxides: When nitrogen oxides interact with water droplets in the air, they produce nitric acid, which contributes to acid rain.

• Oxygen: Oxygen accounts for 21% of the atmosphere. It is extremely reactive and forms compounds with a wide range of other chemicals, and it is required for living creatures to breathe.

• Ozone: The ozone layer, formed by ozone gas in the stratosphere, is critical for the survival of life on Earth’s surface.

• Argon: Argon makes up around 1% of the atmosphere and is mostly produced by the breakdown of potassium in the Earth’s crust. It does not react with other substances since it is an inert gas.

• Water Vapours: Water circulates through all of Earth’s systems in its three states, solid, liquid, and gas. Since it can trap heat, water vapour in the atmosphere acts as a greenhouse gas.

• Carbon Dioxide: Carbon dioxide makes up about 0.03 % of the atmosphere naturally, but it is growing as a result of the combustion of fossil fuels. Carbon dioxide is used by plants and eubacteria during photosynthesis. Through breathing, humans, other animals, and plants contribute to the air. It is a heat-trapping greenhouse gas. 

• Carbon Monoxide: Carbon monoxide in the atmosphere is caused by the combustion of gasoline in automobiles, volcanoes, and forest fires. It’s a lethal gas.

• Methane: Landfills, animals and their manure, and oil and gas wells, all emit methane gas into the atmosphere. It is also produced during the decomposition of organic matter. It is a heat-trapping greenhouse gas.

• Sulphur Dioxide: When coal and oil are burnt, sulphur oxides are created. It is also emitted by volcanoes. Sulphuric acid is formed when sulphur oxides in the atmosphere react with water droplets. Sulphuric acid is a component of acid rain.

Various Properties of Air

As already stated, gases are matter. Gases, like every other matter, have particular features. The following are some examples of frequent properties.

• Colourless and Odourless: Air is usually colourless and odourless. It’s an impenetrable substance that can only be felt. All living things require oxygen to survive. Moving air is referred to as wind.

• Occupy Space: It is a blend of many gases. As a result, they, like all matter, occupy space. A balloon expands when blown because the air poured into it fills the empty area. 

• Exerts Pressure: It has weight, and air pressure is the force exerted by the weight of air. This combination of gases near the surface is denser than at high elevations due to gravity. That explains why the gaseous atmosphere is thinner in the mountains than at ground level.

The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and forms its planetary atmosphere, and is held in place by gravity. The Earth’s atmosphere protects life on the planet by maintaining surface pressure that allows liquid water to remain, absorbing ultraviolet solar radiation, warming the surface through heat retention, and reducing temperature extremes between day and night.

Earth and Atmospheric Science

The study of the atmosphere and its various inner-working physical processes is known as atmospheric science. Meteorology is the study of the atmosphere’s chemistry and physics, with an emphasis on weather forecasting. Climatology is the study of long- and short-term atmospheric changes that characterize average climates and how they evolve as a result of natural and anthropogenic climate variability. The analysis of the upper layers of the atmosphere, where dissociation and ionization are significant, is known as aeronomy. The area of atmospheric science has been expanded to include planetary science and the study of the atmospheres of the solar system’s planets and natural satellites.

Experimental instruments used in atmospheric science include satellites, rocketsondes, radiosondes, weather balloons, and lasers.

Oceanic Sciences 

The mechanics, chemistry, and biology of marine environments are all covered by ocean sciences. Ocean circulation, energy dissipation, marine biology, ecology, biogeochemical cycles, water mass formation and movement, ocean temperature, and salinity, and marine carbon and carbonate chemistry are all topics covered in this area.

Atmospheric Scientist

Atmospheric scientists can work in nearly any area that has to do with the atmosphere. They are more than just meteorologists and weather forecasters; their credentials enable them to conduct research and analysis of the environment in the future, present, and past, ranging from major weather systems to minor impacts on other biological life.

What do Atmospheric Scientists do?

The word “atmospheric science” refers to anyone who studies the atmosphere of our earth. Although the topic includes meteorology (the study of weather), it is not the only aspect of it. Atmospheric scientists will examine the weather and forecast what it will be like in an hour, a day, a week, or the following season. An Atmospheric Scientist, for example, will have the experience to understand the mechanism that will lead to those two phenomena in the first place and will predict when they are supposed to occur, while a meteorologist will understand and predict the results. They’ll study regional trends and create a map of the overall scene, including the causes and effects.

They can work in public health, researching air quality and its effects. This is frequently unrelated to the weather. They may also be able to forecast long-term drought cycles and provide mitigation advice. Short-term weather is just a small part of this job, once again.

Meteorologists concentrate on the current, while atmospheric scientists look back at older data to create an image of past climate, weather, and atmospheric conditions. They are more likely to research historical data (paleoclimate data), such as tree ring information, to determine the composition of the atmosphere. They’ll look at chemistry, climatology, and the nature of weather systems on this planet and those in the solar system, as well as physics.

In India, there are various institutes which offer atmospheric science degrees to the students which are related to the field of earth and atmospheric sciences. Most jobs in atmospheric science include a bachelor’s degree in meteorology or a closely related earth science field. Atmospheric scientists need a master’s degree at the very least, but a Ph. D. is normally needed for research positions.

Atmospheric and Oceanic Sciences

Princeton University and the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory (GFDL) collaborate on the Program of Atmospheric and Oceanic Sciences (AOS). Graduate students, postdoctoral researchers, visiting researchers, permanent research staff, and professors are all hosted by AOS, which is an independent program within the Department of Geosciences. 

Meteorology Programs

Meteorology is a branch of atmospheric science concerned primarily with weather processes and forecasting. The physical, dynamical (a force that causes change or motion), and chemical state of the Earth’s atmosphere, as well as interactions between the atmosphere and the Earth’s surface, are all studied in this area.

To pursue a career in meteorology, one must possess ample interests as well as a high level of education. Meteorologists have a variety of lucrative career options.

Various Meteorology Programs are Enlisted below:

Calcite mineral forms rocks and has the chemical formula CaCO₃. It is widespread and can be found in sedimentary, metamorphic, and igneous rocks all over the world. Some geologists consider it a “ubiquitous mineral,” meaning it can be found anywhere.

Calcite is the most common form of calcium carbonate and is known for its varied and beautiful crystals. Calcite often occurs as scalenohedral and can be commonly twinned as heart-shaped or butterfly twins. The calcite crystals are generally found as rhombohedral terminations; however, there are shallow rhombohedral terminations, also known as nailhead spar.

Calcite is the main component of limestone and marble. These rocks are extremely common and account for a sizable portion of the Earth’s crust. They are one of the world’s largest carbon repositories.

Optical Spar is a highly transparent calcite. It is usually found as spectacular crystals, which are massive, either as marble or as limestone. The calcite can also be seen as earthy aggregates, fibres, nodules, and stalactites. The specimens of calcite specimens can occur in igneous rocks, hydrothermal veins, and metamorphic deposits.

Various Forms of Calcite

There are various forms of calcite that are found in multiple parts of the world.

• Calcite as Oolitic Limestone: Oolitic limestone, a form of calcite is found in Tyrone, Pennsylvania, approximately ten centimetres in size.

• Calcite as translucent onyx: Translucent Onyx, a form of calcite is found in Tecali, Mexico, approximately ten centimetres in size.

• Double refraction in calcite: Iceland Spar, a form of transparent calcite, is found in Chihuahua, Mexico. This specimen exhibits excellent double refraction and is approximately ten centimetres in size.

• Calcite as calcareous tufa: Calcareous Tufa, a form of calcite is found in Mumford, New York, approximately ten centimetres in size.

• Calcite as travertine: Travertine is a form of calcite found in Tivoli, Italy, which is approximately ten centimetres in size.

• Picasso Stone: Picasso Stone, a marbled variety with brown and black marks, is often cut and polished as cabochons to produce stones in jewellery and ornamental crafts.

• White calcite as marble: Calcite in the form of white marble is found in Tate, Georgia, approximately ten centimetres in size.

Calcite Mineral- Natural Occurrence

Calcite is a common constituent of sedimentary rocks, mainly limestone, which is formed primarily from the shells of dead marine organisms. Limestone makes up about 10% of sedimentary rock. It is the main mineral found in metamorphic marble. It can also be found as a vein mineral in hot spring deposits, stalactites and stalagmites in caverns, volcanic or mantle-derived rocks such as carbonatites, kimberlites, and rarer cases, peridotites.

Calcite is a primary constituent of the shells of many marine organisms, including plankton (such as coccoliths and planktic foraminifera), the hard parts of red algae, some sponges, brachiopods, echinoderms, some serpulids, most bryozoa, and parts of some bivalves’ shells (such as oysters and rudists).

Calcite can be found in spectacular form in New Mexico’s Snowy River Cave, where microorganisms are credited with natural formations. Trilobites, which went extinct a quarter billion years ago, had compound eyes with lenses made of clear calcite crystals.

Calcite Formation Process

Calcite formation can occur via a variety of mechanisms, ranging from the classical terrace ledge kink model to the crystallisation of poorly ordered precursor phases (amorphous calcium carbonate, ACC) via an Ostwald ripening process or nanocrystal agglomeration.

Acc Crystallisation Can Take Place in Two Stages:

First, the ACC nanoparticles rapidly dehydrate and crystallise to form individual vaterite particles. Second, the vaterite undergoes a dissolution and reprecipitation mechanism, with the reaction rate controlled by the calcite surface area. The second stage of the reaction occurs at a rate that is approximately ten times slower. Calcite crystallisation, on the other hand, is pH-dependent and Mg-dependent in solution.

During mixing, a neutral starting pH promotes the direct transformation of ACC into calcite. When ACC forms in a solution with a basic initial pH, it transforms to calcite via metastable vaterite, which forms via a spherulitic growth mechanism. A surface-controlled dissolution and recrystallisation mechanism transforms vaterite to calcite in a second stage. Mg has a significant effect on the stability of ACC and its transformation to crystalline CaCO₃, resulting in the formation of calcite directly from ACC.

What is Calcite Chemical Formula?

Calcite Formula: CaCO₃

Calcite Chemical name: Calcium Carbonate

Calcite Mineral – Physical Properties

Calcite Production

The major steps for Calcite production are as mentioned below:

Step 1: Crush the incoming minerals and transfer them to ball mills to convert them to powder form.

Step 2: Sieve the powder form and separate it into the desired grades.

Step 3: Split the powder in 3-micron, 5-micron, 10- micron bags as required.

The important fact is that with 100 tonnes of mine, 99.99 tons is extracted without any further additives.

Calcite Uses

Calcite crystal’s properties make it one of the most widely used minerals. It is used as a building material, abrasive, agricultural soil treatment, construction aggregate, pigment, pharmaceutical, and other applications. It has more applications than nearly any other mineral.

Calcite as Limestone and Marble

Limestone is a sedimentary rock that is primarily composed of calcite. During diagenesis, it is formed by both the chemical precipitation of calcium carbonate and the transformation of shell, coral, faecal, and algal debris into calcite. Limestone is also formed as a deposit in caves as a result of calcium carbonate precipitation.

Marble is a metamorphic rock formed when limestone is heated and pressed. A close examination of a broken piece of marble will usually reveal visible calcite cleavage faces. The degree of metamorphism determines the size of the calcite crystals. Larger calcite crystals are found in marble that has been subjected to higher levels of metamorphism.

Calcite in Construction

The construction industry primarily consumes calcite in the form of limestone and marble. These rocks have been used as dimension stones and in mortar for thousands of years. Many of Egypt’s and Latin America’s pyramids were built with limestone blocks as the primary building material. Today, rough and polished limestone and marble are still popular materials in high-end architecture.

Calcite in limestone and marble are used in modern construction to make cement and concrete. These materials are easily mixed, transported, and placed as a slurry, which hardens into a durable construction material. Concrete is used to construct buildings, highways, bridges, walls, and a variety of other structures.

Calcite Mineral in Acid Neutralization

Calcite has a wide range of applications as an acid neutraliser. Limestones and marbles have been crushed and spread on fields as an acid-neutralising soil treatment for centuries. They are also heated to create lime, which has a much faster reaction rate in the soil.

In the chemical industry, calcite is used as an acid neutraliser. Crushed limestone is dispensed into streams to neutralise their waters in areas where acid mine drainage is a problem.

In medicine, calcium carbonate derived from high-purity limestones or marbles is used. Calcium carbonate is mixed with sugar and flavouring to make chewable tablets that are used to neutralise stomach acids. It is also found in a variety of medications used to treat digestive and other ailments.

Calcium Carbonate Sorbents

Sorbents are substances that can “capture” or “retain” another substance. Limestone is frequently treated and used as a sorbent material in the combustion of fossil fuels. Calcium carbonate reacts with sulphur dioxide and other gases released by combustion, absorbs them, and prevents them from escaping into the atmosphere.

Monuments and Statuary

Marble is a beautiful and easy-to-work-with stone that has long been used for monuments and sculptures. Its lack of significant porosity allows it to withstand freeze-thaw action outdoors, and its low hardness makes it a simple stone to work with. It has been used in projects ranging from the pyramids to a figurine. It is widely used in constructing cemetery markers, statues, mantles, benches, stairways, and other structures.

Many Other Uses

Calcite has a white colour when powdered. Calcite powder is frequently used as a white pigment or “whiting.” Calcite was used in some of the first paints. It is a primary component of whitewash and is used as an inert colouring agent in paint.

Animal feed frequently contains pulverised limestone and marble as a dietary supplement. Cattle that produce milk and chickens that produce eggs require a calcium-rich diet. To increase calcium intake, small amounts of calcium carbonate are frequently added to their feeds.

Calcite Uses in Other Industries

Paper Industry

The calcite is used as filler and coating material in most paper-producing industries to harden or smoothen, as necessary. Calcite allows rapid paper drying in the paper-making process due to its oil absorption feature. This makes it a useful ingredient in newspapers, magazines, and high-quality paper-making factories. Calcite is also used as a filling material for cigarette paper.

Paint Industry

Calcite is used as a pigment material to prevent steel wear, increasing water and chemical resistance.

Tyre Industry

Calcite is the main material used as filler for rubber in tyre-producing factories. With calcite addition, the tyre is usable for a long time without loss of softness which lessens the elongation and stretching.

Plastic Industry

Calcite is also the primary filling material in plastic factories as it helps maintain the thickness everywhere. Also, it provides hardness and flexibility at the same time, along with being resistant to high temperatures.

Agriculture

To obtain larger agro-products from acid-bearing soil types, it is important to supply Ca in increased quantities. This is how life under Earth can be improved, and the pH must be between 6 and 7.5.

Glass-Glass Glue

Calcite increases resistance to chemical effects in glass which is why it is used in glassmaking. It is also used in bottles and window glass making because it brightens the colour of the glass.

The finely ground limestone is used as a filler material in making glass glue due to its oil absorption properties.

Ceramic Industry

Calcite is added to the tile slurry to remove the harmful effects of SiO2 in the medium. It also increases the strength of the ceramic material with its usage by 2-6%. If this percentage is increased, the percentage will change to pink or yellow speckles that will deform at high temperatures.

Water Treatment

Calcite is used to maintain the hardness of the water and can control the watercolour or its cleaning.

Other Sectors

Calcite Distribution Around the World

Calcite is found in almost every continent. There are large hued calcite deposits in Mexico and the USA. The calcite is distributed in the following places as per various nations.