Category: Geography Notes PPT

The tropical wet and dry climate in geology is also called the tropical savanna and is part of the Koppen climate division system that groups climates based on vegetation. Having signs of the monsoon climate, the tropical climate is represented by a wet season and a dry season. It is situated between 5° and 25° latitude, in Africa, Australia, Central and South America, and in Southern Asia. In essence, a tropical season tends to either observe less rainfall than a tropical wet climate or have more pronounced dry seasons.

The article provided below is prepared by the experts on the subject who understand the needs of the students and also the challenges they face while learning the topic or dealing with the tough questions in the exams. The content could be downloaded in PDF format by the students.  It could be accessed through any apple, android or windows device. To the surprise of the student’s, resources are totally free of cost, which satisfies ’s intent to provide affordable education to all.

 

What is the tropical wet-dry climate known for?

Tropical Wet and Dry climate is known for its two seasons i.e.

1. Wet season (summer) 

2. Dry season (winter) 

Generally, the dry season lasts longer. During the dry season, plant life and animal life struggle to tackle the dry conditions, but as the rainy season starts, plants turn green, ponds fill up, and animal life blossoms. What Causes Wet and Dry Seasons? This tropical savanna climate is caused by changing wind and ocean currents.

Tropical Wet Season

The wet season in the tropical savanna usually stays from June to October in the northern hemisphere and from December to April in the southern hemisphere. The rain is an outcome of a combination of warm, tropical air masses from huge bodies of water and then the sun is located higher in the sky. Temperatures remain quite high during the wet season but can drop drastically at night. Depending on the year and the location, the wet season can result in annual rainfall of below 10 inches to more than 50 inches.

Tropical Dry Season

The dry season in tropical savanna remains for most of the year when there is little or no rainfall because of the continental tropical air masses and the sun is lower in the sky. Usually, the higher the latitude of the area, the longer the dry season is disposed to be. Most dry seasons start around November and last through June when the rains return in the northern hemisphere. Dry seasons lean-to last from about May through November in the southern hemisphere. Temperatures reach their highest around the end of the dry season before the rain occurs. The average daily temperature in the dry season usually remains in the upper 70’s Fahrenheit, but, depending on the location, daytime temperatures can soar above 100° Fahrenheit.

Location of Tropical Wet and Dry Climate

Tropical wet and dry climate is typically observed within the tropics. The tropics are two lines of latitude at 23.5° north and 23.5° south of the Equator. Land within this area obtains direct sunlight throughout most of the year. The tropical climate is observed between the tropical wet climate and the tropical dry climates in both the northern and the southern hemispheres. It varies in latitude from between 5° and 10° to between 15° and 20°. Most people realize the tropical savanna to be in Africa, though this climate is also recognized in Brazil, Venezuela, the Caribbean, Central America, and Indo-China, parts of India and even areas of Florida.

How are Dry Climate Regions Identified?

Do you know how we distinguish between a tropical wet and a tropical dry climate?

Tropical dry climates happen in deserts, while tropical wet climates generally are seen along the rainforest belt. Tropical wet and dry climates acknowledge a distinct dry season and a distinct wet season. Places that undergo tropical wet climates receive sufficient rainfall to sustain a population of trees.

How Much Rain Does Tropical Wet and Dry Climate Receive?

Amount and change in precipitation are what provides this climate type with its name. Precipitation only falls in the summer months, generally from May-August with June and July experiencing the heaviest rainfall. The whole dry season generally receives less than 4 inches of rain. During the wet season, a minimum of 25 inches will fall. Some areas of Tropical Savanna in the path of monsoon winds can receive unbelievable amounts of rain. Cherrapunji, India once received more than 1,000 inches of rain in a year! Northern Madagascar reported the record for rain having -71 inches in one day!  Mawsynram, India is popularized as the “wettest place on earth” since it receives an average of 467 inches of rain per year. These incredible rainfall records are because of the seasonal winds called monsoon, which bring along dangerous amounts of rain. 

Approaching geography topics

Geography is a very practical subject and requires some practical bend of mind to deal with it.  To begin with, one should study the subject with pictures and diagrams which depict the whole process in the topic. One can also watch some videos created by the teachers at to help students solidify the concepts properly.

Further, the students should read the previous year question paper of the subject. These question papers (which are also available on ’s website for free) give a realistic view of how a subject should be tackled. The student can judge the difficulty levels of the topics asked in the exam and understand how to pursue them. If the student uses the above-mentioned tips by the mentors, pursuing the topic would eventually become easy.

Build upon your writing speed

Geography is a social sciences subject and to tackle a subject of social sciences, having good writing speed is a must. In order to write faster one has to practice a lot of writing. Writing is one of the skills that can determine a lot of what score you will be getting in the final exams.  Writing speed along with presentation are a few important components of exams. The challenge in the path is time. Therefore, the students are advised to set a timer and practise with the clock.  Make sure you are making conscious efforts to make your writing more presentable.

Water is one of the most vital sources for all living organisms. Although water is a renewable resource, scarcity of quality water is still a big issue in many parts of the world. We need water for various purposes such as to grow food, keep clean, generate electricity, control fire, and most importantly to stay alive.

Types of Water Resources

Saltwater Resources: 

• The planet’s atmosphere is covered in saltwater. However, when it relates to potable water sources, saltwater is actually ineffective. Desalination plants, though they do operate, are in short supply due to the high energy costs associated with the operation.

• Apart from spectacular ocean views, there have been saltwater opportunities through which humans gain profit. Saltwater fish is indeed a staple of many people’s diets around the world. In addition, tidal waters have been used to generate hydroelectric power.

Groundwater Resources: 

• Of all the freshwater resources, groundwater in the water natural resources is perhaps the most abundant. Part of the water that filters down into the soil via layers of dirt, clay, and rock stacks to the uppermost layers, providing water to the plants. 

• This water is in the vadose region, which means it is unsaturated. Instead of water, almost all of the pores in the vadose zone are filled with air.

• Inputs, outputs, and storage are the same for groundwater as they are for surface water. The crucial distinction is that, due to the slow turnover rate, groundwater storage is typically much greater (in volume) than surface water storage in comparison to inputs.

• Because of this distinction, humans may use groundwater in an unsustainable manner over an extended period of time without suffering serious repercussions. Nonetheless, the average rate of drainage above a groundwater source is the upper limit for average groundwater use during the longer run.

Surface Water Resources: 

• The water in lakes and rivers is known as surface water. Potable water, recreation, industry, agriculture, transportation, livestock, and hydroelectric energy are all uses for this water. 

• Groundwater natural resources provide over 63 percent of the municipal water supply. Irrigation relies on surface water for 58 percent of all its water supply. Irrigation relies on groundwater for 58 percent of its water system. 

• Surface water systems have nearly 98 percent of the water used by industry. As a result, maintaining and improving the surface water quality is critical. Watershed entities track streamflow and groundwater management on a regular basis. 

• Flooding and drought conditions are predicted by monitoring streamflow. Since surface water provides most of the water used within the United States, water resources information and management are important. It is a chemical, biological, and physical test that determines how acceptable the water is. 

• Electrical conductivity, temperature, pH, dissolved oxygen levels, phosphorus levels, bacteria levels, and nitrogen levels are evaluated as indicators of water quality.

Though earth is called the water planet as it is occupied by 75 percent of water, this water cannot be used for domestic purposes. Ocean water is saline in nature and is not fit for human consumption. Freshwater is just around 2.7 percent of the total water on the earth. Issues such as global warming and perpetuating water pollution have made a considerable amount of impact on making freshwater unfit for human consumption. 

Uses of Freshwater

Water resources are used in various fields such as agricultural, industrial, domestic, recreational, and environmental activities. Most of the uses require fresh water.

However, around 97 percent of the water on the earth is saltwater and only three percent is freshwater. About two-thirds of the available freshwater is frozen in glaciers and polar ice caps. The remaining freshwater is found underground and a negligible portion of it is present on the ground or in the air.

The following are detailed views on how water is used in different sectors.

Agriculture accounts for about 69 per cent of all water consumption especially in agricultural economies like India. Agriculture thereby becomes the largest consumer of the Earth’s available freshwater.

By 2050, the global water demand for agriculture is estimated to increase by an additional 19% due to irrigation needs. Increasing irrigation needs are likely to put immense pressure on water storage. It is still not concluded whether further expansion of irrigation and additional water withdrawals from rivers and groundwater is possible in the future.

Water is the lifesaver of the industry. It is used for various purposes such as a raw material coolant, a solvent, a transport agent, and as a source of energy. Manufacturing industries are considered to have a considerable share of the total industrial water consumption. Besides, paper and allied products, chemicals, and primary metals are major industrial users of water. Worldwide, the industry consumes around 19 percent of total water consumption. In industrialized countries, the industries use more than half of the water available for human use.

It includes usages like drinking, cleaning, personal hygiene, garden care, cooking, washing of clothes, dishes, vehicles, etc. Since the end of World War II, there has been a trend of people migrating out of the country to the ever-expanding cities. This trend has an important role in our water resources.

The government and communities are in a need to provide large water-supply systems to deliver water to new growing populations and industries. Comparing all water consumption in the world, domestic uses about 12 percent of the total water consumed.

Electricity generated from water is called hydropower. Hydropower is one of the highly renewable sources of electricity in the world. It accounts for around 16 percent of the total electricity generated globally. There are numerous opportunities for hydropower development around the world.

At present, the leading hydropower generating countries are China, the US, Brazil, Canada, India, and Russia.

Navigable waterways are defined as watercourses that can be used to transport interstate or foreign commerce. Moving of agricultural and commercial goods on the water is done on a large scale around various parts of the world.

Water is also used for recreational purposes like boating, swimming, and sporting activities. These usages affect the quality of water and pollute it. The highest priority should be given to public health and drinking water quality while permitting such activities in reservoirs, lakes, and rivers.

Overutilization of Surface and Groundwater

Water scarcity has become a big global issue. The UN has held several conventions on the water in recent decades. Continuous overutilization of surface and groundwater has led to increased water scarcity in the world today.

The depleting sources for high growth in the human population over the centuries and increased man-made water pollution across the world have created unforeseen water scarcity around the globe. As a result, there has been continuous overutilization of the existing water sources due to unconditional growth in the world population.

Groundwater is the major source of water in various parts of the world. However, there has been continuous depletion of this source due to its overexploitation by the rising human population and the rapid rise in industrialization and urbanization in modern times.

Consequences of Overutilization

Water scarcity has now become a very important topic in international diplomacy. From a small village to the United Nations, water scarcity is a widely-discussed topic in decision-making.

Nearly three billion people around the world suffer from water scarcity. International, intrastate and regional rivalries on the water are not new to the world. 

According to World Health Organization (WHO) sources, a combination of the rising global population, economic growth, and climate change means that by the year 2050, more than five billion (52%) of the world’s projected 9.7 billion people will live in areas with freshwater scarcity. Researchers estimated that about 1 billion more people will be living in areas where water demand will exceed surface-water supply.

Climate Change

Scientists, environmentalists, and biologists worldwide are now warning that climate change will have a major impact on the drainage pattern and hydrological cycle of the earth thereby affecting the surface and groundwater availability to a new extent.

Climate change is believed to raise the global temperature at an increasing pace. The increase in temperature affects the hydrological cycle by directly increasing the evaporation of available surface water and vegetation transpiration.

As a result, precipitation amount, timing, and intensity rates are largely affected. It impacts the storage of water in surface and subsurface reservoirs.

Conclusion

Water crisis is ever emerging in India and needs to be properly addressed. The onus of conservation lies with us, the people. Understanding the concept and use of water use, we can think of sustainable use.

Coal is a flammable sedimentary, organic rock. Coal is a fossil fuel that has been consolidated between the other rock strata and is formed from vegetation. It is mainly composed of carbon, as well as other elements such as hydrogen, sulphur, oxygen, and nitrogen. To form coal seams, the combined effects of heat and pressure over millions of years were altered. The energy received by coal today is the same energy that was absorbed by the plants millions of years back. The majority of coal is used in power generation and metallurgy. 

Coal reserves are widely dispersed around the world. However, the United States, Russia, China, and India collectively hold more than half of the world’s recoverable coal reserves. Coal is also the cheapest source of electricity if used near coal mines as its transportation to remote locations is expensive due to its size. As a result, industries that need a significant amount of coal are located near coal mines. 

Coal is used to fuel machines, trains, ships, etc. It is also needed for the production of iron and steel, as well as a variety of chemicals. Coal-tar and chemicals such as ammonia, benzol, and others are generated as by-products of the iron and steel manufacturing process when coal is burned to produce coke.

Occurrence of Coal

Coal is a widespread resource of energy. Around 358.9 million to 298.9 million years ago after the Carboniferous time, the terrestrial plants which are necessary for coal development became abundant. The large sedimentary basins that contain the rocks of the Carboniferous age and younger are virtually known on every continent, including Antarctica. 

Regions such as Alaska and Siberia, which have arctic and subarctic climates have large coal deposits due to the climatic changes and the tectonic motion of the crustal plates that are moved by the ancient continental masses above the earth’s surface. Areas including most of northern Canada and Greenland do not have coal, as the rocks that are found in these areas are from before the Carboniferous period. 

Formation of Coal

• Coal first appeared about 300 million years ago, during the Carboniferous era. The Earth was covered in large, shallow seas and dense forests at the time.

• To begin with, plant matter in wetlands, such as ferns, shrubs, trees, and algae, died and accumulated on the soil.

• This plant matter was then buried underneath the earth’s crust, with no exposure to sunlight.

• As the plant matter got buried deeper under the Earth’s surface, it experienced higher temperatures and pressure.

• The organic plant matter was then decomposed by anaerobic bacteria, which emitted carbon dioxide and methane.

• This continued for thousands of years, resulting in many metres of partly decayed plant matter known as peat.

• Several metres deep inside the Earth, these peat layers store vast quantities of carbon. The resulting peat can be burned as fuel and is a major source of heat energy in countries such as Scotland, Ireland, and Russia.

• When this peat is deeply buried, water and other compounds are forced out by increasing pressure, resulting in the formation of lignite, the lowest quality of coal.

• Growing pressures and temperatures turn lignite coal into better quality “black coals.”

• Lignite is converted into sub-bituminous coal, followed by bituminous coal, and finally anthracite.

 

Major Varieties of Coal

Coalification is a process by which 4 different types of coal are created which include bituminous, lignite, sub-bituminous, and anthracite. The degree of changes that coal undergoes as it matures from peat to anthracite is referred to as the process of coalification. The different types of coals are listed below-

• Anthracite is the best quality of coal. It is composed of 80-90% per cent carbon. It’s hard coal. It is mostly located in the district of Reasi in the state of Jammu and Kashmir in India.

• Bituminous coal is the most common and widely used type of coal. It’s of average size. It is composed of 40-75 per cent carbon. It’s made of soft coal. Most of the coal in India falls into this group.

• Lignite is of poor quality. It has a brown colour to it. It is composed of 30 to 40% carbon.

• Peat is the intermediate stage in the coal formation phase. It is composed of less than 40% carbon. It contains more impurities. The wood pieces are surprisingly present in it.

 

The determination of the quality of each of the coal that is deposited is done by-

1. Depths of burial.

2. The length of time taken by the coal to form in the deposit.

3. The types of vegetation the coal has originated from.

4. The level of pressure and temperatures at those depths.

The composition of coal, in addition to carbon, consists of oxygen, hydrogen, nitrogen, and varying amounts of sulfur. The carbon content in the low-rank coals is low but the content of oxygen and hydrogen is high, while the carbon content in high-rank coals is high but the content of oxygen and hydrogen is low.

World Distribution of Coal

More than 90% of the world’s proven coal reserves are concentrated in only ten countries. The United States tops the list, with more than one-fifth of total proven coal reserves, while China ranks third as the largest producer and user of coal. Mining Technology examines the ten countries with the most coal reserves, as measured by total proved reserves. Here is a table of the largest coal reserves in the world.

After many centuries of exploration, location, size and also the characteristics of most of the countries, the coal deposits in the world now are quite well known. What varies much more than the resource’s measured amount – i.e. the potentially accessible coal in the field – is the level known as proved recoverable reserves. Improved exploration activities and improvements in mining methods will increase the availability of coal in the world, allowing previously inaccessible reserves to be reached.

 

Distribution of Coal in India

Now that we have discussed coal reserves by country, let’s learn about the distribution of coal in India. 

 

As of December 2018, India’s proven coal reserves accounted for more than 9% of the world’s total. The country’s main hard coal deposits are in the eastern states of Jharkhand, Chhattisgarh, Orissa, and West Bengal, which account for more than 70% of the country’s coal reserves. The other major coal-producing states in India are Andhra Pradesh, Madhya Pradesh, and Maharashtra. The majority of the country’s lignite deposits are located in the southern state of Tamil Nadu. 

 

After China and Indonesia, India is the world’s third-largest producer and user of coal. In 2018, it produced 771 Mt of coal (7.9% of the global total). India also consumes 12% of the world’s overall coal use. In 2018, it imported 240 Mt of coal, making it the world’s second-largest coal importer. Coal accounts for more than 70% of India’s electricity production. That’s why distribution of coal in India is vital. 

 

Detailed Distribution of Coal in India

1. The Damodar Valley Coalfield is India’s largest coal reserve. Jharkhand and West Bengal are included in this coalfield area. Jharia in Jharkhand is India’s largest coalfield. The majority of India’s coking coal comes from here. Jayanti, Bokaro, Karanpura, Ramgarh, Giridih, Auranga, Hutar, Daltonganj, and Deogarh are also coalfields in Jharkhand. West Bengal’s major coalfields are Raniganj (India’s oldest coalfield) and Dalingkot in the Darjeeling district.

2. The Mahanadi Valley Coalfield includes areas in Chhattisgarh and Odisha. Korba, Jhilmil, Chirmiri, Bishrampur, Lakhanpur,Birampur, and Sonhat are the major coal mining areas in Chhattisgarh. The most important coalfields in Odisha are the Talcher, Rampur-Himgir, and Ib river coalfields.

3. The Son Valley Coalfield includes parts of Madhya Pradesh and parts of Uttar Pradesh. Singrauli, Sohagpur, Umaria, Pench, Ramkola, and Tatapani are prominent coalfields in the Son Valley.

4. The Godavari Valley Coalfield is located in the Indian states of Andhra Pradesh and Telangana. Singreni, Tandoor, and Sasti are the region’s major coalfields.

5. The Wardha Valley Coalfield, which includes Kampti, Wunfield, Chandrapur, Yavatmal, and Nagpur, is a major coal-mining region in Maharashtra.

6. The Satpura Coalfield is located south of the Narmada River in the Satpura range. Ghorbari, Mahapani, and Patharkheda are major coal-mining areas.

7. The Rajmahal Coalfield (Lalmatia) is a major coal-mining centre in the Rajmahal range, where open-cast mining is practised.

 

Coal Resources

World distribution of coal shows a significant amount of the world’s energy supplies. The estimated coal reserve is 860 billion tonnes. These resources are widely dispersed globally, and current output accounts for 29% of global primary energy consumption. In recent years, the classification of coal resources and reserves has been redefined, with the criteria and codes of conduct followed by the major coal-producing countries being equated on a global scale.

 

Undiscovered coal resources are hypothetical coal reserves that are either distinct from or an extension of the estimated, suggested, and inferred coal resources. Undiscovered coal resources are classified as hypothetical or theoretical based on their degree of certainty. Estimates of hypothetical coal resources are based on very little geologic certainty and typically exist in unmapped and unexplored areas.

 

Coal Deposits World Map

 

()

 

Problems in Estimating World Coal Reserves

The largest coal reserves in the world are difficult to assess. While a lack of reliable data for individual countries contributes to some of the difficulty, two fundamental issues make these estimates challenging and subjective. 

 

The first issue is that there are different definitions of terms such as proven reserves and natural resources. Any commodity’s proven reserves should provide a fairly reliable estimation of the amount that can be recovered under current operational and economic conditions. 

 

A coal bed must have a minimum thickness and be buried no deeper than a certain depth below the Earth’s surface in order to be commercially mineable. These thickness and depth values are not constant and vary depending on coal quality, demand, the ease with which overlying rocks can be extracted or a shaft sunk to enter the coal seam, and so on. 

 

New mining techniques can increase the amount of coal that can be extracted in comparison to the amount that cannot be removed. In underground mining, for example, traditional mining methods leave huge pillars of coal behind to support the overlying rocks while recovering just about half of the coal present. Longwall mining, on the other hand, in which the equipment removes continuous parallel bands of coal, can recover nearly all of the coal present. 

 

The rate at which coal is consumed is the second problem in estimating its reserves. When it comes to global coal supplies, the number of years coal would be available could be more significant than the overall amount of coal resources.

 

Problems Associated With the Use of Coal

Coal is cheap and abundant. Assuming that current rates of consumption and output remain constant, estimates of reserves suggest that there is enough coal to last more than 200 years. However, there are a number of issues associated with the use of coal.

1. Mining activities are risky. Every year, hundreds of coal miners are killed or critically injured. Roof crashes, rock blasts, and fires and explosions are also major mine hazards. The latter occurs when flammable gases trapped in coal (such as methane) are released during mining operations and inadvertently ignited. Methane can be extracted from coal beds prior to mining by using hydraulic fracturing (fracking), which involves injecting high-pressure fluids underground to open fissures in the rock, allowing trapped gas or crude oil to escape through pipes that carry the material to the surface.

2. Coal mines and coal-preparation plants have wreaked havoc on the climate. Surface mining, also known as strip mining, kills natural habitats, while surface mining, known as mountaintop removal mining, changes the topography of the region significantly and irreversibly. Surface areas exposed during mining, as well as coal and rock waste (which was often deposited indiscriminately), weather rapidly, creating a large amount of sediment as well as soluble chemical products such as sulfuric acid and iron sulphates. Sedimentation can cause nearby streams to become clogged.

3. Coal use is associated with different types of air pollution. Many compounds are formed during the incomplete burning or conversion of coal, some of which are carcinogenic. Coal combustion also releases sulphur and nitrogen oxides, which react with atmospheric moisture to form sulfuric and nitric acids, resulting in acid rain. Furthermore, it generates particulate matter (fly ash) that can be carried hundreds of kilometres by winds and solids (bottom ash and slag) that must be disposed of.

 

Coal as an Energy Source

Coal is an abundant resource that can be used as an energy source, a chemical source from which many synthetic substances can be derived, and in the manufacture of coke for metallurgical processes. Coal is a significant source of energy in the generation of electrical power through steam generation. Furthermore, coal gasification and liquefaction provide gaseous and liquid fuels that can be easily transported and stored in tanks. 

 

After a massive increase in coal usage in the early 2000s, fueled mainly by the expansion of China’s economy, global coal use peaked in 2012. Since then, coal consumption has steadily declined, partially offset by rises in natural gas use.

 

The Future

While the availability and affordability of coal are advantageous, these considerations must be weighed against the negative environmental effects of its use. Coal’s future will be determined by the use of low-sulfur varieties, advancements in renewable coal technology, and the procurement of lower-cost alternatives. While the drawbacks of coal energy will reduce demand over time, the lack of a cost-effective substitute could hold this fossil fuel in demand for many years to come. 

 

Conclusion

Coal is a strong carbon-rich substance that is commonly brown or black and occurs in stratified sedimentary deposits. It is one of the most significant primary fossil fuels. Coal is characterised as having more than 50% carbonaceous matter by weight formed by the compaction and hardening of altered plant remains, i.e. peat deposits. 

 

Different types of coal exist due to variations in plant content, degree of coalification, and impurity range. While the majority of coals is found in stratified sedimentary deposits, the deposits may later be subjected to elevated temperatures and pressures caused by igneous intrusions or deformation during orogenesis, resulting in the formation of anthracite and even graphite. While the concentration of carbon in the Earth’s crust is less than 0.1% by weight, it is essential for life and is the primary source of energy for humans.

The amphibole mineral is a mineral belonging to the inosilicate classification of minerals. They are known for and classified as such because of their structural configuration that leads to the formation of a prism or needle-like structures. The amphibole is made up of double-chain silica (SiO4) tetrahedra. In these tetrahedra, the two chains of silica are linked with one another at the vertices and typically contain ions of iron and/or magnesium in their structures. The Amphibole group of minerals is a supergroup according to the International Mineralogical Association as there are two more groups and several subgroups classified within it. 

Naming of Amphibole

The amphibole meaning is derived from the ancient Greek language from the root word amphibolos. The term amphibolos means “double entendre” i.e. ambiguousness. Deriving amphibole meaning from the amphibolos term, the mineral amphibole was first used by René Just Haüy. With this nomenclature tremolite, actinolite and hornblende. Because of the composition and appearance of these minerals, these particular minerals were named amphibole meaning something that is showing dual and ambiguous properties. 

Physical Properties of Amphibole

The following are the physical properties and chemical characteristics of the amphibole mineral:

• Amphibole is made up of double chains of silica in a tetrahedral structure with both the chains being linked to each other at their vertices.

• The crystalline structure of the amphibole contains ions of iron and/or magnesium within it.

• The amphibole mineral can be found in different colors such as green, black, white, yellow, brown or some of its forms can be colorless as well.

• The amphibole structure is known for the formation of two different types of crystals. The two types of crystals formed are either prismatic or needle-like in shape.

• The amphibole chemical composition is essentially made up of hydroxyl or halogen groups within their crystal structure.

• Although, there are similarities in-between certain properties of pyroxene and amphibole, the basic structure of the amphibole crystal is different from the pyroxene crystal as the pyroxene crystal is made up of a single chain of silicates and the amphibole is made up of double chains of silica.

• Amphiboles form cleavage planes at around 120 degrees which is different from the pyroxenes as pyroxenes form the cleavage planes around 90 degrees.

• The objects classified in the amphibole mineral group are also specifically less dense than the corresponding objects that belong to the pyroxene category.

• Optically as well the properties of amphiboles are interesting because optically the amphiboles due to their unique amphibole structure display different colors when viewed or observed from different angles. They have a very strong pleochroism characteristic and a smaller angle of extinction on the plane of symmetry.

Characteristics of Amphibole

The minerals of the amphiboles can originate from either the igneous or metamorphic origin. The common forms of amphibole are present in both the intermediate to felsic igneous rocks rather than mafic igneous rocks because of the iron or magnesium ion content. The characteristics of amphibole found in the rocks and determined by the formation are given as follows:

• The property of the amphibole structure to have double silica chains because of the higher silica content and higher dissolved water content found in the more evolved magmas. These are the conditions that favor the formation of amphiboles over the formation of pyroxenes.

• Amphiboles are primary constituents of the amphibolites which also include actinolite, hornblende, plagioclase, etc.

• Andesites are the ones that contain the highest amount of amphiboles that is 20% of the total composition.

• Another one of the minerals included in the amphibole is the hornblende and is widespread in the igneous and metamorphic rocks and more prominently in the syenites and diorites. 

• The naturally occurring amphibole sometimes contains calcium as the main constituent. 

• The amphiboles formed include the metamorphic rocks the ones developed in limestones by the contact metamorphism and also the ones formed by the alteration of other ferromagnesian minerals like the hornblende which is a product of the pyroxene. After pyroxene, the pseudomorphs of amphibole are known as the uralite.  

• The amphibole formula that is found commonly in the representation of the minerals classified under it is RSi4O11 where R is the specific group present in different minerals.

• Most common of the minerals among is the amphibole asbestos. Four such minerals are commonly known as amphibole asbestos. Those four are anthophyllite, riebeckite, cummingtonite/grunerite asbestos series and tremolite/actinolite asbestos series. The cummingtonite/grunerite are generally known as brown or amosite asbestos, whereas, the riebeckite mineral is known as blue asbestos. All of these are very commonly known as amphibole asbestos.

Use of Amphibole

The amphibole mineral finds its utility for a variety of purposes. Because of its coloring and the ability to exhibit different colors when being viewed from different angles, one of the most prominent uses of amphibole is in decorations. It can be simply shaped as desirable and then kept in the house as a decorative or interior designing item. Some of the observable uses are as paving stones, and as veneers or facings on the buildings. Another one of the uses of amphibole mineral includes its utility as crushed stone for activities such as road construction and railroad bed construction. This is vastly done near the sites where amphobiles are a common occurrence.

General contemplations

Amphiboles are tracked down chiefly in transformative and volcanic rocks; they happen in numerous transformative rocks, particularly those obtained from mafic volcanic rocks (those containing dim hued ferromagnesian minerals) and siliceous dolomites. Amphiboles likewise are significant constituents in an assortment of plutonic and volcanic molten rocks that reach in arrangement from granitic to gabbroic. Amphibole, from the Greek amphibolos, signifying “equivocal,” was named by the popular French crystallographer and mineralogist René-Just Haüy (1801) in reference to the extraordinary assortment of creation and appearance shown by this mineral gathering. There are 5 significant gatherings of amphibole prompting 76 synthetically characterized end-part amphibole pieces as per the British mineralogist Bernard E. Leake. As a result of the wide scope of synthetic replacements allowable in the precious stone design, amphiboles can solidify in volcanic and transformative rocks with a wide scope of mass sciences. Normally amphiboles structure as long kaleidoscopic gems, emanating splashes, and asbestiform (sinewy) totals; in any case, without the guide of compound investigation, it is hard to megascopically distinguish everything except a couple of the more unmistakable end-part amphiboles. The mix of kaleidoscopic structure and two precious stone-formed headings of cleavage at around 56° and 124° is the demonstrative component of most individuals from the amphibole bunch.

Compound structure

The perplexing compound piece of individuals from the amphibole gathering can be communicated by the overall recipe A_0–1B₂C₅T₈O₂₂(OH, F, Cl)₂, where A = Na, K; B = Na, Zn, Li, Ca, Mn, Fe²⁺, Mg; C = Mg, Fe²⁺, Mn, Al, Fe³⁺, Ti, Zn, Cr; and T = Si, Al, Ti. Almost complete replacement might occur among sodium and calcium and among magnesium, ferrous iron, and manganese (Mn). There is restricted replacement between ferric iron and aluminum and among titanium and other C-type cations. Aluminum can to some extent substitute for silicon in the tetrahedral (T) site. Halfway replacement of fluorine (F), chlorine, and oxygen for hydroxyl (OH) in the hydroxyl site is additionally normal. The intricacy of the amphibole equation has led to various mineral names inside the amphibole bunch. In 1997 Leake introduced an exact classification of 76 names that include the compound variety inside this gathering. The mineral classification of the amphiboles is partitioned into four head regions dependent on B-bunch cation inhabitants:

(1) The iron-magnesium-manganese amphibole bunch,

(2) The calcic amphibole bunch,

(3) The sodic-calcic amphibole bunch,

(4) The sodic amphibole bunch.

Actual properties

Long kaleidoscopic, acicular, or sinewy gem propensity, Mohs hardness somewhere in the range of 5 and 6, and two bearings of cleavage converging at around 56° and 124° for the most part do the trick to recognize amphiboles close by examples. The particular gravity upsides of amphiboles range from around 2.9 to 3.6. Amphiboles yield water when warmed in a shut cylinder and wire with trouble in a fire. Their shading goes widely from dry to white, green, brown, dark, blue, or lavender and is connected with the arrangement, primarily the iron substance. Magnesium-rich amphiboles like anthophyllite, cummingtonite, and tremolite are luster or light in shading. The tremolite-ferro actinolite series goes from white to dull green with expanding iron substance. The finely stringy and enormous assortment of actinolite-tremolite known as nephrite jade reaches from green to dark. Normal hornblende is ordinarily dark. Glaucophane and riebeckite are typically blue. Anthophyllite is dim to different shades of green and brown. The cummingtonite-grunerite series happens in different shades of light brown. Sans iron assortments of tremolite containing manganese can have a lavender tone.

The name is “Mako Sica,” which means “land bad.” This Badland National Park is located in the southwestern part of South Dakota. This National Park consists of approximately 244,000 acres of sharply eroded buttes, pinnacles and spires which are being blended with the protected mixed-grass prairie in the United States. This site is desolation at its best, with bare eyes, one cannot find any sort of civilization in this area. and see no sign of civilization.

The land is being ruthlessly ravaged by wind and by water, thus it became picturesque. The Badlands quenches the thirst of wonderland of the bizarre, the colourful spires and pinnacles, with its massive buttes and deep gorges add more to the beauty.

The erosion of these Badlands has revealed layers of sedimentary rocks of different colours, ranging from purple and yellow to tan and grey. The colours red and orange (which is because of the iron oxides) and white (for the volcanic ash) sparks natural beauty in this Badland National Park.

Badland

Badlands are actually a type of drier terrain where there are softer sedimentary rocks. The softer sedimentary rocks are also coupled with clay-rich soils which have extensively faced erosion by the wind and water. Badlands are being characterized by steep slopes, with a lack of vegetation. Features common in Badlands are – Canyons, gullies, ravines, buttes, hoodoos and other geological forms which are quite common in these areas. These features are often difficult to identify and navigate by foot. Generally, Badlands have a spectacular colour to display. The colour ranges from dark black/blue coal stria to bright clays to red scoria.   

Inquisitive enough, how did these remarkable features get their origin? By the process of deposition and erosion, Badlands are being formed naturally. The process of deposition marks the accumulation, over the time period, of the layers of mineral in the material. Different environments like seas, rivers, or tropical zones, deposit varied sorts of clays, silts, and sand. For example, the Badlands formations in the Badlands National Park in South Dakota have undergone a 47-million-year period of deposition, they have spanned three major geologic periods that is the – Cretaceous Period, Late Eocene and the Oligocene Period. This resulted in the clear, distinct layers of sediment being served as a dramatic display.  

Borrego Badlands

These Badlands measure twenty miles wide by another fifteen miles long, into the stark, arid landscape of the Borrego Badlands which stretched across the portion of the enormous Anza-Borrego State Park, located in California’s south-eastern corner. During the sunset and sunrise, the Badlands’ creased and wrinkled ridge structures cast bold shadows which stretches across a maze of the golden hills and the sand-coloured arroyos. Originally the whole view was shaped by water. The fossilized seashells were found in the region, this proves that it was once being submerged under the blend of salty tropical waters which is from the Gulf of California and the freshwater from the Colorado River. 

To enjoy the best view, the best places to get a look at these Badlands’ surreal scenes is from Font’s Point, which is commonly known as California’s Grand Canyon. This point is a popular spot for photographers, especially at the time of sunset or during full-moon nights.

Paria Badlands

The location of Paria Badlands is between Kanab, Utah and Page, which is in Arizona. This takes about an hour or so to fully see the view. They serve as an excellent side trip while heading towards or from any hikes.  

While there is no hiking trail at the Paria Badlands. The structure is a way to wind down from some other hikes in the surrounding areas. Here no hiking is required. The views enjoyed here are pretty impressive and there are scenic views from a couple of steps outside your car. 

How do We Get There?

From Kanab, Utah, you need to take US-89 east, after driving approximately 32.5 miles. There will be a sign which will read “Old Pahreah Townsite.” After which turn left into the large, round gravel parking area, here you will see some plaques and other large stone landmarks. If coming from the Page, Arizona, then take US-89, then drive for 40.5 miles. Here, you will see a sign for “Old Pahreah Townsite.” Then turn right here into this gravel parking area where you will find the plaques and landmarks. 

They basically talk about the history of the area. After you read the plaques head north on the dirt road for about 4.8 miles, then you will come to the best spot for pictures in the Paria Badlands. This same road will eventually then lead you to the Old Paria cemetery which consists of about 20 graves. Near this cemetery area and the parking area, on the south side of the Paria River, there was the old movie set where many several films were being shot from the 1940s through the 1970s. 

Let’s talk about the Halide mineral before we get into Carnallite. Any of a group of naturally occurring inorganic compounds that are salts of the halogen acids is known as a halide mineral (e.g., hydrochloric acid). With the notable exceptions of halite (rock salt), sylvite, and fluorite, such compounds are uncommon and only found in small quantities. The simple halides, halide complexes, and oxyhydroxy-halides are known as three broad groups of halide minerals in terms of composition and structure. These categories are also distinguishable in terms of their modes of occurrence.

Alkali salts, alkaline earth, and transition metals are examples of basic halides. The transition-metal halides are unstable when exposed to air and are soluble in water. The most well-known evaporite mineral is halite, sodium chloride (NaCl); it is found in large beds with other evaporite minerals as a result of the deposition of brines and trapped oceanic water in impermeable basins and their evaporation. Sylvite, potassium chloride (KCl), is also present in small quantities in such beds. Among the simple halides, a few double salts such as carnallite and tachyhydrite formed under conditions close to the formation of halite. Carnallite is also a halide mineral.

Carnallite

Carnallite is a soft, white halide mineral that contains hydrated potassium and magnesium chloride and is used to make fertilisers. Carnallite is found in the upper layers of marine salt deposits, where it tends to be an alteration result of pre-existing salts, along with other chloride minerals. The mineral can be found mostly in salt deposits in northern Germany, as well as in Spain, Tunisia, and the southwestern United States.

Carnallite Formula

Chemical Formula of Carnallite is KMgCl₃·6(H₂O). Slow crystallisation at 25°C will yield synthetic carnallite crystal specimens from 1.5 mole percent KCl and 98.5 mole percent MgCl₂·6H₂O. It has a density of 1.602 g/cm³. Grinding a mixture of hydrated magnesium chloride and potassium chloride can also yield carnallite.

Structure of Carnallite

We discussed the Chemical Formula of Carnallite. Now let’s look in detail about the Structure of Carnallite. 

• Carnallite basic structure has corner- and face-sharing. A network of KCl₆ octahedra exists, with two-thirds of them having the same faces.

• The open spaces within the KCl octahedra are occupied by Mg(H₂O)₆ octahedra.

• The interatomic distance between Mg and H₂O varies between 0.204 and 0.209 nanometers, with an average of 0.2045 nanometers. 

• K and Cl have an interatomic distance of 0.317 to 0.331 nm, with an average of 0.324 nm.

• The estimated density of the resulting structure is 1.587 g/cm³, which is very similar to the measured value of 1.602 g/cm³.

Structure of Carnallite [Carnallite Formula is KMgCl3·6(H2O)]

According to the third of Pauling’s law, sharing one’s face increases the chances of instability. The magnesium ions are encased in water molecules in carnallite. The water molecules serve as charge transmitters, preventing the magnesium and chloride from interacting directly. Each of the five chloride anions is paired with two potassium cations and four water molecules. This means that each of the two potassium ions gives each chloride anion 1/6 of a +1 charge. Each of the four water molecules gives the chloride 1/6 of a +1 charge. The charges add up to six 1/6 positive charges, which offset the chloride’s negative charge. Because of these two factors, the rare face sharing mentioned in Pauling’s second and third rules is appropriate in the carnallite structure.

Physical Properties of Carnallite

The refractive index of carnallite varies from 1.467 to 1.494. Hematite (Fe₂O₃) inclusions in carnallite can cause it to be red. In the thin laminae of hematite, broken shards of iron oxide create red tints. In high humidity, carnallite also deliquesces. This indicates that it is highly soluble in water. Individual crystals are tabular and pseudo-hexagonal, but they are exceedingly uncommon. The forming environment, the lack of cleavage, and fracture are all field indicators of carnallite. Other factors to consider include density, taste, associations with local minerals, and luminescence. Carnallite has a sour flavour. Carnallite has the potential to be both fluorescent and phosphorescent. The potassium in carnallite readily fuses in a blaze, resulting in a violet hue. Carnallite can be distinguished from other evaporate minerals very easily. It has a bitter taste and, unlike halite, no cleavage. Carnallite has a specific gravity of just 1.6 and, unlike kieserite and other non-potassium salts, produces a violet flame when placed in a gas flame. Environment of formation, lack of cleavage, associations, density, deliquescence, fracture, and taste are the best Field Indicators.

Geologic Occurrence

Halite, anhydrite, dolomite, gypsum, kainite, kieserite, polyhalite, and sylvite are examples of mineral associations dependent on physical properties. Evaporites are mineral sediments that contain carnallite minerals. Evaporation of seawater concentrates evaporites. The water inflow must be less than the evaporation or usage levels. This results in a longer evaporation period. When 10%–20% of the original water sample remains after controlled environment experiments, the halides shape. Sylvite makes up about 10% of the total, followed by Carnallite. Carnallite is mainly present in marine deposits that are saline.

Uses

Carnallite is a mineral that is often used in fertilisers. It is a significant potash source. Only sylvite is more important in potash production than carnallite. They’re both rare because they’re among the last evaporites to form. The primary sources of fertiliser are soluble potassium salts. This is due to the difficulty of separating potassium from insoluble potassium feldspar. Carnallite is a minor magnesium source found all over the world. 

Conclusion

Carnallite is a valuable fertiliser since it contains a lot of potash. Potash is mostly obtained from sylvite, but carnallite also contributes significantly. The magnesium production of carnallite is much less important globally, but it is still Russia’s most important source. Potassium is a common element, but it is unfortunately wrapped up in insoluble silicate minerals like potassium feldspars. Since potassium must be in a soluble state to be effective as a fertiliser, soluble potassium salts are the preferred source. Evaporite minerals like carnallite and sylvite, for example, are some of the last minerals to evaporate from sea water, making them difficult to form. In approximately that order, minerals including calcite, dolomite, gypsum, anhydrite, and halite crystallise first. The conditions required for potassium and magnesium salts to form include seawater contained in a cut-off, but not fully isolated basin, similar to the Black Sea. The Black Sea, on the other hand, does not form carnallite because it does not have a warm enough environment to allow for intensive evaporation (this is an evaporite mineral after all). The concentrated brine must not be allowed to leave the basin in order for the salinity to continue to rise. The brine will fall to the basin’s bottom, allowing fresher water to join, bringing more magnesium into the basin. This has the effect of delaying the crystallisation of the salts and increasing the brine’s salinity. If evaporation does not continue in this direction, the minerals mentioned above will fill the basin before the potassium salts crystallise.