Category: Geography Notes PPT

The resources that occur and exist in nature and lead to the existence of others are termed as natural resources which can be renewable or non – renewable as well. Some resources will be entirely exhausted one day but we can slow the pace of their complete exhaustion and extinction by looking out the issues and adopting measures to conserve them. In this article, we will be discussing major natural resources such as land soil water natural vegetation and wildlife resources and their related important concepts. We will learn what kind of resource is soil or how to conserve wildlife or the importance of land and water and other related concepts. These notes will be helpful for the students of Class 6 studying Geography and Environment and also students of upper classes. 

Natural Resources & Their Significance

The resources that exist on our planet in different forms in a natural way without any help or action of humans are called natural resources. They exist independently in nature without the help or interaction of humans. For example, air, water, land, sunlight, minerals, fossil fuels, animals, plants, etc. The major significance of these resources is that they maintain ecological and environmental balance on the Earth because humans usually create unbalance on the Earth. They provide an environment here that makes the possibility for life to exist on the planet. The major five natural resources are land soil water natural vegetation and wildlife resources. 

Land & Soil

Land and soil are two of the most important resources on our planet. The former is considered as the upper lithosphere part of the Earth whereas the latter is a kind of loose and organic material that lies on the land. Both serve as an important resource of Earth but is there any difference between land and soil? Let’s see.

Difference between Land and Soil

Significance 

The importance of soil and land natural resources are mentioned below:

• They both are reasons for the survival of living organisms on the planet.

• Where one side, the land provides space to reside, the other provides food to live.

• The land is home to human beings and animals and other land species whereas soil is also home to various microorganisms.

• They both serve as the base for agriculture activities.

Factors Affecting Land

Following are the factors that can affect land and its productivity:

• The rapid increase in the global population put major stress on land.

• The different types of cultivation patterns can affect the land.

• The quality of the land can also affect its productivity level.

• Excessive use of land and excessive stress can affect its productivity.

• The occurrence of natural disasters such as landslides or earthquakes can affect the land in a large amount.

• Different types of irrigation methods and excessive use of these methods can also affect their health.

Factors Affecting Soil

The following mentioned factors can affect the soil and its productivity:

• The wrong agricultural practices can affect the soil and its fertility can be lost.

• Land pollution can affect it as well.

• The excessive use of chemical fertilizers or pesticides or insecticides can harm the quality of the soil.

• Heavy rainfall, cloud outburst, floods, tsunamis, etc. can harm a large amount of good soil and lead to soil erosion.

• Heavy deforestation directly affects the soil.

Conservation of Soil

Following measures can be taken for its conservation:

• The use of good agricultural activities such as crop rotation or terrace farming, mulching, etc.

• Leaving the soil vacant for some time say years so that it can regain its sufficient fertility level.

• Less use of harmful chemical agricultural products.

• The adoption of organic farming will help conserve the soil.

• Growing more and more trees also helps in their conservation.

Water as a Natural Resource

It is one of the unique features of our planet that lead to the presence of life on it because it consists of liquid water which is essential for survival. Water as a Natural Resource serves various functions but only 2.5 % of the total water that we found on Earth is freshwater that is usable for survival purposes for humans or animals and the rest of the water is saltwater. The list of its various sources includes rivers, lakes, ponds, wetlands, glaciers, oceans, etc.

Factors Affecting Water

The various factors that can affect this natural resource are mentioned below:

• It is used as a raw material in both agricultural and industrial activities, thus putting great stress on this resource.

• Excessive use of irrigation activities can affect the availability of groundwater in some areas.

• Pollution is a major source that is affecting not only its quality but also producing several water-borne diseases.

• Throwing garbage or industrial waste in water affects it.

Conservation of Water Resources

It is very important to conserve this resource which can be done in the following ways:

• Best irrigation practices should be adopted in the agriculture sector such as drip irrigation or sprinkler system etc.

• Recycling industrial water or household water will help in conserving water.

• Rainwater harvesting is a good method to be adopted by everyone.

• Adopting water conservation measures by the households in their homes will lead to a major impact.

Natural Vegetation and Wildlife Resources

These are flora and fauna that exist in nature without any kind of humanitarian aid. The flora that grows naturally is called natural vegetation whereas the several species of fauna kingdom that live on Earth are called wildlife resources. Various factors are there which are affecting their existence on Earth such as increasing temperature and deforestation, damaging the home of the animals, killing them for food and other industrial products, etc.

Conservation of Natural Vegetation and Wildlife Resources

The various measures can be taken to conserve natural resources vegetation and wildlife which are mentioned below:

• Various projects are launched by the National and international organizations for their conservation in which everyone should participate.

• By knowing the status of any wildlife species through the IUCN list, conservation should be done on a priority basis of species that lie in critical endangered, endangered and vulnerable categories.

Conclusion

To conclude what we have discussed above we can say that these natural resources are the gift of nature and these are the gifts that help in the existence of life on the Earth but due to several factors they are deteriorating and for that right conservation measures are required to be taken to save them. In this article, we have covered necessary topics of land soil water natural vegetation and wildlife such as the meaning of the resources, water as a natural resource, the difference between land and soil, etc. As we discussed above, we should take appropriate measures to conserve these natural resources and do whatever is in our hands. These notes will help the students of Class 6 and upper classes to understand the resources and their various issues and how to conserve them.

The Earth, by weight, mostly consists of mafic or ultramafic rocks, but silicic rocks are considered to be more abundant on the surface of the Earth. The common type of mafic rocks is basalt, pyroxene, biotite, etc. In this article, we will talk about this type of rock. We will learn about what are mafic rocks, mafic minerals, their meaning, definitions, features, and examples, etc. This topic will be helpful to understand one of the types of igneous rocks which are formed from magma and which we usually study in Geography, Geography, Earth Sciences, Physical Geography, etc.

Introduction

Rocks are said to be the hard matter which forms after the solidification of the magma and because of various other geographical phenomena. These are generally of three main types which include igneous rocks, sedimentary rocks, and metamorphic rocks. Among these, igneous rocks are said to be the primary rocks because they occur first and then sedimentary rocks form and then the formation of metamorphic rocks happens because of geological processes on the above two types of rocks. If we talk about Igneous rocks, these are formed after the solidification of magma and can be of two types i.e. Intrusive and Extrusive. These are being divided on the basis of where they actually occur. If rock formation is done below the surface of the Earth is known as intrusive igneous whereas if it occurs above the surface of the Earth, it is known as Extrusive rocks. Mafic rock is an example of Intrusive igneous rock.

Meaning of Mafic

It is a portmanteau term that is made up of magnesium and ferric. On the basis of silica content, igneous rocks can be classified into various types. Silica is found in abundance in igneous rocks because of which is considered the basis of classification. On this basis, igneous rocks can be divided into four major types i.e felsic, intermediate, mafic, and ultramafic ( written as per the silica content in decreasing order). Mafic is a kind of igneous rock which are rich in magnesium and iron. This type of rock contain 45 to 55 % silica content and 4 mafic igneous rocks minerals are pyroxene, amphibole, olivine, and mica. Mafic word is sometimes also used as a synonym for dark coloured minerals. 

Definitions

Some of the standard definitions are given below:

• “In Geology, of or relating to rocks rich in dark, ferromagnesian minerals.” – dictionary

• “Mafic describes rocks containing more dark-coloured substances and iron than other rocks.” – Cambridge dictionary.

• “It is Relating to or denoting a group of dark-coloured, mainly ferromagnesian minerals such as pyroxene and olivine and often contrasted with felsic. ( Geology ). – Lexico definition.

• “Mafic is a collective term for minerals present in igneous rocks Or “relating to igneous rocks or silicate minerals.” Or “( Geology ) of or pertaining to igneous rocks that are rich in dark-coloured minerals and that contain magnesium and iron and a comparatively low level of silica.” – Collins Dictionary.

Features

The basic features of mafic rocks are given below:

• This is one of the important types of igneous rocks that are classified on the basis of silica content.

• It is a type of rock that crystallizes from silicate minerals at high temperatures. Sometimes, these rocks are also called basaltic. 

• Olivine, pyroxene, amphibole, and biotite are common rock-forming minerals of mafic.

• Common examples of mafic rocks are basalt, gabbro, diabase, etc.

• They are dark in colour ( whereas felsic rocks are light in colour).

• Chemically, these rocks are consist of magnesium, iron, and calcium.

• Mafic magma has a low content of silica because of which before cooling, mafic lava has a low viscosity.

• The volcanic eruptions consist of mafic lava are less explosively violent as compared to felsic volcanic eruptions.

Additional Information

On the basis of the texture of rocks, different names of mafic rocks are given below in the table:

Different Names of Mafic Rocks

Conclusion

To sum up we can say that mafic is a term which is made up of magnesium and ferric thus used to describe the rocks which are rich in two whereas now it is also used to describe the igneous rocks which are rich in high content of magnesium as well as iron. It is a dark coloured rock that consists of silica content less than felsic and intermediate whereas more than ultramafic igneous rocks. On the basis of the texture of the rocks, different names of mafic rocks can be there. This topic is useful to study whenever we talk about igneous rocks and their types.

An earthquake can be defined as the trembling or shaking of the earth’s surface resulting due to the friction caused by the tectonic plates. These plates are found in the Earth’s crust and are separated by plate boundaries. Any friction in these edges or boundaries results in the formation of seismic waves causing the earth’s surface and the ground to move.

The after-effects of an earthquake are huge resulting in the formation of seismic waves. The movements of these waves shake the surface of the earth and result in earthquakes. 

The aftermath of an earthquake is huge. It destroys several buildings, infrastructure and even loss of life on a severe level. The level of damage caused depends on the intensity of the earthquake. Therefore, many scientists do a study on understanding the ground motions of an earthquake and recording it with the help of a seismograph. This awareness of earthquake geology is very important to predict any future earthquakes and mitigate the hazards caused by them.

In this article, we provided information on the causes of an earthquake and also some methods for reducing earthquake hazards. This article can be referred to by the students as a reference to prepare for their examination.

What Causes an Earthquake?

An earthquake occurs due to the friction caused by two blocks of the earth. These blocks are known as the tectonic plates. The edges of these plates are separated by plate boundaries and the movement of these plates causes a planar fracture in the earth’s crust (also known as fault), thus, resulting in an earthquake.  This surface of friction is also called the fault plane. 

The surface of the earth where the earthquake originated is known as the epicentre. It is a location above the earth’s surface. While the area of origin below the surface of the earth is called the hypocentre of the earthquake. 

An earthquake can be followed by aftershocks. These are occurrences of small earthquakes after a regular interval of time. This occurs mostly after a larger earthquake having a high intensity. The aftershocks of an earthquake may continue for several hours to days or even years depending upon the intensity of the main earthquake.  The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter.

Methods of Reducing Earthquake Hazards

Over the several years, scientists have been trying their best to record the ground motions and do a study on earthquake geology. These studies help scientists to detect the earthquake-prone areas of the world and makes people aware of the occurrence of an earthquake in the near future. The geology of an earthquake is studied through seismograph. This gives the appropriate information on the epicentre and intensity of the earthquake. The size of an earthquake is provided on the Richter scale and the severity of damages caused by earthquakes totally depends on the magnitude of it. Every year, several lifeforms, infrastructures and natural habitats are destroyed due to the consequences of earthquakes. Henceforth, it is important for us to be aware of the precautionary measures to reduce the hazards.

Given below are Some of the Methods of Reducing Earthquake Hazards:

1. To understand and evaluate the damages caused by the strong shaking of the ground.

2. To evaluate and improve the infrastructure and design strategies of the buildings for making them more resistant to earthquakes.

3. To introduce new methods to predict and study the seismic performance of buildings and structures.

4. Improving earthquake provisions of building codes, and

5. Assessing building safety immediately following a damaging quake.

6. To improve the system and methods of seismic monitoring, especially in earthquake-prone areas. 

7. Attaching sensors in the buildings to make people aware and safeguard them from any future earthquake.

Although earthquakes occur in an unpredictable manner, following these methods will somehow reduce the damages caused by earthquakes and will safeguard the people beforehand.

Noctilucent clouds or night-shining clouds are the highest clouds found in the Earth’s atmosphere located in the mesosphere at an altitude around 76 to 85 km (249,000 to 279,000 ft). The cloud consists of ice crystals and is only visible during astronomical twilight. In Latin, the term Noctilucent means “night-shining”. The clouds are most visible during the summer month and when the Sun is below the horizon from latitude between ±50° and ±70°.

The clouds are too faint to be observed during daylight and are visible only when illuminated by sunlight from below the horizon while lower levels of the atmosphere are in Earth’s shadow.

Noctilucent Meaning

The term Noctilucent means “night-shining” and is an indicator as to what makes them special.  Most clouds are dark at night, but night-shining clouds appear to glow a brilliant white or electric blue. Nlc clouds can reflect the light of the sun as shown in the figure given below as they are the highest clouds in the Earth’s atmosphere. The Nlc clouds are located in the mesosphere at an altitude of around 76 to 85 km (249,000 to 279,000 ft).

Noctilucent Clouds Definition

Noctilucent clouds, also known as polar mesospheric clouds, are very thin clouds of water ice crystals located in the Mesosphere at a height of about 75 km to 90 km.

Noctilucent Cloud Discovery 

Noctilucent or night-shining clouds were first observed in 1885, two years after the 1883 eruption of Krakatoa in the straits of Java. 

It is not confirmed whether their appearance had anything to do with the volcanic eruptions or whether their occurrence was due to more people observing the incredibly vibrant sunset caused by volcanic debris into the upper atmosphere by eruptions and contributing to their formation.  

Subsequent studies have shown that noctilucent clouds are not solely caused by volcanic activity, although dust and water vapour could be inserted in the Earth’s atmosphere by a volcanic eruption and contributed to their formation.

The assumption was made by the scientist at that time that clouds were another phenomenon of volcanic ash, but the cloud persisted after the ash liquidated out of the atmosphere.

In 1972, Nlc clouds were first observed from space by an instrument on the OGO – satellite. 

Noctilucent Cloud Formation

The night-shining clouds are made up of small crystals of water ice up to 10 mm in diameter and exist at a height of about 76 to 85 km, higher than any other cloud in the Earth’s atmosphere. Similar to the other clouds. Clouds in the Earth’s lower atmosphere form when water collects on particles, but mesospheric clouds or clouds in the mesosphere may come directly from the water vapour as well as forming on dust particles. 

Nlc clouds required water vapour dust, and very cold temperature to form. The source of both dust and water vapour in Earth’s atmosphere is not known with certainty. The dust was expected to come from micrometres, although particles from volcanoes and dust from the troposphere are also possibilities. Scientists believe that moisture could be lifted through the gas in the tropopause, as well as forming the reaction of methane with hydroxyl radicals in the stratosphere. Noctilucent clouds form mostly in the polar regions because the mesosphere is the coldest in that region. 

Noctilucent Cloud Observation

Nlc clouds are mostly found colourless or pale blue, but occasionally other colours such as red and green are also observed. The attributes of blue colour come from absorption by ozone in the path of sunlight brightening the Nlc clouds. The Nlc clouds appear as featureless bands, but frequently show different patterns such as streaks,  waves, and wavelike undulations.

The Noctilucent occurs during summer from mid-May to mid-August in the northern hemisphere and between mid-November to mid-February in the southern hemisphere. The clouds are very faint and tenuous and may be observed only in twilight around sunrise and sunset when the clouds of the lower atmosphere are in the shadow, but the Nlc clouds are brightened by the Sun.  The clouds are best observed when the Sun is between 6° and 16° below the horizon.

Although night-shining clouds are found in both the hemisphere, they have been observed thousands of times during the northern hemisphere and fewer than 100 times during the southern hemisphere. 

Also, Nlc clouds are made up of small crystals which are not noticeable to the viewer on the ground because they cannot disperse enough light. The size of the crystals may be 30 mm or less.

Noctilucent Cloud  Forms

The noctilucent cloud comes in different forms and patterns. As per the identification scheme introduced by Fogle in 1970, the clouds are classified in five different terms. This classification is further modified and subdivided. In view of the recent research, the World Meteorological Organization now observed four major forms that can be subdivided. The four major forms are:

• Type 1 veils are very fragile and lack definite structure, similar to cirrostratus or inadequately defined cirrus.  

• Type 2 bands are long streaks that rarely appear in roughly parallel groups, usually more widely spaced than the bands or elements seen with cirrocumulus clouds. 

• Type 3 billows are arranged in a closed-space, roughly parallel short streaks that most often look like cirrus. 

• Type 4 whorls are more partial, or more often complete rings of cloud with dark centres. 

Did You Know?

• NLC clouds are the highest cloud in the sky, growing at the edge of space 50 miles above the Earth’s surface.

• Nlc clouds exist in the atmosphere mesosphere layer.

• Nlc clouds are the newest clouds that we all have observed. Scientists first observed the Nlc clouds in 1885 after the same famous explosion of the Krakatoa volcano.

• Nlc clouds occur during summer from mid-May to mid-August in the northern hemisphere and between mid-November and mid – February in the southern hemisphere.

Our country is the most diverse country in the world whether in terms of its culture and heritage or geographical features. Here in this article, you will get a chance to know your country India. This article will help the students of Class 6 and higher classes to get a brief understanding about our country. Read the notes and observe the maps and diagrams properly to retain the information.

Know Your Country India

To know about our country you need to check the world map and map of India (which are given below). These maps will help you to observe where our country lies. Once you know about its location, then you can predict its temperature, rainfall, vegetation, crops, and a lot of things. The important concepts and information about our country are written below:

Location

 

From the maps given above, it can be observed that India has its place in the Northern-Eastern Hemisphere of the globe. The tropic of cancer which lies at 23 1/2° N passes through the country through its center and the standard meridian which is 82°30′ E of the country passes through Mirzapur, Uttar Pradesh. From the map, it can be seen that it lies in the Asia continent and that too in South-Asia.

Climate

From the map, you must have observed that the tropic of cancer passes through India. Thus, it is a tropical country. The climate of the country is not the same at all places and depends upon the topography and the location of the region. The monsoon is a special feature of India’s climate.

Neighbourhood

India is a South Asian country and has a number of neighbouring countries that are connected with India through land or water. Countries near India are also shown on the map below.

Names of Countries that Shared Maritime Border With India:

• Bangladesh

• Bhutan

• China

• Nepal

• Pakistan

• Afghanistan

• Myanmar

• Sri Lanka

Name of Countries that Shared Maritime Border With India:

• Bangladesh

• Indonesia

• Myanmar

• Pakistan

• Sri Lanka

• Maldives

• Thailand

Administration

India is divided into various states and union territories for administrative purposes. Our country was reorganized in 1956 as per the State Reorganization Act and then the country was divided into 14 states and 6 union territories. This division was done on the basis of language. After that, a lot of States and Union territories have been formed. The number of states and union territories is not fixed and keeps on changing as per the requirement of the country. States and UTs can be formed or demolished or merged etc. as per Part 1 of the Constitution of India. The number of States and UTs in different years is shown in the table below:

So, How many states are there in our country right now? (as of 2021)

After the Jammu and Kashmir reorganization Act, 2019, India has 28 states (excluding Jammu and Kashmir).

Number of Union Territories

After Jammu and Kashmir Reorganization Act, 2019 and Dadar and Nagar Haveli and Daman and Diu (Merger of Union Territories) Act, 2020, India has 9 Union Territories (as of 2021).

Physical Division of India

India is gifted with a number of physical features like mountains, plateaus, plains, etc. The physical features of India are listed below and can also be seen on the map:

Himalayas

These mountains are called young fold mountains which lie in the north. These can be divided into the Himalayas, the trans-Himalayas, and the Purvanchal. The Himalayas are further divided into three parts ie. the Great Himalayas or Himadri, the Lesser Himalayas or Himachal and the outer Himalayas and Shiwalik. Trans Himalayas include the Karakoram range, the Zaskar and Ladakh ranges and these lie North of the Himalayas whereas the Purvanchal mountains lie in the North-Eastern side of the country.

Great Indian Desert

It lies in the western side of the country and the Aravalli Hills called the Thar Desert which is the 9th largest desert in the world. It is the Aravalli Hills which are old fold mountains that save the country from the desert sand and arid region.

Northern Plains

These plains are formed because of the sediments brought by the major rivers like Indus, Ganga, Brahmaputra, and their tributaries. These plains are the most fertile land in the country and also densely populated. These can be divided into four parts i.e. Bhabar, Terai, Bhangar and Khadar. 

Deccan Plateau

It is a part of the peninsular plateau of India and the black soil found here is called the Deccan Trap which is formed because of volcanic eruptions. This plateau can be further divided into the Western Ghats and the Eastern Ghats.

Coastal Plains

It runs along the coastal regions of the peninsular plateau and it can also be divided into two parts i.e the eastern coastal plains which run along the Bay of Bengal and the western coastal plains which run along the Arabian Sea.

Islands

Our country has a group of islands as well which are a great source of tourism. There lie 204 islands on the eastern side in the Bay of Bengal called the Andaman and Nicobar Islands which is also a Union Territory and 43 groups of islands are situated on the western side in the Arabian Sea called Lakshadweep Islands which is also a Union Territory of India.

Did You Know?

India is called the land of rivers because of the presence of a number of rivers here and in terms of the geographical area it is the seventh-largest country in the world and the second country in terms of population.

When we talk about placer deposits meaning, it is a natural concentration of heavy minerals induced by the effect of gravity on moving particles. When heavy, stable minerals are liberated from their matrix by the mechanism of weathering, they are slowly washed downslope into streams which rapidly winnow the lighter matrix. Therefore, the heavy minerals become concentrated in river, stream, beach, and lag (debris) gravels and include workable ore deposits. Minerals which form placer deposits constitute high particular gravity, are durable and chemically impervious to weathering.

Mineral Found in Placer Deposits

Minerals that form placer deposits include precious deposits like gold, platinum, copper, zircon and various gemstones apart from magnetite, ilmenite, chromite, cassiterite, rutile, and native monazite.

Factors Influencing Placer Development

Placer development is activated by a combination of tectonic activity and oscillations in climate and sea level. Besides that various other factors are responsible for placer developments that are as follows;-

• Chemical and Physical weathering that eases all forms of erosion

• Release of minerals into sediments that are transported, deposited, sorted, and often reworked.

• Placer deposits occupy quite a huge range of geomorphological features, by which they are more simply categorized.

• Mineral sands, and in places diamonds, prefer coastal surroundings, whereas the other placer minerals are concentrated often in fluvial deposits.

How to Identify the Type of Placer Formed?

Alterations in energy levels and the associative physical attributes of the minerals and sediments identify the style of placer formed. Lag placers outcomes from an increase of energy that culls out the hydraulically lighter particles (lights) close to Earth’s ground surface. Accumulation placers are created by selective settling of hydraulically heavier particles because of reduction in energy. Both styles are seen in all placer types. Multiphase accumulation, repetition of supply, and reworking are common and generally advantageous. Minerals are favorably concentrated and depleted at different scales, particularly in a fluvial environment, by external physical conditions that form localized energy change. Beach deposits of mineral sands are a type of lag deposit.

Based on the nature of its source, some situations should coincide and events take place to develop a significant placer. The most significant economic characteristics are size and grade (from parts per billion for diamonds to wt percent for minerals), all together with bedrock qualities, sediment particle sizes, and mineral size and morphology. Post depositional alterations, particularly the upgrading of ilmenite by alteration, are significant. The maximum distance isolating a placer from its source varies extensively; from less than a kilometer to thousands of kilometers. Diamond, zircon and rutile placers have formed over hundred to thousand kilometers from their sources. Transport distance is increased by high-energy flow in constricted fluvial channels. An understanding of how placers develop, together with the study of gold particle composition and morphology, aids in the search for primary deposits.

Where to Find Placers?

Placers can be found in virtually any area where gold takes place in hard rock (lode) sediments. The gold is released by weathering and glacier or stream action, transported by gravity and hydraulic action to some preferable point of deposition, and concentrated in the process. Generally, the gold does not travel far from the source, so familiarity with the location of the lode sediments is useful. Gold can also be linked with copper and may form placers in the surrounding area of copper deposits, although this happens less frequently.

Causes of Placer Development

Following are the Causes of Placer Formation:

• Geological instances such as subsidence and uplift may cause repeated and prolonged cycles of erosion and concentration, and where these processes have been undergone placer deposits may be enriched.

• Antiquated river channels and several river bench deposits are examples of gold-bearing gravels which have been disposed to a number of such events, subsequent to minimum partial concealment by other deposits, including volcanic substances.

• Residual placer deposits developed in the immediate vicinity of source rocks are generally not the most productive, though exceptions take place where veins supplying the gold were extraordinarily rich.

• Reworking of gold-bearing substances by stream action results in the concentrations required for exploitation.

• In desert areas sediments may result from unexpected flooding and outwash of sporadic streams.