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Chapter 9 Earth, Main processes of the Earth, Igneous rock, Underground…
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Underground Water
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The depth of land where the layer of the underground water started varies, depending on the thickness and location of the layer of soil above it
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Soil and most rocks are porous, causing water to absorb into it. When the soil and rocks are saturated, they cannot absorb water anymore. The stagnant there. The underground water stagnant is also known as an aquifer.
May experience vaporisation due to the heat of magma in the Earth's mantle, causing it to burst into steam and gushes spraying and spurting, hot water within the Earth also comes out as hot springs
Springs are formed when the pressure in the aquifer causes some water to flow out to the surface of the Earth.
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Geohazard
Volcanism
In general, volcanic eruption occurs due to the magma beneath the Earth's crust being forced out by high pressure gases
The gas bubbles exert high pressure. The high pressure causes the magma to erupt out to the surface of the Earth. This volcanic eruption is called volcanism.
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When rocks melt into magma, their volume increases and becomes less dense than the rocks in the surroundings
Tsunami
Is known as seismic waves of the sea, which is a series of waves in a water body caused by the displacement of a large volume of water.
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Earthquake
The earthquake is the shaking of the surface of the surface of the Earth's crust caused by sudden release of energy from within the Earth's crust in the form of seismic waves that move in between the layers of the Earth's crust
The sudden release of energy occurs when the tectonic plates meet and collide abruptly in the area of intersection of the tectonic plates and the fault lines.
Effect of earthquake:
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This results in the destruction of many properties, roads, railways and airports.
The collapse of buildings and landslides due to earthquakes have caused many humans and animals to lose their lives.
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Sinkholes
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The occurrence of sinkholes is related to the types of rocks and soil and also underground water drainage
Sinkholes usually formed due to dissolution of rocks when there are water soluble rocks such as salt or gypsum, or sedimentary rocks containing carbonates, like limestone and dolomite
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Quicksand
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When water in the sand cannot escape, it creates a liquefied soil that loses strength and cannot support weight and will suck down objects that fall into it
Quicksand usually occurs in areas with weak structure of soil such as spring, riverbanks, lakes, swamp or coastal areas.
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Landslide
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The movement of the soil and rocks down the slope under the influence of gravity is due to the instability of the mass of soil and rocks, causing it to move to undergo a restructuring to become more stable
The process of landslides involves ground movements such as earth flow, soil movement, rockfalls, debris flows or mudflows and ice slides
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Acid rain
Formed when acidic gases such as sulphur dioxide and oxides of nitrogen dissolve in water vapour in the atmosphere before falling to the Earth as acid rain in the form of nitric acid and sulphuric acid
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The effect of acid rain:
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Increases the acid content in the soil, making the soil infertile. This affects the yield of crops
Destroys the photosynthesis cells in the leaves. Thus, the leaves cannot carry out photosynthesis. The plants will wither and die
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Aquatic ecosystem will be affected. Aquatic plants and planktons are destroyed due to the reduction in the pH values of the water in the lakes, rivers and oceans
Sedimentary rock
The formation process
Formed by compression of deposited minerals carried by rivers, glasiers and wind
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Its texture and grain can easily be distinguished. For example, shale rock (fine grain) and conglomerate rock (pebble size grains)
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Metamorphic rock
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Very hard, Usually harder than the original rock that formed it
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Fossils
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The remains or traces of organisms whether plants or animals that lived in the past which were naturally preserved in the rocks
Most fossil is found embedded in sedimentary rocks such as limestones, sandstone and shale
Found in the form of skeletons or animal bones, shells, leaves and plant woody parts that have been preserved or in the form of footprints or animal trail only.
The process of fossil formation takes a very long time, which may reach to million of years
Fossils are discovered when the rocks that contain fossils are exposed by natural weathering processes and human exploration activities.
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Hydrothermal
The hot spring area can also become a recreational park and this is a potential attraction of eco-tourism. For example, hot spring in Sungai Klah, Perak and hot spring in Poring, Kundasang, Sabah
Hydrothermal sources that have low to medium temperatures (20c - 150c) are used to supply direct heating to homes, commercial buildings and industries
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commonly occurs near sources of heat in the Earth's crust such as near the volcanoes. An example of hydrothermal is underground hot water that spurts out geysers and hot springs
Circulation refers to the circulation of hot water from the hot rock area to a cold rock area in the Earth's crust
Related to the action of hot water in the Earth's crust. 'Hydro' means water and 'thermal' means temperature
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Economic Minerals
Non-metallic minerals
Include mineral fuels such as petroleum, natural gas and coal
Other examples of non-metallic minerals are sand, limestone, granite, quartz, kaolin and marble
Metallic mineral
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Are found naturally in the Earth's crust as metal ores such as tin ore (cassiterite), iron ore (hematite), pyrite, lead ore (galena) and aluminum ore (bauxite) or found as free metals such as silver and gold
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Economic minerals are materials that have economic values. Economic minerals consist of metallic minerals, non-metallic minerals, and rare earth minerals
The main materials that form the Earth and other planets. Minerals are inorganic solid compounds that are formed naturally
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Atmosphere (Air Zone)
Traps heat, making the Earth's temperature suitable for living things
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Protects living organisms from genetic damage caused by harmful ultraviolet rays and cosmic radiations
Consists of 78% nitrogen, 21% oxygen, 0.03% carbon dioxide and 0.97% inert gases and other elements
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Troposphere
It contains the most cloud. The changes of weather and climate take place here. All weather phenomena such as wind, rain, storm and snow occur in this layer
This layer supports living organisms such as humans, animals and plants
Has the highest air mass, causing it to have the highest air pressure
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Surface water
Surface water may affected by human activities. Therefore, surface water is at risk experiencing the following:
a. Pollution
Surface water can be polluted by waste materials that are released into the rivers, lakes and seas from residential and industrial areas
Surface water near agricultural areas is polluted due to the use of excessive fertilisers and pesticides
b. Dryness
Besides pollution, surface water is also at the risk of getting dry. This may be caused by drought due to global climatic change as well as the phenomenon of global warming
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Surface runoff formed when rainwater could not seep into the soil because the soil is saturated with water due to rainfall exceeding the rate of soil absorption
Rainwater sweeps into the soil and some flows on the surface of the Earth or slopes as surface runoff
Water found on the surface of the Earth such as ponds, lakes, swamps, rivers and seas
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Mesosphere
The rocks in mesosphere layer is extremely hot and can flow gradually due to the convection current of the mantle formed by the heat from the core of the Earth
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Geological Time Scale
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The chronological arrangement of geological events. It is used by geologists and Earth scientists to describe the relationship of events that have occurred during the history of the Earth
Used today in the 18th century and is continuously improved over the time. The geological time scale is considered as estimated real geological time made based on carbon dating using the oldest radiometric techniques and fossil age found in the layer of the rocks.
Is divided into four eras, namely cenozoic, mesozoic, paleozoic and precambrian.
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Thermosphere
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The phenomenon of aurora occurs in the layer. Aurora is a band of colourful lights, resulting from the magnetic field and atmospheric gases
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Ocean Stratification
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The ocean is divided into a few layers known as zone. The zones differ based on the penetration of light (amount of light received)
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Asthenosphere
Temperature at 1300c. High temperature and pressure causes the rocks to melt and become semi solids, enabling the lithosphere to float on this layer
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Composition of the Earth
The rocks on Earth can be divided into three groups based on the formation process, which are the:
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Each group of rocks is formed by a different process and takes a very long time from thousands to millions of years to form
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Hydrosphere (Water zone)
The part of the Earth that is made up of water such as rivers, lakes, oceans, ponds and groundwater, including freshwater, salt water, snow and glaciers.
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Biosphere (Life Zone)
The region on the Earth's surface that supports life such as humans, animals, plants and microorganisms like bacteria, fungi, algae and protozoa
Can be divided into various ecosystems such as grassland, forest, mangrove swamp and desert. Each ecosystem is a habitat to various populations of animals and plants
Mesosphere
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The destruction of meteorites caused by the collision with gas particles takes place in this layer. This resulted in the phenomenon of shooting star or meteor
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Earth Layer
The Earth is made up of 3 layers according to its physical characteristics with are the crust, mantel and core
The mantle consist of lithosphere, asthenosphere and mesosphere
The rock cycle
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The process of formation of igneous, sedimentary and metamorphic rocks can be explained using rock cycle
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Formation of coal
Formed from the remains of plants (trees, ferns, and mosses) that lived millions of years ago in swampy areas
Organic waste materials from the dead plants experienced high pressure and heat due to the pressure exerted by the buried sediment on them and turned them into coal
Earth system
The system consists of four main components, which are interrelated namely geosphere, hydrosphere, biosphere and atmosphere.
Strastosphere
The layer that contains a lot of ozone gas and known as ozone layer is located here (altitude 18 - 38 km)
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Petroleum
Fuels for vehicles, for making solvent, plastic and soap
Gold, Silver
For making coins, jewellery and art works
Tin
For coating cans, making cans, welding electronic devices
Sand
For making bricks, cement and glass items
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