Earth Characteristics PDF

Earth Characteristics 1) Atmosphere Earth has a breathable atmosphere Oxygen is the gar that is required for the life of most Creatures Earth's atmosphere protects us prom radlation. 30% of radiation is reflected away by the atmosphend 25% is absorbed by the Earth's atmosphere. Nitrogen is t...

Earth Characteristics 1) Atmosphere Earth has a breathable atmosphere Oxygen is the gar that is required for the life of most Creatures Earth's atmosphere protects us prom radlation. 30% of radiation is reflected away by the atmosphend 25% is absorbed by the Earth's atmosphere. Nitrogen is the most abundant to the Earth's atmosphere. ▪︎nitrogen - 78% ▪︎oxygen- 21% ▪︎argon- 1% ▪︎carbon dioxide - 0.005% 2.) Hydrosphere The total amount of water in the planet. Earth water is considered to be the most important chemical. 3.) Soil & Vegetation It is a medium of growth The soil promoter growth and providing nutrition to plants. Vegetation - is the general term for plant life. -vegetation produce trees, forest covers, ensures the water and nutrient ayde, and prevents soil and wind evasion. 4.) Light All planets are light from the sun but most of the planets does not use it. Photosynthesis 5.) The sun The distance of the Earth and the sun is the perfect distance. The sun's gravity keeps the Earth on its orbit. 6.) Ozone Layer The sun cotinually pumps out radiation. Heat and light are two examples of radiation and are essential to Earth. (Ozone layer starts at between at 10 to 17 km from Earth's surface but can extend to 50 km) 1% of the UV radiation reaches the Earth's surface small amount of UV rays is beneficial but too Much UV rays can give you sunburn or even skin cancer. Ozone layer prevents us from the UV Rays. 7.) Earths Magnetic field Earth's magnetic Field protects the atmosphere. Earth's core is loaded of molten Iron. Iron is a very magnetic element and cause Earth as a giant magnet. This is why we have the North and south pole. t prevents the solar wind from stripping the Earth's atmosphere. THE FOUR SUBSYSTEMS OF THE EARTH Atmosphere - Gaseous layer, it's also called air. Biosphere - A life, comprised of all living things. Hydrosphere - water , 97.5%-saltwater 2 5% - freshwater. Lithosphere/Geosphere - Geo means ground ATMOSPHERE Exosphere - 10 000 km, Farthest layer. Thermosphere - 85 to 600 km. It has charged particles. Mesosphere - 50 to 85 km, it protects us from space debris Stratosphere - 14.5 to 50km and ozone layer situated here. Troposphere - 14.5 km and least layer GEOSPHERE Crust - outermost layer, made out of silicate materials. Mantle -made mostly on silicate rocks, 2900 km thick. Core - 3400 km, inner most layer, made of Iron & nickle Continental crust - 15 to 70 cm Oceanic Crust-5 to 10 cm Internal heat since it has radioactive material. Bullen Discontinuilty - separates liquid outer core from solid inner core. HYDROSPHERE Clouds & rain is part of the hydrosphere BIOSPHERE Reaches the deep part of the ocean. Depends on 3 spheres. It also provides heat beneath the Earth. How do Earth's sphere interact with each other? No sphere works on it's own. All the spheres in the system interact with one another and overlap to survive. ROCKS & MINERALS -are the essential building blocks of the Geosphere Minerals - minerals are the fundamental components of rocks. -There are 3000 species of Minerals MINERALOGIST -Spudies minerals COMMON ROCK FORMING MINERAL Quartz Plagioclase feldspar Alkali feldspar Micas Amphiboles Pyroxene olivine Calcite PROPERTIES OF MINERALS 1) Color- one of the characteristics of a mineral is color. 2) Luster- standard names for luster include metallic, glassy, pearly, sillky, greasy, and dull. 3) Streak- it refers the color of the mineral in powdered form. -It also refers to the color of the work it leaves bubind apler being rubbed agminst a pryse of ungimed poreelanin. 9) Hardness - is a measure of how resistant a mintral is to scratching Mohs Scale - developed by a German geologist named Friedrich Mohs. 5) Cleavage - is the way in which a mineral breaks along Smooth plot planes is called cleavage. 6) Fracture - When a mineral breaks irregularly, the breaks are called fractures. 7) Crystaline structure or habit - crystal habit is the characteristics external shape of an individual crystall or crystal group. 8) Density – refers to the mass per unit volume. -In minerals, the term specific gravity is used in describing density. Specific Gravity -The specific gravity of a mineral is the ration of its weight compared with the weight of an equal volume of water. 9)Diaphaneity/Amount of transparency- ability to allow light to pass through it. 10) Tenacity - describes the mineral's reaction to stress. 11) SPECIAL PROPERTIES Fluorescence- The fluorescent minerals are those that emit visible light when activated by invisible ultraviolet light (UV), X-rays and/or electron beams. Example is Gypsum Phosphorescence- is the ability of a mineral to glow after the initial activating ultraviolet light is removed. Example is Fluorite Thermoluminescence- is a property of some minerals to glow when they are heated. Example is Calcite Triboluminescence- is a property of some minerals to glow when they are crushed, struck, scratched or even rubbed in some cases. Examples are Calcite and Fluorite. ROCKS -ARE NATURALLY OCCURRING AGGREGATES OF MINERALS, ROCK FRAGMENTS OR ORGANIC MATTER. 3 Rocks main types -Igneous -Sedimentary -Metamorphic INTRUSIVE, OR PLUTONIC, IGNEOUS ROCKS ➤ are formed when rising magma is trapped deep within the Earth, where it cools very slowly over many thousands or millions of years until it finally solidifies. ➤ Slow cooling allows the individual mineral grains sufficient time to grow and form relatively large crystals. ➤Intrusive rocks have a coarse-grained texture with interlocking minerals. ➤Granite is a commonly occurring intrusive rock. EXTRUSIVE OR VOLCANIC, IGNEOUS ROCKS ➤ Extrusive, or volcanic, igneous rocks are produced when magma is erupted at, or very near, the Earth’s surface. ➤ The erupted magma cools and solidifies relatively quickly when it is exposed to the cooler temperatures of the atmosphere. ➤Lava and tuff are two common volcanic rocks. SEDIMENTARY ROCKS ➤Sedimentary rocks are formed from the eroded fragments of pre-existing rocks, or from the skeletal fragments of once- living plants or organisms. ➤Sedimentary rocks are sub-divided into three groups, including: Clastic -are made up of fragments (clasts) of preexisting rocks. Biological -formed when large quantities of living plants or organisms die and accumulate. Chemical – forms when mineral constituents in solution become supersaturated and inorganically precipitate. METAMORPHIC ROCKS ➤ Are formed when a pre-existing rock is subject to high temperature, high pressure, hot and mineral-rich fluid, or a combination of these conditions. ➤Are generally formed deep within the Earth, or where tectonic plates meet. ➤Foliated vs. Non-foliated Foliated rocks- have distinct banding or layers that formed perpendicular to pressure. Nonfoliated rocks- are crystals with blocky shapes and do not have banding. THE ROCK CYCLE -is a conceptual model that explains how geological processes acting on any one of the three main rock types – igneous, sedimentary and metamorphic can change one rock type to another over geological time. In order to understand the Rock Cycle, it is important to understand the rock forming processes: Igneous rock-forming processes involve melting, cooling, and crystallization. Sedimentary rock-forming processes involve weathering, erosion, deposition, burial, and lithification. Metamorphic rock-forming processes involve changes to rock textures and mineral compositions under different temperature, pressure, or hot fluid conditions. Exogenic Processes Can all types of rocks be weathered? Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. The products of weathering and erosion -Are the unconsolidated materials that we find around us on slopes, beneath, beside and on top of glaciers, in stream valleys, on beaches, and in deserts. Weathering – is the breaking down or Dissolving of rocks and minerals on Earth’s Surface. Erosion – carrying away pieces of sediment. (Weathering and erosion always occur together.) Deposition- refers to the accumulation of Sediments (particles) or settling smaller particles in a basin (or a depression) FACTORS AFFECTING WEATHERING Climate – chemical weathering is more effective and rapid in regions with high temperatures and rainfall. Rock Type – Some rocks have different degree of resistance to weathering. Rock Structure – Weathering agents may enter a rock mass through its joints, faults, folds and bedding planes. Slope – Weathering is faster in steeper slopes than in less steep slopes. AGENTS OF EROSION Running Water – does not soak or evaporate runs over the ground, carrying with it rock particles and enters a body of water such as streams, lakes, and oceans. Wind – Loose rock and soil particles are carried away by wind and are deposited at other places. Glaciers – is a large mass of ice and snow that forms in colder parts of the world. Gravity- is a major force that drives erosion and deposition. The Theory of Plate Tectonics -Boundaries, Stresses , and Faults What are plates? The earth's crust and upper mantle (lithosphere) are broken into sections called plates plates move around on top of the mantle like rafts a section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust. What Is The Theory Of Plate Tectonics? the theory that pieces of earth's lithosphere are in constant motions, driven by convection currents in the mantle. Plates move slowly in different direction Cause different geologic events (like earthquake, volcano ,etc.) What makes the Plate move? convection currents in the mantle move the plates as the core heats the slowly-flowing asthenosphere (the elastic/plastic like part of the mantle). Plate Boundaries The edge of Earth’s plates meet at plate boundaries. Extended deep into the lithosphere. Fault - breaks in earth's crust where rocks have slipped past each other. There are 3 Types of Plate Boundaries 1. Divergent Boundaries A plate boundary where two plates move away from each other. How is the rock pulled at Divergent Boundaries? Rock gets THIN in the middle as it is pulled apart. This STRESS is called tension What happens when the rock snaps from the Stress of Tension? A Normal Fault (fault is a break in earth's crust) Rock drops down as it breaks. What happens next at Divergent Boundaries? A geologic feature or event , may form RIFT VALLEYS on continents , SEAFLOOR SPREADING in the ocean. Helpful Hints... Divergent is like dissecting or dividing. If you pull warm bubble gum or silly putty, it will thin in the middle until it is stressed so much that it breaks. Happens on land and under h2o Features of Divergent Boundaries Mid ocean ridges Rift valley Fissure volcanoes 2. Convergent Boundary a plate boundary where two plates move towards each other. boundaries between two plates that are colliding  places where plates crash (or crunch ) together or subduct (one sinks under) 3 Types of Convergent Boundaries Type 1 Ocean plate gliding with less dense continental plate Subduction zone: the process by which oceanic crust sinks beneath a deep ocean trench and back into the mantle at a convergent plate boundary. Volcanoes occur at subduction zone Type 2 Ocean plate colliding with another ocean plate The last dance plates slides under the more dense plate creating a subduction zone called a TRENCH Type 3 A continental plate colliding with another continental plate Have collision zones: - A place where folded and thrust faulted mountains form May form Mountain Ranges. These are like folded mountains, like himalayas or the rockies What happens when the rock is squeezed from the Stress Of Compression ? A REVERSE FAULT Rock is forced upwards as it is squeezed. Helpful Hints... Convergent= “ connecting “ boundaries May work like a trash compactor smashing rock, - Rock goes crunches up to make folded mountains. - Rock goes down under the subduction zone. 3. Transform Boundaries a plate boundary where two plates move past each other in opposite direction. How is the rock broken at transform boundaries? Rock is pushed into opposite directions (or sideways,but no rock is lost ) This stress is called SHEARING What happens next at transform boundaries? May cause earthquakes when the rocks snaps from the pressure. A famous fault of a transform boundary is the san andreas fault in california. What happens when the rock is sheared (or cut )from the stress of shearing? A STRIKE-SLIP FAULT Rocks in each side of the fault Slip past each other as they break. Helpful Hints... Shearing means cutting Transform boundaries run like trains going past each other in different directions and they shake the ground! Fossil Dating How do we know the age of fossils? Scientists use 2 methods to determine the age of fossils: 1. Relative dating 2. Absolute dating Relative and Absolute Dating Imagine someone telling you a story where all the important events happened in the wrong order it might be confusing or even make no sense at all. Being able to tell how old things are and put them in the right order is one of the most important skills archaeologist have. We call this skill dating because it is how we organize our discoveries in , like dates on a calendar. Archaeologist use two kinds of dating methods: relative dating and absolute dating. In relative dating, we determine which things are older or younger based on the relationships. For example, we know from geology that soil layers near the surface of the ground are usually younger than those deeper down. This relationship helps archaeologists no that the objects we find deep in the ground or older than things you find closer to the surface. What is Dating? When geologists date rocks they are determining how long ago they formed. Two ways to do this: - Relative dating - Absolute dating Relative Dating Determining how old something is compared to something else. Use words like older or younger instead of exact numbers. I. Relative Dating Relative dating is when you give the age of a rock or fossil compared to another rock or fossil. Example: rock A is OLDER than rock B. An actual age in years is not determined II. Rules of Relative Dating 1. Law of superposition: when sedimentary rock layers are deposited, younger layers are on top of older deposits. 2. Law of original horizontality : sedimentary rock layers are deposited horizontally. If they are tilted, folded, or broken, it happened later. 3. Law of cross cutting relationship: if an igneous intrusion or a fault cuts through existing rocks, the intrusion or fault is YOUNGER than the rock it cuts through Absolute Dating Determining how old something is Use numbers (in millions of years, mya) Only works for igneous rocks Determines the specific age of a fossil Looks at chemical properties Two types: - Carbon-14 (radio carbon) - Potassium-argon Carbon-14  Also known as radio carbon dating Used to date organic substances Scientist measure the radio carbon and the fossil to determine its age Can only date specimens up to about 60,000 years old Potassium – Argon Dating Scientist determine the age of the rocks surrounding the fossil to determine the fossils age. Used only for inorganic substances (rocks and minerals) Scientist measure the amount of argon and the rock to determine its age Dates rock 60,000 years old and older How absolute Dating Works ➔ When magma or lava cools radioactive elements are incorporated into the minerals. ➔ Examples - Potassium 40 - Uranium 235 ➔ These elements begin to decay at a known rate starting when the rock cools ➔ We can measure how much of the element is left ➔ Tells us how much time has passed since the rock formed. What can we learn from this? Absolute Dating ➔ Helps us determine the age of the earth ➔ Helps us determine when specific events in the history of the earth happened (example extinction of the dinosaurs) Relative Dating ➔ Can help us estimate the time span between major earthquakes, storms, tsunamis etc ➔ And help us determine the order that life forms developed on earth.