Introduction to Physical Geography PDF

Intro To Physical Geography: - demo monday jan 20 What is physical geography? ​ A study of the physical makeup of the earth - the processes and patterns in the natural environment ​ “Geology” - study of the earth -​ “Geo” - earth or land -​ “Ology” - the study of...

Intro To Physical Geography: - demo monday jan 20 What is physical geography? ​ A study of the physical makeup of the earth - the processes and patterns in the natural environment ​ “Geology” - study of the earth -​ “Geo” - earth or land -​ “Ology” - the study of ​ Answers questions like: -​ Why does the world look like the way it does? -​ How did things like volcanoes, mountains & glaciers form? What will we be learning? -​ The layers of the earth -​ Tectonic plates - the formation of the continents of the Earth -​ The physical geography of Canada -​ Formation of rocks, glaciers, and soil -​ Natural disasters Layers of the earth ​ The earth is made up of 3 layers -​ Crust -​ Mantle -​ Core The crust: -​ The crust is where we live - it is the surface of the earth -​ The earth is made of two crust: continental and oceanic -​ Continental crust is thick, mostly formed of various types of rock -​ oceanic crust is found about 5-10 km below sea level and is formed of minerals - mostly magnesium and silicate The Mantle: -​ The largest layer of the earth, it makes up about 85% of the earths total volume -​ The temperature of the mantle ranges from 1,000℃ to 3,700℃ -​ The mantle had never been directly explored - even the most advanced drilling equipment has never gotten beyond the crust -​ Instead, geologists study the mantle by examining rock formations that have moved to the surface of the earth -​ The mantle is always active - it is constantly in motion (fun fact - earth is The Core: -​ Earth’s core is extremely dense and hot - estimated 5,000-6,000℃ -​ The core is divided into 2 sections - the outer core and the inner core -​ The outer core is approximately 2,200 KM thick and is made of liquid iron and nickel -​ The inner core is mostly solid due to the intense heat and pressure that prevents the iron and nickel from melting  ​ The earth is 4.6 Billion years old, the earth did not look the same as it does today ​ A scientist Alfred Wegener suggested all earths land masses collided 300 million years ago to for one supercontinent - he named in Pangaea ​ He had had 4 proofs - 1. He saw 2 continents fit together like a puzzle (south america and africa) - south america laughed at him 2. He looked at some plants and animals from south america and africa and it made more sense for them to be together for the plants and animals. 3. He looked at 2 different changes of mountains north america and europe( appalachians and caledonians) the mountains were the same age and structure - same mountain, same height, same rock, same order - they had to be formed at the same time 4. They found evidence ice sheets once existed/covered in southern africa, south america, india, australia - continental drift, these continents drifted apart to where they are today. They used to be further south ​ J. Tuzo Wilson (Canadian) - sparked new interest in continental drift theory. He helped to explain how the continental drift happened ​ Developed a theory of Plate Tectonics ​ Comes from the greek word “tekton”, meaning builder ​ Go out apart The Theory: -​ Earth's outer shell is broken into thin, curved plates that move laterally(side to side) atop a weaker underlying layer -​ Due to tremendous heat, rock in the asthenosphere is like hot taffy -​ This allows plates to ride on top of hot, flowing rock -​ Plates move because heat is being released from deep inside the earth -​ Convection currents causes hot material to rise and expand (plates diverge) and cooler material to sink and contract (plates converge) -​ Plate Tectonics: -​ A theory that earths outer shell is made up of individual plates that move -​ This explains why we have earthquakes, volcanoes, mountains, and the formation of a new crust -​ The earths crust is not one single piece that fully covers the earth, instead there are several different plates that float on the molten rocks, shifting the plates overtime -​ The earth has been formed out of seven major plates, eight secondary plates, and more than 60 minor plates. These are called the tectonic plates. -​ A tectonic plate is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.  -​ Lithosphere = the lithosphere is the rigid outer layer of the earth and is composed of rocks and minerals. It is made up of the entire crust as well as the upper part of the mantlle. ​ 3 types of plate movements: 1.​ Divergent 2.​ Convergent 3.​ Transform→ rub side to side - earthquakes Why are tectonic plates significant? -​ Plate boundaries are important because they are often associated with earthquakes and volcanos. When earths tectonic plates grind past one another, enormous amounts of energy can be released in the form of earthquakes. -​ Volcanos are also often found near plate boundaries because molten rock from deep within Earth–called magma–can travel upward at these intersections between plates. Divergent Plate Movement -​ When two plates move apart -​ Divergent plate boundary often forms a mountain known as a ridge -​ This feature forms magma from the upper mantle escapes into the space between the spreading tectonic plates -​ an example of a ridge is the Mid-Atlantic ridge, an undersea chain of mountains that formed as two pairs of tectonic plates spread apart: the North American plate and the Eurasian Plate in the North, and the South American Plate and he African Plate i the south -​ When plates diverge new crust is formed - both plates that diverge get larger -​ Most volcanoes occur across divergent lines -​ Plates get bigger Convergent Plate Movement -​ When two plates move toward each other creating a lithospheric collision There are 3 types of convergence: 1.​ Continental plate meets oceanic plate: the rocks that make up oceanic plates are denser than continental. Therefore, oceanic plates slide underneath a continental plate. This process is called subduction. Existing crust is “recycled” by subduction. The crust of the oceanic plate gets melted by the magma. They are most likely to form tsunamis. 2.​ Oceanic plate meets oceanic plate: The older and denser oceanic crust will subduct. This will cause an oceanic trench to form. These trenches are some of the deepest places in the ocean, and they are often the sites of strong earthquakes. 3.​ Continental plate meets continental plate: When two continental plates collide, massive layers of rock are folded, broken, and forced upwards. This forms towering mountain ranges, like the Himalaya, as Earth’s crust is crumpled and pushed upward.  -​ The plates get smaller Transform Plate Movement: ​ A transform plate boundary occurs when two plates slide past each other, horizontally ​ A well-known transform plate boundary is the San Andreas Fault, which is responsible for many of California’s earthquakes. -​ Plates are not made larget or smaller at transform boundaries ​ A single tectonic plate can have multiple types of plate boundaries with other plates that surround it. For instance, the Pacific plate, one of earths largest tectonic plates, includes convergent, divergent, and transform plate boundaries Volacnos/earthquakes: -​ Magma is molten rock that is under crust -​ Lava is over the earths surface -​ Ring of fire is the patterns in the pacific ocean Hot spot: -​ exists in the middle of a plate -​ Everytime it moves it affects crust , you get a row of volcanoes -​ How hawaiian islands were made → Hawaiian chain of volcanos from hot spots -​ More volcanoes are formed in the middle of plates Rocks: Types of rocks: 1.​ Igneous Rocks: forms when magma or lava cools. Most cooling happens either at the bottom or inside crust heart. a)​ Igneous rock that cools below Earths surface: intrusive rocks b)​ Igneous rock formed from lava that cools on the surface: extrusive rocks Igneous: 6 - Baselt, 9 - Granite , 10 - Punice Sedimentary Rocks -​ Created after millions of years of compaction and cementation of loose sediments -​ Compaction: loose sediments become tightly packed and are cemented together by minerals deposited between them -​ For example: limestone, concrete (lime, sand, crushed stone, gravel) Sedimentary: 20 - limestone , 17 - sandstone , 19 - conglomerate , 16 - shale/ fossil , 9/38 - petrified wood , 24 - galena Metamorphic Rocks -​ Changed versions of igneous, sedimentary, other metamorphic rocks -​ Changes occur when the rocks are exposed to heat and pressure. -​ Happen when HEAT AND PRESSURE - MARBLE -​ For example: A metamorphic version of limestone is marble. Metamorphic: 11 - marbles ​ Weathering + Erosion → breaking down a rock 1)​ Flowing water → the force of the H2O(water) - weathers the rock behind it and breaks it down 2)​ Wind - wind picks up pieces of rocks, sand, debris + blows it into other rocks, breaking them down. 3)​ Rain → Constant repeated action (drip of rain) that can create indent on rocks -​ When cold the rain can freeze in the rock + expand cracking it + breaking it apart Canadian shield is the largest - was formed first The affects of the Canadian shield - camp in canadian shield: -​ Removed soil - thin soil limit vegetation growth (size and height of trees) -​ Depressions caused by gouging filled with water - called lakes and rivers now -​ If the ice will scrape the land it will leave lakes and river -​ Formed during pangea Layers of sedimentary rock were uplifted when North America collided with Europe and northern Arica Millions of years of weathering/erosion Fjord - valley between two mountains - glaciers out river valleys Interior Plains - see cows- mainly beef cows - grain farming -​ Layers of sedimentary rock deposited in warm island seas -​ Fossil fuels formed over millions of years -​ Glaciers left rolling landscape on sedimentary rocks -​ Soil deposited from glacial lakes resulted in excellent soil fertility Great lakes - st. lawrence low lands Urban sprawl - unchecked development of mostly single family dwellings -​ Automobile use is necessary to do most activities -​ Easy to build on mostly flat land with soft deposits Innuitian Mountains - some sedimentary layers deposited -​ Some igneous and metamorphic rocks -​ Harsh climate and inaccessibility has slowed development of resources Westcoast Western cordillera -​ Youngest mountain range formed when two plates collide ( north american + pacific) -​ sedimentary layers uplifted -​ igneous and metamorphic as well Challenges - land slides - highest mountains in all of canada, -​ Narrow strip of land -​ Steep slopes and elevation changes -​ Danger of rock slides and avalanches -​ Costs associated with design, building, maintenance, closures