Reviewer Lesson 2 PDF

1. Earth Structure 1.1. Earth’s Crust Composed of solid rocks, mostly basalt and granite. It is the thinnest layer ranging from about 5 km to 70 km and thickness. 1.1.1. Continental Crust Thicker layer of the Earth’s crust that is found under the continents....

1. Earth Structure 1.1. Earth’s Crust Composed of solid rocks, mostly basalt and granite. It is the thinnest layer ranging from about 5 km to 70 km and thickness. 1.1.1. Continental Crust Thicker layer of the Earth’s crust that is found under the continents. 1.1.2. Oceanic Crust thinner layer of the Earth’s crust that is found under the ocean basins. 1.1.3. Mohorovicic discontinuity Boundary of crust and mantle. Moho does not exist at a uniform depth, because not all regions of Earth are equally balanced in isostatic equilibrium. 1.2. Mantle Mostly solid bulk of Earth's interior. 2,900 kilometers (1,802 miles) thick and makes up 84 percent of Earth’s total volume. 1.2.1. Upper Mantle rigid and contains the asthenosphere, a semi-fluid layer that allows the movement of tectonic plates. 1.2.1.1. Lithosphere The solid, outer part of Earth, extending to a depth of about 100 kilometers (62 miles). 1.2.1.2. Asthenosphere Denser, weaker layer beneath the lithospheric mantle. It lies between about 100 kilometers (62 miles) and 410 kilometers (255 miles) beneath Earth’s surface. 1.2.2. Lower Mantle contributes to the overall convection and heat transfer within the Earth’s interior. 1.3. Outer Core extends from 2,900 km to about 5,150 km beneath the Earth’s surface. It mainly consists of liquid iron and nickel. The motion within this layer generates the Earth’s magnetic field. 1.4. Inner Core central part of the Earth. It extends from a depth of about 5,150 km to the Earth’s center at about 6,371 km. the inner core is solid due to the immense pressure at this depth. Composed primarily of iron, with minor amounts of nickel and other lighter elements. 2. Plate Tectonic and Movement theory dealing with the dynamics of Earth’s outer shell—the lithosphere—that revolutionized Earth sciences by providing a uniform context for understanding mountain-building processes, volcanoes, and earthquakes 2.1. Supercontinents 2.1.1. Pannotia (633-573 MYA) Short-lived supercontinent, centered around the south pole. Modern-day Africa was at the center of Pannotia. 2.1.2. Gondwana (550-150 MYA) a supercontinent that existed from about 550 to 180 million years ago. It was formed when  several smaller continents, including what is now South America, Africa, India, Australia, and Antarctica, collided and merged together. 2.1.3. Pangea (336-175 MYA) Earth’s most recent supercontinent. This supercontinent contained nearly all the land on Earth. Took up about 1/3 of Earth’s surface. The other two-thirds of the Earth was a single ocean, named Panthalassa. 2.2. Plate Movement 2.2.1. Alfred Wegener (1888-1930) presented his theory in lectures in 1912 and published it in full in 1915 in his most important work, Die Entstehung der Kontinente und Ozeane (The Origin of Continents and Oceans). 2.2.2. 4 mechanism why tectonic plates moved apart over time 2.2.2.1. Mantle Convection describes the movement of the mantle as it transfers heat from the white-hot core to the brittle lithosphere. Heated from below, cooled from above. 2.2.2.2. Ridge Push one of the main driving forces of plate tectonics. It refers to the pushing force that plates experience as they slide down the raised asthenosphere underneath Mid Ocean Ridges. 2.2.2.3. Slab Pull pulling force exerted by a cold, dense oceanic plate plunging into the mantle due to its own weight. 2.2.2.4. Slab Suction creates a force that pulls down plates as they are subducting and speeds up their movement, creating larger amounts of displacement. 3. Plate Boundaries three-dimensional surface or zone across which there is a significant change in the velocity (speed or direction) of motion of one lithospheric plate relative to the adjacent lithospheric plate. 3.1. Divergent plates move away from each other. This movement results in the creation of new crust as magma rises from the mantle, solidifies, and forms new oceanic crust. 3.2. Convergent tectonic plates collide or come together. When two plates meet, their interactions can result in various geological phenomena. 3.2.1. Continental-Continental two continental plates collide. Since both plates are less dense than the mantle, neither is subducted. They crumple and fold, leading to the formation of large mountain ranges. 3.2.2. Oceanic-Oceanic two oceanic plates collide, one plate is usually subducted under the other. This process creates deep ocean trenches and volcanic island arcs 3.2.3. Oceanic-Continental oceanic plate collides with a continental plate. The denser oceanic plate is subducted  beneath the continental plate, leading to the formation of a trench and volcanic arcs. Also known to generate large magnitude earthquakes. 3.3. Transform two plates slide past each other horizontally. 4. Plate Tectonics and Volcanoes 4.1. Plate Boundaries Most volcanoes are located at plate boundaries. 4.1.1. Divergent plates are moving apart, and magma can rise to the surface, making new crust. 4.1.2. Convergent One plate is pushed beneath another (subduction), forming volcanic arcs. 4.1.3. Transform these boundaries don't create volcanoes but can have effects on nearby volcanic activity. 4.2. Magma Production Moving tectonic plates can create conditions that facilitate magma production. 4.3. Hotspots some volcanoes originate over hotspots, as areas where the magma coming from great depths in the mantle rises through the mantle irrespective of the tectonic plate boundaries. 4.4. Earthquakes and Volcanic Activity The movement of tectonic plates may cause earthquakes, an act that might provoke volcanic eruptions by changing the pressure and pathways of magma. 5. Earthquake and Plate Tectonics Earthquakes are one of the most dramatic and destructive natural phenomena on Earth, and they are directly linked to the movement of massive slabs of the Earth’s crust, known as tectonic plates. 5.1. Reverse Fault Earthquake occurs when tectonic plates collide, causing the hanging wall to be thrust upward over the footwall. 5.2. Normal Fault Earthquake occur when tectonic plates move apart, causing the hanging wall to slip downward relative to the footwall. 5.3. Strike-Slip Earthquake Strike-slip fault earthquakes occur when two tectonic plates slide past each other horizontally.