Earth Science Review Guide PDF

Earth Science Review Guide 1. Distribution of Active Volcanoes, Earthquake Epicenters, and Major Mountain Belts - Active Volcanoes: These are primarily found at tectonic plate boundaries. Most active volcanoes are located along convergent and divergent boundaries....

Earth Science Review Guide 1. Distribution of Active Volcanoes, Earthquake Epicenters, and Major Mountain Belts - Active Volcanoes: These are primarily found at tectonic plate boundaries. Most active volcanoes are located along convergent and divergent boundaries. A well-known example is the Pacific Ring of Fire, where the majority of Earth's volcanoes are concentrated. - Earthquake Epicenters: Earthquakes frequently occur where tectonic plates interact, mainly along fault lines. The location on the Earth's surface directly above where the earthquake originates is called the epicenter. Most epicenters are found near plate boundaries. - Mountain Belts: Major mountain ranges like the Himalayas and the Andes are formed at convergent boundaries where two tectonic plates collide. These collisions cause the crust to crumple and fold, resulting in mountain formation. - Relation to Plate Tectonic Theory: The theory of plate tectonics explains how the movement and interaction of Earth's lithospheric plates lead to the formation of these geological features. As plates move, they create the conditions for volcanic eruptions, earthquakes, and mountain building. 2. Different Types of Plate Boundaries - Divergent Boundaries: At these boundaries, two tectonic plates move away from each other. As they separate, magma rises from beneath the Earth's surface, creating new crust. A famous example is the Mid-Atlantic Ridge. - Convergent Boundaries: At convergent boundaries, two plates move toward each other. When they collide, one plate may be forced beneath the other in a process called subduction. This often results in volcanic activity and the formation of mountain ranges (e.g., the Andes and Himalayas). - Transform Boundaries: Here, two plates slide past each other horizontally. This movement can cause earthquakes. The San Andreas Fault in California is a well-known example of a transform boundary. 3. Different Processes that Occur Along the Plate Boundaries - Subduction: This process occurs at convergent boundaries when one plate sinks beneath another into the mantle. This causes intense volcanic activity, and trenches form at the subduction zones. - Sea-Floor Spreading: Occurs at divergent boundaries, where plates move apart, and magma rises to create new oceanic crust. This is observed at mid-ocean ridges. - Faulting: When stress builds up along a fault line, the rock may break and slip, causing an earthquake. Faults are common at transform boundaries. - Mountain Formation: As plates collide at convergent boundaries, the crust is pushed up, creating large mountain ranges. This happens when neither plate subducts, but both rise and fold, forming ranges like the Himalayas. 4. Possible Causes of Plate Movement - Mantle Convection: Heat from the Earth's core causes convection currents in the mantle, which drag the plates along as they move. - Ridge Push: Newly formed lithosphere at mid-ocean ridges is elevated, causing the plates to slide down and away from the ridge due to gravity. - Slab Pull: The dense, cold part of a plate at a subduction zone pulls the rest of the plate down into the mantle, helping to drive plate motion. 5. Evidence that Supports Plate Movement - Fossil Distribution: Identical fossils of plants and animals, such as the Mesosaurus, have been found on continents that are now far apart, suggesting that these continents were once joined. - Fit of the Continents: The shapes of continents, especially the coastlines of Africa and South America, fit together like pieces of a jigsaw puzzle, indicating that they were once part of a supercontinent. - Paleomagnetism: Studies of Earth's magnetic field recorded in rocks show that the magnetic poles have shifted over time. This supports the theory of sea-floor spreading as new crust is formed and older crust is pushed away. - Distribution of Earthquakes and Volcanoes: Earthquakes and volcanoes are concentrated along tectonic plate boundaries, especially around the Pacific Ocean's Ring of Fire, providing evidence for plate tectonic activity.