Geology topics unit notes
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This document provides an overview of geology topics including plate tectonics, evidence for continental drift, layers of the earth, types of plate boundaries, volcanoes, earthquakes, rocks, minerals, and earth system history. It covers key concepts such as P and S waves, convection currents, types of lava and crystals, and the geological time scale divided into eons, eras, and periods. The multi-page document acts as a study guide for students, with definitions and diagrams related to the structure and dynamics of the Earth.
Geology topics unit notes
- 1. Geology Topics Unit Notes Name: (PLEASE DO NOT LOSE!) Continental Drift: The gradual movement of the continents across the earth. Plate tectonics - The earth’s crust and upper mantle are broken into sections called plates. These plates float on the mantle like rafts (moving very slowly) Evidence For Continental Drift -The Shapes Match -Same fossils found on different continents These are the pictures on the puzzle pieces. -The Same rock structures on different continents -Fossils of Trees and Animals in Antarctica -Magnetic layers in sea floor spreading Gondwondaland and Laurasia were two mega continents before Pangea. Pangea – The “Super Continent” All of the plates were once together 1
- 2. We know the material of the interior of the earth based on how P and S waves move through planet. P Wave: Primary wave. Moves lateral S Wave: Secondary waves. Stronger and move back and fourth. Layers of the Earth Layers formed early in Earth System History (Archean Eon) Gravity pulled heavy elements toward the middle. Pictures for heat transfer Convection - Vertical circulation in which warm rises and cool sinks. Flow of heat by this circulation. Conduction - The movement of heat from one molecule to another. Radiation - Energy that is radiated or transmitted in the form of rays or waves or particles. 2
- 3. The two types of Crust Ocean Crust (Basalt) Continental Crust (Granite) PLATE BOUNDARIES Divergent Boundaries: At divergent boundaries new crust is created as two or more plates pull away from each other. Mid-Atlantic Ridge is like a baseball because it encircles the earth, showing the places where new earth is formed. Convergent Boundaries: Here crust is destroyed and recycled back into the interior of the Earth as one plate dives under another. 3
- 4. Ocean Convergent:Two ocean plates collide and one goes under the other. Archipelago (Island Arc) – Group of volcanic islands formed from ocean curst convergence. Continental Convergence (Mountain Building) 4
- 5. Continent Divergence (Moving apart) Transform-Fault Boundaries: Where two plates are sliding horizontally past one another. (To be discussed more later) Hawaii is caused by a hot spot: A location above an upwelling of magma from the mantle. 5
- 6. VOLCANOES Volcano - An opening in the Earth's crust through which molten magma and gases erupt. The positives of volcanoes -New Land is formed -Release of healthy gases -Many gems and ores worth $ -Hominids used obsidian (cutting tools) to advance -Volcanic ash fertilizes land -Volcanic eruptions formed oceans and early atmosphere. -Tourism The Negatives of Volcanoes - Death and Destruction - Loss of land until…?, Permanent loss of structures. - Release of poisonous and greenhouse gases. - Eruptions can have a tremendous impact on global climate. - Mass extinction events Types of Volcanoes Fissure Shield – Olympus Mons Dome Ash Cinder Composite Caldera: Large crater caused by the violent explosion of a volcano that collapses into a depression. 6
- 7. PARTS OF A VOLCANO Pyroclastic rock: Rock ejected from volcano Lahar - A flow of volcanic ash and water. Magma is beneath the earths surface Lava is above the surface 3 Types of Lava Felsic lava – High in silica. (sticky and chunky) Highly explosive. Mafic lava – Flows more, high in basalt. Intermediate – Has a higher amount of silica (Silica = liquid quartz or sand) Viscosity: Resistance of liquid to flow. High viscosity = Travels slow because of high resistance Low viscosity = travels fast because low resistance 7
- 8. Types of lava when cooled 'A'ā - Rough lava, older and has crystalized, Pronounced “ahh ahh” Pāhoehoe – Fresh lava, (Pa hoy hoy) Basaltic lava that is smooth and flowing. EARTHQUAKES Earthquake – Shaking of the earth’s crust from a sudden release of energy. Movement of tectonic plates against each other cause the plates to fault and fold. Fault – Break / crack where movement occurs. Fold – Collision of crust bends rock layers “stress” Normal Fault – Pulling apart tension causes crust to drop down. Reverse / Thrust Fualt – Compression forces cause crust to move up. Lateral or Strike Slip Fualt – Crust moves alongside each other in opposite directions. 8
- 9. Types of Folds - Compression - Tension - Shearing Seismograph - An instrument used to measure the shaking caused by an earthquake Ritchter Scale - Scale for measuring earthquake magnitude. A magnitude 7.0 earthquake generates 10 times larger amplitude waves than those of a magnitude 6.0. Epicenter: The point on the Earth's surface that is directly above the hypocenter or focus. Just above the earthquake. Tsunami - An ocean wave generated by a submarine earthquake, volcano or landslide. - Can travel across whole oceans. ROCKS AND MINERALS Rock – Mass or grouping of minerals They can be big They can be small Used in buildings Inorganic (non-living) Minerals are natural inorganic (non-living) solids that join together (crystals) to make unique compositions. A crystal is a solid in which the atoms arranged in a repeating pattern. Uses of minerals Gems $ 9
- 10. Ores, Mined for $ Types of crystals. Hexagonal. (Four axes, three are equal in length and lie at an angle of 120° from each other). Triclinic: (3 axis, all unequal and none at 90° angles). Orthorhombic: (All axis unequal in length, and 90° degrees from each other). Monoclinic:All axis unequal in length. Two of them are at right angles to each other, while the third is lies at an angle other than 90°. Tetragonal. (Three axes, two are equal in length, one is unequal.) Isometric: (All three axes are equal in length an at 90° degrees from each other.) 10
- 11. Two main type of minerals Silicate Minerals – Contain silica and oxygen. 75% of all minerals. Non-silicate minerals Physical Property of Minerals- a characteristic that can be observed or measured without changing the identity of the substance. Luster – How light is reflected from a mineral. Metallic (shiny) or non-metallic (dull) Hardness – How easily a mineral can be scratched. Color – Tells what atoms make up the mineral. Streak – The color of the mineral when it is broken up and powdered Specific Gravity – How dense the mineral is? The rock cycle – How one rocks changes into another. Driven by continental drift (plate tectonics) 11
- 12. Igneous Rocks: Molten Earth cooled. Intrusive – Cooled below crust (slow) Larger crystals Extrusive – Cooled on Earth’s surface (faster). Fine grain crystals or no crystals. Classification of Igneous Rocks Basaltic – Dark, heavy (dense), Iron Granitic – Light colored, less heavy, filled with oxygen Andesitic – Between the two Common Igneous Rocks Granite is Igneous Rock types include Quartz and feldspar Basalt Obsidian – Glassy Gabbro Rhyolite Metamorphic – Rock that changed forms due to extreme temperature and pressure Common Metamorphic Rocks Slate Gniess Marble Schist Sedimentary Rocks Sediments are compacted and cemented together Caused by weathering, erosion, and deposition Usually layered Layers can be from old living materials (fossils). 12
- 13. Common Sedimentary Rocks Limestone Sandstone Shale Conglomerate Earth System History Earth History Components Earth system history has physical, chemical, and biological components Uniformitarianism: Laws of nature have not changed over time. The system is fragile. Changes in living conditions for animals have been numerous throughout earth’s history. 99.5% of all things that have ever lived have become extinct. Principle of superposition – Oldest rocks and fossil are on bottom, youngest on top. 13
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- 15. Precambrian Hadean, Archean, and Proterozoic Eon’s Earth’s Molten layers form (Denser to middle) Formation of Earth’s Crust (cooling). Meteorites bombard the planet and carry with it water molecules and amino acids (building blocks of protein). Moon created from comet impact Atmosphere originates (No oxygen yet) Earliest life begins (primitive protocells) Microbes helped produce an oxygen atmosphere through photosynthesis. First Multi-cellular life (many cells) Explosion of new animals (sea) Paleozoic Era Vendian, Cambrian, Ordovican, Silurian, Devonian, Carboniferous, and Permian Periods. Marine invertebrates dominate Jawed Fish Evolve Plants invade land (Oxygen to atmosphere) Insects emerge First Amphibian First Reptiles First winged insect 15
- 16. Mesozoic Era Triassic, Jurassic, Cretaceous Periods Dinosaurs dominate First Birds First Mammals First Flowers K-T Mass Extinction Event, 65mya Cenozoic Era Tertiary, and Quaternary Periods Mammals change Earliest Monkeys Climate becomes drier Panama attaches South America to North America First human hominids Modern Man (Whoa) Civilization Age of Exploration, Industrial and Computer Age SAVE THESE NOTES FOR THE ASSESSMENT Copyright © 2010 Ryan P. Murphy 16
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