GEOL 101 1nd Edition Exam 1 Study Guide Lectures 2 10 Lecture 2 January 15 What are the two main types of Geology Physical understanding the processes Earth activates above and below the surface and historical understanding of the original Earth and how much it has changed overtime What are the two different types of dating Absolute Dating using radioactive decay rates scientists can assign close to accurate number dates in Earth s eras and Relative Dating dates are placed in their proper sequence or order without a number age in years What is the difference between catastrophism and uniformitarianism Catastrophism occurred in the 17th and 18th century and some thought mountains and canyons were developed by catastrophic events that happened shortly before while uniformitarianism is the idea that chemical physical and biological laws today were founded in the past and land formations take millions of years Lecture 3 January 17 Name one principal of Relative Geologic Time Law of Superposition When looking at rocks and sediment layers the oldest rocks are at the bottom and in turn the youngest rocks are on top What are Earth s 5 spheres Hydrosphere water atmosphere air cryosphere ice biosphere life and geosphere rocks What are the two main sources for power The Earth s system is almost always powered by the sun which energizes external processes in the atmosphere hydrosphere and the surface Another source of power is Earth s interior It is mostly heat from the formations of Earth and radioactive decay What are the three different types of rocks Igneous molten rock sedimentary loose weathering and sediments that get packed into a solid rock OR formed by precipitation out of a solution and metamorphic rock from heat and pressure What are the three main layers of composition Crust very thin rocky material which then branches out to continental crust thick high amounts of silicon and aluminum and oceanic crust much thinner high amounts of calcium sodium and iron Mantle solid rocky shell that is composed of peridotite that has high amounts of magnesium and iron Core innermost part of the Earth with high amounts of ironnickel Lecture 4 January 22 What are the three types of boundaries Divergence 2 plates move apart and usually results in new sea floor Convergent Move toward each other and usually results in collision or subduction of oceanic plates Transform plates grind past each other and does not affect lithosphere What does a composition need to be a mineral 1 2 3 4 5 Naturally occurring Inorganic Solid Atom order specific Definite chemical composition What is the order of a rock from smallest to biggest It starts off as a particle neutrons electrons protons then atoms that compound together to make minerals which then make rocks Name at least five physical properties Lust how it looks in reflected light streak color of mineral in powder form cleavage broken planes Hardness resistance to scratches and specific gravity divide weight and volume Lecture 5 January 27 What are the common groups of classification of minerals Silicates Silicon Oxygen Oxides Metal Oxygen Carbohydrates Contains CO3 ions Sulfides Metal Sulfur Native Elements Pure elements Silicates are most important mineral group most abundant What are the basic building blocks of Silicate Isolated Tetrahedra olivine Ring Structures Single Chained Proxene Double Chained Amphibole Group Sheet or Layered Structures Mica Group Complex 3D Structures Feldspar Group Quartz Lecture 6 January 29 Magma consists of what 3 components Melt a liquid portion is composed of mobile ions Solids if any are silicate minerals that came from the melt Volatile gasses dissolved in melt like water vapor carbon dioxide and sulfur dioxide How are igneous rocks classified Texture size shape and arrangement and Composition What s the difference between intrusive and extrusive If magma cools and crystalizes within the earth the rocks are termed intrusive or plutonic If lava cools and crystalizes above the surface the rocks are termed extrusive or volcanic rocks What happened in different rates of cooling The slower the cooling the longer minerals grow and will make large crystals The faster the cooling the less time minerals have to grow and have microscopic crystals REALLY fast cooling form glass no crystals What are the different compositions Felsic Intermediate Mafic Ultramafic Ranging from high silica amounts to low silica amounts Lecture 7 January 31 Why do we name by texture and composition Some rocks have either the same texture but NOT the same composition or different texture but the SAME composition What happens when pressure changes In high pressure rocks are solid in high temperatures while when pressure is reduced the rock will melt Decompression Melting Where do rocks heat up most Most intuitive melt when heated up because temperature goes up as you go deep into earth s crust Rocks in lower crust or upper mantel are already in melting point Lecture 8 February 3 What happens in magma chamber In a magma chamber the magma cools and it forms minerals and depending on the melting point it will form sooner than later Olivine has highest melting point so it crystalizes first Then Pyroxene and Calcium Plagioclase forms and all the others until Quartz the final formation cools and crystalizes to completely solidify the chamber What is Bowen s Reaction Series During the process where it crystalizes the composition of the liquid part of the magma continually changes It can change by early forming minerals removing the elements in the chamber Mafic minerals are first to crystalize The liquid portion is filled with Silica as crystallization continues Lecture 9 February 5 What are the three types of volcanoes Stratovolcanoes Shield volcanoes and Cinder volcanoes What are the 3 factors that result how violent or explosive an eruption can be And control the viscosity Temperature hotter the magma the lower viscosity it has Composition higher silica content high viscosity Felsic Lava while lower silica content low viscosity Mafic Lava Dissolved Gasses water usually increase viscosity The violent eruption is linked to how easy the gasses can escape What is the difference of a crater and a vent Crater is a steep walled depression at summit while a vent is the opening in crater that connects with magma through a pipe circular tubes where magmas travel up from chamber Describe a stratovolcano Stratovolcanoes are composite cones They are the classic large cone