CEE 1030 1nd EditionMidterm Exam # 1 Study Guide Lectures: 1 - 8Lecture 1 (January 21): IntroductionWhat are key concepts in Earth Science?Earth science can be used to predict and prevent natural hazards such as earthquakes, volcanoes, and landslides. Humans also depend on the Earth for valuable resources, so we mustrecognize how we alter the Earth.Three basic rock typesIgneous: cooling and solidification of magmaSedimentary: weathering and layeringMetamorphic: changing heat and pressureVocab termsTransform fault: tectonic plates slide side by sideDivergent: plates move apart, oceans get biggerConvergent: plates collide, form deep ocean trenches and mountainsLecture 2 (January 23): Minerals and Resources What are the basic requirements for minerals?1. An ordered internal structure (atoms are arranged in a structure)2. A specific chemical composition that may vary within a defined range3. Naturally occurring4. An inorganic solidHow do we identify minerals?Crystal form: the external expression of the mineral’s internal structureLuster: the way in which the mineral’s surface reflects the lightColor: the interaction of light with the mineralStreak: the mineral’s color in a powdered formHardness: resistance to abrasion or scratchingCleavage/Fracture: response of crystal to breaking (cleavage is the tendency of the mineral to break along planes of weak bonding)Secondary: “special” properties shown by limited minerals (ex. A reaction to HCl)Vocab termsAtom: the smallest unit of an elementNucleus: contains the mass within an atomProtons: positive charges in an atomNeutrons: neutral charges within an atomElectrons: negative charges within an atomIsotope: atoms that have a different number of neutrons than their usual statePolymorphs: minerals with the same composition but different crystalline structuresLecture 3 (January 28): Igneous RocksHow are igneous rocks formed?Igneous rocks are formed by the solidification of magma (magma is formed through the melting of rocks in the Earth’s mantle). As magma cools, different silicate materials begin to crystallize. Igneous rocks formed at the Earth’s surface are extrusive rocks; igneous rocks formed at a depthare intrusive rocks.How does one classify igneous rocks?Texture: what does the rock look like? What are the size of the crystals?Faster cooling equals smaller crystalsTypes of minerals in rocsChemical compositionWhat are the different igneous textures?Aphanitic: fine-grainedPhaneritic: coarse-grainedPorphyritic: large crystals embedded in a matrix of smaller crystalsPegmatitic: extremely coarse-grained rockPyroclastic: fragmental textureGlassy: very rapid cooling, resulting in obsidianWhat minerals are in igneous rocks?Silicon and oxygen are the fundamental building blocks of igneous rocks. Igneous rocks can contain dark, mafic silicates or light, felsic silicates.How does silicate content affect the viscosity of magma?The more silicate in a magma, the higher the viscosity. This viscosity determines the kind of eruption in a volcano: with lower viscosity (runnier lava), more gas bubbles can escape, so the eruption is less explosive. This is called an effusive lava flow. With higher viscosity, the gas bubbles are trapped as the magma rises, so they eventually explode and cause an explosive eruption. In order of increasing viscosity: basaltic magma, andesitic magma, rhyolitic magma.How does magma form?1. Increase temperature (thermal)2. Decrease the pressure (decompression)3. Add water (fluid-induced)Lecture 4 (January 30): Volcanoes and Other Igneous ActivityTypes of basaltic volcanoesShield volcano: a large, broad, circular shape with gentle dipping slopes (built by successive fluidlava flows from a central vent; the flows travel long distances)Cinder cones (scoria cones): built from ejected gas-rich lava fragments, appear as steep slopes of loose cindersTypes of intermediate rhyolitic volcanoesComposite cones (stratovolcanoes): “classic” volcano, made up of interbedded lava flows and pyroclastic debrisCaldera: occurs when there is magma beneath the earth, an eruption is triggered, and the earthbelow the volcano collapses, creating a huge basinLava dome: occurs when silicon-oxygen rich lava is very viscous and thick, so it is squeezed out of a vent and piles on top of itselfWhat are some important historical volcanic eruptions?Mt. St. Helens, 1980: largest eruption in historic times in the USA, the pressure of the magma in the side of the volcano caused the side to burstMt. Tambora, Indonesia, 1815: largest eruption in historic times, caused significant weather changesVocab termsLava flows: non-explosive eruptionsPyroclastic deposits: explosive eruptionsPahoehoe flow: ropy-textured lava with higher temperature and less viscosityAa flow: rough, blocky lava that results from a loss of gas and temperature (increased viscosity)Submarine eruptions: lava eruptions under water at mid-ocean ridgesPyroclastic flows: a fluidized mix of semi-solid rock fragments and hot expanding gases that flowdown a volcano flankPyroclastic material: fragmentation of magma and rockLahars: volcanic mud flows, from a mixture of volcanic debris and waterDike: a tabular intrusion in layers of rock that cuts across the layersSill: a tabular intrusion in layers of rock that cuts parallel to the layersBatholith: large intrusions in rockLecture 5 (February 4): Weathering and SoilsWhat are Earth’s external processes?Erosion is the first step toward breaking down rocks; it is the physical removal of material by mobile agents such as wind or water. The next step is weathering, which is the process of breaking down (through disintegration) or chemically altering (through decomposition) of rock at Earth’s surface. These processes lead to the formation of sedimentary rock.What are the different kinds of mechanical weathering?Frost weathering: when water gets into cracks of rocks and freezes, it expands and breaks rocks further apartRoot wedging: tree roots grow into cracks of rocks and force them apartSalt wedging: the evaporation of water leads to the growth of salt crystals in rock cracks, furtherwedging them apartThermal expansion: daily temperature changes causes expansion in rocksUnloading: taking off layers of rock lessens the pressure on underlying rocks, creates expansion and exfoliation sheetsWhat are the different kinds of chemical weathering?Dissolution: promoted by acidic waterHydrolysis: reaction of minerals with waterOxidation: exposure to