Final study guide geology PDF

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Test 1 Image of Our Universe Vocabulary  Cosmology- the study of the overall structure & history of the universe  Geocentric model- earth sits motionless at the center of the universe while the moon and the planets whirl around it; everything inside a revolving globe of stars  Heliocentric model- sun at center, earth & planets orbit around it  Universe- all of space & the matter and energy within it  Star- an immense ball of plasma (incandescent gas) that emits intense heat & light  Galaxies- immense groups of stars held together by gravity  Planet- an object that orbits a star, is roughly spherical,  Ecliptic- the plane that the 8 planets orbit on  Terrestrial planets- the inner planets (mercury venus earth mars); consist of a shell of rock surrounding a ball of metal  Giant planets- aka Jovian planets; the outer planets (jupiter saturn uranus neptune)  Gas giants- jupiter & saturn  Ice giants- uranus & neptune  Moon- a sizable body locked in orbit around a planet; all but Mercury & Venus have moons in varying #s  Asteroids- rocky and/or metallic objects  Comets- a ball of ice and dust probably remaining from the formation of the solar system that orbits the sun Forming the Universe Vocabulary  Big Bang theory- all matter and energy everything that now constitutes the universe was initially packed into an infinitesimally small point; the point “exploded” & the universe began about 13.8 billion years ago  Nuclear fusion- the process by which the nuclei of two smaller atoms collide, stick together, and form a new atom w/ a larger nucleus  Vacuum- a region in which the density of matter is extremely low; empty space  Accretionary disk- disk shaped body of gas ice and dust onto which matter falls it ultimately evolves into a solar system  Protostar- dense body of gas that is collapsing inward because of gravitational forces and that may eventually become a star  Nebula- a cloud of gas or dust in space  Nebular theory- overall model for explaining the sequence of stages during which stars & planets formed from a nebula  Supernova-short lives very bright object in space that results from cataclysmic explosion marking the death of a very large star the explosion ejects large quantities of matter into space to form new nebulae Forming the Solar System Including the Earth Vocabulary  Stellar nucleosynthesis- fusion reactions during the life cycle of stars form intermediate-weight elements  Supernova nucleosynthesis- form heavy atoms that have an atomic number greater than that of iron these atoms form during the extremely hot conditions of supernova explosion  Stellar wind- the stream of atoms emitted from a star during its lifetime  Volatile materials- (ex. Hydrogen, helium, methane, ammonia, water, carbon dioxide); can exist as gas at the earth’s surface; beyond a distance (the frost line), some volatiles freeze into ice  Refractory materials- melt only at high temps, condense to form solid soot-sized particles of “dust” in space  Planetesimals- tiny solid pieces of rock and metal that collect in a planetary nebula and eventually accumulate to form a planet  Protoplanets- bodies approaching the size of today’s planets

Radioactive element- one whose nuclei spontaneously emits subatomic particles, or undergoes nuclear fission  Differentiation- denser iron alloy separated out & sank to center of the body, whereas lighter rocky materials remained in a shell surrounding the center; protoplanets develop internal layering Earth Moon and Magnetic Field Vocabulary  Magnetic field- the region affected by the force emanating from a magnet  Dipole- earth’s magnetic field has 2 diff ends (North & South poles)  Magnetosphere- region inside earth’s magnetic shield that is protected from most of the solar winds’ dangerous high-velocity charged particles Introducing the Earth System Vocabulary  Earth System: all the realms on & surrounding the earth’s surface & the interactions among them  Atmosphere- the envelope of gas that surrounds the planet  Groundwater- water filling tiny holes & cracks underground  Hydrosphere- realm including oceans, surface water on land, & groundwater  Cryosphere- frozen portion of the earth’s hydrosphere, including glaciers & permafrost  Geosphere- the solid earth (surface to center) o Land = exposed to the atmosphere o Seafloor = surface portion underwater  Topography- the variation of land surface elevation  Bathymetry- variations in the depth of the seafloor  Minerals- solid natural substance has a crystalline structure & a definable chemical composition, mostly inorganic  Glasses- solid but not crystalline; the atoms are arranged in a semi chaotic way  Rocks- an aggregate of mineral crystals or grains, or a mass of natural glass; igneous sedimentary or metamorphic  Grains- indiv. crystals embedded in rocks or and indiv. fragment derived from a once larger mineral or rock body  Sediments- an accumulation of unattached mineral grains  Metals- a solid composed of metal atoms (iron, aluminum, copper, tin)  Alloy: mixture containing more than one type of metal atom  Melts- form when solid materials become hot and transform into liquid (ex.molten rock like magma and lava; lava is magma that has flowed onto surface)  Volatiles- materials that easily transform into gas at the relatively low temperatures found at the earth’s surface  Silicate rocks- the most common rocks on earth; composed of silicate materials  Biosphere- the aggregate of all living organisms as well as the portion of the earth in which living organisms exist; liquid water must exist  Internal gravity- heat (thermal energy) stored or produced inside the earth  External energy- energy reaching the earth’s surface from outside, mostly from sun Discovering the Earth’s Interior Vocabulary  Seismic waves- vibrations or shocks that pass through the Earth from a location where rock suddenly breaks and slips along a fracture (aka a fault)  Seismometers- measure seismic waves  Earthquake: seismic waves reach the surface of the earth and cause it to shake  Geothermal gradient- the rate of change in temp with depth Basic Characteristics of the Earth’s Layers Vocabulary  Crust- outermost layer of the earth, very thin  Moho- the base of the crust  Mantle- between crust and core; largest part of the Earth in terms of volume; consist entirely of peridotite  Core- outer core (liquid) & inner core (solid) 

Lithosphere- outer layer of the earth, relatively rigid; crust + cooler outermost part of upper mantle (the lithospheric mantle)  Asthenosphere- portion of mantle in which rock is plastic (relatively soft, can flow w/o breaking) Chapter 2 Introduction Vocabulary  Pangaea = supercontinent  Seafloor spreading- as continents move apart, new ocean floor forms between them  Subduction- continents move toward each other when the old ocean floor b/t bends down along the edge of a continent and sinks back down into Earth’s interior Paleomagnetism- Proving That Continents Move Vocabulary  Paleomagnetism- a record of Earth’s magnetic field in the past  Magnetic declination- the angle between the direction that a compass needle points and a line of longitude at a given location  Magnetic inclination- the angle b/t a magnetic field line and the surface of the Earth at a given location  Paleopole- the supposed position of the earth’s magnetic north pole in the past  Apparent polar-wind path- a curving line that the successive positions of dated paleopoles trace out The Discovery of Seafloor Spreading Vocabulary  Mid-ocean ridges- underwater mountain ranges whose peaks lie only about 2-2.5 km below sea level  Fracture zones- narrow bands of vertical cracks and broken-up rock that cut the ocean floor of mid-ocean ridges  Deep-ocean trenches- very deep troughs in the ocean, border volcanic arcs  Volcanic arcs- curving chains of active volcanoes  Seamount chains- underwater mountains, once volcanoes but no longer erupt Evidence for Seafloor Spreading Vocabulary  Magnetic anomaly- the difference b/t the expected strength of the earth’s main dipole field at a certain location & the actual measured strength of the magnetic field at that location  Positive anomalies = places where the field strength is stronger than expected  Negative anomalies = weaker than expected  Marine magnetic anomalies- define distinctive alternating bands of positive and negative anomalies in the ocean  Magnetic reversal- when the earth’s field flips from normal to reversed polarity or vice versa. When earth reverses polarity,just the magnetic field reverses, compasses would point N arrow toward south pole  Magnetic reversal chronology- a history of magnetic reversals for past 4.5 mil years What Do We Mean by Plate Tectonics Vocabulary  Lithosphere- crust + cooler top part of upper mantle; when force is applied it bends or breaks. Ocean lithosphere thinner than land  Asthenosphere- soft/plastic layer composed of warmer mantle beneath lithosphere; flows slowly when force is applied  Seismic belts- where earthquake epicenters tend to be, define the plate boundaries bc that tension generates earthquakes  Active margins- plate boundaries  Passive margins- not plate boundaries  Divergent boundary- 2 plates move apart from e/o so new oceanic lithosphere forms here; these boundaries take place at mid ocean ridges (underwater mountain ranges),  Convergent boundary- 2 plates move toward e/o so that one plate sinks beneath the other subduction occurs at these boundaries  Transform boundary- 2 plates slide sideways past e/o can link 2 ridges, 2 trenches, or a ridge w a trench; a few cut across continental lithosphere 

Divergent Plate Boundaries & Seafloor Spreading Vocabulary  Black smokers- places along ridge axes where hot mineralized water spews out from small chimneys (these chimneys are the black smokers) Convergent Plate Boundaries & Subduction Vocabulary  Subduction: when the oceanic plate sinks beneath the other plate at a convergent boundary, aka a subduction zone or consuming boundary; aka a trench  Accretionary prism- a wedge-shaped mass of sediment that gets scraped up and accumulates when the downgoing plate slides under the overriding plate, like snow when being plowed Transform Plate Boundaries Vocabulary  Fracture zones- belts of broken/irregular seafloor Special Locations in the Plate Mosaic Vocabulary  Triple junction- a point where 3 plate boundaries intersect  Plate-boundary volcanoes- in volcanic arcs & mid-ocean ridges; formed as a consequence of movement along the boundary How Do Plate Boundaries Form and Die Vocabulary  Rifting- a continent splits and separates into 2 continents, forming a new divergent boundary  Collision- a piece of relatively buoyant crust, such as a continent or an island arc, moves into the subduction zone & jams up the system, eliminating a convergent boundary  Continental rift- a linear belt in which continental lithosphere pulls apart  Collision the process during which 2 buoyant pieces of lithosphere converge & squeeze together Moving Plates Vocabulary  Slab-pull force- the force that subducting downgoing plates apply to oceanic lithosphere at a convergent margin  Relative plate velocity- describes the movement of Plate A with respect to Plate B  Absolute plate velocity- describes the movement of both plates relative to a fixed location in the mantle below the plates What is a Mineral Vocabulary  Minerals- solid natural substance has a crystalline structure & a definable chemical composition, mostly inorganic  Geologic processes- solidification of molten rock; direct precipitation from a water solution; solid crystalline materials produced by organisms too  Crystalline solid- a material in which atoms are fixed in an orderly pattern; the pattern = a crystal lattice  Glass: solid but not crystalline; the atoms are arranged in a semichaotic way Beauty in Patterns: Crystals and Their Structure Vocabulary  Crystal- a single, continuous (uninterrupted) piece of a crystalline solid, typically bounded by flat surfaces (crystal faces) that grow naturally as the mineral forms  Diffraction- splitting of light into many tiny beams that interfere with one another, diffraction occurs when waves interact with regularly spaced objects whose spacing is close to the wavelength of the waves  Polymorphs- two different minerals that have the same composition but different crystal structures  Solidification (freezing) of a melt- liquid freezes into a solid (ex. Ice crystals from water)  Biomineralization- when minerals grow at the interface between the physical and biological components of the earth system (ex. Shells on some animals)  Anhedral grains- minerals without well-formed crystal faces  Euhedral crystal- a crystal whose faces are well formed and whose shape reflects crystal form  Geode- a mineral-lined cavity in rock; surface crystals may be euhedral How Can You Tell One Mineral from Another Vocabulary  Color- results from the way a mineral interacts with light

Streak- the color of a powder produced by pulverizing the mineral; scrape the mineral against an unglazed ceramic plate; varies less than the color of the whole crystal  Luster- the way a mineral surface scatters light. Ex. metallic, silky, glassy, pearly, etc  Hardness- a measure of the relative ability of a mineral to resist scratching; the resistance of bonds in the crystal structure to being broken  Specific gravity- the density of a mineral; the ratio between the weight of a volume of the mineral and the weight of an equal volume of 4 degree Celsius water  Crystal habit- the shape of a single crystal with well-formed crystal faces; the character of an aggregate of many well-formed crystals that grew together as a group; internal arrangement of atoms in the crystal  Fracture and cleavage- different minerals fracture/break in different ways; if it breaks into distinct planar surfaces it has cleavage, those surfaces are cleavage planes Organizing Your Knowledge: Mineral Classification Vocabulary  Silicates- over 95% of continental crust & almost 100% of oceanic crust & nearly all of the mantle. Most common minerals on earth  Single chains- in single chain silicate the tetrahedra (building block of silicate materials) link to form a chain by sharing 2 oxygen atoms  Double chains- in a double chain silicate the tetrahedra link by sharing 2 or 3 oxygen atoms  Sheet silicates- the tetrahedra in this group share 3 oxygen atoms, link to form 2-D sheets; cleavage in one direction  Framework silicates- in a framework silicate each tetrahedra shares all 4 oxygen atoms forming 3D structures Something Precious-- Gems Vocabulary  Gemstone- a mineral that has special value b/c it is rare and people consider it beautiful  Gem / jewel- a finished stone ready to be set in jewelry  Facets- the smooth parts of a gem; ground & polished surfaces made with a faceting machine People  Wegenero German meteorologist thought continents had once fit together like puzzle pieces to make a supercontinent known as pangaea, pangaea existed until the end of the Mesozoic Era o he proposed idea of continental drift to explain why continents are no longer all together o Wegener's observations that led him to believe in continental drift  The way continents look as though they fit together like puzzle pieces  Till and striations at a particular location serve as evidence that the region was covered by glaciers in the past, this confused Wegener because he had found till in Southern South America, Southern Africa and Southern India Antarctica and Southern Australia, all these places today are very spread out so how could they all have the same till and all these places except for Antarctica today are located in places that are not cold enough for glaciers to form as a result he determined that the distribution of glaciation at the end of the Paleozoic could explain that the continents were all once together  Distribution of fossils, today different continents provide homes for different species, Wegner however discovered fossils of different species existed on many continents and these species couldn't have swam across the ocean once again supporting his theory of continental drift o 43-44 188 594  Hesso American geologist proposed that as continents drifted apart new ocean floor forms between them, 

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Hess realized that the sediment layer on the ocean floor was thin and that ocean floor was much younger than continents Ridges were younger than deeper parts of ocean floor Hess bought these ideas together and suggested that magma rose upward at mid ocean ridges and that this material solidified to form the basalt of oceanic crust. The new seafloor than moved away from the ridge axis leading to the widening of the ocean basin this is known as seafloor spreading Hess realized that the old ocean floor must be going somewhere else otherwise the earth would be expanding so he suggested that deep ocean trenches might be places where the seafloor sank back into the mantle a process known as subduction Hess suggested that earthquakes at trenches were evidence of subduction Hess theory of seafloor spreading explained how continental drift occurs because continents passively moved apart as the seafloor between them spread at mid ocean ridges and they passively moved together as seafloor between them sank back into mantle or subducted at trenches

Dietz o named Hess theory seafloor spreading  Edwin Hubble o Astronomer found that all distant galaxies were moving away from earth also concluded that the further away the galaxy lies the faster its moving o He recognized that all these observations meant that the volume of the whole universe was increasing this idea was known as expanding universe theory o Expansion began with the big bang  Van Allen o American physicist who first recognized the Van allen radiation belts (thus they are named after him) o Van allen radiation belts lie well within the magnetosphere and trap solar wind particles as well as cosmic rays that were moving so fast they were able to penetrate the weaker outer part of the magnetic field  Von Laue 86 87 o German physicist he found the answer to what the inside of minerals look like o He showed that an X-ray beam passing through a crystal breaks up into many tiny beams to make a pattern of dots on a screen this phenomenon is referred to as diffraction o Diffraction occurs when waves interact with regularly spaced objects whose spacing is close to the wavelengths of the waves o He concluded that for crystal to cause diffraction atoms within it must be regularly spaced and the spacing must be comparable to the wavelength of X-rays o Learned how to use x-ray diffraction patterns as a basis for defining the specific arrangement of atoms in a crystal, this arrangement defines the crystal structure of a mineral  Berzelius 95 o Swedish chemist analyzed minerals and noted chemical similarities among many of them o Established that most minerals can be classified by specifying the principal anion (negative atom) or anionic group (negative molecule) within the mineral o Using this approach is possible to divide the 4000 known minerals into smaller groups Key Info An Image of Our Universe  Our solar system includes 8 planets: mercury venus earth mars jupiter saturn uranus neptune (Pluto did not pull in all particles of matter) 

1.5 Earth’s Moon and Magnetic Field  How did the moon form? Best hypothesis is a protoplanet collided with newborn earth 1.6 Introducing the Earth System  Atmosphere is 78% nitrogen, 21% oxygen, 1% other (argon, CO2, neon, methane, ozone, carbon monoxide, sulfur dioxide)  Surface of the geosphere consists of o Organic chemicals o Minerals o Glasses o Rocks o Grains o Sediments o Metals o Melts o Volatiles  Least to greatest amount of silica- felsic rocks (ex. granite), intermediate rocks, mafic rocks (ex. Basalt and gabbro), and ultramafic rocks (ex. peridotite)  93% of earth’s mass = iron oxygen silicon & magnesium  70% water 30% land  Layers of atmosphere (base to top): troposphere, stratosphere, mesosphere, 1.7 Looking Inward-- Discovering the Earth’s Interior  Earth has 3 principal layers, like a hard boiled egg: crust (like eggshell), denser mantle (egg white), a...