lytwyn geo 1330 exam1

How old is the earth?

4.5 billion years

Covalent Bond

A Chemical bond produced by the sharing of electrons

Hot Spot

A Concentration of heat in the mantle, capable of producing magma that, in turn, extrudes onto Earth's surface. The intraplate volcanism that produced the Hawaiian Islands is one example.

Slab-Pull

A Mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along.

Divergent Boundary

A boundary in which two plates move part, resulting in upwelling of material from the mantle to create new seafloor.

Convergent Boundary

A boundary in which two plates move together, resulting in oceanic lithosphere being thrust beneath an overriding plate, eventually to be reabsorbed into the mantle. It can also involve the collision of two continental plates to create new seafloor.

Spreading Center

A boundary in which two plates slide past one another without creating or destroying lithosphere.

Transform Boundary

A boundary in which two plates slide past one another without creating or destroying lithosphere.

Volcanic Arc

A chain of volcanic islands generally located a few hundred km from a trench where there is active subduction of one oceanic plate beneath another

Island Arc

A chain of volcanic islands generally located a few hundred km from a trench where there is active subduction of one oceanic plate beneath another.

Geomagnetic Reversal

A change in Earth's magnetic field from normal to reverse or vice versa.

Ionic Bond

A chemical bond between two oppositely charged ions formed by the transfer of valence electrons from one atom to the other.

Metallic Bond

A chemical bond present in all metals that may be characterized as an extreme type of electron sharing in which the electrons move freely from atom to atom.

Plate

A coherent unit of Earth's rigid outer layer that includes the crust and upper unit.

Describe collage tectonics. Along what type of plate boundary is collage tectonics most likely to occur? What region(s) of North America formed as a result of collage tectonics?

A collage is an assemblage of micro-continents, arcs, and other crustal fragments accreted along the edge of a continent adjacent to a subduction zone.

Mid-ocean Ridge

A continuous mountainous ridge on the floor of the entire major ocean basins and varying in width from 500-5000 Km (300-3000 Miles). The rifts at the crests of these ridges represent divergent plate boundaries.

Continental Drift

A hypothesis, credited largely to Alfred Wegener, which suggested that all present continents once existed a single supercontinent. Further, beginning about 200 million years ago, the supercontinent began breaking into small continents, which drifted to their present locations.

Carbonates

(CO3)2-

Silicates

(SiO4)4-

Micas

(biotite, muscovite)

Feldspar

(framework silicates)

Olivine

(single tetrahedral)

Color

- A phenomenon of light by which otherwise identical objects may be differentiated.

Fracture Zone

- Linear zone of irregular topography on the deep-ocean floor that follows transform faults and their inactive extensions

Atom

- The smallest particle that exists as an element.

Sedimentary Rock

Accumulate in layers at Earth's surface - Sediments are derived from weathering of preexisting rocks. Example: sandstone and limestone.

Collage Tectonics

An assemblage of micro-continents, arcs, and other crustal fragments accreted along the edge of continent adjacent to a subduction zone.

Ion

An atom or molecule that possesses an electrical charge

Fracture

Any break or rupture in rock along which no appreciable movement has taken place.

What is a system? How does a closed system differ from an open system?

Any size group of interacting parts that form a complex whole. A closed system is a system in which energy moves freely in and out, but the matter does not enter or leave. An open system is a system where energy and matter flow freely in and out of the system.

System

Any size group of interacting parts that form a complex whole. Ex: cooling system in cars, nervous system in animals, etc.

Anion

Atoms that gain electrons and become negative ions. These are the larger of the two spheres

Cation

Atoms, which lose electrons and become positive ions. These are the smaller of the two spheres.

Mantle

Below the asthenosphere | Solid down to a depth of ~2,900 km where it meets the outer core | Composed of Peridotite

Closed System

Energy moves freely in and out - Matter does not enter or leave the system.

Outer Core

Extends from 2,900 km to 5,100 km depth - Consists mainly of molten liquid iron - Source of the earth's magnetic field.

How does a hypothesis differ from a theory?

Hypothesis is an untested explanation while a theory is a well-tested and widely accepted view that agrees with the best explanation of the observable facts.

What are three major rock types and how do they differ from one another?

Igneous: Formed from crystallized magma, or melted metamorphic rock. b. Metamorphic: Formed from sedimentary rock reacting to heat & pressure. c. Sedimentary: Weathered rock that is transported and deposited is compacted and lithified.

Lithosphere

Includes the crust and solid upper portion of the mantle - rigid outer layer of the earth.

Magnetic Time Scale

Time scale of the Earth's magnetic field in the recent past. Developed by establishing the magnetic polarity for lava flows of known age. Major divisions are called "chrons".

Polymorph

Two or more minerals having the same chemical composition but different crystalline structures. Exemplified by the diamond and graphite forms of carbon.

What is atomic number versus atomic weight?

a. Atomic Number is the number of protons in the nucleus of an atom and Atomic Weight is the average of the atomic masses of isotopes for a given element.

What are the various criteria that define a mineral?

a. Atomic Number: number of protons in an atom's nucleus b. Atomic Weight: average of the atomic masses of isotopes for a given element

What material comprises the core? How does the outer core differ from the inner core?

a. The core is composed of iron-nickel alloys with minor amounts of oxygen, silicon, and sulfur. The Outer Core is a liquid layer containing iron in which generates the magnetic field. The Inner Core is solid composed of Iron and Nickel.

What is the mantle and what kind of rock is it composed of?

a. The mantle is below the lithosphere consisting of partially molten mantle. It contains 82% of the Earth's volume. It extends to a depth of 2,900 km. Dominant rock type is Periodtite.

Describe the stages in the formation of an ocean basin (see Fig. 2.22). At what stage is each of the following features: East African Rift; Red Sea; Atlantic Ocean?

a. Upwelling in the mantle associated with broad doming of the lithosphere, tensional forces and buoyant uplifting of the heated lithosphere cause the crust to be broken into large slabs. b. Crust is pulled apart, large blocks sink, generating a continental rift valley. Further spreading generates a narrow sea similar to the Red Sea. c. Eventually, a deep ocean basin and oceanic ridge are created.

Pyroxenes

chain silicates

Amphiboles

double chain silicates)

Quartz (

framework silicates

Crystal Form

Refers to the common or characteristic shape of a crystal, or aggregate of crystals.

What is the lithosphere?

Rigid outer layer of the earth. Includes the crust and solid upper portion of the mantle.

Cleavage

The tendency of a mineral to break along planes of weak bonding

Plate Tectonics

The theory that proposes that Earth's outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, volcanoes, mountains, and the crust itself.

Rift or Rift Valley

A long, narrow trough bounded by normal faults. It represents a region where divergence is taking place

Subduction zone

A long, narrow zone where one lithospheric plate descends beneath another.

Reverse Polarity

A magnetic field opposite to that which presently exists.

Normal Polarity

A magnetic field the same as that which presently exists.

Mantle Plume

A mass of hotter-than-normal mantle material that ascends toward the surface, where it may lead to igneous activity. These plumes of solid yet mobile material may originate as deep s the core-mantle boundary

Ridge Push

A mechanism that may contribute to plate motion. It involves the oceanic lithosphere sliding down the oceanic ridge under the pull of gravity.

Hardness

A mineral's resistance to scratching and abrasion

Deep-Ocean Trench

A narrow elongated depression of the seafloor

Mineral

A naturally occurring, inorganic crystalline material with a unique chemical structure.

Electron

A negatively charged subatomic that has a negligible mass and is found outside an atom's nucleus

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Mohs Scale

A series of 10 minerals used as a standard in determining hardness.

Silicate Tetrahedron

A structure composed of four oxygen atoms surrounding a silicon atom that constitutes the basic building block of silicate minerals.

Neuron

A subatomic particle found in the nucleus of an atom. It is electronically neutral, with a mass approximately equal to that of a proton.

Element

A substance that cannot be decomposed into simpler substances by ordinary chemical or physical means.

Inner Core

Composed mostly of solid iron and nickel. Solid innermost layer of the Earth, about 1216 KM in radius. (From 5,100 KM depth)

Tenacity

Describes a mineral's toughness or its resistance to breaking or deforming.

Describe the nebular hypothesis with regard to the origin of the solar system

Describes the formation of the Solar System. Planets and the Sun formed 5 billion years ago from a cloud of dust and gases. Cloud contracted and began to rotate to form a disk shape. Material gravitated toward the center to form the protosun. Small centers within the disk swept up cloud's debris to form planetesimals

Metamorphic Rock

Formed by changing preexisting igneous, sedimentary or other metamorphic rocks - Driving forces are increased heat and pressure - Ex: Gneiss and Marble

Igneous Rock

Formed from cooling and solidification of magma (molten rock). Example: granite and basalt

Accretionary Wedge

Large, wedge-shaped mass of sediment that accumulates in subduction zones. Sediment is scraped from the subducting oceanic plate and accreted to overriding crustal block.

Describe how some rocks, when formed; end up preserving the direction of the earth's magnetic field.

Lava cools and iron-rich grains magnetize and align themselves in the direction of the existing magnetic lines of force.

Explain the rock cycle.

Magma crystallizes either below the surface or following a volcanic eruption, resulting in igneous rock. b. Igneous rocks exposed at the surface undergo weathering, and sediments are deposited. c. Sediments undergo lithification and form sedimentary rocks. d. If sedimentary rock is buried deep in the earth, it can be subject to great pressure and/or heat and turn into metamorphic rock.

Slab Suction

One of the driving forces of plate motion, it arises from the drag of the subducting plate on the adjacent mantle. It is an induced mantle circulation that pulls both the subducting and overriding plates toward the trench.

Planets

Our solar system consists of the sun, and 8 planets. Over 100 moons and a multitude of asteroids, comets and meteoroids. The orbits of the planets are elliptical around the sun. The planets generally revolve in the same direction around the sun and within the plane of the ecliptic.

Paleomagnetism

Study of the Magnetic Properties of Ancient Rocks provide further evidence that continents drifted over time.

What layer constitutes the rigid plates of the earth?

The Lithosphere

Luster

The appearance or quality of light reflected from the surface of a mineral.

Atomic Number

The average of the atomic masses of isotopes for a given element.

Atomic Weight

The average of the atomic masses of isotopes for a given element.

Solar Nebula

The cloud of interstellar gas and/or dust from which the bodies of our solar system formed. A giant rotating cloud of gas and dust.

Streak

The color of a mineral in a powered form.

Seafloor Spreading -

The hypothesis, first proposed in the 1960s by Harry Hess, which suggested that new oceanic crust is produced at the crests of mid-ocean ridges, which are the sites of divergence.

Rock Cycle

The loop that involves the processes by which one rock changes to another. Illustrates the various processes and paths as earth materials change both on the surface and inside the earth.

Nebular Hypothesis

The planets generally revolve in the same direction around the sun and within the plane of the ecliptic Rotating nebula developed into a flat, disk shape with the protosun (pre-Sun) at the center.

Specific Gravity

The ratio of a substance's weight to the weight of an equal volume of water.

Forearc Basin

The region located between a volcanic arc and an accretionary wedge where shallow-water marine sediments typically accumulate.

Nucleus

The small, heavy core of an atom that contains all of its positive charge and most of its mass.

Isotope

Varieties of the same element that have different mass numbers; their nuclei contain the same number of protons but different numbers of neutrons

Asthenosphere

Weak layer directly below lithosphere consisting of partially molten mantle- also known as the low-velocity zone.

Open System

a System in which both matter and energy flow into and out of the system. Most natural systems are of this type.

Hypothesis

a tentative (untested) explanation. All hypotheses must be: Able to predict (or deduce) future observations (be testable and falsifiable) there must be the possibility it could be proven wrong.

Theory

a well-tested and widely accepted view that the scientific community agrees best explains certain observable facts

What is an ion? What determines whether an element is a cation or anion? Why do certain elements gain or lose electrons? What is the ideal number of electrons in the outer-most electron shell?

a. An ion is either a positively or negatively charged ion. Anions are atoms that gain electrons; cations are atoms that lose electrons. Atoms gain or lose atoms based on the type of bond they form with another atom. Ideal number of electrons in the outermost shell is 8.

Describe how magnetic stripes on the seafloor are formed. How are they related to seafloor spreading and reversals in the earth's magnetic field?

a. As magma solidifies at rifts at the crest of an oceanic ridge, it is magnetized with the polarity of the existing magnetic field. b. Magnetized strip crust gradually increases in width due to seafloor spreading. c. When Earth reverses polarity, newly formed seafloor forms in the middle of the old strip.

Describe each of the major layers of the earth.

a. Crust: Earth's thin, rocky outer skin i. 2 Types of crust: 1. Continental Crust 2. Oceanic Crust b. Mantle: Solid, rocky shell that extend to 2900km 1. Upper Mantle a. Lithosphere: Consists of the entire crust, and uppermost mantle and forms Earth's cool, rigid outer shell. b. Asthenosphere: Below the lithosphere, zone of weak material where rock is easily deformed. 2. Lower Mantle a. D"Layer: Bottom layer of the lower mantle. c. Core: Thought to be an iron-nickel alloy with minor amounts of oxygen, silicon and sulfur. i. 2 Regions of Core 1. Outer Core: Liquid layer where Earth's magnetic field is generated. 2. Inner Core: Solid due to immense pressures existing in the center of the planet.

What is meant by the internal ordering of atoms to form crystal structures? Why are the physical properties of graphite and diamond so different even though both have the same chemical formula? Know that the external expression of a mineral reflects its internal atomic structure.

a. Crystal structures are formed as a result of highly ordered atomic arrangements that can be described as spherically shaped atoms, or ions, which are held together by ionic, covalent, or metallic bonds b. Diamond and graphite have different physical properties due to the conditions under which they form, diamonds form in depths of incredible pressure

Give four lines of evidence that support the theory of continental drift.

a. Fit of the continents b. Fossil evidence c. Rock type and structural similarities d.Paleoclimatic evidence

Know the different ways in which silicate-oxygen tetrahedra are arranged in silicate minerals (isolated, chain, double-chain, sheet, framework). Give one or two mineral examples of each group.

a. Independent tetrahedra: i. Olivine ii. Garnet b. Single chains: i. Augite c. Double chains: i. Hornblende d. Sheet structures: i. Biotite ii. Magnetite e. Three-dimensional framework: i. Potassium feldspar ii. Quartz

How do the inner planets (Terrestrial Planets) differ from the outer planets (Jovian)?

a. Inner Planets are closest to the sun Mercury, Venus, Earth, and Mars. Generally small rocky bodies with densities. Because of their relatively high temperature and weak gravitational fields, were unable to accumulate the lighter components of the nebular cloud. b. Outer Planets are the furthest from the sun Jupiter, Saturn, Uranus, and Neptune. They are larger than terrestrial planets. Because of their low temperatures far from the Sun, formed from ices and rocky/metallic debris, which account for their low density and large size.

Describe ionic bonding; covalent bonding; metallic bonding. Which are stronger, ionic or covalent bonds?

a. Ionic bonding - one or more electrons are transferred from one atoms to another, giving the atoms a net positive or net negative charge, forming ions b. Covalent bonding - when atoms share electrons c. Metallic bonding - when electrons are free to move from one atoms to another d. Ionic bonds are strongest

In what way in terms of atomic number and atomic weight are two elements isotopes of one another?

a. Isotopes of an element behave the same chemically

What are mantle plumes and hotspots? Where do mantle plumes originate? Describe the formation of the Hawaiian Islands in relation to a stationary hotspot.

a. Mantle Plume is a cylindric upwelling of hot rock. As plume ascends through the mantle, confining pressure drops and partial melting occurs. Surface manifestation of this activity is a Hot Spot, an area of volcanism, high heat flow and crustal uplifting. As plates move over the hot spot, chains of volcanic structures are built.

Describe ocean-ocean, ocean-continent, and continent-continent convergence. Identify the type of convergence for each of the following locations; Pacific Northwest, Aleutian Islands, Andes of South America, and Himalayan Mountains.

a. Ocean-Ocean Convergence - Oceanic lithosphere subducts beneath another oceanic plate. Aleutian Islands b. Ocean-Continent Convergence - Oceanic lithosphere subducts beneath continental lithosphere. Andres of South America c. Continent-Continent Convergence - Two continental plates collide. Himalayan Mountains

How does continental crust differ from oceanic crust in terns of thickness and composition?

a. Oceanic crust is roughly 10km thick and is composed of igneous rock basalt, a homogenous composition. Continental Crust averages 33-70km thick and consists of many rock types but closer to Granite.

How does the age of oceanic lithosphere vary within an ocean basin? Where would you expect to find the youngest oceanic lithosphere versus the oldest lithosphere?

a. Older, cooler oceanic lithosphere is located furthest from rift valleys. Youngest oceanic lithosphere is created by magma rising and cooling in the rift valleys.

Describe transform fault boundaries? What is the relation of transform faults to mid-ocean ridges? Give an example of a transform fault boundary on land

a. Plates slide past one another so that lithosphere is neither created nor destroyed. Transform faults are important features in ocean basins: Most join two segments of a mid-ocean ridge along breaks in the oceanic crust known as fracture zones. A few (the San Andreas Fault) cut through continental crust.

Define polymorphs. Give three examples of mineral pairs that are polymorphs of one another.

a. Polymorphs are two minerals with exactly the same chemical composition, but different internal structure and therefore different external forms b. Polymorph pairs: i. Diamond/graphite ii. Calcite/aragonite iii. Basalt/spinel

Describe the various mechanisms that can drive plate tectonics (e.g. mantle convection, slab pull, ridge, push, slab suction).

a. Slab Pull - Results from the sinking of a cold, dense slab of lithosphere. b. Ridge Push - A gravity driven force that results from the elevated position of the ridge. c. Whole-mantle Convection - sinking slabs of cold oceanic lithosphere are the downward limbs of convection cells, while rising mantle plumes carry hot material from the core-mantle boundary toward the surface. d. Layer-cake Convection - Have two largely disconnected convective layers. A dynamic upper layer driven by descending slabs of cold oceanic lithosphere and a sluggish lower layer that carries heat upward without appreciably mixing with the layer above.

Describe the asthenosphere. Where is it located? Why is it weak?

a. The Asthenosphere is the middle region of the upper mantle located between the lithosphere and the transition zone. It is the low-velocity zone. The uppermost asthenosphere is weak because it is near its melting point

Oceanic crust

ranges from 0-10km thick - average composition of basalt.

Continental Crust

ranges from 33-70 km thick - average composition close to granite.

Core

the innermost layer of Earth based on composition. Thought to be largely an iron-nickel alloy with minor amounts of oxygen, silicon, and sulfur.