geo exam 1

1.               What is environmental geology?

-            Human-geology interaction

2.               Describe the impact that increasing human population has on environmental sustainability.

-             Human population is the #1 problem for sustainability.

3.               What is the scientific method, and what is the difference between a hypothesis and a theory?

-            A scientific hypothesis that has undergone rigorous scientific experimentation and is routinely supported by scientific evidence. A hypothesis is a question or prediction, and a theory is made from a hypothesis with enough evidence and research to back the question.

4.               Explain 2 examples of scientific evidence for the Big Bang Theory. How do we know the Big Bang happened?

-             Expansion of the universe and the Cosmic Microwave Background Radiation.

5.               What is Nebular Theory and how does it relate to the formation of the Solar System?

-            Solar system formation begins as dust and gases started to collapse.

-            The nebula contracted into a flattened, rotating disk that is heated by the conversion of gravitational energy into thermal energy.

-            Cooling caused rocks and metallic material to condense into tiny particles.

-            Repeated collisions caused dust-sized particles to gradually collapse into asteroid-size bodies that turned into planets later.

6.               What is deep time and how does it relate to geologic history?

-            Deep time refers to the almost incomprehensible span of time that covers the history of the Earth.

-            5 million years is 66,666 lifetimes and 20 times longer than the existence of humans.

-            Geological: it took 5 million years for the Grand Canyon to form, in geology, 5 million years is young.

7.               Briefly describe the history of life on Earth.

-            Single-celled organisms first lived 3.5 billion years ago, multicellular life was 1 billion years ago, dinosaurs are around 230 million years ago, and humans/mammals began around 66 million years ago.

8.               What are the 3 chemically distinct layers of Earth’s interior and how do they differ?

-            Crust, low density rock and very thin.

-            Mantle, high density rock and thick.

-             Core, metal, thick and has two layers.

9.               What is the difference between the lithosphere, asthenosphere, and the lower mantle? What is the difference between the inner and outer core?

-            The lithosphere is solid and rigid rock, this includes the crust and upper mantle.

-            The asthenosphere is solid and ductile, including the upper mantle.

-            The lower mantle is solid rock, it is very hot and dense.

-            The outer core is liquid metal, and the inner core is solid metal.

10.         Explain how seismology was used to map Earth’s interior.

-            There are p-waves and s-waves that travel through the earth’s interior during earthquakes. Seismic waves travel at different speeds through different materials, so we can use this information to map out the interior.

11.         How do meteorites, volcanic rocks, and Earth’s magnetic field contribute to our understanding of Earth’s interior?

-            Meteorites are leftovers from the formation of the solar system. There are iron meteorites and stony meteorites, earth has some rocks that are like these meteorites’ composition in the mantle.

-            Volcanic rocks are sampled from the earth’s mantle. There are surface rocks and mantle rocks, volcanoes are the only place that you can find this type of rock.

-            The magnetic field is caused by movement of charged iron and nickel ions within earth’s liquid outer core, the moving charged particles create a magnetic field.

12.         What is continental drift and what evidence was suggested by Alfred Wegner to support it?

-            Continental drift is when Pangea, a super continent, drifted and caused continental configuration.

-            He said that the fit of continents, record of past glaciation, ancient climate rock record, fossil evidence, and mountain belts are evidence for continental drift.

13.         How did seafloor mapping and paleomagnetism contribute to the hypothesis of continental drift?’

-            Seafloor mapping was when they used sonar to create a map of the seafloor.

-            There was apparent symmetry and repeating patterns within seafloor topography.

-            Paleomagnetism showed evidence based on magnetic minerals and magnetic history. The seafloor was created and spreads outwards from mid-oceanic ridges, there is magnetic signal in the rocks on the ocean floor.

14.         What are the 3 main types of plate boundaries?

-            Divergent plate boundaries.

-            Convergent plate boundaries.

-            Transform plate boundaries.

15.         Explain the characteristics we expect to find at each type of plate boundary and why. (Where do earthquakes and volcanoes occur? Where is new crust created? Where does mountain building occur?)

-            Divergent: Seafloor spreading (young ocean crust), earthquakes, volcanism (underwater), lithosphere thinning, mountains.

-            Convergent: Subduction, volcanic arcs, earthquakes (shallow and deep), deep ocean trenches.

-            Transform: Shallow earthquakes, river channel formation, land ruptures.

16.         What are the driving forces that create plate motion?

-            Mantle convection, ridge push, slab pull.

17.         What are the 5 defining characteristics of a mineral?

-            Naturally occurring, solid, inorganic, specific chemical composition, and crystalline.

18.         Explain the physical properties of minerals that are used to identify them (e.g., color, luster, hardness, cleavage, specific gravity).

-            Color: easily noticed, least reliable, rarely unique to a certain mineral, impurities mean that some minerals are more than one color.

-            Streak: color of mineral in powdered form, often a different color than the mineral, better tool than color.

-            Luster: how a mineral’s surface reflects light, metallic (very shiny), nonmetallic (pearly, earthy, silky, vitreous, adamantine.

-            Hardness: resistance to scratching, tested by scratching the surface with various tools, measured by Mohs Hardness Scale.

-            Crystal Form: 3 dimensional shape of crystal, some minerals form very distinct and easily identifiable crystal shapes.

-            Cleavage: Tendency of some minerals to break consistently along planes in their crystal structure, minerals break where atomic bonds are weakest, breaks from smooth, flat, light-reflecting surfaces called cleavage planes.

-            Fracture: Minerals whose atomic bonds are equally strong in all directions will break at random, or fracture. Irregular and conchoidal.

-            Smell and Taste: Certain minerals have distinct flavors or smells.

-            Magnetism: some minerals are magnetic.

-            Specific Gravity: mass of mineral/mass of equal volume of water.

-            Reaction to HCI: effervescence

-            Fluorescence: some minerals glow or appear a different color under UV light.

19.         What is the difference between an element and an isotope?

-            An isotope has the same element or atomic number and a different atomic mass.

20.         What are the 4 types of mineral bonds?

-            Covalent, ionic, metallic, van der Waals

21.         Explain how basic chemistry contributes to mineral characteristics and the classification of mineral groups.

-            Certain types of mineral groups are made up of different minerals and ions.

22.         List the common rock-forming mineral groups. What makes silicate minerals unique?

-            Silicates, Carbonates, Oxides, and Native Elements.

23.         List and explain the ways in which minerals form.

-            Hydrothermal: Hot water moves through rocks and picks up different ions that get carried along and precipitated through cracks.

-            Precipitation from water: Saline water evaporates, and salt is left behind.

-            Precipitation from gas: Sulfur forms when volcanic gas precipitates.

-            Solidification from magma: As magma cools, minerals form.

-            Solid State Diffusion: Recrystallization or formation of new minerals in response to pressure.

24.         What is a rock?

-            A rock is a solid aggregate group of minerals.

25.         How and where do the 3 types of rocks form?

-            Igneous: mineral crystals solidify from magma or lava.

-            Sedimentary: form through accumulation of sediment at the Earth’s surface.

-            Metamorphic: pre-existing rocks that are changed by heat, pressure, or fluid activity.

26.         What is the rock cycle?

-            The rock cycle is how rocks change forms through geological, chemical, and physical processes.

27.         What is the difference between intrusive and extrusive igneous rocks?

-            Extrusive: rocks form outside of the earth through volcanic activity, form faster, fine grained/lack of crystal growth.

-            Intrusive: form inside of the earth in magma chambers, take longer, coarse grained.

28.         What is the difference between clastic and biochemical sedimentary rocks?

-            Clastic: sediments are pieces of other rocks, can be pieces of igneous, metamorphic, or sedimentary rocks.

-            Biochemical: Sediments that form through biological or chemical processes like evaporation or precipitation.

29.         What is the difference between foliated and non-foliated metamorphic rocks?

-            Foliated rocks have layers and non-foliated rocks don’t.

30.         Explain the 3 main ways that rocks melt to form magma.

-            Changes in pressure: decompression melting, mantle plumes or hot spots, continental rifts, mid-ocean ridges.

-            Changes in temperature: heat transfer, as magma moves through the mantle it melts surrounding rocks.

-            Changes in composition: addition of water helps break chemical bonds in minerals, subduction zones.

31.         How does magma composition vary and why might it change?

-            Magma from melted mantle rock is mafic, magma from melted continental crust is intermediate or felsic.

-            Assimilation: when pieces of surrounding crust break off into the magma chamber and melt, it changes the composition.

-            Magma-mixing: when two magma chambers merge, they mix together and the composition changes.

32.         What does Bowen’s rection series tell us about igneous rock formation? (Know how to read and interpret the Bowen’s reaction series.)

-            As magma cools, we expect minerals to crystallize in a particular order.

-            Minerals form from magma at different temperatures.

33.         What is fractional crystallization and how does it relate to igneous rock formation?

-            Crystallized minerals are denser than magma and sink to the bottom of the chamber.

-            After magic materials settle, the remaining magma becomes more felsic.

34.         Define each step of sedimentary rock formation: weathering, erosion, transportation, deposition, and lithification.

-            Weathering: a process by which rocks are broken down to form sediment.

-            Erosion: removal of sediment away from rock outcrop.

-            Transportation: Distance of transport affects the size and shape of sediment.

-            Deposition: when sediment settles out after transport and is deposited at the Earth’s surface.

-            Lithification: the process of turning sediment into sedimentary rock through burial, compaction, and cementation.

35.         What is physical weathering? Provide some examples.

-            The breakdown of a rock is produced by physical processes that don’t alter its chemical composition.

-            Repeated exposure to forces at Earth’s surface, activity of organisms, expansion and contraction.

36.         What is chemical weathering? Provide some examples.

-            The breakdown of a rock produced by chemical reactions.

-            Dissolution, Oxidation, Hydrolysis.

37.         Explain how transportation affects sediment shape and size.

-            As sediment travels further, the rounder it gets.

38.         Do low energy depositional environments deposit big or small sediment grains?

-            Small sediment grains are formed in low energy depositional environments.

39.         List examples of depositional environments and the rocks they form.

-            Lake, glacier, tidal flat, rivers, deep sea, beach, desert.

40.         How does biochemical sediment form?

-            Forms through evaporation or precipitation.

41.         Explain how metamorphism changes the texture of rocks and minerals within rocks.

-            Changes are caused by heat, pressure and fluid activity.

42.         What is a protolith?

-            Original rock before metamorphism.

43.         Compare and contrast the 4 main types of metamorphism.

-            Contact: due to heat, pressure is not important; it happens to rocks surrounding magma chambers, decreases with distance from magma chamber.

-            Regional: happens at converging plates during mountain building events, temperate and pressure increases deeper below the mountains.

-            Hydrothermal: due to interaction with hot water, pressure is not important; it happens to rocks surround magma chambers when water is present.

-            Burial: pressure exerted on rocks from overlying material, when sedimentary rocks are buried deep enough, their mineralogy and texture can change.