Review Flashcards
Scientific Method
Method of procedures used in conducting experiments that consist of systematic observation, measurement, and experiment
Steps in the Scientific Method
- Observation
- Hypothesis
- Theory
- Law
Independent Variable
Variable that stands alone and is not changed by other variables
Dependent Variable
Variable that depends on other factors that are measured
* Expected to change as a result of an experimental manipulation of the independent variables
Big Bang Theory
The idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now (and it could still be stretching)
Nebular Theory
The nebular theory proposes that the bodies of our solar system evolved from
an enormous rotating cloud called the solar nebula
Planetary differentiation
separating of different components of
a planet due to physical or chemical behavior
Geologic Time
Split into 3-4 divisions
* Eons - Hadean, Archean, Proterozoic, Phanerozoic
* Eras - Paleozoic, Mesozoic, Cenozoic separated by mass extinctions
* separated by 5 mass extinctions
* Periods - Eras are subdivided into periods
* the basic unit of the geologic time scale
* Epochs - Finer subdivisions of time are possible, periods can be subdivided into epochs
Discuss how a geologist would use relative dating techniques
The earliest layers are the youngest while the deeper ones are the oldest, determine the earth’s history
Law of Original Horizontality
Sediments are deposited in beds (strata) that are horizontal or nearly horizontal and parallel or nearly parallel to Earth’s surface
Law of Original Continuity
trata extend laterally in all directions until they thin or (pinch out) or reach the edge of their environment of deposition
Law of Superposition
In any layered sequence of rock that has not been tilted or overturned,
the youngest layer is at the top and the oldest layer is at the bottom
Law of Inclusion
Any piece of rock (inclusion- rock fragment, crystal, or fossil) that has become included in another rock or body of sediment must be older than the rock or sediment into which it has been incorporated
* The surrounding body of rock is called the matrix
Law of Cross-Cutting Relationships
Any feature (a dike, vein, fracture, or fault) that cuts across a rock or body of sediment must be younger than the rock or sediment that it cuts across
Law of Fossil Assemblages
Similar groups of fossils indicate similar geologic ages for the rocks that
contain them
* rocks containing the same fossils are the same age
Law of Fossil Succession
Organisms preserved as fossils in sedimentary rock appeared,
became extinct, and were succeeded by newer organisms over time
* Different types of fossils indicate different ages.
Law of Unconformities
Surfaces called unconformities represent gaps in the geologic record that formed where ever layers were not deposited for a time or removed by erosion
* Disconformity, Angular unconformity, Nonconformity
What are atoms?
particle of matter that consists of a nucleus of protons and generally neutrons, surrounded by electrons
Nucleus
the positively charged central core of an atom
Protons
a subatomic particle with a positive electrical charge
Neutrons
asubatomicparticle of about the same mass as aprotonbut without an electric charge
Electrons
a stablesubatomicparticle with a charge of negative electricity, travels around an atom
What are ions?
Atoms with a charge due to the unequal numbers of electrons and protons
What is the atomic number and mass number of an element?
Atomic number: The number of protons, mass number of an element is mass number = protons + neutrons
Difference between a parent and daughter particle
Parent: atom before any chemical change Daughter: element formed after radioactive decay
What is radioactive decay?
a spontaneous process in which an isotope of an atom (the parent) loses particles from its nucleus to form an isotope of a new element (the daughter)
What is a half-life?
the time it takes for one-half of the parent radioactive element to decay to a daughter product
What rocks are used for radiometric dating?
igneous rocks and minerals are best for age dating
Topographic Maps
Two dimensional representations of three-dimensional landscapes
viewed from above
Elevation is shown above sea level using
contour lines
Contour Interval
difference in elevation between each contour line
Contour Interval math
Subtract the two index contours.
800 ft - 700 ft = 100 ft
Take the difference of the index contours and divide it by the number of lines.
100 ft/5 line = 20ft
Index contour
Bold contour lines that have the elevation labelled
Relief
difference between highest and lowest elevations
Highest Elevation – Lowest Elevation
840 ft – 700 ft = 140ft
Gradient
the slope between any two defined points on a map.
𝑮𝒓𝒂𝒅𝒊𝒆𝒏𝒕 = 𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑒𝑙𝑒𝑣𝑎𝑡𝑖𝑜𝑛 / 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒
Who is Alfred Wegener and Harry Hess?
Alfred Wegener - Continental Drift Hypothesis: All continents were once joint into a single landmass that broke apart, with the various fragments (continents) moving with respect to one another. Evidence used in support of continental drift hypothesis: Fit of the continents, Fossil evidence, Rock type and structural similarities, Paleoclimatic evidence
Harry Hess - Seafloor Spreading Hypothesis: The origin of new oceanic crust occurs at spreading ridges where 2 plates move away from each other, eventually being consumed at subduction zones (A long narrow zone where one lithospheric plate descends beneath another)
What is continental Drift?
the movement of continents resulting from the motion of tectonic plates
What is seafloor spreading?
tectonic plates split apart from each other
What are convergent, divergent, and transform plate boundaries?
Convergent: Boundary between two plates that are moving toward each other, Divergent: Boundary between two plates that are
moving away from each other, Transform: Plates slide past one another, and no new lithosphere is created or destroyed
Discuss the different types of plate boundaries and the faults that are associated with them
Convergent: Reverse Faults, Divergent: Normal faults, Transform: Strike-slip faults
What is paleomagnetism?
When magma cools, magnetic iron-bearing minerals align themselves with Earth’s magnetic field/ study of magnetic fields recorded in rocks, sediment, or archeological materials
What are mantle plumes and hot spots?
Mantle plumes: A rising plume of hot mantle material
(magma) not normally associated with a plate boundary, Hot spots: A localized zone of melting below the lithosphere that overlies a mantle plume
What drives plate motion?
Mantle convection drives plate motion, Molten rock in Earth’s mantle is
stirred by heat trying to escape, Upwelling and cooling of magma at mid-ocean ridges push plates apart, inking slab “pulls” the rest of the plate away from the ridge
What two pieces of information would researchers need to have to calculate the rate of plate motion for seafloor spreading?
Distance and time
Math for calculating rate:
Rate = Distance / Time
Time = Distance / Rate
Distance = Rate x Time
Define an earthquake and the mechanism which causes them
Earthquake: The vibration of Earth, produced by the rapid release of energy and movements that produce earthquakes are usually associated with large fractures in Earth’s crust called faults (A break in a rock mass along which movement has occurred)
Explain how seismologists can determine the location of an epicenter of an earthquake
The epicenter of an earthquake is located using the difference in velocities of P and S waves. Three station recordings (seismograms) are needed to locate an epicenter.
Be able to recognize a logical pattern between plate tectonics and earthquakes
A good fit exists between the plate tectonics model and the global distribution of earthquakes. Only shallow-focus earthquakes occur along divergent and transform fault boundaries, deep focus earthquakes only occur in association with convergent plate boundaries, subduction zones, and oceanic trenches.
Compare and contrast surface, primary, and secondary waves
Surface, primary, and secondary waves are all seismic waves, but surface waves are its own category of seismic waves and are much more destructive while primary and secondary are body waves and travel through the earth’s interior
Explain Elastic Rebound Theory
the sudden release of stored strain (energy) in rocks that results in movement along a fault