Earth Systems 3209
Review Sheet – Unit 2
 Understand the following terms:
Law of Uniformitarianism
Uniform Processes
Catastrophism
Catastrophes
Mass Extinctions
Relative Time
Absolute Time
Law of Superposition
Principle of Cross-cutting Relations
Principle of Inclusions
Law of Original Horizontality
Principle of Fossil Succession
Index Fossil
Unconformity
Erosion
Angular Unconformity
Disconformity
Nonconformity
Glacial Varves
Growth (Tree) Rings
Radioactive Dating
Strata
Weathering
Transportation
Deposition
Compaction
Fault
Intrusion of Magma
Extrusion of Lava
Buried Lava Flow
Correlation (Rock and Fossil)
Contact Metamorphism (Baking)
Isotope
Neutron
Mass Number
Radioactive Element
Parent Isotope
Daughter Isotope
Radioactive Decay
Half Life
Isotope Pair
Parent:Daughter Ratio
Leaching
Hydrothermal Fluids
Metamorphism
Percentage
Fraction
Radioactive Decay Curve
Geologic Time
Fossil
Remain
Trace
Precambrian
Paleozoic Era
Mesozoic Era
Cenozoic Era
Eon
Era
Period
Epoch
Rapid Burial
Hard Body Parts
Anoxic (Low Oxygen)
Fine-grained Sediment
Evolutionary Pathway
Petrifaction
Replacement
Carbonization
Mold and Cast
Preserved Intact
Coprolites
Gastrolites
Imprints
Burrows
Internal Structures
External Structures
Age of Invertebrates
Age of Fishes
Age of Amphibians
Age of Reptiles
Age of Mammals
James Hutton
Charles Lyell
William Strata Smith
Nicholas Steno
Cambrian Period
Quaternary Period
Holocene Epoch
Phanerozoic
Proterozoic
Hadean
Archean
Permian Period – Triassic Period Boundary
Cretaceous Period – Tertiary Period Boundary
Pangaea
 Understand the following topics/questions/concepts:
1. Define uniformitarianism.
2. Distinguish between uniformitarianism and catastrophism.
3. Use uniformitarianism to explain why certain events will occur again in
the future.
4. Distinguish between relative time and absolute time.
5. Understand relative dating techniques/principals/laws, which include:
Law of superposition; Principle of cross-cutting relations; Principle of
inclusions; Law of original horizontality; Principle of fossil succession;
index fossils; and unconformities (angular unconformity, disconformity,
and nonconformity).
6. Be able to interpret the steps in the formation of geologic cross-sections
using techniques/principals/laws (See Point Above). (Core Lab 1).
7. Know your cross-section symbols (i.e. rock symbols).
8. Understand buried lava flows versus magma intrusions.
9. Understand absolute dating techniques/processes/features, which include:
glacial varves; growth rings; and radioactive dating.
10.Define half-life, isotope, parent elements, and daughter elements.
11.Know the isotope pairs (e.g. U-238 decays to Pb-206).
12.STSE 2 – “Labrador Zircons and their Link to Radiometric Dating and
Absolute Dating”. (Geochronology, isotope pairs, limitations of
radioactive dating, zircon, U-Pb system.)
13.Know how to do the different radioactive dating problems. (THERE
ARE FIVE DIFFERENT TYPES OF PROBLEMS.)
14.Know the sources of error and limitations of radioactive dating.
15.Be able to use a radioactive decay curve.
16.What is the age of Earth? When did life on Earth explode? When did
trilobites and other marine species go into extinction? When did
dinosaurs and other reptiles go into extinction?
17.Understand the importance of fossils in determining the geologic time
scale. (e.g., evolutions, extinctions.)
18.Why is Precambrian time considered to be a very uncertain time?
19.Know the importance of the following dates: 4.54 Ba; 545 Ma; 248 Ma;
and 65 Ma.
20.Define fossil.
21.What three conditions are necessary for fossilization?
22.Describe the different types or methods of fossilization?
23.Core Lab 2 – “Estimating Dinosaur Size and Speed from Trackways”.
(Trackway, gait, foot length, leg length, body length, stride length,
relative stride, herbivore, carnivore, dimensionless speed, movement
type.) Know how to calculate each!
24.Know the divisions of the geologic time scale. (i.e. eons, eras, periods,
epochs.)
25.Why did the Precambrian have the least amount of life forms?
26.Recognize that the Phanerozoic eon represents the emergence of complex
life forms. (Starts at 545 Ma.)
27.What are the three eras that comprise the Phanerozoic eon?
28.List the life forms that dominate each era. (“Since I Found Flying Angels
Riding Brooms Forget Medicine”.)
29.Know the “Ages” as they relate to the different eras.
30. Know the two mass extinction events, which include: Permian Period –
Triassic Period (248 Ma – Extinction of trilobites and other marine
species); and Cretaceous Period – Tertiary Period (65 Ma – Extinction of
dinosaurs).