Earth History
GEOL 2110
Midterm 1
Preparation/Review
Style of Questions
• Matching term w/ definition, person w/
notable accomplishment
• Short definition of concepts/processes
• Name some of multiple characteristics
REVIEW PowerPoints!!
Understand Figures in Text.
Dramatic vs. Subtle Geological Events
Be able to give examples of each
Scales of Geologic Time
Important People and their
Contributions to Geological Concepts
Leonardo Da Vinci
Nicholas Steno
Georges L. Buffon
A.G. Werner
James Hutton
Cuvier & Brongniart
William Smith
Lamarck
Charles Lyell
Charles Darwin
Gregor Mendel
Lord Kelvin
Hall and Dana
Alfred Wegener
Geological Concepts and Principles
Concepts
Principles
• Cosmogony
• Superposition
• Neptunism
• Original Horizontality
• Plutonism
• Lateral Continuity
• Catastrophism
• Walther’s Law
• Uniformitarianism • Fossil Correlation
• Actualism
• Index Fossils
• Evolution by Natural Selection
• Continental Drift and Sea-floor Spreading
Characteristics of a Scientific Theory
• Based on facts, but not a statement of
certainty or truth
• Testable – holds up to repeated testing
• Predictive – forward and backward in time
• Explains many related natural phenomenon
• Deemed by a majority of scientists to have a
high probability of being correct
Know the differences between a hypothesis,
theory, and paradigm
On the Origin of Species
Know Darwin’s 5
principle areas of
evidence that support
his theory of
Evolution by Natural
Selection
Genetic Theory
The Mechanism behind Evolution
Categories of Stratigraphic Units
(Fundamental Units) and Relative Time
Lithostratigraphic (formation) – principle of superposition
Lithodemic (intrusion) – principle of cross-cutting
relationships
Biostratigraphic (biozone) – principle of fossil correlation
Magnetopolarity
Pedostratigraphic
Allostratigraphic
Types of Unconformities
and Regional/Global Time Markers
Absolute Age Dating
Understand the meaning of:
• element vs. isotope
• radioactive vs. stable isotope
• types of radioactive decay
• parent vs. daughter isotope
• decay rate of a radioactive isotope
• half-life of a radioactive isotope
The Solar Nebula Theory
Seismic Imaging the Deep Earth
Layers of the Earth
OCEANIC
CRUST
CONTINENTAL
CRUST
SiO2
47%
56%
Al2O3
16%
18%
FeO
13%
9%
MgO
10%
3%
CaO
10%
4%
Na2O
2%
5.5%
K2 O
0.7%
2.5%
TiO2
1.1%
1.3%
P2O5
0.2%
0.7%
MANTLE
SiO2 – 45%
MgO – 37%
CORE
Fe – 86%
S – 10%
Ni – 4%
FeO – 8%
Al2O3 – 4%
CaO – 3%
others – 3%
---Mohorovicic
Discontinuity
= chondritic
meteorites
Compositional
Layers
Physical
Layers
Continental Crust
Distillation of Ocean Crust by Partial Melting
Evidence in Solid Solution Minerals
OCEANIC
CRUST
CONTINENTAL
CRUST
SiO2
47%
56%
Al2O3
16%
18%
FeO
13%
9%
MgO
10%
3%
CaO
10%
4%
Na2O
2%
5.5%
K2 O
0.7%
2.5%
TiO2
1.1%
1.3%
P2O5
0.2%
0.7%
Present-day Formation of Crust
A Double Distillation Process
Melting the Mantle Makes Mafic Magma – ALWAYS
Melting Crust Makes Intermediate to Felsic Magma
Evidence of Plate Tectonics
 Fit of the continents
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Fossil record indicating former land bridges
Similar geologic structures
Similar paleoclimates
Apparent polar wandering of continents
Topography of the seafloor
Magnetic polarity “striping” of seafloor
Distribution of volcanoes and mountains
Distribution of earthquakes (Benioff zones)
Young age of the seafloor
Age distribution of volcanic islands
Types and Features of Plate Boundaries