EOSC 110 MIDTERM 1&2 QUESTIONS AND ANSWERS
Recognize the length of geologic time over which Earth's interior and surficial processes
have operated - Answer -Pre-Cambrian (4570 Ma)
- Hadean
- Archean
- Protozoic
Cambrian (540)
Mesozoic (250)
Cenozoic (65)
Explain how we can date rocks using radioactive isotopes - Answer -- Decay of
isotopes occur at a steady rate
- Can compare parent to daughter nucleus
- Happens in half lives
Discuss lines of evidence for the age of the Earth - Answer -- Fossil dating: Fossils
correspond to an era
- Tree-ring dating: Each ring represents a year
- Varves: Layers of sedimentary rock
- Magnetism: Poles switch, can be seen in volcanic rocks
Define the following terms: isotope, half-life, parent isotope, daughter isotope,
radioactive decay. - Answer -- Isotope: Unstable ion due to lack of a full valence shell
- Half life: Half of the time it takes for the parent isotope to decay into daughter
Parent: Initial material
Daughter: Final material
Radio active decay: Spontaneous release of atoms
Describe how the geologic time scale evolved from a combination of relative and
absolute age-dating techniques - Answer -Relative
- Fossil dating: Finding the genus patterns of fossils identifies the 5 major extinctions
- Magnetism:
- Sedimentary rocks: Formed from carbon
Absolute
- Radioactive decay
Apply the principles of relative dating to deciphering the geologic history of an area -
Answer -- Superposition: Lowest layer is oldest
- Lateral continuity: Layers form in a lateral direction
- Original Horizontallity: Deformity causes layers to tilt
, - Cross-cutting: Layers that cut through are younge
- Faunal succession: Fossils found lower layers are older
- Inclusions: Fragments are younger
Describe Earth's geologic eras with defined age boundaries - Answer -Pre-cambrian
(4570)
- Early life
Cambrian (540)
- life with skeletons
Mesozoic (250)
- Dinosaurs
Cenozoic (65)
- Humanity
Illustrate and label the layers of the Earth (inner core, outer core, mantle, oceanic and
continental crust) and describe the basic properties (composition, strength) of these
layers. - Answer -- Inner core: solid
- Outer core: liquid
- Mantle: Solid, rigid, less dense than crust
- Oceanic: Thinner, more dense
- Continental: Thicker, less dense
Identify the components of the lithosphere. - Answer -- Uppermost mantle + crust
- Rigid yet brittle
Recognize and interpret associations between observations of the Earth (data sets such
as global topography, volcanoes, earthquakes, age of the sea floor) and plate
boundaries - Answer -Global topography: Thickness and density is lower at plate
boundaries where lithosphere is being subducted
Volcanoes: Convergent plate boundary as ocean-ocean move together and sediments
pushing up create magma
Earthquakes: Convergent / transform boundaries
Age of sea floor: Divergent boundaries cause decompression and thus partial melting of
the mantle, creating magma and new sea floor
Describe and draw the different types of plate boundaries (divergent, convergent and
transform) - Answer -- Divergent: Moving away
- Convergent: Moving into each other
- Transform: Sliding across
Recognize and interpret associations between plate boundaries and associated
features (e.g., trenches, mountains, volcanoes, earthquakes) - Answer -- Trenches:
Convergent boundaries subduct older more dense underneath
Recognize the length of geologic time over which Earth's interior and surficial processes
have operated - Answer -Pre-Cambrian (4570 Ma)
- Hadean
- Archean
- Protozoic
Cambrian (540)
Mesozoic (250)
Cenozoic (65)
Explain how we can date rocks using radioactive isotopes - Answer -- Decay of
isotopes occur at a steady rate
- Can compare parent to daughter nucleus
- Happens in half lives
Discuss lines of evidence for the age of the Earth - Answer -- Fossil dating: Fossils
correspond to an era
- Tree-ring dating: Each ring represents a year
- Varves: Layers of sedimentary rock
- Magnetism: Poles switch, can be seen in volcanic rocks
Define the following terms: isotope, half-life, parent isotope, daughter isotope,
radioactive decay. - Answer -- Isotope: Unstable ion due to lack of a full valence shell
- Half life: Half of the time it takes for the parent isotope to decay into daughter
Parent: Initial material
Daughter: Final material
Radio active decay: Spontaneous release of atoms
Describe how the geologic time scale evolved from a combination of relative and
absolute age-dating techniques - Answer -Relative
- Fossil dating: Finding the genus patterns of fossils identifies the 5 major extinctions
- Magnetism:
- Sedimentary rocks: Formed from carbon
Absolute
- Radioactive decay
Apply the principles of relative dating to deciphering the geologic history of an area -
Answer -- Superposition: Lowest layer is oldest
- Lateral continuity: Layers form in a lateral direction
- Original Horizontallity: Deformity causes layers to tilt
, - Cross-cutting: Layers that cut through are younge
- Faunal succession: Fossils found lower layers are older
- Inclusions: Fragments are younger
Describe Earth's geologic eras with defined age boundaries - Answer -Pre-cambrian
(4570)
- Early life
Cambrian (540)
- life with skeletons
Mesozoic (250)
- Dinosaurs
Cenozoic (65)
- Humanity
Illustrate and label the layers of the Earth (inner core, outer core, mantle, oceanic and
continental crust) and describe the basic properties (composition, strength) of these
layers. - Answer -- Inner core: solid
- Outer core: liquid
- Mantle: Solid, rigid, less dense than crust
- Oceanic: Thinner, more dense
- Continental: Thicker, less dense
Identify the components of the lithosphere. - Answer -- Uppermost mantle + crust
- Rigid yet brittle
Recognize and interpret associations between observations of the Earth (data sets such
as global topography, volcanoes, earthquakes, age of the sea floor) and plate
boundaries - Answer -Global topography: Thickness and density is lower at plate
boundaries where lithosphere is being subducted
Volcanoes: Convergent plate boundary as ocean-ocean move together and sediments
pushing up create magma
Earthquakes: Convergent / transform boundaries
Age of sea floor: Divergent boundaries cause decompression and thus partial melting of
the mantle, creating magma and new sea floor
Describe and draw the different types of plate boundaries (divergent, convergent and
transform) - Answer -- Divergent: Moving away
- Convergent: Moving into each other
- Transform: Sliding across
Recognize and interpret associations between plate boundaries and associated
features (e.g., trenches, mountains, volcanoes, earthquakes) - Answer -- Trenches:
Convergent boundaries subduct older more dense underneath
