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Question
What is the importance of cyanobacteria for our atmosphere? What did they produce and how? What happened to the first materials they produced?Answer
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Related questions
Q:
What kind of radioactive decay is present in this image?
A) Alpha decay
B) Beta decay
C) Electron capture
Q:
Which rock layer is the oldest in this image?
Q:
Assuming that humans went extinct today, do you think that they would be good index fossils? Why or why not?
Q:
You are studying an outcrop where the base layer is limestone and the layer directly on top of that is sandstone. Near the base of the sandstone are small, weathered pieces of limestone entirely contained within the sandstone. Explain how these pieces of limestone came to be contained within the sandstone.
Q:
One method of geologic dating is dendrochronology, or the science of tree ring dating. Based on what you know about tree rings, how could you determine the age of the tree? Would this be an example of relative dating or numerical dating?
Q:
Match the relative dating principles with the correct definition.
A) Missing time.
B) Faults, fractures are younger than the rocks they cut through.
C) Sedimentary layers/lava
D) The oldest is on the bottom, the youngest on top.
E) Rocks extend in all directions until they reach the edge of a basin or pinch out.
F) Chunks of weathered rock are older than the rock they are contained in.
1. Superposition
2. Original horizontality
3. Lateral Continuity
4. Cross-Cutting Relationships
5. Unconformities
6. Inclusions
Q:
A detrital sedimentary rock can be radiometrically dated because the clasts formed at the same time as the rock.
Q:
Hadean is an informal term used by many geologists to refer to the earliest interval of Earth's history.
Q:
The oldest rocks on Earth date back to 4.28 billion years old and were found in western Australia.
Q:
Carbon-14 dating is useful for paleontologists researching dinosaurs.
Q:
By putting events in order, scientists can use the order to determine how long ago certain geologic events took place.
Q:
Which of the following would make the best index fossil: olenellus (522-510 million years ago), flexicalymene (~490-418 million years ago), and phacops (~418-360 million years ago).
A) Olenellus
B) Flexicalymene
C) Phacops
Q:
In what era is the Jurassic period?
A) Precambrian
B) Paleozoic
C) Mesozoic
D) Cenozoic
Q:
What does "-zoic" in the eras of the geologic time scale refer to?
A) Life
B) Water
C) Rock
D) Fossilization
Q:
Which era are we currently in?
A) Mesozoic
B) Precambrian
C) Paleozoic
D) Cenozoic
Q:
What is the effective maximum range for carbon-14 dating?
A) 100,000 years
B) 70,000 years
C) 10,000 years
D) 13,000 years
Q:
What is the half-life of potassium-40?
A) 1.3 billion years
B) 704 million years
C) 14.1 billion years
D) 4.5 billion years
Q:
You are an archaeologist researching artifacts left behind by Francisco Pizzaro's conquest of Peru in the 1530s. In order to confirm the authenticity of the leather artifacts, you are performing radiometric dating using an isotope pair that has a half-life of 250 years. In order for the artifacts to date back to the time of Pizzaro's conquest, approximately how much original radioactive isotope must be left in the artifacts?
A) 50%
B) 25%
C) 75%
D) 12.5%
Q:
If 235U has 92 protons, how many neutrons does it have?
A) 25
B) 92
C) 143
D) 235
Q:
What is an isotope?
A) An atom that has more or fewer neutrons than it should
B) An atom that has more or fewer electrons than it should
C) An atom that has double the protons of a stable atom
D) A nucleus of an atom that has split during the decay process
Q:
What is stratigraphic correlation?
A) Dividing up rock layers into new ones based on mineral content
B) Matching up rocks of similar age in different regions
C) Putting events in order from first to last
D) Matching up continental coasts based on matching shapes
Q:
________ is the scientific study of fossils.
A) Quaternary geology
B) Volcanology
C) Geomorphology
D) Paleontology
Q:
Metamorphic facies derive their names from those metamorphic rocks specifically formed from a ________ parent.
A) basaltic
B) granitic
C) shale
D) obsidian
Q:
Which of the following is a metamorphic facies?
A) Kaolinite
B) Staurolite
C) Eclogite
D) Quartzite
Q:
________ is a widespread type of metamorphism typically associated with mountain building.
A) Pyrometamorphism
B) Burial metamorphism
C) Shock metamorphism
D) Regional metamorphism
Q:
Generally speaking, how does the chemical composition of most metamorphic rocks compare to that of the parent rock?
A) Their chemical composition will be nearly the same.
B) In order to be a metamorphic rock, the chemical composition must change by 50 percent.
C) There will be a complete compositional change.
D) Knowing the chemical composition is not necessary to understand metamorphic rocks.
Q:
Which of the following rocks represents the highest grade of metamorphism?
A) Biotite schist
B) Quartzite
C) Phyllite
D) Gneiss
Q:
Which of the following is the parent rock of quartzite?
A) Limestone
B) Conglomerate
C) Granite
D) Sandstone
Q:
What is the minimum depth at which subduction zone metamorphism will occur?
A) 0 km
B) 30 km
C) 25 km
D) 13 km
Q:
What kind of metamorphism will occur if the environmental conditions are 400C and 5 kilobars?
A) Hydrothermal
B) Contact
C) Regional
D) Subduction zone