Geology Exam # 3 Questions And Correct
Answers
Which of the following first appeared in the Mesozoic Era?
Dinosaurs
Fossils are more likely to be preserved under which conditions?
Rapid burial
Which of the following first appeared in the Paleozoic Era?
Flowering plants, insects, fish, and reptiles
The radioactive isotope X, decays to the stable isotope Y. The 1/2 life of this process is 1500 million
yrs. If the original amount of X has been reduced by 50%, how old is the rock that contains isotope X?
3000 million years
The radioactive isotope X, decays to the stable isotope Y. The 1/2 life of this process is 300 million yrs.
If the original amount of X has been reduced by 94%, how old is the rock that contains isotope X?
1200 million years
A layer of shale lies above a layer of limestone. Each layer contains different fossils. Which are
potential explanations for these contrasts?
Layers are formed in different environments containing different species, the fossils represent
organisms living at different times in Earth's history
Match the following parent isotopes with their daughter isotopes-
Thorium-lead, rubidium-strontium, potassium-argon, uranium-lead
The 1/2 life of a radioactive isotope 100 million yrs. Scientists testing a rock sample discover that the
ratio of parent and daughter isotopes indicates that the rock is 200 million years old. What % of
parent isotopes would be present in the sample?
25%
Which of the four organisms were the last to show up in the geologic record
dinosaurs
Which organisms were found in the oldest rocks?
stromatolites
If you began with 4000 radioactive isotopes, how many parent isotopes and daughter isotopes would
be left after two half lives?
1000 parent; 3000 daughter
Which radioactive isotope would be best to use to date the age of charcoal in a Native American fire
pit?
Carbon
, Approx. what age was determined for the oldest rocks that have been found on Earth?
4 billion yrs
Ages were calculated for 4 rocks. Which of the following rocks would be classified as Precambrian
Rock D-720 million yrs, Rock B-2000 million yrs, Rock C-3800 million yrs
Radioactive decay allows scientists to determine..
When lava erupted, when granitic magma solidified below ground, when metamorphism
recrystallized calcite minerals in marble
The principle of original horizontality states that
sedimentary rocks are deposited as horizontal layers
If you began with 4000 radioactive isotopes, how many parent isotopes and daughter isotopes would
be left after one half lives?
2000 parent; 2000 daughter
Which of the following 1st appeared in the Paleozoic Era?
insects, reptiles, fish
Fossils are more likely to be preserved under which conditions
rapid burial
Which of the following appeared in the Cenozoic Era?
large mammals
Global extinction events mark the boundaries between which time intervals?
Mesozoic and Cenozoic, Paleozoic and Mesozoic
If you began with 800 grams of radioactive isotopes, how much of the parent isotopes would be left
after two half lives?
400 grams
Identify the phrase that best fits the blank in the following sentence. Ice is to glaciers as ________ to
moraines
Till is
What are the two principal gases that make up 99% of dry air?
nitrogen and oxygen
Which is the most accurate statement about sea level changes over Earth's history?
Sea level is rising and but has been higher in the geologic past
Answers
Which of the following first appeared in the Mesozoic Era?
Dinosaurs
Fossils are more likely to be preserved under which conditions?
Rapid burial
Which of the following first appeared in the Paleozoic Era?
Flowering plants, insects, fish, and reptiles
The radioactive isotope X, decays to the stable isotope Y. The 1/2 life of this process is 1500 million
yrs. If the original amount of X has been reduced by 50%, how old is the rock that contains isotope X?
3000 million years
The radioactive isotope X, decays to the stable isotope Y. The 1/2 life of this process is 300 million yrs.
If the original amount of X has been reduced by 94%, how old is the rock that contains isotope X?
1200 million years
A layer of shale lies above a layer of limestone. Each layer contains different fossils. Which are
potential explanations for these contrasts?
Layers are formed in different environments containing different species, the fossils represent
organisms living at different times in Earth's history
Match the following parent isotopes with their daughter isotopes-
Thorium-lead, rubidium-strontium, potassium-argon, uranium-lead
The 1/2 life of a radioactive isotope 100 million yrs. Scientists testing a rock sample discover that the
ratio of parent and daughter isotopes indicates that the rock is 200 million years old. What % of
parent isotopes would be present in the sample?
25%
Which of the four organisms were the last to show up in the geologic record
dinosaurs
Which organisms were found in the oldest rocks?
stromatolites
If you began with 4000 radioactive isotopes, how many parent isotopes and daughter isotopes would
be left after two half lives?
1000 parent; 3000 daughter
Which radioactive isotope would be best to use to date the age of charcoal in a Native American fire
pit?
Carbon
, Approx. what age was determined for the oldest rocks that have been found on Earth?
4 billion yrs
Ages were calculated for 4 rocks. Which of the following rocks would be classified as Precambrian
Rock D-720 million yrs, Rock B-2000 million yrs, Rock C-3800 million yrs
Radioactive decay allows scientists to determine..
When lava erupted, when granitic magma solidified below ground, when metamorphism
recrystallized calcite minerals in marble
The principle of original horizontality states that
sedimentary rocks are deposited as horizontal layers
If you began with 4000 radioactive isotopes, how many parent isotopes and daughter isotopes would
be left after one half lives?
2000 parent; 2000 daughter
Which of the following 1st appeared in the Paleozoic Era?
insects, reptiles, fish
Fossils are more likely to be preserved under which conditions
rapid burial
Which of the following appeared in the Cenozoic Era?
large mammals
Global extinction events mark the boundaries between which time intervals?
Mesozoic and Cenozoic, Paleozoic and Mesozoic
If you began with 800 grams of radioactive isotopes, how much of the parent isotopes would be left
after two half lives?
400 grams
Identify the phrase that best fits the blank in the following sentence. Ice is to glaciers as ________ to
moraines
Till is
What are the two principal gases that make up 99% of dry air?
nitrogen and oxygen
Which is the most accurate statement about sea level changes over Earth's history?
Sea level is rising and but has been higher in the geologic past
