Post Lab Assesment 5
If 80 grams of a radioactive isotope starts to decay, how much is left after 4 half lives?
5 grams
Which principle is used to infer that a fault is younger than the rocks it displaces?
Cross-cutting relations
Which time interval is longest?
Eons
Fossils have been around for approximately 20% of Earth's history?
False
The isotope rubidium 87 decays to strontium 87 over a half-life of 48.8 billion years. These isotopes would have experienced nearly one half life in the oldest rocks on Earth.
False
If a radioactive isotope has a half life of 100 million years. What proportion of the radioactive isotope will have been converted to daughter products after 200 million years?
NOT 25%, not 75, not 50
Which principle is used to infer that tilted rocks must have undergone an episode of deformation subsequent to their formation?
Original horizontality
Which event happened first?
Pangea split first
Which of the following are Eons?
Proterozoic Phanerozoic
Which principle is used to infer that rocks toward the bottom of a sequence of layers are older than those near the top?
Superposition
Which represents the longest interval of geologic time?
Time between the appearance of the first bacteria and when oxygen began to accumulate in the atmosphere
Dinosaurs became extinct between the Mesozoic and Cenozoic eras.
True
Which event happened last?
age of dinosaurs
Which event happened first?
age of fishes
The isotope Beryllium-10 decays to Boron-10 over a half-life of 1.5 million years. These isotopes would have experienced nearly three half lives in the oldest rocks on Earth.
false
The isotope Carbon-14 decays to Nitrogen-14 over a half-life of 5730 million years. These isotopes could be used to determine the age of rocks formed early in the Cenozoic Era.
false
The principle of original horizontality states that
sedimentary rocks are formed as horizontal layers.
The isotope Beryllium-10 decays to Boron-10 over a half-life of 1.5 million years. These isotopes would have experienced four half lives in igneous rocks that were 6 million years old.
true
Imagine that North Carolina was submerged by s sudden rise in sea level. New layers of sediment are deposited on the recently submerged land surface. What is the technical name for the surface that lies between the former land surface and the new layers?
unconformity
