Chapter 10 Flashcards
Geologic Time (20 cards)
What does radiometric dating use to estimate the age of geologic samples?
Naturally Occuring Radioactivity
When an organism dies, what happens to the amount of radiocarbon in its tissue?
It decreases consistenly according to the half-life clock.
What is the principle of superposition?
A relative age dating principle that states the oldest rocks are located the farthest down
Choose the type of decay described here: The nucleus of an atom emits a single particle consisting of 2 protons and 2 neutrons. The resulting formation is a daughter isotope with 2 fewer protons than the parent isotope.
Alpha Decay
Which best describes beta decay?
The nucleus emits a negative particle that changes one of the neutrons into a proton.
After one half-life, a sample will contain twice the number of atoms that were originally present.
FALSE
Which of the following constitutes the largest segment of geologic time?
Eon
The process in which an element spontaneously transforms itself into another isotope is called?
Radioactivity
The geologic time scale is based on__.
Fossil Correlation
The time needed for half of the parent atoms of a radioactive substance to decay into daughter atoms is termed?
Half-life
Our best estimate for the age of the Earth is __.
4.5 billion years
Which rule of relative dating would a geologist apply to determine the relative age of a fault?
Cross-cutting relationships
A geologist observes uplifted metamorphic rocks that are overlain by a bed of horizontal sedimentary rock layers. This is an example of___.
nonconformity
Unconformities in sedimentary rock strata indicate that:
- There was a time period during which no record of depostition was preserved. & 2. The tilted layers of rock must be younger than the layers depostited horizontally
The process of correlation relies on which principle?
Successive layers of sedimentary strata contain similar sets of fossils.
What happens to all radioactive isotopes that undergo radioactive decay?
They transform into a new isotope.
Which rule of relative dating would a geologist apply to determine the relative age of an igneous intrusion?
Cross-cutting relationships
How does an angular unconformity form?
Older rocks are tilted, eroded, and overlain by younger rocks.
Time unrepresented in a rock sequence as a result of erosion is called a(an) __.
unconformity
Which of the following is the oldest chapter of geologic time?
Precambrian
