ch 13 Flashcards
Age in years of a rock or other objects
absolute age
Absolute age provides a specific time frame for dating geological events.
Thin film of carbon residue preserved as a fossil
carbon film
Carbon films are often found in sedimentary rock and can provide insights into ancient life.
A type of body fossil that forms when crystals fill a mold, or sediments wash into a mold and harden into rock
cast
Casts can provide detailed information about the organism’s shape and structure.
Remains, imprints, or traces of prehistoric organisms
fossil
Fossils can indicate when and where organisms lived and how they interacted with their environment.
Time it takes for half of the atoms of an isotope to decay
half-life
Half-life is a critical concept in radiometric dating.
Remains of species that existed on Earth for a relatively short time, were abundant and widespread geographically
index fossil
Index fossils are used by geologists to assign ages to rock layers.
A type of body fossil that forms in rock when an organism with hard parts is buried, decays or dissolves, leaving a cavity in the rock
mold
Molds can provide a negative imprint of the organism.
Fossils in which the spaces inside are filled with minerals from groundwater
permineralized remains
This process preserves the original structure of the organism in great detail.
In undisturbed rock layers, the oldest rocks are on the bottom and the rocks become progressively younger toward the to
Principle of Superposition
This principle is fundamental in establishing the relative ages of rock layers.
Process in which some isotopes break down into other isotopes and particles
radioactive decay
This process can lead to the formation of new elements.
Process used to calculate the absolute age of rock by measuring the ratio of parent isotope to daughter product in a mineral
radiometric dating
Knowing the half-life of the parent isotope is essential for accurate dating.
The age of something compared with other things
relative age
Relative age helps to establish a sequence of events in geological history.
Gap in the rock layer due to erosion or periods without any deposition
unconformity
Unconformities can indicate significant geological events or changes in the environment.
Principle stating that Earth’s processes occurring today are similar to those that occurred in the past
uniformitarianism
This principle supports the idea that studying current geological processes can help us understand past events.
Process that uses the properties of atoms in rocks and other objects to determine their ages
absolute dating
Absolute dating provides a specific age rather than a range.
