Geologic Column Flashcards

Study Notes

Relative dating determines the age of an object or event in relation to others, rather than providing an exact age.
Absolute dating measures the actual age of an event or object in years, offering precise chronological data.

An isotope is an atom that has the same number of protons but a different number of neutrons, resulting in varied atomic mass for the same element.
Radioactive decay refers to the process where unstable isotopes transform into stable isotopes, potentially changing the original element.
Radiometric dating estimates the age of an object by calculating the ratio between parent isotopes (original) and daughter isotopes (decay products).
The half-life of an isotope is the duration required for half of its radioactive atoms to decay, crucial for radiometric dating accuracy.

A geologic column is a stratified arrangement of rock layers, with the oldest layers located at the bottom.
An unconformity signifies a gap in the geological record due to erosion or prolonged periods without sediment deposition.
Paleontology is the study of fossils, which are critical for understanding past life forms and environments.
A fossil is a preserved trace or remnant of an organism from the past, commonly found in sedimentary rock.

An index fossil is a fossil exclusive to a specific geological age, aiding in dating rock layers.
A trace fossil is a mark created in soft sediment by an animal's movement, providing insight into behaviors and environments.

Extinction refers to the complete loss of every member of a species, a critical aspect of biological and ecological history.
Uniformitarianism is the principle that past geological processes can be understood through current processes, suggesting a stable Earth.
Catastrophism proposes that significant geological changes occur suddenly, often due to extraordinary events.
The law of superposition states that in undisturbed layers, younger rocks are positioned above older rocks, establishing a relative chronological framework.