Rock Layers Flashcards

Flashcards about rock layers and stratigraphy

Stratification or bedding

Layering that happens in sedimentary and igneous rocks formed at the surface of the earth.

Stratigraphy

Branch of geology that deals with the description, correlation, and interpretation of stratified sediments and stratified rocks on & within the Earth.

Stratified Rocks

Layers of rocks.

Law of Original Horizontality

Sediments are deposited in Flat Layers. If not disturbed, they maintain original horizontality.

Law of Superpositon

Heavist- deepest- oldest, Lightest- settled on top-youngest.

Principle of Uniformitarianism

The current geologic processes, such as volcanism, erosion and weathering are the same processes that were at work in the past.

Relative Age

Determines the comparative age where the layers of rocks were formed and is limited in identifying which layer was made first and which was made last.

Absolute Age

Is the use of records of radioactive decay in rocks to determine the exact age

Isotopes

Atoms of the same element (same number of proton) but with different number of neutrons.

Parent Material

Unstable isotope, radioactive.

Daughter Material

Stable element, decay product.

Radiometric Dating

Comparing the amount of radioactive and nonradioactive isotopes to determine rock age

Half-Life

Is the time taken for the radioactivity of a specified isotope to turn to half of its original value.

Relative Dating

is the process of comparing and correlating rock layers to determine the relative age of rocks.

Absolute Dating

is the process of determining the age of materials like rocks and fossils or rock Layers; It uses radioactive isotopes(radioactive decay & half-life principles) to identify the exact age of the materials.

Geologic Time Scale

Serves as the calendar for events in Earth's history.

Inclusion

Rock fragments found in another rock/layer must be existing before being part of the rock.

Faunal Succession

Rock layers contain fossils that can be used to identify and correlate rocks.

Correlation

Is the process of showing that rocks or geologic events that occur at different locations are of the same age.