Name______
Guide Notes Relative Dating
Relative Dating- is used to arrange______, and the rocks they leave behind, in a ______. The method of reading the order is called ______(layers of rock are called ______). Relative dating does not provide actual ______/_____ for the rocks.
Relative Age - is the “age” of a ______or ______compared to the ages of other rocks or strata.
Principle of Superposition - as ______ rocks form, they are deposited on ______ rock layers. Principle of Superposition in undisturbed layers, the oldest is on the ______and ______ layers are younger.
Principle of Original Horizontality - The law states that layers of sediment were originally ______horizontally under the action of gravity.
Principal of Fossil Succession- Also known as the______, is based on the observation that sedimentary rock strata contain fossilized flora (plants) and fauna (animals), and that these ______succeed each other vertically in a specific, reliable order that can be identified over wide horizontal distances.
Principle of Cross-Cutting Relationships- An igneous/metamorphic rock, ______, or other ______must be younger than any rock across which it cuts.
Uniformitarianism- is the idea that the ______ occurring on earth today are ______ to those that occurred in the past. Uniformitarianism basically says “The ______is the key to the ______.” Uniformitarianism is the idea that geological features formed ______over ______periods of time. Uniformitarianism claims the Earth is ______years old.
CROSS-CUTTING RELATIONSHIPS
Extrusions- are ______ rocks layers that form on the surface when ______ hardens. Extrusions are always ______ than the layers over which they form.
Intrusions are igneous rocks that form when ______ pushes up into rock layers. Intrusions are always ______ than the rock layers they invade.
Faults- are ______ in the earth’s crust. A fault is always ______ than the rock it cuts through.
Folds- occur when rock layers are ______together and ______or ______.
Unconformities- are gaps in the rock sequence (caused by the ______ of rock layers).
Angular Unconformity- occur when rock layers are ______or ______, and then worn down by erosion and weathering.
Disconformities- are ______created when erosion occurs on an overlying rock layer.
Nonconformity- are formed when ______rock overlays igneous or metamorphic rocks.
INDEX FOSSILS AND CORRELATION
Correlation- is using rock and fossil evidence to ______dating at different ______.
Index Fossils are used for ______the rock ______ in which they are found. Index Fossils are species that were ______ all over the earth, but existed for shorter periods of time.