Relative Time Scale Flashcards
Define Biostratigraphy
About layers of specific beds of rock
Define chronostratigraphic
Chronostratigraphic correlation matches rocks of the same age, even though they are made of different lithologies. Different lithologies of sedimentary rocks can form at the same time at different geographic locations because depositional environments vary geographically
Define stratigraphy and its principles
Principle of Super position
Principle of original horizantality
principle of lateral continuity
Is the study of layerd sedimentary rocks
Define principle superposition
In an otherwise undisturbed sequence of sedimentary strata, or rock layers, the layers on the bottom are the oldest and layers above them are younger.
Principle of original horizontality
Layered rocks are generally laid down flat at their formation.
Principle of lateral continuity
Layered rocks can be assumed to continue if interrupted within its area of deposition.
Relative time dating princples
Principle of Cross-Cutting relationships
Principle of Inclusions
Principle of Fossil Succession
Angular disconformity ** mid term question, on the previous midterm. Grand Canyon
Two rock layers that have different angles of deposition relative to horizontal.
The Phanerozoic strata in most of the Grand Canyon are horizontal. However, near the bottom horizontal strata overlie tilted strata. This is known as the Great Unconformity and is an example of an angular unconformity. The lower strata were tilted by tectonic processes that disturbed their original horizontality and caused the strata to be eroded. Later, horizontal strata were deposited on top of the tilted strata creating the angular unconformity
How does intrusive igenous rocks play into relative time
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Define Dike
A narrow igneous intrusion that cuts through existing rock, not along bedding planes.
Define sill
A type of dike that is parallel to bedding planes within the bedrock.
Define principle of inclusion
Primarily for sedimentary rocks, check text
Define Principle of Fossil Succession
stratiphed rocks of different layers, have different fossils and evolutionary organisms in them.
Define Detrital zircons
Detrital sedimentary rocks are less useful because they are made of minerals derived from multiple parent sources with potentially many dates. However, scientists can use igneous events to date sedimentary sequences
define disconformity
wo layered rocks that may seem conformable, but an erosional surface exist between them.
