Unit 8 Flashcards
What is the geological time scale?
This is a way to represent deep time it’s divided up based on the events that have happened in earths past
What are the three categories time is divided into
Aeons errors and periods
What can the age of a rock tell us?
It can establish timelines of geological events, it could determine the rate or speed of a geological process, it could help predict what might occur in the future
What is absolute dating?
Used to determine how much time has past sense of rock has formed measures radioactive decay of isotopes, and it’s used to determine the time of crystallization of a mineral
Explain isotopic dating
Atoms of an unstable isotope, will the K into a stable element overtime. The rate at which an unstable isotope decay is constant throughout geological time.
What is relative dating?
Sedimentary rocks, do not contain materials/minerals that can be dated a topically, mineral compounds, making up sedimentary. Rocks are sourced from other rocks, such as weathered or eroded oak crops, if we absolute sedimentary rocks, we are getting aged dates for their original weathered and eroded rocks
What are the seven geological principles?
Superposition, horizontality, lateral continuity, crosscutting relationships, inclusion, faunal succession, unconformities
What is law of superposition?
Newer rock beds, above older rock beds the exception being the rock beds, have been overturned by tectonic influence
What is the principle of original horizontality
All rock layers originally deposited horizontally under the action of gravity, sediment accumulation on surfaces of low relief or flat. Looks like a layer cake.
What is principle of lateral continuity?
Originally deposited layers of rock extended laterally in all directions until either thinning out or being cut off by a different rock layer, or later event
What is principle of crosscutting relationships?
A rock feature that cuts across another feature must be younger than the rock feature cuts
What is principle of inclusion?
Small fragments of one rock type that are embedded in another rock type must be older than the rock there in Kingston
What is faunal succession?
Fossil diagnosis of a time period can help us sign an age date a.k.a. biostratigraphic dating you need to understand the sequence of evolution in order to place rocks incorrect order
What are unconformities
Geological features representing periods of erosion or non-disposition. They indicate noncontinuous sediment deposition. It’s an interruption in the process of depositing and sedimentary rocks.
What are the four unconformity types?
Non-conformity, angular, unconformity, disconformity, paraconformity
