Unit 5 Lecture 2: Absolute Dating
1-organism dies 2- covered with layers of sediment 3-sediment turns into rock. what is relative dating? using the law if superposition and fossils to come up with a rough idea or sequence of events in earths history. what is absolute dating? using radioactive elements to calculate the date. more accurate than relative dating. any method of determing whether an event or object is older or younger than other events or objects. superposition. A principle that states that younger rocks lie above older rocks if the layers have not been disturbed. geologic column. an arrangement of rock layers in which the oldest rocks are at the bottom. absolute dating. Rates of Deposition. By studying rates of deposition, scientists can estimate absolute age. Not always accurate because rates changes over time or within depositional events. Varve. A banded layer of sand and silt that is deposited annually in a lake. Coarse summer layers and an overlaying fine layer. Radiometric Dating.
Some images used in this set are licensed under the Creative Commons through Flickr. Click to see the original works with their full license. What is Relative Dating? What is Law of superposition? What is an unconformity? Describe the three types of unconformities.
What does extinct mean? What is a fossil? How organisms change over a period of time. What type of rocks contain fossils?
Absolute or Chronometric Dating. Click to view the picture. The space is sometimes filled with mud.
How do most fossils form? Organism dies and is buried by sediment that hardens into rock.
What is the process where minerals replace all or most of an organisms body parts? What are the two most common types of fossils?
Absolute dating methods (ANT)
Takes the same shape of the plant or animal. The space is sometimes filled with mud. The mud hardens and turns into rock. These are not hollow. Looks like the shape of the living thing carved into a rock.
The inside of the sedimentary rock is a hollow space that takes the shape of the once living thing. Fossil that records behaviors or activities of an organism. Fossil where the delicate parts of the organism are preserved. What substances will preserve original remains? Fossils that have not been permineralized, and are not casts, molds, or link fossils.
Preserved fossils or original remains. What is radioactive decay? Unstable nuclei break apart and release energy. What is a half-life? The amount of time is takes for one-half of the parent substance to decay into daughter product.
What is radiometric dating? What kinds of rocks can we perform radiometric dating on?
What is radiocarbon dating? Using the decay of Carbon parent to get the absolute age organic objects ie. What is an isotope? Same element with different numbers of neutrons.
What is the difference between relative age and absolute age? Relative age is saying a rock layer is older than the one above it and younger than the one below.
Finding the absolute age of a sample by determining the relative percentages of a radioactive parent isotope and stable daughter isotope. A banded layer of sand and silt that is deposited annually in a lake. What are the two most common types of fossils?
Absolute age is placing an approximate date on the rock such as 4. Can scientists use radiometric dating to determine the absolute age of sedimentary rocks? We must relate them to other layers surrounding the sedimentary layer. What is the Law of Original Horizontality? Sedimentary layers tend to be laid down in flat layers.
What is the Law of Crosscutting Relationships? If a geologic feature cuts across another feature or layer, then that other feature is older and was there first. Upgrade to remove ads.
Relative Dating/Absolute Dating