Table of Contents
- 1 What can make it difficult to determine the age of rock layers?
- 2 Why is it difficult to determine the absolute age of a rock?
- 3 How can Folding change rock layers?
- 4 What is the main problem with using index fossils to determine the age of a rock layer?
- 5 How can we accurately determine the age of a rock or fossil by measuring its?
- 6 How is the age of a rock determined quizlet?
What can make it difficult to determine the age of rock layers?
Movements along faults can make it harder for geologists to determine the relative ages of rock layers.
Why is it difficult to determine the absolute age of a rock?
Determining the absolute age of a sedimentary rock can be quite difficult since a sedimentary rock is formed by different rock particles. Because of this, radioactive dating can only give the age of the particles but not the entire rock.
How do you determine the age of a layer of rock?
Cross dating is a method of using fossils to determine the relative age of a rock. Fossil remains have been found in rocks of all ages with the simplest of organisms being found in the oldest of rocks. The more basic the organism the older the rock is.
What are Unconformities What do we know about their relative age?
An unconformity is a gap in rock layers. They occur where older rock layers eroded away completely before new rock layers were deposited. Other clues help determine the relative ages of rocks in different places. They include key beds and index fossils.
How can Folding change rock layers?
Folding changes rock layers in the following steps:
- Rocks undergo compression when the plates move.
- Compression causes the rock layer to fold.
- The folding continues and causes the rock layer to bend completely over.
- The rocks become completely folded over. The younger rocks are now at the bottom.
What is the main problem with using index fossils to determine the age of a rock layer?
What is the main problem with using index fossils to determine the age of a rock layer? Scientists assign an age to the fossil on the basis of which layer it came from, then apply that same age to layers in other locations where the same fossil occurs. This problematic idea is called circular reasoning.
Why is it difficult to determine the age of our planet?
This makes finding an exact age for Earth difficult, because the original rocks that formed on the planet at the earliest stages of its creation are no longer here. The oldest rocks that have been found are about 3.8-billion years old, though some tiny minerals have been dated at 4.2 billion years.
Why is it difficult to assign a numerical age to a sedimentary rock quizlet?
It may be difficult to assign an exact age to a sedimentary rock because it is made up of many different rocks, therefore, possessing many different ages. How might a numerical date for a layer of sedimentary rock be determined?
How can we accurately determine the age of a rock or fossil by measuring its?
Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.
How is the age of a rock determined quizlet?
A rock’s age based on the number of years since the rock formed. According to the Law of Superposition, in horizontal sedimentary rock layers the oldest layer is at the bottom. To determine relative age, geologists also study extrusions and intrusions of igneous rock, faults, gaps in the geologic record and inclusions.
Why does the age of an inclusion have to be older than the rock in which it is found?
The principle of inclusions and components explains that, with sedimentary rocks, if inclusions (or clasts) are found in a formation, then the inclusions must be older than the formation that contains them. As a result, xenoliths are older than the rock which contains them.