Dating on earth wiki
Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another.
Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials.
Techniques include tree rings in timbers, radiocarbon dating of wood or bones, and trapped charge dating methods such as thermoluminescence dating of glazed ceramics.
Coins found in excavations may have their production date written on them, or there may be written records describing the coin and when it was used, allowing the site to be associated with a particular calendar year.
For graduate school, they both attended the University of Iowa, where he was awarded an M. After World War II, the Pattersons returned to Chicago, where Laurie took a research job as an infrared spectroscopist to support Patterson while he studied for his Ph. When Patterson returned to the University of Chicago to work under his research adviser Harrison Brown, Brown, knowing about Patterson's experience with mass spec, teamed him up with George Tilton to do geological aging on zircons.
The Earth's magnetic field has two main components.
Within these weaker areas the local directions and intensities change gradually (secular variation).
A compass does not point to the true North Pole but to direction that is a function of the North Magnetic Pole and the local secular variation to yield a magnetic declination.
The direction and magnitude of the magnetic field of the Earth at a particular location varies with time, and can be used to constrain the age of materials.
In conjunction with techniques such as radiometric dating, the technique can be used to construct and calibrate the geomagnetic polarity time scale.
The Permian through Jurassic stratigraphy of the Colorado Plateau area of southeastern Utah is a great example of Original Horizontality and the Law of Superposition, two important ideas used in relative dating.