Granite age for Scottish highlands
http://www.sciencecourseware.org/VirtualDatingDemo/files/10_IsochronPreCertificate.html
http://en.wikipedia.org/wiki/Geology_of_Scotland
To determine the age of granite in the Scottish Highlands, we need to consider the geological history of the region. The Scottish Highlands primarily consist of rocks from the Caledonian Orogeny, a long-lasting mountain-building event that occurred during the Paleozoic Era. Granite is an intrusive igneous rock formed from the slow cooling and solidification of magma beneath the Earth's surface.
To estimate the age of the granite in the Scottish Highlands, geologists use a method called radiometric dating, specifically using the decay of isotopes. One commonly used radiometric dating technique is potassium-argon (K-Ar) dating.
Here's how it works: Potassium (K) is a naturally occurring element with an isotope called potassium-40 (K-40). Over time, K-40 decays into argon-40 (Ar-40) at a known rate. By measuring the amount of K-40 and Ar-40 in a rock sample, scientists can calculate how long it has been since the rock crystallized from magma.
To date the granite in the Scottish Highlands, geologists collect samples of the rock, typically using a hammer and chisel. These samples are then taken to a laboratory, where they undergo various tests, such as mineral separation and preparation for analysis.
In the case of K-Ar dating, the rock sample is crushed into smaller pieces and heated to release the gases trapped within the minerals. These gases are then analyzed using a mass spectrometer to determine the ratio of potassium to argon isotopes. Based on this ratio and the known decay rate of K-40, scientists can estimate the age of the granite.
It is important to note that dating the granite in the Scottish Highlands is a complex process, and scientists often use multiple dating methods to cross-validate their results. Additionally, the age of the granite can vary across different locations within the Scottish Highlands, so multiple samples may need to be collected and analyzed to get a comprehensive picture of the region's granite age.