Changes

Once a rock has been collected, zircons are extracted using a series of techniques such as using a [[sieve]], [[heavy liquid]], shaking table, and [[magnetic separation]] to separate minerals based on differing densities and properties. Zircon crystals are then mounted to an epoxy or metal disc-shaped slide,<ref name="Microprobe prep"> "[http://shrimprg.stanford.edu/ Sample Preparation]". SHRIMP RG Sample Preparation. USGS. Retrieved 8 Oct 2014.</ref> where they can be shaved to about half thickness to reveal their internal structure. From here, they can be imaged using [[cathodoluminescence]] to make any zonations in the mineral visible. If zonation is apparent, multiple measurements of Ti abundance can be taken from the center to the rim to give the temperature evolution of the crystal.  

Once a rock has been collected, zircons are extracted using a series of techniques such as using a [[sieve]], [[heavy liquid]], shaking table, and [[magnetic separation]] to separate minerals based on differing densities and properties. Zircon crystals are then mounted to an epoxy or metal disc-shaped slide,<ref name="Microprobe prep"> "[http://shrimprg.stanford.edu/ Sample Preparation]". SHRIMP RG Sample Preparation. USGS. Retrieved 8 Oct 2014.</ref> where they can be shaved to about half thickness to reveal their internal structure. From here, they can be imaged using [[cathodoluminescence]] to make any zonations in the mineral visible. If zonation is apparent, multiple measurements of Ti abundance can be taken from the center to the rim to give the temperature evolution of the crystal.  

The final step involves measuring the abundance of titanium in a specific location on a zircon crystal with an ion microprobe. For this, the chemical compositions of the zircons is measure using [[secondary ion mass spectrometry]]. The sample is bombarded with a beam of primary ions, and the charge and mass of the ejected secondary ions are measured to determine the chemical composition at the point of contact. The quantitative value for titanium content is then compared to a known relationship of titanium incorporation and temperature to determine the crystallization temperature of that zone of the zircon. The titanium-to-temperature relationship was calculated using in situ radiometrically dated zircons with known melt temperatures from the surrounding rock. This Ti-in-zircon measurement can be done several times in zoned zircons, which may record the temperature evolution that resulted from many geologic events.<ref name="Watson Wark Thomas 2006" /><ref name="Watson and Harrison 2005" /><ref name="hoskin and schaltegger, comp of zircon">Hoskin, P.W.; Schaltegger, Urs. "The composition of zircon and igneous and metamorphic petrogenesis". Reviews in Mineralogy and Geochemistry 53 (1): 27–62. doi:10.2113/0530027.</ref>

The final step involves measuring the abundance of titanium in a specific location on a zircon crystal with an ion microprobe. For this, the chemical compositions of the zircons is measure using [[secondary ion mass spectrometry]]. The sample is bombarded with a beam of primary ions, and the charge and mass of the ejected secondary ions are measured to determine the chemical composition at the point of contact. The quantitative value for titanium content is then compared to a known relationship of titanium incorporation and temperature to determine the crystallization temperature of that zone of the zircon. The titanium-to-temperature relationship was calculated using in situ radiometrically dated zircons with known melt temperatures from the surrounding rock. This Ti-in-zircon measurement can be done several times in zoned zircons, which may record the temperature evolution that resulted from many geologic events.<ref name="Watson Wark Thomas 2006" /><ref name="Watson and Harrison 2005" /><ref name="hoskin and schaltegger, comp of zircon">Hoskin, P. W., & U. Schaltegger, The composition of zircon and igneous and metamorphic petrogenesis". Reviews in Mineralogy and Geochemistry 53 (1): 27–62. doi:10.2113/0530027.</ref>

==Uses==

==Uses==