 Other information to be coupled with age of zircon  Need to be done in-situ, so analysis can be performed on the same spot or very near;  Provide additional information on physical conditions or petrogenesis of the source rocks.

 Radiogenic isotopes – Hf isotopes (model ages and time of extraction from mantle)  Stable isotopes – Oxygen isotopes – contributions from pre-existing crust;  Temperature from Ti-thermometers – physical conditions of zircon formation  Other (less common) – REE distributions other trace elements.

 Radiogenic isotopes (Lu-Hf decay) similar in behavior to Nd isotopes; less used conventionally;  The great advantage of Hf isotopes is that they can be measured in situ via laser ablation using MC-ICP-MS  Zircons have high Hf, low Lu concentrations;  Newer setups (with two instruments) can utilize split-stream technology to measure age and Hf isotopes simultaneously.

 Usually expressed as Epsilon Hf units, just like Nd isotopes;  Positive  (Hf) values reflect primitive mantle sources, whereas lower values, sometimes highly negative, are indicative of old crustal components;  Model ages represent approximate values of extraction from a mantle reservoir (such as DM or CHUR), and broadly represent lithospheric residence ages.

Zhang et al., 2014, Lithos

 Zircon  18 O is a good indicator of pre-existing crust, just like quartz or other rock-forming minerals are in igneous rocks  Zircon is in some ways better because is not prone to secondary modifications  Mantle  18 O=5.5 permil (relative to SMOW)  Crustal values are anywhere from 6 to 15  Complementary tool to Hf isotopes, strictly identifies pre-existing crust.

 Zircon  18 O need not be measured in-situ and is a common tool for igneous petrogenesis;  In provenance studies, the strategy is to measure oxygen isotopes in conjunction with age, Hf isotopes etc;  In-situ oxygen isotopes are being measured with high precision on small (few micron) spots using SIMS and equivalent instruments.

 Calibrated in the 1980s with major improvements over the past 5 years  Ti concentration (measurable in-situ by SIMS) is directly proportional to the temperature of zircon formation;  Spots dated by ICP can be assigned a physical property, namely temperature.  Published papers show zircon grew in the age range anywhere from 350 to >1000 C.

 Ti concentration is directly proportional to the crystallization temperature (various calibrations, but mostly due to Harrison and Watson);  Measurement can be performed by SIMS at very fine scale, microns.

 Mantle-like, primitive Hf and  18 O  Temperatures are C, relatively low  Zircons from these rocks indicate that silica differentiation here took place by closed system fractionation of some mantle-derived basalts.