Diagnostic analysis of zircon by in-situ isotopic microbeam analysis

Abstract

Although U-Pb isotopic analysis of zircon is well established for constraining the timing of high-temperature geological events, chronological data are often open to multiple interpretations. However, dating is not the only tool in the microbeam analyst's kit; such methods have the unique ability to measure a variety of other elements (e.g. Ti, Hf and REEs), on a sub-30 micron scale, in polished sections that preserve paragenetic mineral relationships. Three unusual examples demonstrate the diagnostic value of such information. Microbeam analysis of zircon with diagnostic chemical and textural relationships to host lithologies makes the assignation of age data to geological events far from arbitrary.