Visualizing, interpreting and comparing detrital zircon age and Hf isotope data in basin analysis – a graphical approach

The development of fast and reliable instrumental methods for U-Pb dating and Lu-Hf isotope analysis of zircon has caused detrital zircon to become a popular provenance indicator for clastic sediments and an important tool in basin analysis. In parallel with the increasing ease of access to data, advanced methods of data interpretation have been developed. The downside of some techniques for visualization and comparison of detrital zircon distribution patterns is that the results are difficult to relate to what the zircon grains really record: The age and nature of geological processes in a protosource terrane. Some simple methods of data presentation and inter-sample comparison that preserve a direct and intuitively understandable relationship between the data and the age of zircon-forming processes in the protosource are proposed here: Comparison of confidence intervals around empirical, cumulative distribution curves combined with the use of a plot of upper vs. lower quartile values of cumulative zircon U-Pb age or Lu-Hf model age distributions. This approach allows a robust and transparent separation to be made between samples whose detrital zircon distributions are indistinguishable from each other, and those that are more or less similar. Furthermore, it allows simple comparison between detrital zircon distributions and the geological age record of potential protosource terranes, or the detrital zircon distributions of possible sedimentary precursors.