Geochronology enables us to determine the age of rocks and minerals. The variety of isotopic geochronological techniques give complementary information on, for example, the timing of igneous or metamorphic crystallisation, as is often the case for...
Geochronology enables us to determine the age of rocks and minerals. The variety of isotopic geochronological techniques give complementary information on, for example, the timing of igneous or metamorphic crystallisation, as is often the case for the U/Pb zircon technique, or the timing of cooling of a mineral through a given 'closure' temperature, as may be the case for the 40Ar/39Ar technique. The basis of isotope geochronology is the naturally occurring decay of unstable 'parent' radionuclides to stable 'daughter' isotopes. Utilising our knowledge of the length of the half-lives of different radioactive isotopes, we are able to calculate the time since a particular daughter isotope began to accumulate within the rock or mineral. Since the ability to understand the temporal evolution of rock systems is of fundamental importance, a complete geochronology database is a powerful tool. The Gawler Craton occupies much of central South Australia, and is comprised of Late Archaean to Mesoproterozoic rocks. The Gawler Craton contains some highly prospective rock systems, for example the Olympic FeO-Cu-Au Province, the Central Gawler Gold Province, and the Harris Greenstone Belt, and is thus of critical economic importance to South Australia. For details on the geology and geochronology of the Gawler Craton the reader is referred to: Drexel et al. (1993), Daly et al. (1998) and Fanning et al. (2007). The present compilation provides a collation of all publicly available geochronology obtained from across the Gawler Craton, enabling users to trace original references and to rapidly compare results between different localities and samples. Samples analysed via U/Pb and 40Ar/39Ar techniques are included in this compilation. The U/Pb data includes data obtained via the Kober (Pb/Pb), SHRIMP and ID-TIMS techniques, and via U/Th/Pb electron microprobe chemical analysis. The compilation is divided into sections, depending upon the mineral analysed and the method used, with sections laid out for zircon, monazite, titanite and apatite U/Pb geochronology, and for 40Ar/39Ar geochronology. For details on the different methods the reader is referred to Fanning et al. (2007), which provides a summary of the different U/Pb techniques. For details on the 40Ar/39Ar method see McDougall and Harrison (1999). In this compilation a summary of the age results are given, with all interpretations being summarised from the original data sources. Descriptions of each sample and sample context have been abbreviated from the original source, and every effort has been made to ensure that the abbreviated descriptions contain the most salient points for each sample. The samples are presented in order of date of publication, with the earliest published data being presented first. Note that in the case of PIRSA rock samples where a 'RS' number was originally given, this identifier has been retained in the compilation, with the later designated 'R' number being indicated in brackets. Lastly, an earnest request to users of this compilation is here made: if you know of any data that are not included within this compilation which could be, please bring such deficiency to the attention of the compiler, as every effort is being made to make the dataset as complete as possible.
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