9655250
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU9655250
| Property | Value |
|---|---|
| id | 9655250 |
| igsn | 10.60494/39xr-1e16 |
| sample_id | 779-5 |
| eno | 912545 |
| sampling_feature_name | 779-5 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| stratigraphic_unit | Reedy Creek Granodiorite |
| geological_province | Delamerian Orogen |
| sample_remark | Foden et al. (2006): Zircons were separated from the strongly foliated granodiorite (01RC183) and undeformed diorite (779-5) whose emplacement brackets the terminal Delamerian D3 deformation at Reedy Creek. The larger zircons from the diorite (779/5) have very similar morphologies to those from the granodiorite (01RC183), indicating possible inheritance, and are consistent with the observed disaggregation of granodiorite blocks collapsed into the intruding diorite. To minimize the possibility of analyzing inherited xenocrysts, only small acicular zircons (a morphology not present in the granodiorite) were analyzed. Individual acicular crystals did not supply sufficient Pb for analysis, so several (6-10) were loaded into each filament. Seven filaments were analyzed in a total of 37 heating steps. Of these, 26 gave age errors of <2% (<10 Ma) and were used in the age calculations. Analysis of the Pb evaporated from the diorite during each of the heating steps give a very well-defined age plateau with a younger limit of 489 +/- 5 Ma and an older limit at 493 +/- 4 Ma. The mean value of the ages forming this plateau is 491 +/- 1 Ma (2sigma). By selecting a single morphological zircon type, our results have successfully isolated a single phase of zircon crystallization for the Reedy Creek diorite. The range within the age–heating step plateau (5 Ma) represents a good example of the degree of reproducibility anticipated in the analysis of single-stage Cambrian zircons by the evaporation technique. However, it is clear that despite the data quality, the granodiorite and crosscutting diorite have identical ages within error. This (492 +/- 2 Ma) must also therefore be the age of the terminal D3 Delamerian deformation at Reedy Creek and is the same as that of the younger magmatic event affecting the Monarto granite south of Reedy Creek. |
| earth_materials | Y |
| structural_measurements | None |
| inorganic_geochemistry | None |
| organic_geochemistry | None |
| geochronology | None |
| isotope_groups | None |
| hydrochemistry | None |
| rock_properties | None |
| mineralogy | None |
| thin_sections | None |
| repository_samples | None |
| mineral_deposit_samples | None |
| mineral_deposit_waste_samples | None |
| linked_files | None |
| other_geological_data | None |
| project_name | None |
| gda94_longitude | 139.2170028 |
| gda94_latitude | -34.9286749 |
| sample_originator | Foden, J.D. |
| date_acquired | 3000-01-01 00:00:00 |
| Links |
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