2172122
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2172122
| Property | Value |
|---|---|
| id | 2172122 |
| igsn | 10273/AU2172122 |
| sample_id | BB5469 |
| eno | 577538 |
| sampling_feature_name | BB5469 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| stratigraphic_unit | Hodgkinson Formation |
| geological_province | Hodgkinson Province |
| sample_remark | This sample was collected from an outcrop in a belt of Hodgkinson Formation rocks assigned to informal subunit Dham. This belt forms a major, northerly trending zone, 15-20 km wide and 100 km long, distinguished from nearby subunits to the west by paler tones on ternary radiometric images. The belt was sampled for zircon geochronology to determine if it contains relatively young zircons (anticipated from its easterly position), and to compare the resultant detrital zircon age spectrum with the spectra yielded by samples collected from other subunits in the formation. The sample was collected from a thick, subvertical sandstone bed exposed in the bed of a tributary of the Mitchell River, on the downstream side of the crossing of the main road to Groganville (abandoned site). The sandstone contains scattered grains of detrital muscovite, and is interlayered with an assemblage of mainly thin- to medium-bedded, finer grained sandstone, siltstone and mudstone. The sandstone is dark grey, fine- to coarse-grained (0.1-0.6 mm, average 0.3 mm), and poorly sorted, with 15-20% matrix. Most grains are angular to subangular, with some subrounded to rounded grains. Quartz, as monocrystalline grains, is the dominant framework mineral (70%). Many of the grains are characterised by only slightly undulose extinction (in contrast to many of the other sandstones analysed from the formation) and a few have subhedral outlines, suggesting a volcanic origin. The sandstone also contains minor (8%) plagioclase (generally only slightly altered), K-feldspar, detrital muscovite and polycrystalline quartz grains, and accessory chlorite, zircon, and tourmaline. Detrital muscovite shows undulose extinction, and cleavage planes are commonly curved or bent. The sandstone also contains minor calcite, and sparse (2-3%), small (up to 0.6 mm) clasts of very fine-grained schist, chert, mafic volcanics, mudstone, ribbon quartz, and quartzite. Sericite is common in the matrix. |
| earth_materials | Y |
| structural_measurements | None |
| inorganic_geochemistry | Y |
| organic_geochemistry | None |
| geochronology | Y |
| isotope_groups | None |
| hydrochemistry | None |
| rock_properties | None |
| mineralogy | None |
| thin_sections | None |
| repository_samples | Y |
| mineral_deposit_samples | None |
| mineral_deposit_waste_samples | None |
| linked_files | None |
| other_geological_data | None |
| project_name | None |
| gda94_longitude | 144.5933509 |
| gda94_latitude | -16.6064072 |
| sample_originator | Kositcin, N. |
| date_acquired | None |
| Links |
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