2172120
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2172120
| Property | Value |
|---|---|
| id | 2172120 |
| igsn | 10273/AU2172120 |
| sample_id | BB5472 |
| eno | 577536 |
| sampling_feature_name | BB5472 |
| 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 | The sample was collected from a thick, subvertical bed of dark grey sandstone on the eastern bank of Limestone Creek, on the downstream side of the road to Groganville (abandoned site). These rocks form part of subunit Dhr3, which consists of thin to medium-bedded sandstone, siltstone and mudstone, with scattered thicker (up to 50 cm thick) sandstone beds. It is extensively deformed, particularly the mudstone-rich parts, which show 'broken formation' development in places. The unit forms part of a belt up to 2.5 km wide extending for 40 km from south of the Mitchell River north-northwestwards towards the Palmer River. It was originally mapped as part of informal subunit Dham (Bultitude et al. 1998), but was subsequently delineated as a discrete subunit based on airborne radiometric imagery, where its distinctive dark tones on ternary radiometric images contrast markedly with the paler tones of the adjacent Hodgkinson Formation rocks. The average grainsize of the framework components is 0.5 mm, with most grains in the 0.1-0.6 mm range. A noteworthy feature is the presence of a minor component of larger grains in the 1-2 mm size range; polycrystalline quartz grains are relatively common in this population. Most framework grains are angular to subangular, with some subrounded to rounded grains. Quartz, as monocrystalline grains showing undulose extinction, is the dominant framework mineral (70%). The sandstone also contains minor plagioclase (generally only slightly sericitised), detrital muscovite and lesser biotite, scarce K-feldspar, polycrystalline quartz, and chlorite (at least some of which replaces biotite), rare calcite, and accessory zircon and tourmaline. Detrital micas show undulose extinction, and cleavage planes are commonly curved or bent. Lithic fragments (up to 1.5 mm) are scarce (<5%) and consist mainly of mudstone, siltstone, chert, and schist. Intraformational mudstone fragments form the largest clasts. Matrix components make up 15-20% of the rock. |
| 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 | 144.320864 |
| gda94_latitude | -16.4622245 |
| sample_originator | Kositcin, N. |
| date_acquired | None |
| Links |
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