2172121
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2172121
| Property | Value |
|---|---|
| id | 2172121 |
| igsn | 10273/AU2172121 |
| sample_id | BB5484 |
| eno | 577537 |
| sampling_feature_name | BB5484 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| stratigraphic_unit | Kitoba Member |
| geological_province | Hodgkinson Province |
| sample_remark | The sample is from a prominent outcrop of massive grey sandstone on the western side of the Burke Developmental Road, in the far west of the Hodgkinson Formation <200 m from the contact with the Chillagoe Formation. The Kitoba Member is distinguished by prominent thick, amalgamated intervals of coarse-grained sandstone, implying that the western Hodgkinson Province was more proximal to source than the central part. The Kitoba Member is the westernmost subunit in the Hodgkinson Formation. It is faulted against the Chillagoe Formation to the west and the OK Member to the east. The age of the member is unknown, but may be only slightly younger than (or even contemporaneous with) the Chillagoe Formation. The Kitoba Member is interpreted to represent the base of the Hodgkinson Formation in this part of the province, and was sampled for geochronology to determine if its maximum depositional age supports this interpretation. The sandstone contains a range of lithic clasts (including mudstone, siltstone, fine-grained sandstone, quartzite, muscovite schist, ribbon quartz, rare mafic volcanics and rare myrmekite) up to 3 cm across, and is poorly sorted (0.3-4 mm; average 1 mm), with 10% matrix. Framework clasts are angular to subangular and dominated by monocrystalline quartz (60%) and little-altered feldspar (15-20%) comprising plagioclase and K-feldspar in equal amounts. Some K-feldspar grains are coarse (up to 4 mm), with subhedral outlines and well-preserved crystal shapes, implying they have not been transported far. The sandstone contains minor lithic fragments (5%), micas (5%; mainly muscovite, but also biotite replaced by chlorite), polycrystalline quartz (3%), and accessory zircon, titanite and tourmaline. The matrix comprises quartz, feldspar, sericite, chlorite and epidote. Monocrystalline quartz invariably shows undulose extinction. Muscovite is deformed, with undulose extinction and curved or bent cleavage planes. Some plagioclase grains have curved twin planes. |
| 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 | 144.1535531 |
| gda94_latitude | -16.8015136 |
| sample_originator | Kositcin, N. |
| date_acquired | None |
| Links |
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