9964923
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU9964923
| Property | Value |
|---|---|
| id | 9964923 |
| igsn | 10.60494/bnh7-hy79 |
| sample_id | BB6080 |
| eno | 929479 |
| sampling_feature_name | KASO_0048_1 |
| sampling_feature_type | borehole |
| sample_type | core |
| sampling_method | core conventional |
| material_class | rock |
| stratigraphic_unit | solid geology unit Pv |
| geological_province | None |
| sample_remark | The rhyolite is extensively altered (kaolinised, chloritised) and devoid of obvious macroscopic fabrics or structures, apart from variations in the abundance of crystals and crystal size. Rhyolite intersected in the upper part of the basement interval, from ca 86.1 m to 89.5 m, has a very fine-grained groundmass with scattered relatively small quartz and sparse, altered feldspar crystals compared to rhyolite intersected from ca 89.5 m to EOH. The latter contains prominent, relatively coarse, white and scarce pale pink K-feldspar crystals, as well as glassy quartz grains. Many of the K-feldspar crystals are angular and probably represent broken juvenile grains. Zircon grains are euhedral-subhedral, show no evidence of rounding, and commonly also represent broken fragments; some show bipyramidal terminations typical of igneous zircons. Observed variations in crystal content, size, and shape imply the rhyolite is a primary pyroclastic (fine ash) deposit. and is referred to here as a crystal tuff. The tuff is pervasively altered and is relatively soft, but coherent. Clay minerals (kaolinite, halloysite?), chlorite, and a black, unidentified mineral are common. The black mineral is particularly abundant in the upper metre or so of the basement interval — as discrete grains dispersed throughout the groundmass, as aggregates of numerous small grains, and as grains concentrated in thin veinlets. Feldspar grains are extensively kaolinised and kaolin forms irregular lenses and scattered patches up to ca 2 cm thick. Tuff examined in detail contains ca 15-20% crystals and rare, small lithic fragments. Quartz grains are commonly euhedral-subhedral and embayed, and many retain vestiges of an original bipyramidal habit indicating they are probably juvenile grains. The smaller angular quartz grains are thought to represent broken fragments of larger grains. |
| earth_materials | Y |
| structural_measurements | None |
| inorganic_geochemistry | None |
| organic_geochemistry | None |
| geochronology | Y |
| 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 | 143.3957823 |
| gda94_latitude | -17.6500988 |
| sample_originator | Bultitude, R.J. |
| date_acquired | None |
| Links |
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