2771363
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2771363
| Property | Value |
|---|---|
| id | 2771363 |
| igsn | 10273/AU2771363 |
| sample_id | ERIVLMC0946.01 |
| eno | 628632 |
| sampling_feature_name | ERIVLMC0946 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | None |
| geological_province | Central NSW - Omeo Province |
| sample_remark | Greenish-white porphyritic rhyolite, featuring phenocrysts of quartz and feldspar up to 3 mm long in a very fine-grained siliceous groundmass. In thin section, this porphyritic rhyolite contains relatively sparse phenocrysts (10-12%) 1-3 mm in length, comprising quartz (5%), plagioclase (3%), and less commonly, K-feldspar (1-2%). Rare ferromagnesian phases are prismatic and finer-grained (less than 1 mm), and probably represent primary amphibole that has been altered to iron oxides, clay minerals and sericite. The groundmass comprises sericite and fine-grained quartzofeldspathic material in a recrystallised granophyric texture. The rhyolite is associated with very weathered metasedimentary rocks (brown claystone, mudstone and sandy mudstone, coarse-grained lithic sandstone, and clast-supported conglomerate featuring fine-grained lithic fragments as granules and small pebbles); however, the relationship between the rhyolite and the enclosing metasedimentary rocks is unclear. A pavement exposure on the northern verge of Stanyer Road shows a sharp contact between the two rock types, so their juxtaposition could be structural rather than stratigraphic. Warren et al. (1995) mapped the metasedimentary rocks as Combaning Formation, which is locally fossiliferous in exposures farther north, and contains a faunal assemblage indicating a latest Silurian to earliest Devonian age (Sherwin, 1986). If the stratigraphic assignment of the sedimentary rocks is correct, and rhyolite eruption was coeval with deposition of the sedimentary rocks, a magmatic crystallisation age of c. 420-415 Ma is indicated for the rhyolite. |
| 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 | 147.68599 |
| gda94_latitude | -34.805382 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2018-05-11 00:00:00 |
| Links |
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