2612798
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2612798
| Property | Value |
|---|---|
| id | 2612798 |
| igsn | 10273/AU2612798 |
| sample_id | ERIVKFB0213.01 |
| eno | 600707 |
| sampling_feature_name | ERIVKFB0213 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | Soldiers Quarry Member |
| geological_province | Central NSW - Omeo Province |
| sample_remark | Coherent, crystal-rich and coarse-grained porphyritic dacite. In thin section, it features evenly distributed K-feldspar megacrysts up to 4 cm long. Some are pink, most are perthitic and altered to clay minerals, and many exhibit overgrowths. Phenocrysts total about 35% of the rock, and include 5% quartz (1-7 mm, and commonly embayed), 5% plagioclase (3-10 mm, and variably sericite-altered), and 10% biotite (0.5-4 mm, and altered to chlorite and opaque oxide minerals), as single crystals, or in glomerophyric clusters. In addition to K-feldspar, both quartz and plagioclase crystals exhibit overgrowths, and plagioclase is sericite-altered. The groundmass is recrystallised in a granoblastic texture. This texture and the crystal overgrowths suggest the unit has been contact metamorphosed (Bull, 2017). The unit is part of the Soldiers Quarry Member, which is the sole coherent volcanic unit recognised within the predominantly volcaniclastic quartz- and garnet-bearing S-type Budginigi Ignimbrite (Bull, 2017). The Budginigi Ignimbrite, and the I-type, amphibole-bearing 412.6 +/- 2.5 Ma Wallandoon Ignimbrite (Bull, 2017; see also GSNSW ERIVKFB0141.01), together make up the Early Devonian Culcairn Group. The southern exposures of Budginigi Ignimbrite have previously been dated: one sample from Big Budginigi Hill (about 40 km S of Soldiers Quarry) yielded U-Pb SHRIMP dates of 415.0 +/- 2.3 Ma from zircon and 412.8 +/- 3.5 Ma from monazite (Bodorkos et al., 2016), and a second crystal-rich ignimbrite, E of the Great Yambla Range (about 30 km S of Soldiers Quarry) yielded a U-Pb SHRIMP zircon date of 413.6 +/- 2.2 Ma (GSNSW ERIVKFB0308.01). The Budginigi Ignimbrite N of the township of Culcairn (including the Soldiers Quarry Member and the spatially associated but undivided volcaniclastic facies) have not previously been dated, although it is likely these too are Early Devonian in age. |
| structural_measurements | None |
| inorganic_geochemistry | None |
| organic_geochemistry | None |
| geochronology | Y |
| isotope_groups | None |
| hydrochemistry | None |
| rock_properties | None |
| mineralogy | Y |
| 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 | 147.053538 |
| gda94_latitude | -35.61047 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2016-04-21 00:00:00 |
| Links |
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