2771351
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2771351
| Property | Value |
|---|---|
| id | 2771351 |
| igsn | 10273/AU2771351 |
| sample_id | ERIVMAE1365.01 |
| eno | 628622 |
| sampling_feature_name | ERIVMAE1365 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | Belmore Granite |
| geological_province | Central NSW - Omeo Province |
| sample_remark | Weakly foliated inequigranular biotite granite featuring euhedral milky-white plagioclase phenocrysts up to 12 mm long. Clustered biotite plates constitute about 20% of the rock, and are moderately aligned to define a weak NW-trending tectonic foliation. The granite hosts rare microgranitic enclaves with diffuse margins, biotite-rich surmicaceous enclaves, and lumps of xenolithic quartz (Eastlake, 2018). In thin section, it comprises quartz (45%), plagioclase (28%), biotite (20%), K-feldspar (5%) and muscovite (4%), with accessory apatite and zircon. Plagioclase crystals are 1-5 mm long; most show distinct compositional zoning, and in some cases a weak cellular texture. Fine-grained secondary sericite is developed in some cores. Quartz shows sutured quartz-quartz boundaries and subgrain development. Discontinuous trails of aggregated red-brown biotite (individual crystals 0.5-4 mm) define a weak secondary foliation. Most biotite is stippled with radiogenic inclusions, and apatite and secondary iron-rich chlorite is sparsely developed along biotite cleavage planes. Fine-grained primary muscovite (less than 0.5 mm) is typically associated with biotite. Potassium-feldspar forms rare interstitial crystals with a weak dusting of secondary clay minerals. Minor myrmekite replacements are locally present at crystal margins. This biotite granite is the primary constituent of the Belmore Granite, an S-type granite of the Tom Groggin Suite, within the Koetong Supersuite (Chappell et al., 1991). This elongate (14 x 3 km) pluton underlies a narrow NNW-trending valley that parallels Westbrook Road in the SE corner of the Tarcutta 1:100 000 area (Eastlake, 2018). The Belmore Granite chemically and petrographically resembles the nearby S-type Green Hills Granodiorite (428.3 +/- 2.1 Ma; Bodorkos et al., 2015). The 414.2 +/- 2.3 Ma Caloola Dacite (ERIVMAE1815.01) crosscuts the S part of the Belmore Granite, and provides a minimum age for the pluton. |
| structural_measurements | None |
| inorganic_geochemistry | Y |
| 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 | 147.846212 |
| gda94_latitude | -35.441768 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2018-05-08 00:00:00 |
| Links |
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