2771355
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2771355
| Property | Value |
|---|---|
| id | 2771355 |
| igsn | 10273/AU2771355 |
| sample_id | ERIVMAE1615.01 |
| eno | 627025 |
| sampling_feature_name | ERIVMAE1615 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | Claremont Gabbronorite |
| geological_province | Central NSW - Omeo Province |
| sample_remark | Medium- to coarse-grained subequigranular hornblende-rich Claremont Gabbronorite. Dark green amphibole constitutes at least 40% of the rock, and plagioclase laths are up to 10 mm (Eastlake, 2018). In thin section, it comprises plagioclase (58%), hornblende (23%), clinopyroxene and orthopyroxene (12% combined), as well as minor opaque minerals (3%, ilmenite and sulphide minerals), quartz (2%), and accessory apatite and zircon. Andesine plagioclase forms subhedral blades 1-7 mm long with width\:length from 1\:2 to 1\:5. They feature polysynthetic and Carlsbad twining, and zoned outer margins. Hornblende is orange-brown, and forms anhedral interstitial crystals up to 5 mm. Most have ragged patchy cores of clinopyroxene or, less commonly, orthopyroxene. Subordinate brownish-green hornblende forms interstitial crystals, and rims on orange-brown hornblende cores. Accessory apatite forms blades up to 2.7 mm, some of which are 'tubes' featuring hollow cores parallel to the c-axis. Primary hornblende is partly replaced by secondary actinolite and chlorite, and plagioclase is sericite-altered. Rare quartz occurs in the interstices between plagioclase blades, in a vermicular intergrowth with slightly turbid K-feldspar veneers nucleated at plagioclase margins. Some of these interstices also host minor iron-rich chlorite, and carbonate minerals. The Claremont Gabbronorite is a small body, cropping out over an area of about 250 x 150 m. It is surrounded (and hosted) by the 430.4 +/- 2.0 Ma I-type Ellerslie Granodiorite (ERIVMAE1819.01). It was targeted for U-Pb SHRIMP zircon geochronology to establish whether it is associated with intermediate to mafic plutonic rocks of Silurian age to the NE (e.g. Bodorkos et al., 2013\; Glen, 2013\; Bell, 2020), or those of Early Devonian age to the NW and N (e.g. Cairns, 1997\; Black et al., 2003\; 2004\; Fraser et al., 2014\; Waltenberg et al., 2016). |
| 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 | 147.940652 |
| gda94_latitude | -35.26421 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2018-05-10 00:00:00 |
| Links |
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