2678312
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2678312
| Property | Value |
|---|---|
| id | 2678312 |
| igsn | 10273/AU2678312 |
| sample_id | NSWSJAF0173.01A |
| eno | 621277 |
| sampling_feature_name | DD12NV0016 |
| sampling_feature_type | borehole |
| sample_type | core |
| sampling_method | core diamond |
| material_class | rock |
| stratigraphic_unit | None |
| geological_province | Cobar Basin |
| sample_remark | This sample of I-type quartz diorite was taken from diamond drillhole DD12NV0016 (159.75-162.0 m), where it intrudes polymictic pebble- to cobble-conglomerate of the earliest Devonian Shume Formation, in the Amphitheatre Group of the Cobar Supergroup (MacRae, 1987). The quartz diorite is part of a compositionally complex high-level stock of I-type granodiorite, diorite and miarolitic leucosyenogranite emplaced along a NNE-oriented fault (Fitzherbert et al., 2017). Deeper in the drillhole, the succession is intruded by cordierite-biotite granite (336.4-338.1 m) and coarse-grained S-type granite (445.05-445.75 m). Primary skarn mineralisation is of calcic iron–copper type, and although it is best characterised in a drillhole several kilometres NW of DD12NV0016, the skarn chemistry is consistent with a causative pluton of I-type composition (similar to the sampled quartz diorite) at depth (Fitzherbert et al., 2017). Thus it is possible that the quartz diorite constrains the timing of skarn mineralisation, consistent with previous work in the southern Cobar Basin (e.g. Mallee Bull; Brown et al., 2013; 2015) which suggested a link between mineralisation and high-level I-type intrusions along NNW-trending faults associated with the Rookery Fault (Fitzherbert et al., 2017). In thin section, this rock comprises interlocking calcic plagioclase and hornblende-rimmed clinopyroxene and orthopyroxene, 1-2 mm in size. Plagioclase (45%) forms euhedral, compositionally zoned laths with calcic cores (featuring weak sericite-epidote alteration) and pronounced sodic rims. Clinopyroxene and orthopyroxene (35-40%) occur in equal proportions, as euhedral lath-shaped grains invariably rimmed by yellow-green to olive green-brown hornblende. Opaque oxide minerals (7%) are anhedral to skeletal to sub-graphic, and are invariably enveloped by a narrow rim of biotite. Quartz (7-10%) is interstitial and associated with sodic plagioclase, K-feldspar and fine acicular apatite needles. |
| earth_materials | Y |
| 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 | 145.9908502 |
| gda94_latitude | -32.1890282 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2017-08-30 00:00:00 |
| Links |
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