2678313
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2678313
| Property | Value |
|---|---|
| id | 2678313 |
| igsn | 10273/AU2678313 |
| sample_id | NSWSJAF0171.01A |
| eno | 621275 |
| sampling_feature_name | DD98CL003 |
| sampling_feature_type | borehole |
| sample_type | core |
| sampling_method | core diamond |
| material_class | rock |
| stratigraphic_unit | Wild Wave Granodiorite |
| geological_province | Lachlan Orogen |
| sample_remark | This sample was taken from diamond drillhole DD98CL003 (168-170 m) in the Lucknow inlier locality NE of Cobar. It is a coarse-grained I-type granodiorite, comprising quartz, plagioclase, K-feldspar and biotite, with accessory apatite, magnetite and zircon. The granodiorite is fairly uniformly altered (sericite, carbonate, chlorite, epidote, talc) and sulfides are disseminated throughout some parts of the body. In drillcore, the granodiorite is interpreted to intrude metasedimentary rocks of the Ordovician Girilambone Group, and the granodiorite is directly overlain by unmetamorphosed limestone of the lowermost Cobar Basin, which in turn is overlain by a conglomerate package containing cobble- to pebble sized clasts of granodiorite. The relative age relationships suggest that the unroofed granodiorite was available for erosion and deposition into the latest Silurian to earliest Devonian basal Cobar Basin, which in turn indicates a minimum Late Silurian age for emplacement of the pluton into the Girilambone Group. This is inconsistent with the biotite Rb-Sr age of 418 +/- 2 Ma obtained for the Wild Wave Granodiorite by Glen et al. (1983); however, more recently, an unnamed tonalite intruding the Girilambone Group about 9 km to the north yielded a U–Pb SHRIMP zircon age of 424.9 +/- 2.0 Ma (Jones et al., 2020). In thin section, this porphyritic biotite granodiorite features plagioclase and quartz phenocrysts 1-2 mm long, with lesser K-feldspar and chlorite-carbonate-replaced igneous biotite (no primary biotite is preserved). The fine-grained (0.1-0.2 mm) matrix is dominated by equigranular quartz and feldspar, and K-feldspar also forms poikilitic intergrowths throughout the matrix. Plagioclase is invariably clouded with abundant sericite. Secondary carbonate minerals are locally abundant. |
| 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 | 145.924609 |
| gda94_latitude | -31.466139 |
| sample_originator | Geological Survey of New South Wales (GSNSW) |
| date_acquired | 2017-08-30 00:00:00 |
| Links |
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