{ "type":"Feature", "geometry":{ "type":"Point", "coordinates":[ 141.09158, -32.591466, 150.18168 ] }, "properties":{ "igsn":"10.60494/ham3-0614", "sample_id":"2023330028", "eno":867066, "sampling_feature_name":"NDILLK12", "sampling_feature_type":"borehole", "sample_type":"half core", "sampling_method":"core drilling", "material_class":"rock", "stratigraphic_unit":null, "geological_province":"Delamerian Orogen", "sample_remark":"Mole et al. (2024): Drillhole NDILLK12 samples a NE-trending zone of mostly non-magnetic sedimentary rocks (of which sample 9652095/2023330027, with a maximum depositional age of 603.5 +/- 7.2 Ma, is representative) cross-cut by numerous NW-trending magnetic lineaments. None of the major magnetic lineaments were intersected in drillcore. However, a thin (<1 m), slightly magnetic dyke in drill-hole NDILLK12 intrudes the non-magnetic sedimentary rocks and is probably analogous to the more prominent magnetic lineaments in the NE-tending zone. Hole NDILLK12 was drilled using a conventional drill-rig to a total depth of 237.8 m and obtained a ~100 metre diamond-core basement intersection. This mostly consisted of laminated and foliated siltstone and graphitic shale. A weak foliation is oriented sub-parallel to bedding. The sedimentary rocks are multiply deformed: D1 is more ductile, associated with pervasive foliation, while D2 is characterised by more brittle-ductile folding and faulting. Olivine basalt dykes (of which the current sample 9652090/2023330028 is representative) cross-cut D1 and D2 structures and have undulose margins, but are in turn crosscut by some veins. Dykes have well-preserved chilled margins and zoned cores, with abundant phenocrysts towards their centres. They also exhibit some alteration associated with the overprinting quartz-carbonate veins. The basaltic dyke intrudes foliated (D1), folded and brecciated (D2) sedimentary rocks; hence the relative relationships indicate the timing of the dyke is late/syn-folding (D2). As a result, this age of this dyke may provide a minimum age for D1 and D2, with the latter potentially close to the age of the dyke. The dyke is also deformed and cross-cut by some extensional veins, which may be related to D2. If this is the case, the dyke provides a maximum age on D2. Chilled margin and grainsize variations are observed from the centre to the edge of the dyke, where phenocrysts are absent. Some alteration is present around quartz-carbonate veins that cross-cut the dyke. The true thickness of the main intersection is likely ~30-50 cm, with several smaller intervals of 3-5 cm. The porphyritic central part of dyke was sampled for geochronology. The margins of the basalt are perpendicular to bedding and foliation in the siltstone, suggesting this is an intrusion, rather than a lava flow. In thin section, sample 9652090/2023330028 is an extensively carbonate-serpentine-sericite altered moderately porphyritic olivine basalt. The basalt comprises 5-7% phenocrysts set in a very fine-grained feldspar and clay-carbonate-serpentine-sericite replaced ex-glassy groundmass. The only phenocryst phase is ex-olivine that is completely replaced by massive granular carbonate, colourless serpentine and likely zeolite; serpentine mesh textures and carbonate lined fractures are visible at the narrow end of the thin section. Ex-olivine is mostly euhedral, typically flattened-hexagonal in shape with most grains 0.7-2.5 mm in size. Some grains display groundmass embayment. The groundmass of the basalt comprises an interlocking mesh of fine-grained slender plagioclase laths (0.1-0.3 mm) and lesser fine-grained (up to 0.4 mm) often euhedral ex-olivine surrounded by very-fine grained massive green-brown clay-replaced ex-glassy groundmass. The groundmass is studded with abundant hematite replace Fe-oxide (ex-magnetite) minerals; magnetite is preserved as inclusions to olivine. The basalt is intruded by a narrow bifurcating sparsely vesicular (carbonate filled vesicles up to 0.2 mm) basaltic micro-dyke that has a greater percentage of devitrified ex-glassy groundmass and a finer grain-size (groundmass 0.05-0.15 mm) that the basalt host.", "earth_materials":"Y", "structural_measurements":null, "inorganic_geochemistry":null, "organic_geochemistry":null, "geochronology":"Y", "isotope_groups":null, "hydrochemistry":null, "rock_properties":null, "mineralogy":null, "thin_sections":null, "repository_samples":"Y", "mineral_deposit_samples":null, "mineral_deposit_waste_samples":null, "linked_files":null, "other_geological_data":null, "project_name":"EFTF - Darling-Curnamona-Delamarian (DCD)", "gda94_longitude":141.09158, "gda94_latitude":-32.591466, "sample_originator":"Clark, A.", "date_acquired":"2023-11-26T00:00:00" }, "id":9652090, "prev":9652089, "next":9652094, "links":[ { "type":"application/json", "rel":"root", "title":"The landing page of this server as JSON", "href":"https://linkeddata.pid.geoscience.gov.au?f=json" }, { "type":"text/html", "rel":"root", "title":"The landing page of this server as HTML", "href":"https://linkeddata.pid.geoscience.gov.au?f=html" }, { "rel":"self", "type":"application/geo+json", "title":"This document as JSON", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp/items/9652090?f=json" }, { "rel":"alternate", "type":"application/ld+json", "title":"This document as RDF (JSON-LD)", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp/items/9652090?f=jsonld" }, { "rel":"alternate", "type":"text/html", "title":"This document as HTML", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp/items/9652090?f=html" }, { "rel":"collection", "type":"application/json", "title":"Sample", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp" }, { "rel":"prev", "type":"application/json", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp/items/9652089?f=json" }, { "rel":"next", "type":"application/json", "href":"https://linkeddata.pid.geoscience.gov.au/collections/sp/items/9652094?f=json" } ], "pid":"https://pid.geoscience.gov.au/sample/AU9652090" }