7935701
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU7935701
| Property | Value |
|---|---|
| id | 7935701 |
| igsn | 10273/AU7935701 |
| sample_id | TSC46043 |
| eno | 16096 |
| sampling_feature_name | Tilana 1 |
| sampling_feature_type | borehole |
| sample_type | borehole specimen |
| sampling_method | drilling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | None |
| geological_province | Tasmanian Cenozoic alkaline province |
| sample_remark | The rock is a medium to fine grained gabbro composed essentially of plagioclase and pyroxene in approximately equal proportions. Because the rock chips are generally finer than 4-5 mm, accurate estimation of abundance of the mineral components is difficult. Pyroxene is purplish-brown in colour and occurs as subophitic plates up to 2 mm in length. Smaller (0.5 mm) euhedral and non-ophitic crystals are also common. Very little alteration of the pyroxene has occurred. Plagioclase occurs as narrow laths, up to 1 mm in length, enclosed or partially enclosed by the pyroxene but more commonly, as tabular to equidimensional grains. An extensive, cloudy alteration is present in much of the feldspar but the refractive index appears to be close to 1.55, suggesting it is andesine. The plagioclase is therefore less calcic than in normal gabbros. Compositional zoning is present and many grains show unusual recrystallisation or replacement textures. Both isotropic and weakly birefringent ?zeolites are present as replacement grains within the feldspar. These minerals also occur as interstitial patches. Pale green chloritic alteration in sheaf and rosette-like masses is also present in the feldspar. Small apatite granules are common and opaque grains (possibly ilmenite) make up about 5% of the rock and are intimately intergrown with a red-brown biotite. The ilmenite frequently has a skeletal structure and very fine ?secondary opaque lamellae have formed along the cleavage planes of calcite. The rock is too altered for total rock K-Ar dating and there is insufficient biotite present to permit a suitable mineral concentrate to be prepared. The pyroxene is the only fresh and sufficiently abundant mineral present that could be used for K-Ar dating. |
| structural_measurements | None |
| inorganic_geochemistry | None |
| organic_geochemistry | None |
| geochronology | None |
| isotope_groups | None |
| hydrochemistry | None |
| rock_properties | None |
| mineralogy | None |
| thin_sections | None |
| repository_samples | None |
| mineral_deposit_samples | None |
| mineral_deposit_waste_samples | None |
| linked_files | None |
| other_geological_data | None |
| project_name | EFTF - Isotopic Atlas of Australia |
| gda94_longitude | 145.979667 |
| gda94_latitude | -39.892015 |
| sample_originator | Waltenberg, K. |
| date_acquired | 2000-01-01 00:00:00 |
| Links |
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