2786115
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU2786115
| Property | Value |
|---|---|
| id | 2786115 |
| igsn | 10273/AU2786115 |
| sample_id | 2018339537 |
| eno | 627934 |
| sampling_feature_name | DDH005 |
| sampling_feature_type | borehole |
| sample_type | core |
| sampling_method | core diamond |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | Alroy Formation |
| geological_province | Warramunga Province |
| sample_remark | Sample ET2786115 was selected to constrain the timing and conditions of tectono-metamorphism in the East Tennant area. It is a cordierite-andalusite gneiss obtained from a downhole depth of 169 m in drill hole DDH005, drilled in 2008 by Jacaranda Minerals (Collins, 2009). It is representative of a ~50 m interval of steeply-dipping pelitic gneiss and schist within the Alroy Formation (Collins, 2009, Clark et al., 2021a). A sample from this interval, immediately adjacent to our U-Pb monazite sample, returned a U-Pb zircon maximum deposition age of ca. 1873 Ma (Cross et al., 2020). Sample ET2786115 contains andalusite, sillimanite, biotite, muscovite, plagioclase, K-feldspar, quartz and minor cordierite. The sample exhibits subtle compositional layering defined by varying proportions of biotite, muscovite and quartz. Biotite and rare muscovite define a strong schistose fabric parallel to the compositional layering. Muscovite more commonly occurs as coarse, tabular grains that crosscut the foliation. Andalusite (up to 5 mm) is poikiloblastic and contains inclusions of foliation-parallel biotite and quartz. Andalusite grains are surrounded by biotite and, locally, sillimanite. The modal abundance of andalusite is estimated to be 1-3%. Sillimanite (fibrolite) locally overgrows but also parallels the main fabric. Sillimanite is heterogeneously distributed, and its overall abundance is estimated to be 5-10%. Rare (<3%) cordierite is aligned with the main fabric and is mostly altered to sericite. Quartz commonly exhibits amoeboid grain boundaries. Subtle chessboard extinction textures are discernible locally. Apatite and tourmaline are minor, matrix accessory phases. Monazite forms subhedral grains up to 50 um long, sub-parallel to the main fabric, and mostly associated with biotite-sillimanite domains that show little evidence of retrograde alteration. No monazite was observed as inclusions within andalusite. Monazite grains appear unzoned in BSE images. |
| structural_measurements | None |
| inorganic_geochemistry | None |
| organic_geochemistry | None |
| geochronology | Y |
| 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 - East Tennant Project |
| gda94_longitude | 135.95583 |
| gda94_latitude | -19.520077 |
| sample_originator | Schofield, A. |
| date_acquired | 2018-06-19 00:00:00 |
| Links |
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