1839469
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU1839469
| Property | Value |
|---|---|
| id | 1839469 |
| igsn | 10273/AU1839469 |
| sample_id | 2006677001 |
| eno | 13998 |
| sampling_feature_name | Munro 1 |
| sampling_feature_type | borehole |
| sample_type | core |
| sampling_method | core diamond |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | Munro granite |
| geological_province | Kalkarindji Igneous Province |
| sample_remark | Paraphrased from Williams (1972; WAPET well completion report): "MESOSCOPIC: Uniform fine- to medium-grained granite comprising dark green, vaguely decussate chloritic grains in a groundmass of pink feldspar. Discrete quartz grains are not evident. The rock is cut by a 2 mm wide vein of green prehnite. MICROSCOPIC: The rock is dominated (70%) by micrographic intergrowths of quartz and untwinned potassium feldspar (orthoclase?). Many intergrowths have cores of sodic plagioclase around which micrographic material has grown as coronas. The micrographic grains are equant and up to 1.5 mm across (average about 0.8 mm). Orthoclase is brownish due to kaolinisation. Albitic plagioclase (15%) forms laths and equant subhedra and anhedra up to 1.2 mm across, commonly rimmed by micrographic quartz and orthoclase. It too is kaolinised and many grains are partly replaced by chlorite and/or granular epidote. Within the framework of interlocked micrographic grains, anhedral chlorite (15%) is up to 0.8 mm across, and commonly aggregated into vaguely decussate clumps. About half the chlorite replaced biotite, but some has undoubtedly replaced plagioclase. Leucoxenised ilmenite (0.5%) forms scattered anhedra up to 0.4 mm across. Apatite is common as tiny slender prisms scattered through the micrographic quartz and orthoclase. Zircon is very rare. The secondary vein evident in hand specimen is dominated by fine-grained prehnite; quartz, chlorite and epidote together comprise <2% of the vein. Widespread deuteric alteration is manifested as kaolinised orthoclase and albite, epidotised plagioclase, chloritised plagioclase and biotite, and leucoxenised ilmenite. NAME: Fine- to medium-grained chloritised biotite micrographic granite." Jourdan et al. (2014; Geology 42, 543-546) interpreted this rock as the differentiated centre of a thick dolerite sill, and noted the presence of mafic enclaves in hand specimen, possibly derived from earlier-erupted basalt trapped in this intrusive rock. |
| structural_measurements | None |
| inorganic_geochemistry | Y |
| organic_geochemistry | None |
| geochronology | Y |
| isotope_groups | None |
| hydrochemistry | None |
| rock_properties | None |
| mineralogy | Y |
| thin_sections | None |
| repository_samples | Y |
| mineral_deposit_samples | None |
| mineral_deposit_waste_samples | None |
| linked_files | None |
| other_geological_data | Y |
| project_name | None |
| gda94_longitude | 122.4757535 |
| gda94_latitude | -19.8616742 |
| sample_originator | Cassidy, K.F. |
| date_acquired | 2006-03-28 00:00:00 |
| Links |
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