7935629
Persistent Identifier: https://pid.geoscience.gov.au/sample/AU7935629
| Property | Value |
|---|---|
| id | 7935629 |
| igsn | 10273/AU7935629 |
| sample_id | MSH186 |
| eno | 816999 |
| sampling_feature_name | R001921 |
| sampling_feature_type | field site |
| sample_type | outcrop specimen |
| sampling_method | outcrop sampling |
| material_class | rock |
| earth_materials | Y |
| stratigraphic_unit | George River Granodiorite |
| geological_province | Northeast Tasmania Element |
| sample_remark | McClenaghan & Higgins (1993): Biotite K-Ar ages for the George River phase (Samples 37851, G1, MBT256, MBT257 & 258, MSH167 & 168, MSH173, MSH186) are mostly consistent (averaged K-Ar age 392.2 +/- 1.2 Ma). Sample G1 is youngest at ~380 Ma; it comes from N of the Gardens pluton & sample 40523 returned a Rb-Sr age ~383 Ma; collected near the same point, which are distant from the other sample locations. This suggests a possibe resetting assoicated with the Poimena pluton emplacement and that if it were responsible for this resetting then it must be present at shallow depth in that area. The age obtained from a muscovite granite dyke (sample MSH166; ~397 Ma) intruding the GR pluton is the same as the oldest age from the GR pluton (MSH167; ~398 Ma), thus confirming the reliability of the older ages for this phase. The GR pluton intrudes the Mathinna Supergroup, and comprises intrusive phases ranging from biotite hornblende granodiorite to biotite granite. It includes rock units previously described as George River granodiorite, Akaroa granodiorite and Grants Point granite. Another biotite-hornblende granodiorite mass (Gardens pluton), with minor areas of biotite granodiorite, outcrops on the coast at The Gardens and extends inland to the NW. The George River and Gardens plutons are similar in petrographic character and have the same mafic mineral foliation, so it seems probable these are part of the same pluton. The GR pluton at St Helens Head is intruded by muscovite granite dykes which only occur in that body. Dolerite dykes, widespread throughout eastern Tasmania & the Furneaux Group islands, intrude many plutons, and are particularly common in the Gardens and Poimena plutons. The dykes are inferred to be similar Devonian age to the granitic rocks, as on Flinders Island a dolerite dyke is crosscut by a quartz-feldspar porphyry dyke, assumed to be comagmatic with the host granites. |
| 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 | 148.2785554 |
| gda94_latitude | -41.3780665 |
| sample_originator | Waltenberg, K. |
| date_acquired | 2000-01-01 00:00:00 |
| Links |
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