The University of Southampton
University of Southampton Institutional Repository

Rubidium-strontium geochronology of the encounter bay granite and adjacent Metasedimentary rocks, South Australia

Rubidium-strontium geochronology of the encounter bay granite and adjacent Metasedimentary rocks, South Australia
Rubidium-strontium geochronology of the encounter bay granite and adjacent Metasedimentary rocks, South Australia
Rubidium?strontium and strontium isotope data for eight whole?rock samples of granite varieties from the Encounter Bay area, South Australia, yield an isochron age of 487 ± 37 m.y. Two specimens of albitised granite, formed as a result of late?stage metasomatic alteration of original megacrystic granite, conform to this isochron. These data support a genetic relation between granites and late?stage metasomatic alteration as suspected from field, petrographical and geochemical studies. Eight samples from contiguous Kanmantoo Group metasedimentary rocks have an isochron age of 487 ± 60 m.y. Thus this metamorphic event is coincident with emplacement of the Encounter Bay Granite.

The initial Sr87Sr86 ratio for the Encounter Bay Granite (0.719) is significantly higher than initial ratios for the Palmer (0.709) and Anabama (0.705) Granites from the same region and can be attributed to either remobilisation or incorporation of strontium from older crustal material in the intrusion. The apparent initial Sr87/Sr86 ratio for the Kanmantoo Group metasedimentary rocks (0.722) can not be distinguished from that for the Encounter Bay Granite within the analytical uncertainties. Compatability of ages and high initial Sr87Sr86 ratios suggest that the granites formed by remobilisation of associated crustal rock.
0812-0099
259-266
Dasch, E.J.
0df47385-3fa9-4a2b-8edb-9bf7e3723763
Milnes, A.R.
f0cbf958-c413-4855-a3e8-f4ebc6701386
Nesbitt, R.W.
6a124ad1-4e6d-4407-b92f-592f7fd682e4
Dasch, E.J.
0df47385-3fa9-4a2b-8edb-9bf7e3723763
Milnes, A.R.
f0cbf958-c413-4855-a3e8-f4ebc6701386
Nesbitt, R.W.
6a124ad1-4e6d-4407-b92f-592f7fd682e4

Dasch, E.J., Milnes, A.R. and Nesbitt, R.W. (1971) Rubidium-strontium geochronology of the encounter bay granite and adjacent Metasedimentary rocks, South Australia. Journal of the Geological Society of Australia, 18 (3), 259-266. (doi:10.1080/00167617108728765).

Record type: Article

Abstract

Rubidium?strontium and strontium isotope data for eight whole?rock samples of granite varieties from the Encounter Bay area, South Australia, yield an isochron age of 487 ± 37 m.y. Two specimens of albitised granite, formed as a result of late?stage metasomatic alteration of original megacrystic granite, conform to this isochron. These data support a genetic relation between granites and late?stage metasomatic alteration as suspected from field, petrographical and geochemical studies. Eight samples from contiguous Kanmantoo Group metasedimentary rocks have an isochron age of 487 ± 60 m.y. Thus this metamorphic event is coincident with emplacement of the Encounter Bay Granite.

The initial Sr87Sr86 ratio for the Encounter Bay Granite (0.719) is significantly higher than initial ratios for the Palmer (0.709) and Anabama (0.705) Granites from the same region and can be attributed to either remobilisation or incorporation of strontium from older crustal material in the intrusion. The apparent initial Sr87/Sr86 ratio for the Kanmantoo Group metasedimentary rocks (0.722) can not be distinguished from that for the Encounter Bay Granite within the analytical uncertainties. Compatability of ages and high initial Sr87Sr86 ratios suggest that the granites formed by remobilisation of associated crustal rock.

Full text not available from this repository.

More information

Published date: 1971
Organisations: Geochemistry

Identifiers

Local EPrints ID: 361869
URI: https://eprints.soton.ac.uk/id/eprint/361869
ISSN: 0812-0099
PURE UUID: 4fbe3fa2-ac58-4d70-a1b1-5a600fd360dc

Catalogue record

Date deposited: 04 Feb 2014 16:54
Last modified: 18 Jul 2017 02:57

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×