The University of Southampton
University of Southampton Institutional Repository

Crystallisation of an alkali-olivine basalt under controlled PO2, PH2O conditions

Crystallisation of an alkali-olivine basalt under controlled PO2, PH2O conditions
Crystallisation of an alkali-olivine basalt under controlled PO2, PH2O conditions
An alkali-basalt from Hualalai, Hawaii, previously examined by Yoder and Tilley (1962) has been crystallised under controlled PO2 at 2 kb total pressure. Significant differences, in the order of appearance of the phases result from lowering the PO2 from 10?0.7 to about 10?10 atm. In particular magnetite, present at 1100 °C in the unbuffered runs does not crystallise until below 900 °C in the oxygen controlled runs. There is a drop of up to 50 °C on the liquidus of the system if the oxygen is controlled at the quartz-fayalite-magnetite buffer. Calcium amphiboles crystallised under such conditions are nepheline normative and rich in titanium and aluminium. Decreasing the water content but maintaining total pressure at 2 kb results in an increase in the melting point of the amphibole. There is no data in the runs to support the concept of a primary amphibole gabbro crystallising from a basaltic melt of this composition. Rather, the amphibole would form by reaction of the pyroxene with the liquid, or direct growth at lower temperatures from a basaltic mineralogy.
0031-9201
309-315
Nesbitt, R.W.
6a124ad1-4e6d-4407-b92f-592f7fd682e4
Hamilton, D.L.
b42f01c1-f95a-47e1-9199-2d1523ee9214
Nesbitt, R.W.
6a124ad1-4e6d-4407-b92f-592f7fd682e4
Hamilton, D.L.
b42f01c1-f95a-47e1-9199-2d1523ee9214

Nesbitt, R.W. and Hamilton, D.L. (1970) Crystallisation of an alkali-olivine basalt under controlled PO2, PH2O conditions. Physics of the Earth and Planetary Interiors, 3, 309-315. (doi:10.1016/0031-9201(70)90067-1).

Record type: Article

Abstract

An alkali-basalt from Hualalai, Hawaii, previously examined by Yoder and Tilley (1962) has been crystallised under controlled PO2 at 2 kb total pressure. Significant differences, in the order of appearance of the phases result from lowering the PO2 from 10?0.7 to about 10?10 atm. In particular magnetite, present at 1100 °C in the unbuffered runs does not crystallise until below 900 °C in the oxygen controlled runs. There is a drop of up to 50 °C on the liquidus of the system if the oxygen is controlled at the quartz-fayalite-magnetite buffer. Calcium amphiboles crystallised under such conditions are nepheline normative and rich in titanium and aluminium. Decreasing the water content but maintaining total pressure at 2 kb results in an increase in the melting point of the amphibole. There is no data in the runs to support the concept of a primary amphibole gabbro crystallising from a basaltic melt of this composition. Rather, the amphibole would form by reaction of the pyroxene with the liquid, or direct growth at lower temperatures from a basaltic mineralogy.

This record has no associated files available for download.

More information

Published date: April 1970
Organisations: Geochemistry

Identifiers

Local EPrints ID: 361876
URI: http://eprints.soton.ac.uk/id/eprint/361876
ISSN: 0031-9201
PURE UUID: 0d789731-9077-4444-a0ab-6ec3d5a69500

Catalogue record

Date deposited: 04 Feb 2014 17:13
Last modified: 14 Mar 2024 15:57

Export record

Altmetrics

Contributors

Author: R.W. Nesbitt
Author: D.L. Hamilton

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 http://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.

×