The University of Southampton
University of Southampton Institutional Repository

A new tetragonal silicate mineral occurring as inclusions in lower-mantle diamonds

Record type: Article

Aluminium is one of a small group of elements-Si, Mg, Fe, Al, Ca and O-that form the bulk of the Earth's mantle. In the upper mantle, Al is largely contained in minerals with a garnet structure. But the mineral transformations associated with the breakdown of garnet structures in the uppermost lower mantle have been a matter of uncertainty(1-9). Here we report the discovery of a new aluminous mineral, present as inclusions in diamonds of lower-mantle origin found at Sao Luiz, Brazil(10). This phase has a stoichiometric garnet composition similar to pyrope-almandine but has a distinct tetragonal structure (space group I (4) over bar 2d), and is here referred to by the acronym TAPP (tetragonal almandine-pyrope phase). Although TAPP has not been recognized in experimental studies, we suggest that it is nevertheless a primary rather than retrogressive phase and has a limited stability held in relatively aluminous bulk compositions in the uppermost lower mantle. TAPP, like garnet, would lead to relatively low densities for basic rocks compared with peridotites (assumed to be the dominant mantle rocks), and we suggest therefore that it may play an important role in determining density differences and the dynamics of segregation between ultrabasic and basic compositions in the mantle(7,11,12).

Full text not available from this repository.

Citation

Harris, J., Hutchison, M. T., Hursthouse, M., Light, M. and Harte, B. (1997) A new tetragonal silicate mineral occurring as inclusions in lower-mantle diamonds Nature, 387, (6632), pp. 486-488. (doi:10.1038/387486a0).

More information

Published date: 1997

Identifiers

Local EPrints ID: 15327
URI: http://eprints.soton.ac.uk/id/eprint/15327
ISSN: 0028-0836
PURE UUID: f240c70e-c7ee-4715-90f8-790f25af0d42

Catalogue record

Date deposited: 12 Apr 2005
Last modified: 17 Jul 2017 16:49

Export record

Altmetrics

Contributors

Author: J. Harris
Author: M. T. Hutchison
Author: M. Hursthouse
Author: M. Light
Author: B. Harte

University divisions


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.

×