St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Earth & Environmental Sciences and Geography & Sustainable Development (Schools of)
  • Geography & Geosciences (Previous name for currents schools of Earth & Environmental Sciences and ...)
  • Geography & Geosciences Theses
  • View Item
  •   St Andrews Research Repository
  • Earth & Environmental Sciences and Geography & Sustainable Development (Schools of)
  • Geography & Geosciences (Previous name for currents schools of Earth & Environmental Sciences and ...)
  • Geography & Geosciences Theses
  • View Item
  •   St Andrews Research Repository
  • Earth & Environmental Sciences and Geography & Sustainable Development (Schools of)
  • Geography & Geosciences (Previous name for currents schools of Earth & Environmental Sciences and ...)
  • Geography & Geosciences Theses
  • View Item
  • Register / Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Geology and petrology of the margin of the Rhum ultrabasic intrusion, Inner Hebrides, Scotland

Thumbnail
View/Open
RichardCGreenwoodPhDThesis.pdf (65.67Mb)
Date
1988
Author
Greenwood, Richard C.
Supervisor
Donaldson, Colin
Keywords
Geology of Rhum Tertiary
Metadata
Show full item record
Abstract
Country rocks surrounding the Rhum Tertiary ultrabasic complex have experienced severe thermal metamorphism, partial melting and mobilization resulting in the formation of extensive areas of intrusion breccia. Evidence from several sources indicates a maximum temperature in the country rocks of 960 ±40⁰C. Contrary to previous suggestions the complex was not emplaced as a fault block enclosed by a "Marginal Gabbro", but formed in situ at a depth of less than lKm. Large-scale layering continues to within 2m of the country rocks, and shows no change in either thickness or orientation close to the contact. Small-scale layers at Harris Bay thin and terminate towards the contact with the Western Granophyre. Strontium isotope data shows that the margins of the complex have experienced considerable crustal contamination. Contamination may have taken place by mixing of anatectic country rock melt with the resident basaltic liquid during boundary flow. Whole-rock and isotope geochemistry suggests that marginal microgranodiorite ("hybrid rocks") formed during a process of combined assimilation and fractional crystallization. Lead isotope data indicate that rocks of the ultrabasic complex, as well as earlier Tertiary granophres and felsites, were contaminated with Lewisian lead. The crustal level at which this took place and the processes involved remain unclear. Oxygen isotope analyses show that rocks of the contact zone have undergone large-scale exchange with heated, meteoric fluids. In response to inflation of the complex the country rocks experienced considerable deformation, and in places the chamber roof underwent gravity collapse. Deformation resulted in increased country rock permeability, thus enhancing hydrothermal circulation and promoting high-cooling rates along the ·contact zone. A consequence of this process is the local preservation of quenched ultrabasic material at Harris Bay, and the ubiquitous development of rapid growth textures in all lithologies within the contact zone.
Type
Thesis, PhD Doctor of Philosophy
Collections
  • Geography & Geosciences Theses
URI
http://hdl.handle.net/10023/7123

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter