Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Mineralogical Magazine Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Mineralogical Magazine; February 2000; v. 64; no. 1; p. 113-120
© 2000 Mineralogical Society of Great Britain and Ireland
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Graham, N. T.
Right arrow Articles by Callaghan, B.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Plagioclase-rich microgranular inclusions from the late-Caledonian Galway Granite, Connemara, Ireland

N. T. Graham1, M. Feely2,* and B. Callaghan2

1 Department of Earth Sciences, Parks Road, University of Oxford, England
2 Department of Geology, National University of Ireland, Galway, Ireland

* E-mail: martin.feely{at}nuigalway.ie

We report on the occurrence, petrology and geochemistry of recently recognized leucocratic plagioclase-rich microgranular inclusions hosted by two granite facies in the late-Caledonian Galway Granite, Connemara, Ireland. They have been recorded at 66 localities along an ESE trending, 4 km wide corridor which incorporates the contact zone between their host granites (i.e. The Megacrystic Granite and the Mingling and Mixing Zone Granodiorite). The inclusions are discoidal in shape and oriented parallel to the general ESE trending foliation in the granites with the most elongate (6.0 x 0.6 cm) occurring in zones of strongest fabric intensity. Contacts between the inclusions and the host granite are sharp with no chilled margin visible. They display a fine-grained (<1 mm) interlocking texture with occasional crystals of plagioclase ranging up to 2 mm in length. Microprobe analysis shows that the plagioclase is essentially oligoclase (An22–32) in composition and is similar to that (i.e. An21–30) occurring in the host granites. Furthermore, the oligoclase accounts for between 61 and 78% of the mode which is reflected in the major element chemistry of the inclusions. Other minerals (in decending order of abundance) include K-feldspar, quartz, biotite and magnetite. The origin of the inclusions is unclear. However, the results of the microprobe analysis provide evidence of a link between them and their host granites.

KEYWORDS: Galway granite, microgranular inclusions, oligoclase, synneusis, melt segregation






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Mineralogical Society of Great Britain and Ireland