Reviewing the occurrences of this type of alteration as it relates to those
enigmatic Fe-Oxide (+-Cu, Au, P, REE and a good deal of the rest of the
periodic table!) systems which includes
A) regional alteration in: Northern Fennoscandia, the Cloncurry district
and the Chilean coastal belt;
B) deposit related alteration at: Kiruna, El Romeral, Mount Elliot, Eloise,
Starra, Bidjovagge & Pahtohavare
The concensus is the following assemblages are the most common:
Albite or Oligoclase, Actinolite, Diopside, Scapolite, Quartz, Titanite,
Magnetite, Hematite.
An Na/Ca bearing feldspar is essential whilst you can mix and match the
other phases. Scapolite is ubiquitous more or less in a lot of camps,
represents the Cl-rich brines most likely.
===================================================
Dr Richard Herrington
Department of Mineralogy
The Natural History Museum
Cromwell Road
London SW7 5BD
United Kingdom
Tel: +44 (0)207 942 5528
Fax: +44 (0)207 942 5537
Email: [log in to unmask]
Websites: http://www.nhm.ac.uk/mineralogy/intro/project5/index.htm
http://www.nhm.ac.uk/mineralogy/research/ores.htm
===================================================
|