Dear Desmond
I had similar problem in my PhD thesis. In the field you should just look at the veins. Most of these minerals come with quartz. But sometimes it gets diddicult to distinguish these minerals especially in small veins. You have to make some thin sections.
Good luck.
Alireza Karimzadeh
University of Tabriz
Iran
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From: Desmond Leech[SMTP:[log in to unmask]]
Sent: Wednesday, January 10, 2001 4:54 PM
To: [log in to unmask]
Subject: Calc-sodic alteration
Hello all,
The magnetite deposits of Chile have reported Ca-Na alteration
envelopes surrounding the ore zones, which are reported as evidence
for a metasomatic genesis to theses deposits. My problem is how to
identify this type of alteration in the field, especially when it is
reported in a fine to medium grained tonalitic to dioritic host rock.
Unfortunately the host rocks contain appreciable amounts of primary
Ca and
Na minerals ( ie actinolite, diopside, albite).
Has anybody encountered such alteration and do you have any ideas for
the
field identification of this alteration, especially in tonalites and
volcaniclastic rocks.
Many thanks in advance,
Des Leech
-----------------------------------
Desmond Leech
Centre for Earth and Environmental Science Research,
School of Earth Sciences and Geography,
Kingston University,
Penrhyn Road,
Surrey KT1 2EE.
PH. (0)20 85472000 ext 2215
FAX (0)20 85477497
EMAIL [log in to unmask]
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