Dear Colleagues,

     For the last year we have been working on the stable isotope
geochemistry of analcite- and natrolite-bearing rocks. For water extraction
and isotopic analyses we have largely followed the works of Karlsson and
Clayton (1990.a, b; 1991), with satisfactory results.

     When interpreting data at the light of the above mentioned works,
analcite tells us an interesting story, but we are uncertain as it regards
the natrolite; particularly its channel water.

     Karlsson and Clayton (1990.b) indicate that natrolite channel water
*MAY* reflect sample site water (it does not reflect laboratory water
vapour, according to them), but the evidence is not as strong as for
analcite.
A literature search was unsuccessful in finding new sound data regarding
natrolite, so our question goes ...:

     Has any of you published any recent work that we are unaware of
regarding the isotopic behaviour of natrolite, and especially its channel
water? In its defect, will anybody have unpublished data that could be
shared? Feng and Savin (1991) published a first paper dealing with
analytical techniques for zeolites, but natrolite was not considered. Has
the series been continued, and natrolite studied?

     Any further advice?

Thanks for your time.

J.G. Mitchell, Newcastle, U.K.
C. Recio, Salamanca, Spain

     Refs.:

- Karlsson, H.R. and Clayton, R.N. (1990.a) "Oxygen isotope fractionation
between analcime and water: An experimental study". GCA, 54, 1359-1368.

- Karlsson, H.R. and Clayton, R.N. (1990.b) "Oxygen and hydrogen isotope
geochemistry of zeolites". GCA, 54, 1369-1386.


- Karlsson, H.R. and Clayton, R.N. (1991) "Analcime phenocrysts in igneous
rocks: Primary or secondary?". Am. Min., 76, 189-199.

- Feng, X. and Savin, S.M. (1991) "Oxygen isotope studies of zeolites:
Stilbite, analcime, heulandite, and clinoptilolite - I. Analytical
technique". In: Taylor, O'Neil & Kaplan (Eds.) "Stable isotope
geochemistry: A tribute to Samuel Epstein". Geochem. Soc. Spec. Pub., 3,
pp. 271-283.


*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#
Clemente Recio
Laboratorio de Isotopos Estables
Univ. de Salamanca                         Phone: (+34) 23 294400, Ext. 1540
37008-Salamanca                          Fax:   (+34) 23 294514
Spain                                              E-mail [log in to unmask]
*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#