Single-mineral oxyoen iootope thermometry

369 ~NALYSIS

OF

ACRYLIC

FOR

232TH

AND

238U

DAUCHTERS

C.M. M I L T O N

E.D. EARLE, ~ N D R . J . E . D E A L (Atomic Energy of Canada, Research Company, Chalk River Nuclear Laboratories, Chalk River, Ontario K0J

SIHfiL~-HINERAL OXYOEN IgOTOP'E TllE~MOHETRY JAMES R. O~NEIL, Du[It. G e o l . S c i . , U n i v . of Michigan. A n n A r b o r , HI 4 8 1 0 9 - I 0 6 3 WILLIAM J . PICKTIIORN, U.S. G e n t . S u r e , , Menlo PO~R, CA, 0 4 0 2 5

1J0) The

Gamma

and

beta

rays

from

208T1

the ends of the Th and U decay potential sources of background neutrino detector proposed for Sudbury, Ontario. To eliminate completely, the 232Th end 238U vessel housing the however reductions if it c a n b e s h o ~ m

and

21&Bi

near

chains are in the hea~ ware a d e e p m i n e in this background in t h e a c r y l i c

D20 should be at fg.g-1 levels to < 1 0 "12 g . g - 1 a r e a c c e p t a b l e that their decay chains a r e i:,

secular equilibrium. Concentrations of these two elements in s a m p ] ~ of acrylic were measured by mass spectroscopy at three

laboratories.

We

have

obtained

good

agreements

with their results by alpha following chemical separation of U, T h a n d R a in t h e a s h f r o m a 10 k g s a m le. In addition the values 234U 230Th 2~6Ra, and 228Th ~32Th have indicated that both chains sre

spectrometry

essentially in secular equilibrium. Large samples, counting times in excess of two weeks, and the application of clean room techniques have enabled us to achieve a sensitivity o f 5 x 1 0 "13 g.g~l for both 238U and 232Th.

isotopic

dlfterenL

compositions

of

oxygen

in

or B t r u o t u r a l sites 1, or m i n e r a l s s h o u l d be d i f f e r e n t bocnuoc the v i b r a t i o n a l frequencies and frcquoncy a h l f t a a e B o c l a t e d ~ I t h t h e h o n d a to oxygen at the v a r l o u a 81tOS are d l f f e r c n t . 3 h o u l d a m i n e r a l form In I n t e r n a l oxygen isotope equilibrium and r c t a i n t h e s e compoaltlone after formation, the isotopic /'ractlonatlen b e t w e e n oxygon Jn ono s a t e and the others, olther Indlvlduolly or In oomblnmtlon, could provide a sensitive 5Ingle-mineral thermometer, Attempts were po~itlon9

molecules

made p r e v i o u s l y to dotcrmlne the oxygen ISOtOpe fraotlonatlons b e t w e e n t o e a n d PO. i n apalitc8 and b o t w c o n a i u m l n o e i l l c a t c oxygen

and 011 i n h y d r o u s

minoral~, but the methods are uuopeet, i n d e e d t h e number o f I m p o r t a n t mlnerole f o r which s u c h dctermlnallons have any c h a n c e of o u c c o n a I s vary llmltcd. ~e have d e v e l o p e d a t e c h n i q u e of a n a l y s i s of a l u n l t e . KAIe(SO*}*(OlI)~, whcreby the i s o t o p i c componltteno o f t h e S04 and OH g r o u p s Jan be d e t e r m i n e d s e p a r a t e l y and u~ed

unamblguou61y. Normally oxyRen bonded to hydro~on in OH g r o u p s s h o u l d be t s o t o p i c a l l y lighter t h a n o x y g e n b o n d e d to o t h o r e l e m e n t a ( 5 1 , AI, c , S, O L C . ) and d r a m a t i c a l l y so a t low tomperaturoa of f o r m a t i o n . NO n u p e r £ e n e alunlte analyzed to d a t c Io in I n t e r n a l ~-o

an~ l h c s o . - o l l f r a c t l o n a t l o n a for Iho~c low t e m p e r a t u r e m l n e r a l a v a r y from - I . 5 3.2 perml/. ][ypog0ne nlunltco, on t h e o t h e r h a n d , a p p e a r to bc I s o t o p l c a l l y well behaved With internal fraotlonatlonl of 5 , 0 to lO,O pormll that are c.rrelatcd well with temperaturcl determined from phaso e q u i l i b r i a conelderetlone, T h e s e r e ~ u l t ~ have b o t h praotlcal and t h e o r e t i c a l lntcreet,

equilibrium to

: ~L"

AYDA T LAKE

D:AGE~ESIS

AND

eE~ArED

ENV[#ONMENTAL

ASPECTS.

~

~O~A~!~.

and

G,

Y.F.

GAIL-A~D,

L.

PHILI°~E,

~ABOUILLE

C.

MICMAmD.

+Laboratoire de anO I . P . G , P * ,

Geochlm:e

PARIS,

EutrophlSation

Eau.,

des

Paris 7

Untvers*te

~ANCE)

processes

a,e

closely

iimkeO

~ith

nutrients c~ncentrat~ons in ~ater but it appears, fol ~o~z~q ~ a ~ y authors, that o r t h o p h o s p h a t e (S,R,P.) is tme main i : ~ l t l n g ~actor, Our s t u c l e s O~evlouslw c~esente~

~

chemlstrles a

the ~ater ~ol~mn emphasize Of ~artlcJlate

large ~art of the ~ sca~enqe~

t~es

the

sediment-~ate~ onto

~uanti~

a complete <¢¢Ie,

these

t.o and

~l~es

elements in

of

e~:~it

iron o~Ides

the

a ~ulte

o~

s~mQtlon

has

related

DO~h m a j o r ~]ear

m~e~al~sat~on. ~-a-~t:tat~eelv

(SWI) entraooeo order

to

the chemical

Dehav10~r

O~

investigated

pore

~ater.

minor

While

~i~or just

~n t h e

sed~

Concent,atiom

elements

in

Ocmlnate~

ieadin 9 to the

~e~uce~

or

in

c~emlstrv

3~lolzers

red

oartlcules,

bee~

and

couple~

The~efore~

in the O.Ic zone

interface

~dsorbed

~ent

the

iron an~ S.~.P..

Dy

~ater

the

organic

electron

Dro-

~ore

~on-

~atter

accepters

Delo~ tme swl

:~O3,

are 50~,

Meant t~e ma~n codex ~e~CtlOnS are the Fe(IIl~ O~ideS ,eOuctlon a~d ~e~ha~OQe~es;s. The S.~.~. Oro~11e is

~,~:~e d i ~ e c e ~ ~

the

from

~edlme~t

the others an~ suggests o i ~ s l o n to the ,ater c~lumm in addition to

OCSSl~Ie a~so~Dtlom ~

a~thi~enlE

mineral ~reci¢;tatlon

at ~eoth. 5cm ~eic. the SWI. Crom this ~acQe set 0¢ ~ata, a s s ~ g s t e a ~ ~ t a t e . ~e are a~le to ~er~ve +tce~++metric a ~ Oia~enezlc ~ode~s ~n~c~ aLlo. ~s to ~a,~ify

~ne

Jie-~ts • ~.es

~la~enetlc

~rocesses.

Concentration

~ra

at the SWI are Jsed to =alcJlate d~r+~s~g o+ ~ut+~e~ts, F~r S~P ~t ~a~ e~aluate~ to ~oc

+~xs

+or t~e .PoLe !a+e

m3~al

to

t~e~

the

t:on

~o

the

~p,xt

~eOime~t the

"i,~*

acts

e~t~o~Pisat~

s~r*ace ~

as

the

a~d r~¢er

a reservoir process

is

appro*~.at~vety

La

Vevre.

anO ~s q u i t e

its

T~ere

=~ntr:bu impor~art,

R O O M - T E M P E R A T U R E E Q U A T I O N OF STATE OF CaSiO3 PEROVSKITE M, T A R R I D A and P. RICHET. (Institut de Physique du Globe, 4 place Jussieu, 75005 Paris) C a l c i u m has a significant abundance in the lower m a n t l e , the " m i n e r a l o g y o f w h i c h s h o u l d c o n s i s t mainly o f ( M g , F e ) S i O 3 perovsklte. C a l c i u m , however, has a very limited solubility in this phase and its likely host in the m a n t l e is C a S i 0 3 with a cubic perovskite structure as s y n t h e s i z e d by L i e (1975). L i t t l e is known about the p h y s i c a l properties of this perovskite because it transforms to an amorphous p h a s e when q u e n c h e d to 1 bar. In this study we have d e t e r m i n e d the equation o f state of C a S i O 3 perovskite, a property o f basic geophysical importance. A w o l l a s t o n i t e g l a s s s t a r t i n g p r o d u c t has been laser heated at 950 Kbar in a diamond anvil cell with a s m a l l a m o u n t o f ruby included for p r e s s u r e measurements. Six r e f l e c t i o n s , all o f w h i c h are consistent with the reported c u b i c cell o f CaSiO3 perovskite, are a p p a r e n t in the p o w d e r diffraction patterns o b t a i n e d with a standard X - r a y generator. Prom these observations the lattice p a r a m e t e r o f the s y n t h e s i z e d p e r u v s k i t e has been m e a s u r e d from 170 Kbar, the pressure in the cell after the synthesis, to more than 5 0 0 Kbar. Equations of state have been fitted to the compression data to derive the l - b a r volume and the bulk m o d u l i , K o and K'o. T h e s e r e s u l t s will be presented and discussed, together with some implications.