LI DISTRIBUTION BETWEEN CHlORITE

AND ALBITE IN A COMMON VAPOR PHASE

By

PE.TER VIlKS t B•SC •

A Thesis

i , - / Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirements

for the J;)egree

Maste~ of Science

• McMaster University March 1981 MASTER OF SCIENCE (1981) McMASTER UNIVERSITY " (Geology) Hamilton, Ontario .

TITLE: Li.Distribution between Chlorite and Albite in a Common Vapor Phase

AUTHOR: Peter Vilks, B.Sc. (Dalhousie University) ..

SUPERVISOR: Denis M. Shaw

NUMBER OF PAGES: i-x, 1-95

•

ii A·,BSTRACT

This stooy a.ttempted to examine the process of L1 enrichment in spilites by testing the hypothesis that 1i is concentrated in meta-

morphosed basa~ts,from hydrothermal solutions in the temperature ran~e \ ".! 0 400 to 700QC and at.a 1.5 kb pressure. Using a double-capsule technique

I 1i was partitioned between albite and chlorite in a common vapor phase. These were used since they are commonly found in the greenschist

facies and chlerite is susJ;ected to be the main Li host. The chlorite

(clinochlore) and albite were grown from synthetic gels. A few exper~ . ,- " L iments were also attempted with a 'natural albite and 'hatural Fe-chlorite• • 11 analysts was carried out by atomic absorption and neutron activation. . . A variation between temperature and the partition coefficient

of 1i between albite and chlorite could not be resolved. Therefore, the average partition coefficlent from all synthetic experimen~s was Dalb-enl =

0.,56 :!: .06. The p::trtition coeft;icient in the natural system was not ,..J'-"" significantly higher, (na.lb-chl..= 0.81 ! .46).' Considerable doubt exists . . as to the accuracy, of the vapor- partition coefficients because

of the poor Li mass balance. A range of ~ssible vapor-mineral distri­ butions was obtained:

measured predicted from Li mass balance Dvap-alb 2.77 :!: 6.45 S.97:!: 7.99 Dvap..ehl 1.10 .! 2.31' 2.89 :!: 3.J4

iii The measured Li partition coefficients do not 'explain the behavior of Li in spilites because too much Li went into the albite, and vap,-chl the D' was not less than 1.00 so ~~t most hydrothermal waters do not contain enough Li to produce the observed enrichment in'spilites.

Lithium may be precipitat:ed in spilites at lower temperatures or' pres- sures thari those in this study.

I "J

, ',' iv

• ".

ACKNOWLEIXiEMENTS \ \ ,. i I am very grateful to my supervisor, Dr. Denis Shaw, for Z

introducing me to my thesis topic and for providing valuable guidance

through out the project. I am also indebted to Dr.. Brian Burley for

supervis~he hydrothermal synthesi~ and for making available the equipmen~of his experimental laboratory. .1I..

I would also like to thank Pat Fung for introducing.me to

the laboratory hydrothermal. proceed~es. Dr. James Kramer provided

me with a very useful insight into aqueous chemistry. I also appreciate

{' the help, otto Mudroch gave me fe>r the EDAX analysis and I would like

to thank Dan Thompson for a sample of chlorite from Whitefish Falls.

Finally I would like to thank Gary Beakhouse for calmly

acceptiDg the presence o~ hydrothermal bombs in his office•

..

v -' 'I'ABLE OF CONTENTS Page CHAPrJt:;R I INTRODUCTION .1

I-I Introduction 1 i 1-2 Previous work on Li distribution. 2 1-3 Geochemistry of Li 4 1-4 Definitions 6 1-5 Measurement of distribution coefficients 10 CHAPTER II EXPERIMENTS AND, DATA PROCESSING 13 11-1 Experimental proceedure 13 II-2 Analytical errors 15

I II-:3 Experimental errors 20 11-4 Li mass balance and calculation of Li vapor concentrations 21

CHAPl'ER III DATA AND DATA EVALUATION 25 111-1 Was equilibrium achieved? 25 ' 111-2 Lithium distributions 29 111-), Analytical uncertainty ,and variation,of Dalb-chl 43 I1I~ Location of 'lithium in the mineral phases 46

CHAPl'ER IV CONCLUSIONS 49 IV-l Statement on measured Li distributions 49 IV-2 Comparison to published Li distributions between vapor and minerals 50 IV-3 Comparison. to Li. concentration'in natural chlorite and albite 52 ·IV::l}--Alternate mechanisms of Li enrichment in spilites :A-

vi Page ~ CHAPI'ER A APPENDIX .56 A-I Experimental proceedure .56 A-2 Preparation of"gels and Li standard gels 60 A-J P.roceedures with atomic absorption 62 A-4 Alpha track Li 'analysis. 64

~~. A-5 Natural chlorite and albite 72 A-6 Lithium concentrations in the vapor phase and lithium vapor-mineral distributions 74 ( A-7 NatUre af tl)e vapor ~hase in equilibrium with the minerals 77 '(

! -.. C'" .<

\ ~

..

vii

I / Llsr OF TABLES Page TABLE

I-I Properties of Li, Na, K, Rb, Cs, and Mg 5 II-I International reference samples .16 II-2 Li det~ction limits with atomic a~sorption 17 II-J Li detection limits wi~h activation analysis 19 n-4 Li mass balance and vapor composition 23' III-l Diffractograms of albite and chlorite grown from the same gel 26 0 III-2 Av~~e ~istribution coefficient, at 500 C 29

III-3 Lithium distributions, )0 III-4" Average Li distributions 32 I,II-5 T stati&tio for two means J3 IV-l Li/K exhhange isotherms be~ween and and sanidine and ph1ogopite 50 A-I Gold tubing and pressure vessels 56 A-2 Materials used in gel preparation 60 A-3 Lithium-gel standards 62 " A.:J+ Alpha counts of Li standards and calibration line regression coefficients 69 A-5 Alpha counts per area.. and Li concentrations 70 ,A-6 .. Measured Li in Ab-l and chlorite from Whitefish Falls 72 A-7 Analysis o~ chlorite from Whitefish Falls using' the energy dispersive system (EDAX) on the electron

I microscope .' 73

~.

, .

vi'ii Page

A~ X-ray diffraction study on Ab-l and Fe-chlorites 7) A-9 Li concentrations in vapor and vapor-mineral Li distributions calculated from measured and ¥ . predicted Li amounts in the yapor· i 75 A-IO Averaged vapor-mineral partition coefficients 77 A-II Mg, Fe, Al and Na analysis of international reference samples 78 A-12 Molalities of major cations in vapor 80 ) A-I) Reactions shown in figure A-) 8) A-14 Activity coe~ficients and activi~y ratios 86 A-15 Variations-of activity ratios with temperature 90 Q , ~•

ix , "

Q LIST OF FIGURES Page FIGURE I-I Li/K exchange isotherms between sanidine and muscovite and a vapor at 600o C and 1 kb.

I-Z Li/K exchange isotherm between sanidine and 0 '\ muscovite at 600 and 1 kb. 3 1-3 Li/K exchange isotherm between vapor and phlogopite 0 at 600 C and 1 kb. 3 11-1 Cali',,!ation line-for sample group P 18- III-l Individual lithium partition coefficients betwe~n o ' albite and chlorite at 500 C ¥ersus time 27 0 III-Z Li in albite versus Li in chlorite at 400 C 35 0 1II-3 Li in albite v~~ 11 in chlorite at 500 C J6 '-c 0 1II4 L1 in albite versus Li in chlorite at 600 C 37 111-5 Li in albite versus Li in ~hlorite at 7qoO C 38 1II-6 Li in albite versus,Li in chlorite at all temperatures 39 1II-7 Li in albite versus Li -in chlorite in the natural system 40 111-8 Li partition coefficfent between albite and.chlorite • 1 . versus.1onic ~rength of the vapor ~ 1V-l Li/K parti~!fp_coefficient betwee~ vapor and minerals versus the Li/K ratio in the'vapor 51 A-I Selected calibration curves relating alpha C. counts to ppm L1 68 A-:) Activity diagram in the, system Na 0-MgO-Al 0 - z z 3 SiOz-HzO' 88

'1 , I

'.1.' \ I / \ \X, ',' , , .. ..

CHAPl'ER I e_'

INTRODUCTION

I-I Purpose of the study

Shaw et. a1. (1977) have shown that ~pilitised

contain more Li ( average::: 75 ppn ) than fresh basalts ( averag~ ::: 12

ppn ). 'Lithium was show!V,to increase with weight percent ,H 0 and ( 2 "', with a decrease i~ the ratio caO/A1 0 . Since H 0 increases and CC?-0 2 3 2 decreases wtth spilitisation' of basalts Shaw et. a1. (1977) sugge!3t

chara~teristic that Li increase is .,;.. of spilitization• Shaw et. al. (1977) predicted the Li/Na ~tio of the fluid~

which produce spilitisation. These predictions were limited because r ' the mechanism of Li uptake in spilites is not clearly understood~ Floyd (1977) indicated that Li was enriched in chlorite-rich p;l..tphes.

Unpublished. ion probe data of J. V. Smith also show that ti is c.on­

centrated in chlorite.

The purpose of this study is to improve our understanding

of Li behavior during spilitisation. Two essent\al secondary minerals.

:'(1,) in spilites are chlorite and albite. Therefor'e, this study wili try

to determine the distribution of Li between these two minerals" in a

cOlllJl1on vapor phase. This ~ould'demonstrate 'whether' or not Li prefers

to enter chlorite. The Li/Na'raj;.io

I .. 2

In summary, this study will test ~he hypothesis that Li

distribution be~ween albite and chlorite in a common, vapor phase at 400 to 700°· C ?llq 1.5 kb can explain 11 u~ake in spilitised ~salts.

'\ ~2 Previous work on Li distribution Volfinger (1970) measured Li and K exchange between mus­

covite and vapor, and sanidine an~" vapor at 600° C and 1 kb. !'1uscovite

- '\, might be considered as a mica analogue to. chlorite, and sanidine as

an analogue to albite. The. exchange isotherms for both ~inerals ar~

curved with the increasing atomic ratio G! Li/K ( Figures I~I and 1-2 ).

Lithium prefers to enter muscovit.e·' between aJ.og (Li/K) of -2.5 lO musc and -1. Volfinger and Robert (1979) measur.ed Li and K exchange between phl'qgopite and vapor ( FiguJ;"e 1-3). This exchange isotherm is also , . curved'with Li prefering to enter phlogopite at loglO (Li/K)phlog less

~\ than.- 2.). Matsui et. ale (1977) reported partition coeffi~ients be.tween phenocrysts and ground.l1lass for Li and other elements. The 'minerals included olivine, aug~t~, ( ~oun~ss-min = 0.20 ), . , . Li

hornblende, and biotite.. A.plagioclase/augite Li distribution in a bronzitite was. Dplag- aug ='0.76. The autho1Z'S also used Onuma diagrams Li .. to show that Li should enter the same siteslas Mg. ~ Liotard e~•. al. (1979) measured partition coefficients "between plagioclase and matrix from a calk-alkaline suite in Peru.,

. matrix-plag matrix-p'~~ In an~esite D varieo. from 0.40 to 2.27. In dacite D ~ U Li 4 ' matrix-plag' 6 ~n o.2~ was 0.5 to .17. rhyolite DLi was to 0.36. •

,

Fi~e I-I Li/K exchange isotherms between ~anidine and mus­ covite a?d a vapor phase at 6000 C' and 1 kb. Ratios are in atomic numbers. (Volfinger, 1970)-

., FigUre 1-2 Li/K exchange isotherm between sarlidine and muscovite at 6000 C and 1 kb. The isotherm is calculated from the results ;. in figure I-I. (Volfinger, 1970)

Figure 1-) Li/K eXchange isotherm between vapor and phlogopite at 6000 C and 1 kb. Ratios arE> in atomic numbers. (Volfinger and 'Robert, 1979) J

--~- .. ,,~------.1 ~------...,

j :: J,' ~-:

I ' I -~ ,I . j - • '- I ...... ::::.. -:::--- ~.J c:­ I o

1 I , i '--,------.: ...-3 .2 _I ",.,ri /V~ ~ -;;J~-/ 'Js:.::n. --....

Fi!tJI"; I-I Figure 1-2

I ! I I I I , ! , p. o. I,0 g- i • ,:J I . v I- ! " . ! ~, I.' , -J:"" ,'; -=.i I I / I I , --.;-~" I." " ,Il I i.,)

-~,I.--~ I

" 'I' •

4

1-3 Geochemistry of lithium

Lithium is a group 1 alkali metal with the atomic number

of 3 and an atomic weight of 6.~. It has two naturally occup-ing

isotopes (6Li = 7.4%; 7Li = 92 .f:r/o). Lithium has two electrons in the s-l orbital and one electron

in the 5-2 orbital. The latter electron is lost very easily, leavins

it with the ~lectron configuration of helium. Since Li is easilv ionized into a cation it is very reactive. Lithium has the highest

polarizing power of all the alkalies. This leads to low solubilities of various salts such as the fluoride, carbonate, and phosphate, and

to a tendancy for covalent bond formation.and solvation.

The small size of the Li ion makes substitution with Na

.. • +3' +2 +2 difficult. A similar 10n1C rad1us to Al , Fe , and Mg makes sub-

stitution'with these elements possible. Lit~ has similar geochemical behaviour to Mg. In bonds with Li is found in four-fbld and six-fold COOrdination. other properties of Li, as well as Na, K, Rb,

Cs, and Mg are summarized in table I-I. In an exchange reaction with an anionic ligand the order

of preference is Li < Na < K < Rb < Cs. If bonding is purely electro- static the cation with the smallest solvation radius will be preferred.

Lithium, with~he largest solvation radius, is least preferred. (Cotton and Wilkins~n y.

~conomic concentrat~ons of Li may be recovered from certain

. Important Li minerals ~ecovered from pegmatites include

{.