Calcium-rich inclusion solutions in fluorite from the Strzegom pegmatites, Lower Silesia

Vol. 34, No. 1·2

.ANDRZEJ

KOZl.OWSKI

aet.

gealaglca pOlonica

Warlzawa 1984

Calcium-rich incluSion solutions in fluorite from the Strzegom pegmatites, Lower Silesia

ABSTRACT: Inclusians jn flumtites from peg:matitic dr1.llSeS in the Stnegom maBSif bea!r aqlUeoUB solutioos with cakhJm chlOll.'ide as the

roam

solute com,po-

nen:t. HOIl'lOgeJlIitm'bioo temperatures were meas,ured. (165 to 180°C) and the phys.ico.

-chemleal analysis of incIlusion fl.u.i.d !behavior durilng treemng doWlll Ito -130°C was performed. ThiS yields the following fluid COIrJI)Osiltdon::

HsO -

76 wit. "" CaCl.

- 18 . wt.^o/&, NaCl - 6 wt. '/0; ThediBcuss.ioo preseuted. of possible presenoe of oflber saltsl U!

INTRODUCTION

The granitoid massif Strzegom-Sob6tka of Variscan age

in

Lower Silesia bears numerous vein and warld-famous drusy pegmatites with the extensive mineral association. The earliest observations on mineral assemblages of this massif were summarized by Traube (1888)

and

next by Michell (1941). Fersman (1960. pp. 135-137) and Kowalski (1967).

The controversial problem of pegmatite genesis which has widely been discussed _ _

from

variOUB viewpoints in many cOuntries

(e.

g.. Andersen 1931; Hess 1933; Bjerlykke 1934; F.ersm.an 1952, 1960; Jahns 1953; Ru- denko 1972; Nenec 1976; Koz):owski 1978) does not yield a definite bearing upon

the

role of hydrothennal solutions in fonnation

_of

the medium-and late-stage minetal parageneses in pegmatites. 'The studies by means of the inclusion methods of hydrothermal fluids that formed minerals in the Strzegom

~gmatites

are still scarce _{and ·} incomplete (KozIowski 1973. 1981; Kozlowski

&

Karwowski 1973, 1sr74, 1976).

This

paper is a contrilbution

_to

the knowledge

of

parent fluids of the late- -stage fIuorite-bearing parageneses in the pegmatite druses. .

AcknowlqJl1ements. The Authocr wishes :to admo'W'le4dge the gram of the P<>- :tocki's 'FOlmdaItion., whlch made ;POS&iNe 'his 'wOrks with fluid ~ as a visit\Jing

6fc'ien.tmt

at thtl U 1:3. Geo1.ogica:l Survey lsaiboratorie8.

132 A. KOZl.OWSKI

METHODS

The routine mebhQd8 of the notIl-destrulcti.ve itllclusion studies were used. The homogenization. temperllJt;ua:els (Th) of fluid i.nclil.llS.ians were performed: 0iIl: the Author's construction micros'cope heating stage with the precision i=2°C. The ftreezi:ng runs were made by the Author in the E. Roedder's laboratories, U.s. Geo:- logilCal Survey, National CeDter at Restoo, Vd'11!l1inia. The useld freezing/beating rxUcroscope gas-flO'W stage (Werre & al. 1979) y;ielded resWts 'Wi:th preclBion UoC in temperature range from 0 to -10°C 8Ild '" l°e at -70 to _100°C. The prepantioos were made by double-side poil.is:lJLng of cleavage cbi:pB of fluorite crysta1s. B.eI'ractIWe fIDc&es of lalboratory.,prepared salt solutd.<lIlS w.ere measured at temperature 20°

' ±

0.1 CC by refractameI;ric method.

THE INVESTIGATED SPECIMENS

The fluorite specimens for inclusion studies were taken from typical pegmatite druses in the quarry No. 18 at StrZegom-Grabina. Fluorite- -bearing paragenesis crystallized

in

the pegmatite zone cOiIlBisting of gray and smoky quartz, albite, microcline, and

biotite

partly or com- pletely . altered in chlorite; Usually epidote,

later

than the previous minerals precedes .here fluorite; it

was

however, also .partly coeval with fluorite and partly younger. other minerals paragenetic

with

fluorite are represented by rock crystal, chlorite (strzegomite

=

striegovite), tourmaline, and locally calcite. Strzegomite fll'equently forms zones of inclusions of O.n mm size in fluorite crystals. Brownish-gray, blue-gray or pale blue, almost colorless tourmaline needles up

to

1 cm long and 0.1 to 0.5 mm thick, either pierce fluorite crystals or occur as solid . inclusions in

the

latter:. Calcite and the zeolites are later than fluorite

in all

the studied druses.

Fluorite crystals al"e octahedral, mare or less deformed, of light to very pale violet oolor

with

a· p-eeniSh-blue tint, and with intensive violet zones outlining the octahedral habit. The deep violet zones are 0.1-0.5 mm thick and frequently are associated

with

prima1'y in- clusions of fluid or: fluid plus trapped minerals.

FLUID INCLUSIONS

Fluid inclusions in the Strzegom fluorites have

first

been described

over a century ago (von Lassaulx 1877), but tentative determination of

the

Th

range (160-205°C) was performed about ten yeaLl"S ago (Koz)ow-

ski

&

Karwowski 1973). More detailed data on

Th

of fluid inclusions in

the Strzegom fluarite are given by. Lenkowski (1983),

who

extended the

Th

values range to 130-255°C for pegmatitic druse floorites and

120-390°C for vein fluorites. Some

Th

values (130-185°C) are also

submitted by Janeczek (1983), and they do not fall out the above limits.

ACTA GEOLOGICA PCLONICA. VOL. 34 A. KOZ1:.0WSKI. PLo 1

Fluid inclusion (0.38 mm long) i.n fluorite from the Strzegom pegmatite 1 - Rocm temperature

2 - frozen to -60⁰

3 - at _32°C. ice orystals only

, - at -39.2°C, flilUng recrystalliz.ed to large crystals, "?" - marks doubtful liquid +gas CO2

5 - at -72°C, boundary betwe€n host fluorite and liquid phase is invisible 6 - at -40·C, separation of ice (i) and hydrohalite (h) crystals

INCLUSION, SOLUTIONS IN FLUOlUTE

133

The studied fiuorite crystals yielded

Th

from 165 to 180°C and the inclusions used for freezing runs had even a more narrow

Th range~

from 172

to

180°C. Hence, these

Th

values plaCe the crystals under study in the middle of

Th

range hitherto

lmown

fOlj' the Strzegom pegmatite fluOIrites.

Free7Jiing studies were peI'lformed 0Il1 several la:rge (0.1'--0.4 mm) two-phase irdusions ccnta'iDilcg' typica'l ti.1lirlg, i.e. gas

'<

^ldquid (Pl. 1, Fjg. 1). The in- clusions were undoubtedly. primary and under the microscope they did not S'how vi- sible traces of any kind of leakage or epigerietic alterations changing phase ra- tios. Unlike this deSCription, most inclusions were first submitted to the freezing runs cm heatmg, and two ccnt.rol 0IIleS were f.irst homogenized and next frozen.

No substaDblal differences ~ fOlllJ/d. '

Dur.ing sillg1e :rapid f.reedng down to -130°C the mclusiJOtn filldlng did not crystallize as it usually occurs in so large inclusions. Only a series of freezing- -~ shooks caused bIreak otf rnetas1able ~rooo1ing 80d crystalllzation at

~O to --6'lOC. raWly to -'7tOOC (lP1 1, F,ig. 2). The erysta.l1ization f1ront moved f'l"OIn

one of the inclusion corners, usually with sharp edge or POint, evidently stimula- ting CJ."3"&ta1HzaMoo..

, The frozen inclusiOlIlS started the eutectic melting at Te: from -54 to -58°C, approxilnately. The 10lW precision of. Te determ:ination. was ca'USEld by daffieult' ab8ervaticm of fiIrst portion of ]liquid in ql8que inclusd.O'IlIS filled by aggregate of fine crystells. However, the Te value indicates that the molusd.on ftl:1intg is essen- tially CaCl.-NaCI-HaO solutiO!Il, becaw;e Te in this ,system equals -52°C (Yanateva 1946; some sources give the value -55QC, e.g. Borisenko 1975). Thus, the inclu- sion. was in the point E cm. the CaClr-NaCl-HaO plot (Text-fig. 1), with theore- ., ti!eal _68.8 eutectics

an

incl·usion filling, consisting of 1.8 wt.

°/.

NaCl, 29.4 wt.

°/.

CaCI ••

wt.

'I,

HJP (Cmwioro 1981), plUiS ex.oess NaCl as NaCl· 2Ha0 (hydr.ohaHte) 8lIld 11.0 ice. If NaCI is more abulnidant in the solutm; CaCJ..· &HJP (anwcticite) meltB first and during the T increase the ~ starts to follow the cotretic curve separatiing the hydrohalite+eo1utim and ice+so11.1JUon fields. IIDclusdon filli!ng is now the mixture of ice and hydro'halite crystals floatllng in NaCI+

+caCl. solution, with dec.reasdng hydrohaHte ooatem. In :tile xepresenl;ative of the studied inclusions the last hyldrohaUte cry~ melted

at

--412.3OC and the system left the cotectic curve in the point B (Text ... fig. 1), starting to move across the field of lce+soluUOQ.

, The point B may be used fOIl" determination _of fbe CaCl. to NaCI ratio by the

lever method. For the sWktiei! mclusioos thi:s is 25 W'f.l.

'I.

^CaCl. in dry salts. ' From this moment, lice :is the 0IIlly crystal phase

m

iJnclusLon ~. 1, Fig. 3).

However, _'the detemlJrnation _of the last meltfalog bydrohalite crystal is not a trivial aperatioo. _I.n mixfure of many crystals it is posaiIble to miss it aDd to determine the point B ea<meaIJISly. Recrystallizatioo. of the mclusion ccmrtent from few small cryl!fl;a·llb.atioo nuclei may be recommended (Pl. 1, Fig. 4), as well as a use .of-op- ti'Cai fea't1lrES: -ice has Iow refractive .indices (in ID 1.3091, n. 1.3105 at -1 CC) a'Ild pa.ral.lel light extlnctioo due hexagonal strocture. but monoclinic hyUrohalite has Oblique JdJght ext..intf.on. PrqperIy made recry'lPf;allizatioll causes qtUilte good se- pen¥tion fo hydrobaI!1Ie and f.ce (Pl. 1, Fjg. 6).

Melting of ice crystals occru.rs somewhere between the paillt B and the H,O corner for solutions of variouB salt coocentrations. lIIl the 9bu.died maJteria1 the last iee crystal melted at Tm 21.1 QC (point A in Text-fig. 1). This helps to de-

termine

the total salt' cOOCenJtratdan CaCI.+ NaCl in the lJOlutLon filliJDg mclmion,

134 A. KOZl.OWSKI

equal here 24 wL'l. (point C in Text..-. 1). ThUB,

combiIninc

data from points D and C, the main COII\'IXmeDifs at iDclusion fillitIg are: H.O - 78 wt.-I. CaClz - 18 wt. '/" and NaCl - 6 wt. ^0/0.

Some adcli:tliDDBl oibservalti.'ODs were made dwiDg h'eezfIDg rl.llM. During attempts of crystallization of the whole i.nclusiO!D filling from few ice or/am:! hy- drohalifle c.rysta·]s (t. e. (]I], the path from A to E excluding etal1t 21Dd fiInaol points) a pad of the filling rema'ined in meta.stable liquid .state (PI. 1, Fig. 5) even. at temperature aB law as -126°C, i. e. much belOW' the eutediic tempera1lllre. This probably s~ be explained by strong ten~ of IIlaIny ca1d.um sa1!t solu1xloos to metastablllty. At temperaturea -72 to -1J8°C in. 8UCh roDS only 4()-,30 vol.'l.

of inclusion was OOC'I.Wied by solution, contam:ing almast excll.Bively 'all CaCI.

solute present in the mclusion, i.e. very CIOIlWentratted.

CcmcentratiOlD of caCI. in tha.t remnaut solI\1f1i.,oo caused the phenQl'DtlllOll at·

disappearance of the phase ooWldary between the solution and the crystal- fluorite, best visible at -70 to-80oC. This means that the remnant solution reached such ooncentlratloo thilt ita refaJOtmve index equal!S he ~ :iodex of f1fu<rite (1.434 at 20°C). Meaa:uremen1:s of refI18Ctive indices' at sol'1llfS.Oll8 of salts that are reasonable an hy'drot'belrlnal soluti.OO$ (Text-fig. 2) prove that anly CaCll

is

the

Fig. 1. Pa!rt of the plot txt the CaCl.--NaCl-H.osyil'tan

!With the

path Of evolu- tion. of the studied iIDclt.JSfioo flWids (E-B-A); :weight pm:ent&, data tr.om Yanarteva

(1948); see tezt for otbelt" explaoaUODB

INCLUSION SOLUTIONS IN FLUORITE 135

8fI:IPropa:date salt: solutdon of 40

e

CaCls iJn 100 ml of SOilutiGn has wo ,re.fractf/ve index 1.434 (at 20OC). Temperature varlaUons cbange the refractive index va:lue . but not so eseeotdally to 'm8Ide this ev.idance inva1id.

DUl'IIllg free7Jllng l'II.II:I$ the searoh for liquid

co.

iIi ·iDclUillions was made a:nd .specif·ic feature IWBB OIbBervefd .w.hich may be iz:Iiter1preted er.roneowlly u riIrn of liq!Ui.d CO. aroU!Ild _pS lUJb:le jn a vaeuole eIllIbedIcieId :10 me+hydrohallte, Where salt solutioo. from DIther pa:rtl; CIf Jnc1:ueioo. 'was sucked or dnjecIied, fat'llllilDg liquid layer. HOWE!Ve"r, the sma:1l "~lc" b~le in \he left pari of iDcluslon (pI. 1,

Fig.<; 4 _ 5 ; marked "?") C8D!Dot be expla:fned satisfa'C!t!olrily, a.lthough _1~ looks

like liquilli plus gas Co..

1.48

1.42 1.40 1.31 1.36

1.34

..

lit

..,

Fluorite

---

A~: ~

~~

• • KCI

.~:~

i 1.320=---~=---~~----~~----~---5LO---~60

-

.. 1.44 FluOrite

>

---~-

~,.a .w~

:; 1.40

1.32=---~=_----~~----~~----~~~--~~---J

o

G/l00ML

Fig. 2. Befrdve iondices of solUtions of scme selec1:ed salts

,136 A. KOZl.OWSKl

FINAL REMARKS

The presence of calcium-rich late-stage solutions in the Strzegom pegmatites might be also deduced from the abundant occurrence of ot- her (than fluorite) calcium minerals: epidote, Ca-zeolites, calcite. The source of calcium may

be

expected in the extensive process of plagio- clase (oligoclase) albitization (Kozlowski

&

NoWlikowski 1981, Nowa ..

kowski

&

Kodowski 1983), which precedes the fluorite fonnation. The fluorite crystallization from calcium-rich solution should be limit-ed by the inflow of fluo' rine, immediately oonswned for CaFll precipitation.

Those solutions were supposedly low in magnesium, carbonate and sul- fate ions, becaus·e otherwise sellaite MgFll (Sc'haefer

&

Striiobel 1979), carbonates or sulfates would occur in inclusions as daughter minerals.

The only caUon, the presence of which is possible in limited amount in the inclusion fluid,

is

potassium.

SimilaJl." calcium-rich fluids are not extraordinary in various endo- gene geological environments and they have hitherto been recognized

also

in the scheelite deposits (Hing 19'79), in metamorphic rocks (Craw- fon!

&

al. 1979), and in present-day rift zones (Hardie 1978).

Institute 0/ Geochemistrtl Mineralogy and Petrography

0/ the Warsaw UniverBtty, Al. ZWiTki i WiguTt/ 93, 02-089 Warszawa, Poland

REFERENCES

ANDERSEN O. 1931. Dl.sc:u8ai.Gl. at cer-tain phaSe(! ~ ~ geIleSis.at pegmatites.

Norsk Geol. Tid.sskr., 12, 1-56. Oslo.

BJ0RL YK:KE

:a

1934. The mLneral pal'&gIe'DeSie.~ .clal!si1icaMon of. the gra~ite

pegma.tites Off IvelaDd, Setesdal, SoI.It.bern, NGl'WllY •. Norsk 'Geot T~dsskT •• l {

(3), 211-311. Oslo. '

BORISENKO A. S. 1975. Determilnation of carilonates and, blcao:tbolnaltes at sodium i!D. solutions m gas-lJquid iincluSli.alJs, by. c:r;ratile.try. JI)ethod. TriJ,rjyZSOVMO.

2. 98-104. Novoefb1l'8k.

eRA WFORD M. L. 1981. Phase equilibria -in aqueous fluid inclusions. Short course in fluid ~nclusions: applications to petrology, 75,....100. Cs.'py. . KRAUSS D. W. & HOLLISTER L.S. 1979. Pet.r.Qlopc and fluid lnclusi~'study of,

e'alc-6ilicate rocks. PIliInce R~, Brdtlsh-Columbia... .timer .. J.Sci., 279 (10),

1135-1159. New Haven. .

FERSMAN A. E. 1952. Mlil.eraJ.ogy of granite ,,peganatites: Selec'ted workS, 1.

9-80. AN SSSR Publishing House; MOBOOIW. .' . '

-- 1960. Pegma.tdtes: Selected warks, 8. AN SSSR Publishing House;, Mosco.w.

HARDLE L. A. 1978. Ev8(pOl'li:tes. rirf1lI!lg BQd the role

o.t

CeClt hydrothermal bri- nes. GeoZ. Soc. Amer. Abstracts with Programs, 10, 416. Washington.

HESS F. L. 1933. Pegmat£tes. Econ. Geo!., 28 (5). 447'-462. Lancaster.

RING T.T. 1979. The geDeSis of the Kdng lslaInd 3I::hesldJte ~I,phin) depoott. as detarmilned from fluid inclusions aDd mineral chemfJcal zoll1ilng studies.· Ph. D. disserta«on. La Trobe Univ.;Melbourne. . . JAHNS

R.:a

1953. The genesis of pegmatiJtes. Amer. Mineral., 38 (7-8). 563-598.

MenaBha.

JANECZEK J. 1983. TrlllDoSfOll1mations at minerals in pegmatdotes from Strzegom (Lower Silesia). Arch. Mineral.,' 89 (1), 39-051. Wat'SzaJW8.

INCLUSION SOLUTIONS IN FLUORlTE

137 KOW ALSKI W. 1967. GeochemiBtry lead, barium Mineral., 27 (1), and 53-a44. Warsmwa. B'IlraDiIrl.'Um in Sudetic at potassium, sodium, calcium, rubidium, granttolids and their pegma'tiltes. _Arch.

KOZLOWSKI A. 1973. granl.tofds (Lower Pos:t~tic stlesda). Acta GeoZ. polon., quartz of the 2S St~ (2), 341-363. Warszawa. and Kar~

1978. PI!leumatolytic aDd hydrothermal acUvity iIn the Karlronosze - Izera block.. Acta Geo," Polon., 28 (2), 171~222. Warszawa. . 1981. Inclwdan c.rycmetry

m

fluOl'lite :ftrom the Strzecom pegmatliltes (Abat.).

Sctentijic Session "igne formata' 81", 13-14. Wlld. Geo1.; Warszawa.

& KlARWIOWLSIKI L. 19'13. Bromine and chilorine in g,aseous-liquid inclu&1ons in hydrothermal minera.ls from Lower Silesia. Arch. Mineral., 31, 281-295.

WaI'5ZalW8.

& - 1974. Ch1ormelbromiJDe ratio iIn flUlid mclwicms. Econ. GeoZ., 68 (2), 208-271. Lancaster.

& - 1976. Bromiale-chlorllle ratdo in hyd!'othermal solutions. Bromine in salt deposm SIld brIiDes as geoc.hemical indicator, 364----\i70. Moscow Univ.

Publishing House; Moscow.

& .. NCCWAKQWSKI A. 1961. Ortgjn and form~an ccm,iditiJcmB O!f albite in pegmatiteS.

m

graoiJtes tram KaIrkalOlSlZe and strzegom, (AJbst.). Scientific Session "igne formata' 81", 1~13. WlId. Geol.; Wal"S7:awa.

LASSAULX A. von. 1877. De!' Fluorit von Striegau und K6n'igshayn in Schlesien. Zeitschr. f. KrystaUogr. u. Mineral., 1 (4), 359----\i70. Leipzig.

LENKOWSKl W. 1983. Physf.oo-chemical COIldltioos _-~a1;ure of crystallization at the low- mdnera1 palr8genESeS in the Sttrzegom ma6Sdf. Arch. Mineral., 39 (1), 53-66. Warszawa.

MICHELL W. Amer. Mineral., D. 1941. 26 (4), Parag~ ~275. of Menasba. the pegmatJlte nti!nera.]s _O!f StlriegBu, Siilesia.

N1tMEc _ulnd D. 1976. Versuch einer Mihrens. Chem. Erde, pangenet:iBchen

as,

126-157. Ber'lfIn.· AlnalY8e der Pegm8ltite BOhmens _I NOWAKOWSKI pegmatites. Arch. Mineral., A.. & KOZLOWSKI 39 (1). Wars.za.wa. _A. 1983. Orllgfn of alb6.tein the granitoid RUDENKO S. _{wordm at} Leningrad Univ. Publushing House; I,.en.!.nvad. A. scientists 1972. Development of the Leningrad Mining Institute. Pegmati:tes, 3----\i5. of kIoowl~ an the pegmatd:te genesjs in SCHAEFER B. & STR'O'BEL G. 1979. Hydrothermal solubility of fluorite symem CaF~I..--HaO. Neues Jahrb. f. Mineral., (5), 233-240. Stuttgari

m.

the TRAUBE H. 1888. Die Md!nerale Schlesiens. _J. U. Kern's Verlag; Breslall.

WERRE R. W., A novel Abstract with Programs, g~f1aw Jr.., BODNAR flWd inclus·ion heat1ng/freezillg 9tage. 11 (7), 539. R. J., BETHKE P. M. & BARTON P. Wash~. Geol. Soc. Amer.

a,

Jil'. 1979.

YANATEVA O. K. 1946. Solubility polytberms in the system CaCli-MgCl.-H,O and C8Cl..--HaO. Zh. Pnkl. Khimii, 19, 709-722. Moscow. .

136 A. KOZl.OWBXI

A. KOZLOWSKI

BOZTWOBY WAPNlOWE W .INKLUZJACB WE PLUOBYCIE Z PEGMATYTOW . 8TBZEGO~

(StreBzczenie)

Prozedm£otem pracy jest UBt8ileaie aldaidu ro()flJbwQr6w maclerzystyoh fluarytu z pegmaty:tOw Strzegamda meted, badlanda lIl!klu.zji flulda1n.yC'h, ktoryoh telniPera- tury IraInogeo;izacji 'WyDOIIUy od liJ5 do 180OC. ZaIttosowano zaIm.r8r1.anie iDkl'IJZji do tellltPera:t.Ull"Y -130°C (pI. I), a na&tlplfe fizylrochemicznfl 8IDa1~ ~an

w ink:luzjQch podcza& :zmian temperatury (f:ig. 1) :l pcrOwoanie wJsBnooScl optycz- nY'Ch roztwor6w w mkluzjach ~ rozItworillw syotetycm;ych

<-.

2). Stwierdmno, ze badane fluory:ty krysta:lizawaly z rozt.wor:u, 0 sklatdzfe 76'1. wag. H.O, ·1~/. wag.

CaCI. i ~/. wag. Neel. SIIdad ten Ja do~ rzadk!l, ale • wyJ,'tkawy w !l"<lmla1-

tych !r000wll£kaclJ. ~h.