TIIE AMERICAN MINERALOGIST, VOL. 56, SEPTEMBER-OCTOBER' 1971

NEW OCCURRBNCE OF YUGAWARALITE FROM THE

CHENA HOT SPRINGS AREA, ALASKA1

G. DoNarl EnEnluN, R. C. Enn, Fr-onBNcB Wnnnn,

aNp L. B. Bn.n'rrv, U. S. Geological Suroey,Menlo Park, California 94025.

ABSTRACT

Yugawaralite (CaAlzSieOro'4IIzO)' a relatively rare calcium zeolite, was found in a new

locality near chena Hot springs, east-central Alaska in a geologic setting that difiers from

that described for occurrences in Japan and Iceland. It occurs as well-formed' quartz-

encrusted crystals up to 8 mm long, elongate along the a axis and tabular parallel to [ 0101.

reported by previous workers.

Chemical analysis shows SiOz 61.47, AI2OB 17.38, FerOr<0.04, TiOr<0.01, MgO(0'01,

CaO 8.51, SrO 0.21, NazO 0.06, KrO 0.09, HrO+ 9.33, t{zo- 2.79, total 99.90 wt' /6' In

apparent deficiency of cations lruror/(nro+no):1.09] disappears if H+, which is 0.3737

ions per formula in excess of that required by an ideal SH:o in the unit cell, is present as

oxonium ion.

Thermogravimetric analysis gives good agreement with TGA curves from the tlpe

Iocality. Ion-exchange values determined show a low-exchange capacity as compared with

most zeolites. Infrared absorption spectra obtained are distinctive but have similarities

to tlose of the heulandite grouP.

INrnooucrroN

Yugawaralite, a relatively rare calcium zerolite, was first described by

Sakurai and Hayashi (1952) fiom "Fudo-no-taki" Fall, near Yugawara

Hot Spring, Kanagawa Prefecture, Japan. It has since been reported

from Heinabergsjiikull, southeastern Iceland (Barrer and Marshall' 1965;

Walker, in pressl See Kerr and Williams, 1969, p. 1190); the Onikobe

geothermal area of northeast Japan (Seki and Okumura, 1968); Shimoda'

Shizuoka Prefecture, central Japan (Sameshima, 1969); and the Tanzawa

Mountaihs area of central Japan (Seki el el., 1969). We here report on a

new occurrence of yugawaralite in a geologic settiDg different from those

eprlier described. To facilitate comparigon, this first complete description

since that of Sakurai and Hayashi (1952) includes corrected and refined

I Publication authorized by the Director, U' S. Geological Survey'

1699

1700 EBERLEIN, ERD, WEBER, AND BEATTY

crystallographic data obtained by restudying samples from the typelocality.

Unless otherwise specified, all statementsto material from the vicinity of Chena Hot

EXPLANATION

AlluviumCnve| sand, and silt

N!

Porphyritic quartz monzonite

F|iTnrfimIII/JJJJJIII

Gray- black multicolored phyllite and;slateStippling idicates honlels

.

Quartzite, metachen, and argilliteSti ppl i ng i ndi c ates honle t,

f/7-Calcareous phyllite

: -:---\Con tac t

Dashed where nferred

l**lQuartzite, quartz muscovite, and

biotite schist

Index and geologic sketch maps of yugarvaralitelocalitl', Chena River area. Alaska i

regarding yugawaralite referSprings, Alaska.

FrBr,n OccuRRENcE AND GEoLocrc SETTTNG

The new occurrence of yugawaralite is in the yukon-Tanana uplandon the north bank of the chena River, approximately 40 miles east ofFai rbanks, Alaska (NW1/4NWlf 4, sec.20,T. I N. , R. I E. , Fai rbanksmeridian). The upland is underlain by complexly folded and faultedschist, gneiss, quartzite, phyll ite, slate, and metachert of precambrianor early Paleozoic age which have been intruded by granitic rocks ofMesozoic and Tertiary age.

Yugawaralite, associated with quartz, laumontite, stelrerite (Erd, et al.,1967), and sti lbite, occurs mainly in a sil iceous xenolith about 150 feetlong and 60 f eet wide near the edge of a small porphyritic quartz monzo-nite piuton 1-| miles long and f mile wide (Fig. 1). The quirtz monzoniteplutc-n may be an apophysis of a much larger intrusive that is exposedacross the chena valley to the southeast. The host rock of the yugawaral-ite is brecciated, sugary-textured metachert, or very fitr. g.uio.d quart-zite that is veined with quartz, chalcedony, and. minor opal. At ioint

)

)

t s C

) zo i

I rv ^ sN U <9 iE= E

e

3

d =

z H< xg iIe

5 t 0 M T L E S

Frc. 1.

VUGAWARALIT E FROM A LASKA t70l

intersections, quartz-encrusted yugawaralite erystals up to 8 mm long

coat joint surfaces and v\rg-like enlargements. Locally, fractures are com-

pletely filled with yugawaralite, quartz,'stellerite, stilbite, and laumon-

tite. A film of hydrous irbn oxide coats quartz and'the surface of many

yugawaralite crystals. Crystals of stellerite and stilbite are closely associ-

ated with the yugawaralite (Fig..2). A soft white powdery coating of

Iaumontite commonly occurs on crystals of yugawaralite, stellerite,

stilbite, and quartz in the vugs.The quartz monzonite contains 25-30 percent plagioclase (Anas15),

35-40 percent quartz, 25-30 percent potassium feldspar, and about 5

percent biotite; accessory minerals are zircon, allanite, greenish-brown

tourmaline, and cerite. Potassium feldspar occurs as xenomorphic

phenocrysts, up to 1-] cm in diameter, that enclose the other minerals.

The pluton has many. features in common with other intrusives in the

Yukon-Tanana Upland that have yielded tate Cretaceous to early

Tertiary isotopic dates.

Frc. 2. Yugawaralite (y) and stibite (s) encased in quartz (q) scalenohedrons

1702 EBDRLEIN, ERD, WEBER, AND BEATTY

At least three episodes of fracturing-and late mineral deposition areindicated:

(1) Early minor fracturing of the host rock and introd.uction of whitevein quartz that probably was derived from the enclosing siliceoushost rocks.

(2) Brecciation and recementation by chalcedony and white quartz,probably at the time of intrusion by quartz monzonite.

(3) Late fracturing and introduction of quartz, yugawaralite, stelleriteand./ot stilbite, laumontite, chalcedony and "minor opal in theorder given.

The association of yugawaralite with laumontite and quartz in an areaof thermal-spring activity near Yugawara Hot Spring, Japan (Sakuraiand Hayashi, I9S2); the occurrence of yugawaralite with laumontite,analcime, and quartz in a drill-hole core at an active geothermal area atnortheast Japan (seki and okumura, 1968); and the fact that the Alas!.aoccurrence is only 14 miles from chena Hot springs suggest the possibil-ity of a similar geothermal origin. There is, however, no evidence of pastor present thermal spring activity at the yugawaralite locality. Further-more, th.e. chena Hot Springs are dilute thermal waters of probablemeteoric fuiqin that contain considerable silica and sulfate ions, Lut littlecalcium afld magnesium. very little mineral deposition is now takingplace at Chena Hot Springs.

GBocgBurcer, IuplrcarroNs

The geochemistry of zeolites and their natural associations have beenreviewgd and brought into better perspective by coombs et at,. (19s9),Senderov (1965), and seki et at. (1969); and significant contriburions rothe understanding of high-silica calcium zeolite assemblages have been

perature range 200o-300oc. Deposition probably occurred from relativelyalkaline aqueous solutions in which the activity of silica was equal to orexceeded that of quartz.

Cnvsrnr,rocRApEy

X-ray dota. The fuh\,0k1, h\t, hhI, and, hll reciprocal nets were photo-graphed using Zr-filtered Mo radiation. systematic absences indicate the

Y UGAW ARA LIT' E FROM A LASKA 1703

space group to be either Pa or P2fa.1 Yugawaralite from Alaska andJapan is piezoelectric at various frequency intervals between 1.3 and3.6 MHz. Furthermore, pyroelectricity and etch-pit symmetry (de-scribed below) confirm the absence of centrosymmetry. These data agreewith the findings of Barrer and Marshall (1965, p. 485), Kerr and Wil-I iams (1967, p. 222), and Leimer and Slaughter (1969, p. 94), all ofwhom, by statistical study of intensities, found yugawaralite to be non-centrosymmetric. Our data for the unit cells of yugawaralite from Alaskaand from the type locality at Yugawara Hot Spring, Kanagawa Prefec-ture, Japan, are shown in Table 1.

Our X-ray powder data for yugawaralite from Chena, Alaska (Table 2)agree closely with such data for yugawaralite from Heinabergsjcikull,Iceland (Barrer and Marshall, 1965, Table 3) and from the Onikobe andTanzawa Mountains areas, Japan (Seki and Okumura, 1968, Table 2).Our data for yugawaralite from the type locality (Table 2) agree well withthose given for yugawaralite from this locality by Neumann et al. (1957,Pl. VII, no. 49) and by Seki (written communicatipn, 1965), but they arein poor agreement with the original X-ray powder data of Sakurai andHayashi (1952). The later data of Sakurai (1953) and Harada et al.(1969a) for material from the type locality are in good accord with ours.

Morphology. Crystals of yugawaralite are tabular to lath-like, flattenedparallel to the most prominent form {010 } , and elongate on o. Some largercrystals occur in elongate tabular aggregates of as ma.ny as eight indi-viduals oriented parallel to { 0 10 } . The central crystals of such aggregatestend to be thickest and longest with progressively thinner and shortercrystals developed outward alongb. The crystals are euhedral; no twin-ning was observed. No doubly terminated crystals were found. The formsnoted and the interfacial angles measures on 18 crystals are shown inTable 3. A typical crystal is sketched as Figure 3.

Morphological departures from centrosymmetry are slight; this is con-sistent with the presence of a pseudocenter for the yugawaralite frame-work reported by Kerr and Will iams (1967, p. 223; 1969, p. 1188).Nonetheless, the absence of a center of symmetry is expressed byperceptible differences in the interfacial angles oI l\hll and {0ft7} domes

r We have followed the recommendation of the Commission on Crystallographic Data,International Union of Crystallography (Kennard, Speakman, and Donnay, 1967) intawng cla in designating the space group. Transformation from tle setting of previousworkers (space group Pc) may be accomplished by use of the matrix 01T/0T0/100. Thesetting of sakurai and Hayashi (1952) may be transformed to our setting by using thematrix 00T/0T0/$ 00.

1704 EBERLEIN, ERD, WEBER, AND BEATTY

TABLE ].. UNIT-CELL DATA FOR YUGAI,IAMI,ITE

Chena Hot Springs, Alaskaa Yugawara Hor Spring, JapanD

Crys ta l sys ten

Space group

c

B

Cell voluoe

Ce1l content

Density (ca1cular.ed)

Spectfic gravlty (neasured)

Monocl inic

gd

10. 04310.0021

13. 99 7 iO. OO3i .

6 .725!O.OO2L

111 'L1 | 11 |

881 . 5 r0 .283

2 [CaA12Si .EOl 6 . 4H2O]

2 .225 gcm -

2 .22rO.Otc

2 . 2 2 ! O . O L d

Monocl lnic

10. 05o io . oo2! ,

14 .00810. OO3L

6.7 2g !O,OOzf ' ,

111 '11 | 11 '

883 . 3tO. 3;,3

2 [ CaA12 St60t 6 . 4H20 ]

2.221 gcm-3

2.22 !O .Ord

t In l t iu l paraneiers fron idray single-crystal precession data, Final

paraneters fron least-squares ref lnement of X{ay powder data (Tab1e 2).

b u . s . N a t i o . o l M u s e u m S p e c l n e n N o . 1 0 1 3 4 .

c Determined by the sink-f1oat method and centr i fuging using bromoforh-

a c e t o n e m i x t u r e s w h o s e s p e c i f i c g r a v i t i e s w e r e c h e c k e d v i E h a W e s t p h a l b a l a n c e "

d Detemlned in CO14 using a Beman balance (average value referred to

d i s t i l l e d s a t e r a r 4 0 C ) ,

and by solution effects upon these domes, the llkl,l domes being invari-ably more corroded than domes of the lype lUkll. Furthermore, thepedion (001) is normally less well developed than the pedion (001) andIocally may be absent altogether.

Natural etch pits, produced by weathering, by Iate hydrothermal solu-tions, or perhaps by cold groundwater of appropriate pH, are present(Fig. 4), especially on {101} and (001). The pits appear to be formed bycentrosymmetric pairs which, if considered alone as evidence, would indi-cate h igher symmetry. The p i ts are made up to {010} , {110} , and {021}on {OtO} and of (001) and {110} on (001). Etching with dilute HF pro-duces curved,triangqlar (shield-shaped) pits (Fig. 5) whose bases areparallel to c and whose sltitudes are parallel to o. The pedion (100) anddomes {ftftO} show practically no effects of solution by natural weather-iog.

YUGAWARA LIT E FROM A LASKA

TSLE 2. X-RAY DIFFMCTION DATA TOR YI'GAIIAMLITE

Observed

h h t d h h u ( & ) I ( c a r c . ) b I ( c a 1 c . ) c

1705

65

605

5 4

3

5I 719

52

I4

185

6 , 0100.0

1 . 0

3 , 13 3 . 6 I46 .7 |0 . 4 )

7 5 . 8

0 . 8

0 . 24 . 0

3 . 1

,;'.; IL2.3 )

2 . 02 . 6

0 . 42 . r l

e s . 1 |! 4 . 7 )

o . 7

1 4 . 52 7 . L

3 . 0

1 , 0

010IIOo20001II I011r20I2L200o2r03020L210

1 1 1130

22L1 2 1

040

25Lr40TL2

20L31t2022rr0022L2141o1204131072232r22r2 2 2022320240

050247

23I2131330517322 I I

1 3 . 9 9 7 3 . 37 . 7 8 3 8 . 55 . 9 9 9 3 7 . 06 . 2 7 0 6 . 85 . 8 0 9 1 0 0 . 0s . 7 2 2 0 . 45 . 5 0 6 2 . 84 . 7 L 7 0 . 54 . 6 4 2 2 9 . 44 . 6 7 0 5 4 . 24 . O O O ) . 2

4 . 6 4 L 8 3 . 14 , 4 4 0 5 , 64 . 4 0 5 1 3 . 94 . 2 9 3 3 6 . 04 . 1 7 6 1 9 . 33 . 8 9 2 7 . 83 . 8 6 8 0 . 73 . 7 9 L 1 . 0

5 . t l J J . J

3 , 4 9 9 0 , 13 . 3 0 5 4 . 73 . 2 9 0 2 . 93 . 2 7 8 1 . 53 . 2 6 4 5 . 43 . 2 4 3 7 , 3

3 . 2 2 3 1 1 . 93 . L 9 2 2 . 83 . 1 5 0 2 . 73 . 1 3 5 6 . 0

3 . 0 6 9 0 . 13 . 0 5 9 1 . 11 . 0 5 6 9 t . 23 . 0 4 7 1 5 . 93 . 0 3 0 2 . 02 . 9 9 4 3 . 52 . 9 3 5 r 5 . 02 . 9 0 5 2 2 . 92 . 8 5 1 4 . 12 . 8 5 1 0 . 82 . 8 0 3 0 , 5

2 . 7 9 9 0 . 02 . 7 9 4 0 . 42 . 7 6 5 1 5 . 32 . 7 2 7 0 . 42 . 7 1 5 1 3 . 82 . 7 0 L 4 . 52 . 6 8 2 t l , 82 . 6 5 7 4 . 02 . 6 4 5 9 . 4

1 3 . 91 . 7 86 . 9 9

5 . 6 2

4 . 6 6 8

4 . 4 3 94 . 4 0 24 . 2 9 34 . r 7 7

3 . 8 6 7

3 , 7 6 83 . 7 4 0

3.30r

3 . 2 6 3

3 . 1 0 8

3 . 0 5 6

2 , 9 9 62 . 9 3 62 . 9 0 52 . 8 6 02 . 8 4 6

2 . 7 5 5

2 . 7 1 5

2 . 6 8 22 . 6 5 72 . 6 4 4

3 . 2 3 7 2 9

3 . 1 9 3 6

3 . 1 3 2 63 . 1 1 0 5

3 . 0 5 7 1 0 0

2 . 7 6 7 1 2

2 , 1 1 8 1 1

2 . 6 8 6 1 3

2 . 6 4 8 9

Yugauars Hot Spr lng ,Japane

dnwtx> l

1 4 . 0 67 . 8 0 47 0 1 3 r6 . 2 7 4

4 . 6 7 2 7 0

4 . 5 5 2 6 74 . 4 4 2 84 . 4 L 0 1 04 , 2 9 5 2 64 , L 7 9 1 43 . 8 9 7 4

3 , 7 7 0 1

6 4

322 0

I4

1 0

1

30

55

2-998 42-938 102 . 9 0 4 2 2

2 - 8 5 6 3

0 . 00 , 9

1 5 . 70 . 0

2 . 8

Plus add i t iona l l ines a l l w i th I < 9

a A1 l ce lcu la ted spac lngs (A laska mter ia l ) l l sEea l fo r dhLa2.640 L .

lndices froE least-squares analysls of X-ray powde! alata using the digital

computer plogran of Evans eJ dL. (1963r,

" Va lues fo r the lnCens l t les o f the d i f f rac t ion rox im uere ca lcu la ted

from the atonic paleeters given by Ker. and Hl1fias (1969) usitrg the coquter

prog le o f Bore and sDi th (1969) .

t A . fo .

b , bu t ca lcu la ted f .on the a tomic pareeters o f Le ioer sd

Slaushter (1969) .

d Sp l i t o f a t ra lyzed (unr reared) sanpfe . X- ray d i f f rac to@ter con i l l t lons

are : Char t No. X-3084; Cu/N l rad ls t lon rCuL = I .54 I8 l ; s t l i con used s

in te rna l s tandard ; scanned a t 1 /4o 20 per adute ,e

U.S. Ndt lona l Museun Spec inen No. 10134. Char t No. X-3094. Other X- ray

d i f f rac toEeter cond i i ions as fo r " .

o

H

l d H

F i B. o

€ kq o

. PI N H

E Oo o lN J I d

O E €g od ! F

o id o u9 p . oH , ,

o > E

d o

a p 4

! ! oo od @

d oo F 5

6 p 9

EBERLEIN, ERD, WEBER, AND BEATTY

O 0 6 d @ d O 6 O O € )t o o $ o o 6 4 0 i o NIl 6

O O @ N $ - l O @ 6 - t oo o @ N N + O c l d o Nn d d i d

o o o o o N @ o @ o a +o o o o d 4 Q d o d N 4

o o o o o n @ 6 Q 6 - 6 06 6 6 h A S N { C | O @

- - /6 d o r s o H t s 6 6 N+ d o { 9 N h o o N N

Io l

@ i o l 6 Q { 6 6 0 f r $a d 6 o N N N o o r \ 9

d d r l

d 6 0 0 0 d i @ 6 N 6 ii s o o o + o 4 4 0 $ o

d @ c J O O d g c l - N 6 6N 6 6 5 6 6 5 @ O d + 6

d d d d d

+ 6 0 0 0 s @ d t s N o oi o o o o h o H H N 4 d

H 6 0 0 0 d @ o + t s 6 @N 4 6 0 6 6 { @ O d S 6

d d H d i

o o o o 6 { @ s o s N 6o o o o d 6 6 N 4 N O O

o o o o 0 @ d H d d s {6 6 6 4 0 N d N i o 9

I I

o 9 0 d 0 9 0 s 6 N o 6o 6 o o i { o N 6 O N N

o 6 0 0 0 6 N d H : s d6 @ 6 6 O N H c r d S $

l l

d t d o o o H d d l d l i t d l oo o d c i i N $ N 9 d so o o i i o o o o o d +

O o o d a S > x > x { {L I

d

66o

Ho

g

d

$,

oF

ts@

il

s@

il

N

N

c;

l

;

d 9

[ [

o + 6

o . . . d. . s . .

d o NN ' n i l

. ' s qo . . . r

d q {

t706

HFI.l

3

ots&o

Fil

H

E

oz

s

YUGAWARALITE FROM ALASKA

C t

1707

Frc. 3. Drawing showing optical orientation andtypical habit of yuga$'aralite from Alaska

The yugawaralite crystals are commonly enclosed by a quartz "en-

velope" composed of clear massive quartz terminating in small (to 0.3

mm long), multiple, scalenohedral crystals (Fig. 2). The envelope has a

maximum thickness of about 1.0 mm. The quartz forms on the {010},{001}, and {0ftr1 surfaces of yugawaralite, but breaks away at the inter-

fdce, especiatly easil! if immersed in water. The smooth inner surface

oI the quartz replicates the {010} yugawaralite surface. Outlines of pro-gressite zonal growth are best seen on thi$ surfdce, marked by edges

_1a

1708 EBERLEIN. ERD, WEBER. AND BIJATTY

Ftc. 4. Shield-shaped pits produced on (010) surface by etching with cold diluteHF. Note etch striae parallel to, near center of photograoh. (In air).

Frc. 5. Natural etch pits on (010) surface. (In air)

YUGAWARALITE F'ROM ALASKA I7O9

parallel to o and c. The pomparative width of lhe zonal bands shows thegrowth rate to be fastest along the o axis. A few quartz scalenohedronswere found intergrown with {0ft1 } and {001} forms of yugawaralite, butq.uartz is rarely present on {100} or {110}. Some l,ugawaralite crystalscontain fluid inclusions aligned parallel to the a axis.

AII the yugawaralite crystals that we examined were attached to thematrix surface by the antilogous end of the o axis. Many references tosimilar phenomena of attachment and unequal growth rates on polaraxes are found in Grigor'ev (1965, p. 24).

Puvsrcar, AND OPTTcAL PRoPERTTES

The physical and optical properties of yugawaralite are summarized inTable 4; the optical orientation is shown in Figure 3.

Indices of refraction for sodium Iight were determined with immersionIiquids checked by means of an Abb6 refractometer at the temperature ofdetermination. Crystals were oriented for measurement by means of thespindle'stage (Wilcox, 1959). The optical orientation data were mea-sured with a 4-axis universal stage using small single crystals immersedin a l iquid (n: 1.500) within a Waldmann sphere. When immersed in dis-tilled water the orientation remains unchanged, but the observed opticaxial angle (2H") is lowered (from 71') to 48o. A similar change in opticaxial angle of a stellerite crystal from the Alaskan locality was reportedby Eberlein and Christ (1968), who demonstrated that the value oI 2H"was directly related to the chemical potential of water in the crystal. Thedispersion remains r(u, distinct.

We find all crystals of yugawaralite examined from Alaska and fromthe type locality were optically negative rather than positive (Sakuraiand Hayashi, 1952; Sakurai, 1953; Harada et a|,.,I969a, and 6 and Leimerand Slaughter , 1969).

ZoNruc

An optical zoning was observed in crystals examined from both the newAlaska occurrence and near Yugawara Hot Spring, Japan. The zoning,which is displayed by differences in interference tint and extinction angleamong transitional bands 10-125 pm wide parallel to crystal edges, ismost obvious in sections parallel to the prominent {010 } form and is en-hanced by heating. Etching heated or unheated crystals with dilute HFproduces striae (Fig. 5) coincident with the zone boundaries. The causeof the observed zoning has not been determined, but such zoning may be

the result of compositional variations. Although no compositional vari-ation in Al, Si, or Ca could be detected in two independent electron micro-probe studies of heated and unheated crystals, the possibility remains

17 r0 EBERLEIN, ERDi WDBERJ AND BEATTY

TASLE 4. PHYSICAI. A{D OPTICAI PROPERTIES OF YI'GAWAXALITE

Chena, Alaska Yugawara Hot Spring, Jape

PHYSICA],

Cleavage

FractureHatdnessFuslbt l l tyElectr lcal

MagnetlcLulnescenceColorStreakL u s t e r

Trangparence

OPTICAL

C o l o rPleochrolsn

o { n p z s ' g ;

B lnoz s "c;

Y lnoz s. c;2Yo

CharacterDispersion

Orlentat lon

Optlc axlalplane

{ 1 0 1 } i u p e r f 6 c t ; { 4 o l{ I00} diEt ioct

conchoidal5+5plezoelectr lc;pyroelectr ic

nomagnetLcnonfluoreacentcolor legswhit evl treous; pearlylr ldeseence on {010}tlanspardnt tosenl- transparent

color lessnonp 1eo ch !o I c

t . 4 9 2 ! 0 , 0 0 2

1 . 4 9 8 1 0 . 0 0 2

1 . 5 0 2 r 0 . 0 0 2

7 L " ! 2 '

btaxtal (-)

Z < u , d i s t i o c t ,

hor izontal\aa - - \2"

7 = bX 1 c = ' ! o

I toloi

Hatada e.t oL.( I969a,b)

tnperfectb

color less to whltevhite

vitreoue

transparent

B .

L .496

L.497

1 . 5 0 4

2v-. - 78"I

btaxial (+)t<U; veak

x + 4Z = b

(Yac = 6'-70)

Itolo)

a U.s. Nat lonal Museuo specinen No. 10134.

b f t , . r" i " part ing along {010}, a plane of paral lel growth' .

that the zoning is related either to differences in atomic Al-Si distributionbelow the detection Iimit of the probe or to trace-element distribution,especially of transition elements (Table 6).

Crreurcer, PnopnnrrnsAnaJysis. A sample of yrrgawaralite was purified by centrifuging a nonmagnetic fractionin bromoform-alcohol mixtures. The resulting concentrate was split into two fractions, oneof which was heated to 60oc in 1 : I HCI for 20 minutes to remove a thin film of hydrous ironoxide that adhered to some of the untreated grains. The purity and composition of the un-treated and acid-treated fractions were checked by X-ray difiraction, optical methods, andinfrared analysis. No distinction between the two fractions was made by these tests. Theonly identifiable impurity determined by X-ray and optical examination was Iess than 3percent quartz.

{ 1 0 i } t u p e r f e c t , { 4 O f } ,{100} dlst tnct

conchoidal5+

piezoelectr lc;pyroeLectr icnomaBnetLcnonfluoreacentcolor lesswhltevi treous; pearly

lr ldescence oa {010}tranaparent toseDL-transparent

coLorlessnonpleochroLc

1 . 4 9 3 1 0 . 0 0 2

1 . 4 9 9 ! 0 . 0 0 2

1 . 5 0 3 1 0 , 0 0 2

7 2 ' ! 2 '

biaxlal (-)

z < u , d i s t L n c t ,

hor izontal

z = b

Itolo)

YUGAW ARALIT E FROM A LASKA t 7 t l

The untreated fraction (3.63 g) and acid-treated fraction @.37) S of sample 64AWtl42

were submitted for analysis. Within the limit of the procedures used, no siSnificant difier-

ence between the two fractions could be detected (Tables 5, 6). SiO2 was determined colori-

metrically using the molybdenum blue method adapted for silicate rock analysis by Shapiro

and Brannock (1962). AI2O3 and CaO plus sro were determined gravimetrically. Flame

photometry was used for the determination of sro and the alkalis. Fe:Oa, Tio2, Mno, and

MgO were atalyzed by various colorimetric methods. The values obtained were less than

the accepted lower limits of detection for the procedures used. Total water was obtained by

{using the sample with a flux for t hour at 1000oC and calculating the weight loss.

The apparent deficiency of cations [(ntror/(nro+Ro):1'09] shown by the analysis

(Table 5) disappears if H+, which is 0.3737 ions per formula in excess of that required by an

idealSHzO in the unit cell, is present as oxonium ion.

Solubitrity. Yugawaralite is insoluble or nearly so in hot concentrated HCl, HNOa, HzSOr,

aqua regia, and water. It is only slightly attacked by a hot concentrated solution of KOH

but is soluble in HF and decomposes readily in KOH and NarCO, fusions. Etching. witlr

dilute HF produces, in addition to the etch pits mentioned above, striations on 1010fparallel to crystal edges, especially prominent parallel to c. (Fig. 5). The striations coincide

with tlle zone boundaries, detected optically in heated material. The corroded rounded

{ oof } and { oal } ior-s, compared with the fresh or only slightlv pitted (100) ana lnnolforms, are evidence of difierential solubility during hydrothermal or weathering processes.

Pyrognosti.cs. When heated in a closed tube, small fragments give ofi water, turn opaque

white, and develop prominent cracks at temperatures below red heat. Heated before a

blowpipe, the grains first become white and opaque, then, with continued heating, colorless

and transparent with rounded edges.

TnnRMer, Dar,c.

Dehyilralion. Samples of yugawaralite were heated in covered platinum crucibles in an

electric furnace at various temperatures and for various periods of time. The samples

were weighed as soon as possible upon removal from the furnace and at various times there-

after to determine the rate of rehydration. One molecule of water is lost by 106o, the second

by 350", and the third and part of the fourth by 435oC. The final loss of a fraction of a mole-

cule (about 0.5 percent weight loss) occurs at 9C0-1000oC.

The physical changes accompanying dehydration are of interest. There is a marked

pFoelectric effect evidenced by grains clumping together when the first molecule of water

is lost. The pyroelectric effect is noted up to 350oc, at which point the grains turn white and

are opaque in air (but are transparent in immersion oils). At about 435oC, a phase change

accompanies the loss of the third and partial fourth molecules of water. (This phase will be

described in a later note.) Two intersecting sets of cracks develop at this temperature. One

set is approximately perpendicular to { 001 } or roughly parallel to [401 ] and the other set

is parallel to the o axis. Those parallel to [4ot ] are widely spaced, continuous, Iong (some

1.5 mm), and relatively broad (approximately 5 pm). Those parallel to a ate numerous'

closely spaced, interrupted, short (averaging about 0.1 mm), and narrow (<1-2 pm)'

At about 935oC yugawaralite melts to a translucent glass that becomes transparent at

about 970oC. With continued heating to 1040oC, crystals of anorthite and p-cristobalite

slowly develop in the clear glass.

Rehyilration. complete rehydration of yugawaralite is achieved in about 5 hours from

106oC, 13 hours lrom 350oC, and 3 days from 435oC (when heated for one-halJ hour at this

17 12 EBERLEIN, ERD, WEBER, AND BEAI-TY

temperature). when heated at 435oc for a longer period of time (more than 5 hours), thenew phase appears. No rehydration of the new phase to yugawaralite was detected byrveight gain or by examination of the X-ray powder data after the new phase had been keptin a humidi f ier for 3 months.

TABLE 5. CIIEI.{ICAL ANALYSI]S OF YUGAWAMLITE FRO}I ALASKA

Oxide Weight percertt Ion - ar o n s / t o m u r a

sio2

A1203

Fe2O3

Ti02

Mgo

CaC)

Sr0

Na2O

Kzo

H2o-

Hzo-

Total

Unt rca ted Ac id t rea ted

^ . + l !D a -

At+3

Ie+3

M"12

^ + 2b r ' _

Na*l

K+r

olrl

^ , , - lu n _

! L , 6 + Z U tI

4 ,1486 )

0 . 0046

15.9907

0 . 0 0 3 0

1 ,8467

o .0247

0 . 0236

0 . 0233

12 .604s - )

I 1 6 . 3 7 3 73 . 7 6 e 2 )

Oxygen renainder

T ^ f ! , 1 i h . r o p

z J . o z o J

80 .0000

6 r . 4 4

17 .43

< 0 , 0 5

< 0 . 0 1

<0 . 05

8 . 5 1

o . 2 7

0 . 0 7

0 . 0 6

9 . 2 3

2 . 8 4

99 .90

o r . q /

1 7 . 3 8

< 0 . 0 4

< 0 . 0 1

< 0 , 0 1

8 , 5 1

0 , 2 I

0 . 0 6

0 . 0 9

o ? ?

2 . 7 9

9 9 . 9 0

Leon ice B. Beat ty , ana lys t .

a Ca lc r r la t ions based on ana l -ys is o f ac id - t rea ted mater ia l a f t .e r deduc t ing

3% qwar tz (=58,41"1 S iO2) and ass i .gn ing we lgh t percentages o f Fe2O3(=0 '03) and

MgO(=0.01) on the bas is o f quant i ta t i ve spec t rograph ic ana lyses (Tab le 6 ) .

Ions per fo rnu la were ca lcu l -aLed fo l low ing the an ion-based hydrogen-equ iva len t

method programned in Ex tended A lgo1 (Jackson e t a l . , 1967)

N o r n a l i z i n g f a c t o r = L 2 , L 6 9 1 ,

Weigh t percentage c ' f oxygen = 52 . -59 .

F o r n u l a = ( K 9 . 9 2 N a e . s 2 C a 1 . 6 5 S r 0 . o z ) ( A 1 , * . 1 5 5 i 1 1 . s 4 ) O 3 2 ' 8 U 2 o

Dens iLy = 2 .2 -2 t gcm-3 (ca lcu laLed fo r th is conPos i t ion aDd neasurcd

e e l l v o l u m c - 8 8 1 , 5 , 1 3 ) .

YUGAWARA LITE FROM ALASKA

TABLE 6. SPECTROGMPHI.C ANALYSIS OF YUGAWAMLITE FRO}I ALASKAA

1713

Unt reaLedb

lJe igh t percent

Ac ld t rea tedb

Welght per-cent.

T C

Mg"

T1c

ltnc

Ag

D A

C r

cuc

Ni

- c5 r

0 . 0 2 4

0 . 010

0 . 0010

0 .0002

< . 00007

0 . 0028

0 . 005

0 . 0003

0 . 0 0 0 5

0 . 0015

0 . 2 0

0 . 026

0 . 0043

0. 0008

0 . 0006

< . 00007

0 . 0024

0 . 007

0 . 0 0 0 9

0 . 0 0 0 s

0 . 003

0 . 1 7

a Anounts o f ma jor e lenents shown in Tab le 5 .

b Ch. r " Heropou l -os , anaLys t . Semiquant i ta t i ve spec t rograPh ic ana lyses

e x c e p t a s n o t e d u n r l e r c .

L o o k e d f o r b u t n o t f o u n d : K , P , A s , A u , B , B a , B l ,

C d , C e , C o , G e , H f , I I g , I n , L a , L i , I l o , N ' b , P b , P d , P t , R e , S b ' S c , S n , T a '

T e , T h , T t , U , V , I ' 1 , Y , Y b , Z t t , Z r , [ o r l i n r i t s o f s e n s l t i v i t y s e c B a s t r o n

e r a L . ( r 9 6 0 ) .

c Rober t E . l lays , ana lys t . Quant l ta t i ve spec t r :ograph ic ana lyses . The

rcsu l ts have an ovcra l l accuracy o f !15 rve igh t pcrcenE except near the l im iLs

o f d e t c c t l o n r v h e r e o u l 1 ' o D e d i g i E i s r e p o r t e d .

Thermograz'imetric analysis. A thermogravimetric analysis of a 117.2 mg sample of 1'uga-

waralite was carried out by F. O. Simond using a Chevenard thermobalance and a heating

rate of 4"C/minute. 'Ihe

resulting curve is shown in Figure 6. The first molecule of water is

lost between 110-175oC, the second from 350 440o, and the third and a fraction of the

fourth from 440-500'; the final loss occurs by 1000"C. Because of the rate of heating, these

temperatures are apparently higher than those determined by the isothermal method de-

scribed above. The results are in good agreement with the TGA curves obtained by Sakurai

and Hayashi (1952) Sak:"ai (1953), and Imai et a.I. (1964) for y'ugawaralite from the type

t7 t4 EBERLEIN, ERD, WEBER, AND BEATTY

TEMPERATURE IN CC

Frc. 6. Thermogravimetric curve for y-ugawaralite from Chena River area, Alaska

locality and with the data of Barrer and Marshall (19fl,,p.492) f.or the synthetic strontiumanalog.

fox Excsaxcn

The ion-exchange values for yugawaralite were determined by Harry C. Starkey (writ-ten communication, 1967). The mineral has a total exchange capacity of 4.3 meq/100 g,which is attributable to Caz+, as no exchangeable Na+, K+, Mg2+, or Sr2+ was detected. Thedeterminations were made by leaching the sample for 16 hours in lN neutral NHrCl. Thesamples were separated from the leachates by centrifuging and were washed with methylalcohol; the washings were added to the leachates, which were retained for cation analysis.The exchange capacity was determined by ammonia distillation of the samples Ca2+and Mgz+ were determined by versene titration, Na+ and K+ by flame photometry, andSr2+ by atomic absorption. Hawkins (1967), using a difierent ion-exchange method, ob-tained cation-exchange capacities ranging from 14.4 to 100 meg/100 g for the syntheticstrontium analog of yrrgawaralite.

The exchange capacity of yrrgawaralite is very low compared with that of zeolites

WAVENUMBERS (cm-t)

, 1 , , , , L , , , l r , . | 1 , , , , 1 , , , , t , , , . t , , . , r . , . . I

7 I 9 t 0 i l t 2 t 3 t 4 t 5

WAVELENGTH (rrrr)

Irro. 7 Infrared spectra of Alaskan yugalvaralite in the frequencyregion 650-1500 cm-r. Irving Breger, analyst

3 rsJ

F- , ^(, rvU=

2 5UIEUo-

YUGAW ARALIT E FROM ALASKA 171.5

(Carroll, 1959, p. 769-771); it compares more closely with the low exchange capacities re-

ported for natural and synthetic wairakite (Ames, 1966, Table 1), bikitaite (Phinney and

Stewart, 1961, p. D355), and buddingtonite (Erd et d.,1964,p.844-845). Ferrierite may

also be included in this group, for Vaughan (1966, p. 987) noted Ihat". .. prolonged etch-

ing with hot acid does not remove a significant amount of Mg2+ from ferrierite."

Ir.rlnenro AssonprroN Ar.rer.vsrs

The spectra of yrrgawaralite were obtained by I. Breger using both untreated and acid-

treated samples. One mg of each sample was mixed with 300 mg KBr and pressed into a

25-mm disc. The spectra showed no change when the discs were run at room temperature

and at 110oC against a 300-mg KBr reference pellet, and no difierence could be detected

between the curves of the untreated and acid-treated samples. The region 65G-1500 cm-r

of the untreated samples is shown in Figure 7. In addition to the absorption maxima shown

here, there are peaks at 1631 and 3436 cm-r which may be assigned to H-O-H bending and

to residual water (-HzO-) respectively. There is no indication of structural water. (-HO+)

at temperatures to 110oC. The spectra are distinctive but compare most closely wittr

spectra for stilbite and heulandite of the infrared spectra for zeolites obtained by Moenke

(1962). This agrees with the findings of Kerr and Williams (1967, p. 224) who note that

yugawaralite has similarities to the heulandite grolrp but represents a unique structural

group of zeolites.

AcKNowrEDGrcNTs

We wish to thank the many people who helped in this study. We are especially indebted

to our colleagues of the U. S. Geological Survey: Irving Breger, for infrared spectra; JoanR. Clark, piezoelectric tests; Judith A. Konnert, the calculation of intensities indicated in

Table 2; Terry C. Keith, mineral separations; Chris Heropoulos and Robert Mays, spectro-

graphic analysesl Norman Prime, photographic work; Kenji Sakamoto, translations from

Japanese; J. M. Short, electron microprobe study; Fred Simon, TGA; and Harry Starkey,

ion exchange data.Yugawaralite from the type locality was kindly furnished by Paul E. Desautels, of the

U. S. National Museum. Dr. Harry H. Wieder, U. S. Naval OrdnanceLaboratory, Corona,

Calif., tested for pyroelectricity, and Travis Hudson, San Jose State College, studied sam-

ples with the electron microprobe. We also wish to thank Dr. Y6tar6 Seki, Dept of Founda-

tion Engineering, Saitama University, for many helpful discussions and for data on yuga-

waralite from the Tanzawa Mountains, Japan, before publication. Dr. Kazuo Harada,

Central Research Laboratory, Sumitomo Metal Mining Co., Ichikawa, Japan, graciously

supplied us with crystals of yugawaralite collected from the type locality by K. Sakurai,

and sent us a copy of his and his co-workers' 1969 manuscript prior to its publication-

FinaIIy, we are indebted to Joan R. Clark and Richard A. Sheppard, U. S. Geological

Survey, and Kurt Servos, Menlo College, for their critical review of the manuscript and

their helpful suggestions for its improvement

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Manuscri.pt recei,red,, February 17, 1971; accepted Jor publication, April 23, 1971.