25 Graphical Analysis of Zeolite Mineral Assemblages from the Bay of Fundy Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
Area, Nova Scotia ALDEN B. CARPENTER Department of Geology, University of Missouri, Columbia, Mo. 65201
Zeolites occur in consistent combinations throughout a wide area in the Bay of Fundy region. Three-phase zeolitebearing assemblages observed include quartz-analciteheulandite, analcite-mesolite-thomsonite, heulandite-mesolite—thomsonite, analcite—chabazite-heulandite, and analcite-natrolite-stilbite. The stability fields of these minerals can be represented conveniently on activity-activity diagrams. These facts indicate that the appropriate experimental work can provide data which may be used for making quantitative estimates of the conditions under which these zeolites form.
'Hphe c h e m i c a l compositions of the n a t u r a l l y o c c u r r i n g s o d i u m - c a l c i u m zeolites c a n be expressed i n terms of the f o u r - c o m p o n e n t system NaAlSi04-CaAl Si20 -Si02-H 0. T h i s system m a y be represented g r a p h i c a l l y o n t r i a n g u l a r c o o r d i n a t e p a p e r , u s i n g the first 3 c o m p o n e n t s a n d p r o j e c t i n g a l l compositions f r o m H 0 to this p l a n e . T h e g e n e r a l r a n g e of v a r i a t i o n i n the c h e m i c a l c o m p o s i t i o n of the c o m m o n s o d i u m c a l c i u m zeolites is s h o w n b y this p r o j e c t i o n i n F i g u r e 1. A
2
8
2
2
Z e o l i t e occurrences i n the B a y of F u n d y area, N o v a Scotia, are r e p o r t e d here for 2 localities. T h e m i n e r a l assemblages i n the a l t e r e d basalts at C a p e B l o m i d o n i n c l u d e ( 1 ) h e u l a n d i t e - l a u m o n t i t e , ( 2 ) a n a l cite-heulandite, (3) quartz-analcite-heulandite, (4) analcite-mesolitethomsonite, a n d ( 5 ) h e u l a n d i t e - m e s o l i t e - t h o m s o n i t e . T h e s e d a t a are s u m m a r i z e d i n F i g u r e 2. T h e s p a t i a l relationships of the m i n e r a l s i n assemblages 2, 4, a n d 5 i n d i c a t e that a l l of the zeolites i n e a c h of these assemblages w e r e g r o w i n g 328 In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
25.
Zeolite
CARPENTER
Mineral
329
Assemblages
NaAISi0
CoAI Si 0
4
2
2
8
Figure 1. General range of variation in the chemical composition of the common sodium-calcium zeolites Q = quartz H = heulandite S = stilbite A = analcite C = chabazite L = laumontite Ν = natrolite Ms = mesolite Τ = thomsonite Se = scolecite
NaAISi0
4
Figure 2. semblages
CaAlgSigOg
Common zeolite mineral as at Cape Blomidon, Nova Scotia
X = observed three-phase assemblage x = observed two-phase assemblage Other abbreviations as in Figure 1 contemporaneously
at some p o i n t i n t i m e . I n assemblage 3, t h e q u a r t z
is present as e u h e d r a l crystals b u t appears to b e o l d e r t h a n the h e u l a n d ite a n d analcite. Since t h e q u a r t z does n o t s h o w e v i d e n c e o f c o r r o s i o n ,
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
330
MOLECULAR SIEVE ZEOLITES
1
the q u a r t z - a n a l c i t e - h e u l a n d i t e is r e g a r d e d t e n t a t i v e l y as a n e q u i l i b r i u m assemblage.
T h e assemblages
and thomsonite-laumontite
analcite-natrolite,
natrohte-thomsonite,
a r e i n f e r r e d f r o m t h e g e o m e t r y o f t h e phase
diagram. T h e m i n e r a l assemblages a t Wasson's B l u f f a r e ( 1 ) h e u l a n d i t e - s t i l bite, ( 2 ) chabazite-stilbite, ( 3 ) chabazite-natrolite chabazite-heulandite,
(3), (4)
(5) analcite-natrolite-stilbite, a n d (6)
analcitegmehnite-
s t i l b i t e - q u a r t z . T h e s e d a t a a r e s u m m a r i z e d i n F i g u r e s 3 a n d 4. T h e s p a t i a l relationships of t h e m i n e r a l s i n assemblages 3, 4, a n d 5 Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
i n d i c a t e that a l l of t h e zeolites i n e a c h of these assemblages w e r e g r o w i n g contemporaneously
at some p o i n t i n t i m e .
I n a l l of t h e h e u l a n d i t e -
s t i l b i t e specimens, t h e stilbite appears t o b e y o u n g e r t h a n t h e h e u l a n d i t e a n d there does n o t a p p e a r t o b e a n y g o o d i n d i c a t i o n o f a p e r i o d o f c o n -
NaAISiQj
CaAlgSigOg
Figure 3. Early minerals assemblages at Wassons Scotia
and mineral Bluff, Nova
SiCL
AQ
NaAISi0
4
CaAlgSLjOg
Figure 4. Stilbite-bearing mineral assemblages at Wassons Bluff, Nova Scotia
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
25.
Zeolite
CARPENTER
temporaneous growth.
Mineral
331
Assemblages
H e u l a n d i t e a n d s t i l b i t e f r o m t h r o u g h o u t the B a y
of F u n d y area h a v e v e r y s i m i l a r or i d e n t i c a l N a / C a a n d A l / S i ratios. T h e s e m i n e r a l s are thus r e l a t e d , i n this p a r t i c u l a r r e g i o n , b y the r e a c t i o n Nao.33Ko.08Cao.97Al .35SÎ6.650i8 · 6 H 0 + 2
H 0 —->
2
2
Nao.33Ko.08Cao.97Al .35Sl6.650l8 · 7 H 0 2
heulandite
+
2
w a t e r —•
stilbite
F r o m this r e l a t i o n s h i p a n d a s s u m i n g that the zeolites f o r m e d d u r i n g a Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
p e r i o d of f a l l i n g temperatures, one w o u l d expect the 2 m i n e r a l s to coexist i n e q u i l i b r i u m for o n l y a short t i m e a n d that stilbite s h o u l d b e
the
y o u n g e r m i n e r a l . F o r this reason a n d because stilbite i n fact does a p p e a r to be y o u n g e r t h a n h e u l a n d i t e , it is assumed that s t i l b i t e - b e a r i n g assemblages f o r m e d later a n d at l o w e r temperatures t h a n h e u l a n d i t e - b e a r i n g assemblages. T h e o c c u r r e n c e of g m e l i n i t e ( a s s e m b l a g e 6 ) presents some p r o b l e m s i n i n t e r p r e t a t i o n . I n the one s p e c i m e n a v a i l a b l e for study, the g m e l i n i t e crystals w e r e d e p o s i t e d o n top of
fine-grained
euhedral quartz, and both
of these m i n e r a l s are p a r t i a l l y c o a t e d b y s t i l b i t e . T h e g m e l i n i t e crystals are s o m e w h a t c o r r o d e d , b u t this m a y be the result of exposure to r a i n water.
G m e l i n i t e f r o m F i v e Islands
(3),
near Wasson's
B l u f f , is v e r y
n e a r l y a p u r e l y s o d i c zeolite a n d the refractive i n d e x of the Bluff sample ( n
0
=
Wasson's
1.463) indicates that i t is also v e r y sodic.
Sodium
g m e l i n i t e is c h e m i c a l l y r e l a t e d to analcite b y the r e a c t i o n NaAlSi 0 2
6
· H 0 + 2
analcite
2 H 0 -> N a A l S i 0 2
2
+ water—•
6
· 3H 0 2
gmelinite
T h e a b u n d a n c e of analcite i n c e r t a i n types of s e d i m e n t a r y rocks a n d the g e n e r a l r a r i t y of
g m e l i n i t e suggests that s o d i c g m e l i n i t e is
generally
unstable w i t h respect to analcite p l u s w a t e r . C o o m b s et al. (1)
have p o i n t e d out that the s e q u e n c e of m i n e r a l s
at a l o c a l i t y m a y be a f u n c t i o n of the c h a n g i n g c h e m i c a l c o m p o s i t i o n the d e p o s i t i n g solutions or c h a n g i n g P - T conditions or b o t h . s t r u c t i o n of q u a l i t a t i v e a c t i v i t y - a c t i v i t y d i a g r a m s , s i m i l a r i n
The
of
con-
appearance
to the c h e m i c a l p o t e n t i a l d i a g r a m s u s e d b y K o r z h i n s k i i ( 2 ) , is u s e f u l for o b t a i n i n g some i n s i g h t i n t o the r e l a t i o n s h i p b e t w e e n m i n e r a l o g y solution composition. compositions
and
T h e d i a g r a m i n F i g u r e 5 is b a s e d o n the m i n e r a l
a n d m i n e r a l assemblages at C a p e B l o m i d o n s u m m a r i z e d i n
F i g u r e 2 a n d s h o u l d b e v a l i d for the t e m p e r a t u r e range i m p l i e d b y t h a t set of d a t a . T h i s d i a g r a m also indicates that a n e q u i l i b r i u m assemblage of
3 zeolites
i n the system
N a A l S i 0 - C a A l 2 S i 2 0 8 - S i 0 2 - H 0 coexists 4
w i t h a n a q u e o u s s o l u t i o n of u n i q u e c h e m i c a l
2
composition.
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
332
M O L E C U L A R SIEVE ZEOLITES
1
Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
Quartz Saturation-^
Log
C a
Q
Figure 5. Qualitative activity-activity diagram for a portion of the system NaAlSiO -CaAl Si 0 -Si0 -H 0 for temperatures and pressures, mineral compositions implied by Figure 2 A
2
2
8
2
2
Phase e q u i h b r i u m studies o n t h e stabilities o f t h e three-phase
min-
e r a l assemblages l i s t e d a b o v e a n d d e t e r m i n a t i o n s o f t h e c h e m i c a l c o m p o s i t i o n o f a q u e o u s solutions i n e q u i l i b r i u m w i t h these assemblages w i l l p r o v i d e d a t a w h i c h c a n b e u s e d f o r a q u a n t i t a t i v e assessment o f t h e c o n d i t i o n s u n d e r w h i c h these a n d other c o m p a r a b l e zeolite occurrences have formed.
Acknowledgment I t h a n k P . B l a i r H o s t e t l e r f o r r e a d i n g t h e m a n u s c r i p t a n d offering m a n y u s e f u l suggestions.
D . H e r m a n Jackson a n d G l e n W . H e c k m a n
assisted i n p r e p a r i n g a c o m p i l a t i o n o f zeolite c h e m i c a l analyses. investigation was supported
This
b y a Grant-In-Aid-Of-Research from the
Society of the Sigma X i .
Literature Cited (1) Coombs, D. S., Ellis, A. J., Fyfe, W. S., Taylor, A. M., Geochim. Cosmochim. Acta 1959, 17, 53. (2) Korzhinskii, D. S., "Physicochemical Basis of the Analysis of the Paragenesis of Minerals," Consultants Bureau, New York, 1959. (3) Walker, T. L., Parsons, A. L., Univ. of Toronto Studies,Geol.Ser. 1922, 14, 13. R E C E I V E D F e b r u a r y 4, 1970.
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
25.
CARPENTER
Zeolite
Mineral
Assemblages
333
Discussion V . C . Juan ( N a t i o n a l T a i w a n U n i v e r s i t y , T a i p e i , T a i w a n ) : Zeolites a n d l o w - t e m p e r a t u r e p l a g i o c l a s e c a n b e closely c o r r e l a t e d . W e h a v e d o n e w o r k w i t h thomsonite d e h y d r a t e d i n t o a n o r t h i t e , a n a l c i m e i n t o a l b i t e , a n d i n b e t w e e n w i t h i n t e r m e d i a t e p l a g i o c l a s e i n t o a n association of a n a l c i m e , g a r r o n i t e , a n d thomsonite. T h e d i v i s i o n s b e t w e e n different zeolites
Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 1, 2015 | http://pubs.acs.org Publication Date: August 1, 1974 | doi: 10.1021/ba-1971-0101.ch025
are also c o r r e l a t e d w i t h the s t r u c t u r a l d i v i s i o n of p l a g i o c l a s e . A . B . Carpenter: T h a n k y o u for y o u r c o m m e n t s . Y o u r r e m a r k s a g a i n illustrate the v a l u e of a g r a p h i c a l m e t h o d w h i c h c a n s h o w the r e l a t i o n ships b e t w e e n zeolites a n d p l a g i o c l a s e feldspars.
In Molecular Sieve Zeolites-I; Flanigen, E., et al.; Advances in Chemistry; American Chemical Society: Washington, DC, 1974.
