Origin of the beeri (Israel) sulfur deposit

Geology - Elsevier Printed in The Netherlands

Chemical

Publishing

Company, Amsterdam

ORIGIN OF THE BEERI (ISRAEL) SULFUR DEPOSIT 1

A. NISSENBAUMand I.R. KAPLAN Department of Geology, University of California, Los Angeles, Calif. (U.S.A.); Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Calif. (U.S.A.) (Received October I0, 1966)

SUMMARY

A sulfur deposit from Upper Pleistocene sandstone in Beeri, Israel, is described. Elemental sulfur closely a s s o c i a t e d with organic m a t t e r is disseminated throughout the sediment. Oxidation of the sulfur has lowered the pH of the sediment to below 3.0, causing dissolution of the carbonate cement. The organic m a t t e r r e s e m b l e s humic acid in c h a r a c t e r . The 14C age of this m a t e r i a l and a s s o c i a t e d organic mats is about 30,000 y e a r s B.P. 13C/12C isotope m e a s u r e m e n t s showed an anomalous depletion in 13 C in the organic m a t t e r (6 13C -75 to -90%o). 348/32S isotope ratios of the elemental sulfur showed it to be isotopically heavier (6 34S + 27%0 ) than the associated sulfate (5 34S + 25%0 ) and heavier than p r e s e n t day mean sea water sulfate. The suggested origin for the deposit is a lagoonal environment in which sulfate was completely reduced to sulfide, with subsequent oxidation to elemental sulfur. The low 13C/12C value of the organic m a t t e r indicates that isotopically light carbon, perhaps in the form of methane, may have been the starting carbon s o u r c e for biological metabolism, or that a sequential r e c y c l i n g of carbon occurred.

INTRODUCTION The coastal plain of I s r a e l , bordering the Mediterranean Sea is lined by a s e r i e s of parallel carbonate cemented Pleistocene sandstone ridges locally known as "Kurkar", (Bentor, 1959), probably formed during eustatic changes of sea level in the Pleistocene. In the south, along the Gaza strip (Fig.l), there is an a r e a of about 1 km2 containing sandstone highly enriched in elemental sulfur and organic matter. This a r e a is known as the Gaza or B e e r i sulfur q u a r r i e s . The Beeri sulfur deposit was c o m m e r c i a l l y mined between 1930 and 1942, yielding an average of 15% by weight sulfur from open pit miI}ing (Dessau, 1951). Few ~Iescriptions of the sulfur o c c u r r e n c e have appeared in the e a r l i e r l i t e r a t u r e (Blanckeahorn, 1930; P i c a r d , 1952), generally ascribing the origin of the sulfur to t h r e e m e c h a n i s m s : (1) volcanism or h o t - s p r i n g gases, 1publication No.513, 'Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Calif. (U.S.A.) Chem. Geol., 1 (1966) 295-316

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~tGulfofAltaba Fig.1. Location map of the Beeri sulfur deposit. (2) seepages from petroleum or gas r e s e r v o i r s , (3) in situ formation in lagoons. These conclusions were based entirely on field observations. The present study was undertaken to reevaluate the previous conclusions by undertaking both field and l a b o r a t o r y investigations of the stratigraphy, sediments, m i n e r a l s , and organic components present. Several s u r p r i s i n g results were obtained in the study, suggesting a complex origin for both the sulfur and the organic m a t t e r .

296

Chem. Geol.,1 (1966) 295-316

STRATIGRAPHY AND LITHOLOGY

The B e e r i sulfur q u a r r i e s occur in the littoral--continental facies of the Pleshet F o r m a t i o n ( I s s a r , 1961) of Upper Pleistocene Age. Blake (1935) studieda nearby section in Wadi Nakhabyr having s i m i l a r lithofacies to the B e e r i deposit, and proposed a shallow m a r i n e o r coastal flood plane environment, of Upper Pliocene Age. P i c a r d (1930) and Kashai (1951) each gave brief descriptions of the lithological sequences based on field observations. The exposures now p r e s e n t have led us to c o n s t r u c t a generalized s t r a t i g r a p h y of the section based on the lithological units present, as shown in Fig.2. A brief description of each unit" shown follows below. $C

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METERS

Fig.2. Schematic

cross-section

in the Beeri

sulfur deposit. L = loess;

W S S = white sandstone; B S S = brown sandstone; L Z = clayey limonite zone; B C S S = brown clayey sandstone with algal mats; B L S S = black sandstone; L C S S = light colored sandstone; Q Z S = silcrete; dashed zone indicates silt-

rich m e m b e r . Light

colored

sandstone

(LCSS)

The bottom m e m b e r of the section is a c o a r s e , and s o m e t i m e s red, c a l c a r eous sandstone s i m i l a r to the "Kurkar" composing the ridges in other p a r t s of the coastal plain. It was not observed in the p r e s e n t survey, but has been d e s c r i b e d by P i c a r d (1930) from e a r l i e r exposures.

Black

sandstone

(BLSS)

The second unit is c o m p r i s e d of a black sandstone varying in thickness from 3 t o 7 m . The sand grains a r e usually sub-rounded with medium sorting in the size range of 0.15--0.35 mm. The unit is rich in sulfur and organic matter, which both determine the color and form the cementing agents (Plate IA, C). On breaking open a fresh surface of this rock, sulfur dioxide could be detected by smell.

Silcrete

(QZS)

Within the black sandstone m e m b e r exist s p a r s e l y distributed lenses of a pseudo-quartzite. The lenses, usually about 80 cm long and 20 cm high, are extremely hard and a r e mottled lustrous g r e y in appearance. The contact Chem. Geol.,l (1966) 295-316

297

PLATEI

with the s u r r o u n d i n g c r u m b l y b l a c k sandstone "is s h a r p , however i n c l u s i o n s of both b l a c k s a n d s t o n e and sulfur can be found d i s s e m i n a t e d throughout such a l e a s . M i c r o s c o p i c i n s p e c t i o n of a thin s e c t i o n r e v e a l e d that the c e m e n t i n g m a t e r i a l is a m i x t u r e of chalcedony and opal. The quartz g r a i n s a r e a n g u l a r with n u m e r o u s invaginations ( P l a t e IC), s u g g e s t i n g in situ d i s s o l u t i o n of the q u a r t z p a r t i c l e s , which was a p r o b a b l e s o u r c e for the s i l i c a c e m e n t . T h e s e l e n s e s a p p e a r s i m i l a r to the d e s c r i p t i o n given for South A f r i c a n (Du Toit, 1954) and A u s t r a l i a n ( W i l l i a m s o n , 1957) o c c u r r e n c e s of low t e m p e r a t u r e s u r f a c e " q u a r t z i t e s " , which have been t e r m e d " s i l c r e t e " .

Brown clayey sandstone with algal m a t s (BCSS) I n t e r l a y e r e d with unit BLSS is a light brown s i l t y sandstone. It a p p e a r s to fill b a s i n s and t r e n c h e s in the o r i g i n a l topography. C h a r a c t e r i s t i c of this m e m b e r is the high s i l t - c l a y content and the o c c u r r e n c e of n u m e r o u s s m a l l e u h e d r a l gypsum c r y s t a l s and a b l a c k o r g a n i c mat. T h i s l a s t m a t e r i a l a p p e a r s a s b r i t t l e l a y e r s g e n e r a l l y 1 mm thick. Its total a r e a l d i s t r i b u t i o n could not be a c c u r a t e l y d e t e r m i n e d f r o m the a v a i l a b l e o u t c r o p s , but a p p e a r s to c o v e r at l e a s t 2,000 m2 in a bed t h i c k n e s s of 4 or 5 m. T h r e e g r o s s f e a t u r e s a p p e a r to be s t r i k i n g ; the i n t e r b e d d i n g with the s i l t - s a n d m a t r i x ( P l a t e IIB,D), a c l o s e a s s o c i a t i o n with e l e m e n t a l s u l f u r ( P l a t e IIA) and the d o u b l e - e d g e d a p p e a r a n c e ( P l a t e IIC) which a p p e a r s to r i s e f r o m l a y e r s of o r g a n i c m a t t e r c u r l i n g at the edges. In a h o r i z o n t a l plane, t h e s e m a t s show a p r e f e r r e d o r i e n t a t i o n in a polygonal p a t t e r n s i m i l a r to filling of mud c r a c k s and have a s t r i k i n g r e s e m b l e n c e to d r i e d a l g a l m a t s from the P e r s i a n Gulf (Illing et al., 1965). A t h i n - s e c t i o n of the m a t s embedded in r e s i n and cut at r i g h t a n g l e s to the l a r g e s u r f a c e i s shown in P l a t e IB. H e r e it is evident that s o m e l a y e r i n g is p r e s e n t . A t t e m p t s to detect c e l l u l a r s t r u c t u r e or to obtain i n t e r p r e t a b l e e l e c t r o n m i c r o s c o p e p i c t u r e s , however, have so f a r failed.

Clayey limonite zone (LZ) T h i s i s a c l a y - r i c h g y p s i f e r o u s sandstone about 0.5-2 m thick i m m e d i a t e l y o v e r l y i n g the o r g a n i c m a t s . It has s e v e r a l yellow l i m o n i t i c bands each about 3 cm thick and lying 5-10 cm a p a r t , enabling the bed to be t r a c e d along many of the w a l l s of the p i t s . W h e r e the l a y e r t h i c k e n s , g r e e n i s h clay and s i l t b e c o m e m o r e evident, n u m e r o u s e u h e d r a l c r y s t a l s of gypsum a r e

Plate I T h i n - s e c t i o n s of s e d i m e n t s f r o m the B e e r i sulfur deposit. A. Sandstone c e m e n t e d by i r g a n i c m a t t e r (black) and s u l f u r ( d a r k g r e y , high relief). B. V e r t i c a l s e c t i o n through an o r g a n i c mat. C. Sandstone c e m e n t e d by o r g a n i c m a t t e r (black). D. S i l c r e t e ; s i l i c a c e m e n t e d sandstone ( p a r a l l e l nicols).

Chem. Geol., 1 (1966) 295-316

299

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p r e s e n t and small concretions of iron-oxide and green clay a r e visible, plus some fibrous iron sulfates. In the southernmost section white bands of alunite - A12(SO4)3 a r e a s s o c i a t e d with gypsiferous clay and sand.

White sandstone (WSS) This m e m b e r is a white bleached sandstone containing poorly sorted, frosted quartz grains. Within this l a y e r a r e white concretions composed of angular, highly c o r r o d e d quartz grains, cemented by opal and aluminum hydroxide.

Loess (L) Overlying the complex is a cover of loess, probably of Recent eolian origin (Ginzburg and Yaalon, 1961).

SULFUR ANDGYPSUM The sulfur is generally found in two habits: a p r i s m a t i c euhedral type and as a cement. The f o r m e r may grow into large p r i s m a t i c c r y s t a l s up to 2 cm in length or to form small granules a few mm long. The large p r i s m s a r e generally found in the white bleached sandstone and may r e p r e s e n t an aggregation either through concentration by condensation of sulfur v a p o r s circulating in sand i n t e r s t i c e s or by residual removal of organic components. The s m a l l e r c r y s t a l s a r e usually a s s o c i a t e d with the organic mats (Plate HA) or the limonitic layer (LZ) above them. Much of the d a r k e r , o r g a n i c - r i c h sandstone contains sulfur as a cement (Plate IA ), amounting s o m e t i m e s to 20% by weight of the rock. The gypsum is p r e s e n t in various f o r m s , from fine s i l t - s i z e to large euhedral selenite c r y s t a l s 10 cm long. In some sections of the brown sandstone (BCSS) twinning of c r y s t a l s was abundant suggesting growth in place. This is further supported by m i c r o s c o p i c observation of quartz grains within gypsum c r y s t a l s , suggesting growth of the gypsum in loosely compacted sandstone. Gypsum appeared most abundant in a r e a s of highest oxidation, where it was a s s o c i a t e d with hydrous iron oxides. LABORATORY STUDIES

Sulfur isotopes A s e r i e s of sulfur compounds were analyzed for their 34S/32S ratio by simultaneous collection m a s s s p e c t r o m e t r y . Plate II Organic mats. A. Organic mat and sulfur (arrow) in unit BCSS. B. Organic mats in sandstone. C. Organic mat separated from the sandstone. D. Pseudopolygonaldistribution of the organic mats. Chem. Geol., 1 (1966) 295-316

301

Sample preparation Soluble s u l f a t e was f i r s t e x t r a c t e d by r a p i d l y w a s h i n g the g r o u n d s a m p l e with cold w a t e r ( 4 - 5 ° C ) . Acid s o l u b l e s u l f a t e was r e m o v e d by e x t r a c t i n g with 1 : 4 h y d r o c h l o r i c acid. A f t e r d r y i n g at 50°C the s a m p l e was r e - e x t r a c t e d with m e t h a n o l to r e m o v e o r g a n i c s u l f u r and then with hot a c e t o n e o r b e n z e n e to e x t r a c t e l e m e n t a l s u l f u r . E l e m e n t a l s u l f u r was p u r i f i e d by r e c r y s t a l l i z a t i o n f r o m b e n z e n e a n d c o m b u s t e d to s u l f u r dioxide for m a s s s p e c t r o m e t r y . T h e o r g a n i c s u l f u r was o x i d i z e d with a b r o m i n e - a q u a r e g i a m i x t u r e and the s u l f a t e p r e c i p i t a t e d with a s o l u t i o n of b a r i u m c h l o r i d e following K a p l a n et al. (1963). T h e b a r i u m s u l f a t e p r e c i p i t a t e s w e r e r e d u c e d and c o n v e r t e d to s u l f u r dioxide a c c o r d i n g to the m e t h o d of R a f t e r (1957).

Results V a l u e s o b t a i n e d for the d i f f e r e n t m e a s u r e m e n t s a r e g i v e n in T a b l e I. Two

TABLE I 5 34S values of sulfur compounds from the Beeri sulfur quarries I Sample Acid-soluble Organic sulfate sulfur 1. 2. 3. 4. 5. 6. 7. 8. 9.

Beeri 2, unit BLSS Beeri 3, unit BCSS Beeri 5, unit WSS Beeri 10, unit BCSS Beeri 12, unit BLSS Beeri 2A, unit BLSS Large gypsum crystals, unit LZ Algal mats in unit BCSS Formation water fromdrilling at the quarries; depth 400 m 10. Water-soluble sulfate, unit B L S S

+24.1 +27.5 +24.7 +24.8 +26.5 +27.4 +23.3 +15.3 +24.0

Average for samples 1-6

+25..2

+17.7

Elemental S° +27.0 +27.2 +26.1 +28.8 +27.5

+22.9

+27.3

1All values given relative to meteorite sulfur. u n e x p e c t e d r e s u l t s a r e b r i e f l y s t a t e d below: (1) high e n r i c h m e n t of 34S a s c o m p a r e d to o t h e r s e d i m e n t a r y s u l f u r d e p o s i t s f r o m the gulf of M e x i c o ( F e e l e y and Kulp, 1957), Sicily, ( D e s s a u et a l . , 1962) and U.S.S.R. ( V i n o g r a d o v et al., 1964); (2) a n a v e r a g e e n r i c h m e n t of 32S in the s u l f a t e r e l a t i v e to the e l e m e n t a l s u l f u r . T h e 34S v a l u e s a r e h i g h e r than that r e p o r t e d for s u l f u r in p e t r o l e u m (Thode et al., 1958) and e v e n h i g h e r than the r e p o r t e d s p r e a d of sulfate f r o m s e a w a t e r (+19 to +23 %o). T h e v a l u e for the l a r g e g y p s u m c r y s t a l s m a y r e p r e s e n t the o r i g i n a l d i s s o l v e d s u l f u r c o m p o n e n t of s e a w a t e r . The r e s u l t s a r e a l s o m o r e p o s i t i v e than those o b t a i n e d f r o m v o l c a n i c and h o t - s p r i n g e n v i r o n m e n t s ( R a f t e r and W i l s o n , 1963). A g r o u n d - w a t e r o r i g i n m i g h t be e x p e c t e d for the s u l f a t e , e s p e c i a l l y if it i s l e a c h i n g e v a p o r i t e s , but a s i n g l e v a l u e o b t a i n e d f r o m a r e c e n t d r i l l i n g n e a r the q u a r r i e s in the Sakie F o r m a t i o n (Neogene) at depth of 400 m y i e l d e d ~ 34S = +15.3%o or at l e a s t 10%o l i g h t e r t h a n the a v e r a g e v a l u e for s u l f a t e in the q u a r r i e s . T h e v a l u e for "organic" s u l f u r is l i g h t e r t h a n the o t h e r s and m a y 302

Chem. Geol., 1 (1966) 295-316

r e p r e s e n t a s l i g h t 32S e n r i c h m e n t o v e r that found in the e n v i r o n m e n t of growth a s shown by K a p l a n et a l . (1963) for m a r i n e A l g a e . E n r i c h m e n t of 32S i n the s u l f a t e r e l a t i v e to s u l f u r c a n only m e a n that the f o r m e r w a s f o r m e d f r o m the l a t t e r a n d that m o s t of the s u l f a t e now p r e s e n t in the q u a r r i e s i s s e c o n d a r y and p o s t - d e p o s i t i o n a l , a r i s i n g f r o m o x i d a t i o n of e l e m e n t a l s u l f u r . Only the l a r g e r g y p s u m c r y s t a l s found in the o x i d i z e d LZ h o r i z o n ( F i g . 2 ) m a y be p r i m a r y . E v i d e n c e for i n s i t u o x i d a t i o n w a s o b t a i n e d f r o m a s m e l l of s u l f u r dioxide in one o r two l o c a t i o n s of h o r i zon BSS. Sulfur dioxide w a s a l s o s e p a r a t e d f r o m a 1.5 kg s a n d s t o n e s a m p l e , y i e l d i n g a c o n c e n t r a t i o n of 6 p . p . m .

pH and Eh M e a s u r e m e n t s of pH a n d Eh w e r e m a d e d i r e c t l y in the field, a n d in the l a b o r a t o r y the day a f t e r c o l l e c t i o n .

Method T h e e l e c t r o d e s w e r e p l a c e d d i r e c t l y into a s l u r r y of d i s t i l l e d w a t e r and d i s p e r s e d s e d i m e n t . I n the field, about 15 g of s a m p l e and a s i m i l a r weight of w a t e r w a s used; i n the l a b o r a t o r y 20 g s a m p l e and 10 g w a t e r w e r e u s e d .

Results V a l u e s shown in T a b l e II a r e e x t r e m e s for m e a s u r e m e n t s m a d e on n a t u r a l e n v i r o n m e n t s ( B a n s B e c k i n g et a l . , 1960). T h e r e s u l t s c o r r e s p o n d c l o s e l y to a s u l f u r o x i d i z i n g e n v i r o n m e n t found e i t h e r in n a t u r e o r in b a c t e r i a l c u l t u r e s . Somewhat h i g h e r pH v a l u e s in the LZ bed m a y r e p r e s e n t n e u t r a l i z a t i o n of the f r e e a c i d by c a l c i u m and i r o n p r o p o r t i o n a l l y e n r i c h e d in the s i l t l a y e r s . T h e r e d o x p o t e n t i a l shows that the p r e s e n t e n v i r o n m e n t is highly o x i d i z i n g .

Water-soluble sulfate and iron Method T h e homogeni~.ed s a m p l e w a s e x t r a c t e d for a few m i n u t e s with b o i l i n g w a t e r a n d f i l t e r e d . Sulfate w a s p r e c i p i t a t e d with b a r i u m c h l o r i d e a n d i r o n c o n v e r t e d to the t h i o c y a n a t e c o m p l e x a n d m e a s u r e d c o l o r i m e t r i c a l l y . Acid s o l u b l e i r o n w a s e x t r a c t e d with a 1:4 h y d r o c h l o r i c - a c i d s o l u t i o n on a separate sample. TABLE II pH and Eh measurements from the Beeri sulfur quarries Sample

Beeri 1, Beeri 2, Beeri 6, Beeri 7, Beeri 8, Beeri 12,

pH

unit unit unit unit unit unit

BLSS BLSS BCSS LZ BCSS BLSS

Chen~. Geol., 1 (1966) 295-316

field 1.9 1.2 1.4 3.8 1.1 1.0

laboratory 1.3 0.8 1.3 3.0 1.0 0.7

Eh (laboratory) (mV) +525 +490 +425 +425 +405 +470 303

TABLE III Partial analyses of sandstones from Beeri

Sample

Beeri Beeri Beeri Beeri Beeri Beeri

1, 2, 3, 4, 10, 12,

pH

unit unit unit unit unit unit

BLSS BLSS BCSS BCSS BLSS BLSS

1.9 1.2 2.4 3.4 1.2 1.0

Org. C

(%)

Water-soluble sulfate (%)

Water-soluble Fe (%)

Acid-soluble Fe (%)

0.7 6.7 4.3 3.9

0.35 0.54 0.57 0.20 12.0 3.5

0.10 0.18 0.15 0.09

0.12 0.19 0.23 0.42

0.42

0.58

Results T h e d a t a shown in T a b l e III s u g g e s t a r e l a t i o n s h i p b e t w e e n (a) w a t e r - s o l u b l e s u l f a t e a n d w a t e r - s o l u b l e i r o n and (b) pH a n d w a t e r - s o l u b l e i r o n . It i s p r o b a b l e t h a t a c o n s i d e r a b l e a m o u n t of the s u l f a t e i s f o r m i n g a t p r e s e n t . S i n c e t h e r e i s p r a c t i c a l l y no c a r b o n a t e a v a i l a b l e , the a c i d f o r m e d p r o b a b l y r e a c t s with i r o n a n d a l u m i n u m c o m p o u n d s in the s i l t s a n d c l a y s c o n v e r t i n g it to s o l u b l e i r o n s u l f a t e and a l u m i n u m s u l f a t e s . Such a l t e r a t i o n p r o d u c t s a r e not u n c o m m o n in d e s e r t e n v i r o n m e n t s a n d h a v e b e e n r e p o r t e d by S a s s et al. (1965) f r o m o t h e r l o c a t i o n s in s o u t h e r n I s r a e l . T h e r e s u l t s show t h a t the i r o n p r e s e n t a p p e a r s to be m a i n l y in a w a t e r - s o l u b l e f o r m , e x c e p t in the one c a s e w h e r e the pH w a s h i g h e s t .

Bacterial activity In o r d e r to d e t e r m i n e to what e x t e n t a l t e r a t i o n m i g h t be due to b a c t e r i a l o x i d a t i o n , l i q u i d c u l t u r e m e d i a w e r e f o r m u l i z e d to s e a r c h f o r Thiobacillus thiooxidans, T. thioparus, T. ferrooxidans and Ferrobacillus ferrooxidan s . A s u b s t r a t e of both e l e m e n t a l s u l f u r a n d t h i o s u l f a t e w a s u s e d , a n d i n n o c u l a t i o n s w e r e m a d e in the f i e l d . A l l t h e i n n o c u l a t e d m e d i a p r o v e d s t e r i l e a f t e r t h r e e m o n t h s of i n c u b a t i o n . S a m p l i n g w a s m a d e in A p r i l , s h o r t l y a f t e r the end of the w i n t e r r a i n s e a s o n . S t e r i l i t y of the e n v i r o n m e n t p r o b a b l y i n d i c a t e s t h a t m o s t s o l u b l e n u t r i e n t s h a v e b e e n r e m o v e d and t h a t d e h y d r a t i o n d u r i n g t h e d r y p e r i o d s k i l l s the o r g a n i s m s ,

Carbon and hydrogen isotopes I s o t o p e s t u d i e s w e r e m a d e on s e v e r a l c a r b o n - c o n t a i n i n g c o m p o n e n t s , both o r g a n i c a n d i n o r g a n i c , to h e l p e l u c i d a t e the m e c h a n i s m of s u l f u r f o r m a t i o n .

Methods (1) C a r b o n a t e . An a t t e m p t w a s m a d e to s e p a r a t e out i n o r g a n i c c a r b o n a t e f r o m the s a n d s t o n e by b o i l i n g 1-2 kg q u a n t i t i e s of the r o c k s with 1:1 h y d r o c h l o r i c a c i d and a b s o r b i n g the p r o d u c e d c a r b o n d i o x i d e in a b a r i u m h y d r o x i d e - sodium hydroxide solution. (2) E x t r a c t s of the s e d i m e n t w e r e m a d e f i r s t by e x t r a c t i n g with b e n z e n e 304

Chem. Geol., 1 (1966) 295-316

o r a 60:40 b e n z e n e - m e t h a n o l m i x t u r e . T h e s u l f u r w a s r e m o v e d f r o m t h e e x t r a c t by f r a c t i o n a l c r y s t a l l i z a t i o n f r o m t h e s o l v e n t . Next, t h e r e s i d u a l s e d i m e n t w a s e x t r a c t e d with 0.5 N NaOH s o l u t i o n u n t i l t h e s e d i m e n t b e c a m e c o l o r l e s s . T h i s e x t r a c t i s c a l l e d " h u m i c a c i d " a n d w a s f u r t h e r p u r i f i e d by c o n s e c u t i v e p r e c i p i t a t i o n f r o m a l k a l i n e s o l u t i o n with 5% HC1, w a s h i n g a n d r e s o l u b i l i z a t i o n w i t h a l k a l i to s e p a r a t e it f r o m i n o r g a n i c m a t e r i a l . F i n a l l y it w a s d i a l i z e d to r e m o v e w a t e r - s o l u b l e s a l t s . (3) P r e p a r a t i o n f o r i s o t o p e s t u d i e s . T h e s a m p l e s w e r e p r e p a r e d f o r i s o t o p e a n a l y s e s a s CO2 g a s f o l l o w i n g the p r o c e d u r e s o u t l i n e d by C r a i g (1953). T h e s i n g l e D / H v a l u e w a s p e r f o r m e d b y p a s s i n g the l i b e r a t e d H 2 0 t h r o u g h a u r a n i u m f u r n a c e a n d c a p t u r i n g the H 2 g a s . T h e o r g a n i c m a t s w e r e c o m b u s t e d d i r e c t l y a f t e r r e m o v a l of a l l v i s i b l e s u l f u r m e c h a n i c a l l y and by w a s h i n g w i t h hot b e n z e n e . (4) I s o t o p e m e a s u r e m e n t s . A l l i s o t o p e m e a s u r e m e n t s w e r e m a d e on N i e r - M c K i n n e y t y p e d u a l c o l l e c t i n g m a s s s p e c t r o m e t e r s in the l a b o r a t o r i e s of T . A . R a f t e r ( I n s t i t u t e of N u c l e a r S c i e n c e s , New Z e a l a n d ) , S. E p s t e i n ( C a l t e c h . ) , a n d S.R. S i l v e r m a n ( C h e v r o n R e s e a r c h C o . , C a l i f o r n i a ) .

Results T h e m o s t s u r p r i s i n g r e s u l t , i s the c o n s i s t e n t l y low 5 13C v a l u e ( r e l a t i v e to t h e P . D . B . s t a n d a r d ) f o r t h e o r g a n i c c o m p o n e n t s s e p a r a t e d f r o m the s e d i m e n t . A v e r a g e s a r e -85.3%o f o r the o r g a n i c m a t s , a n d -80.9%o f o r the o r g a n i c s o l v e n t e x t r a c t s . Since s o m e of t h e s e v a l u e s a p p e a r to b e t h e l o w e s t y e t r e p o r t e d a n d t h e r e f o r e q u i t e u n u s u a l , it would a p p e a r t h a t the two c o m p o n e n t s a r e g e n e r i c a l l y r e l a t e d . T h e r e s u l t s a r e shown in T a b l e IV a n d c o m p a r i s o n s a r e g i v e n with t h r e e h u m i c a c i d e x t r a c t s s e p a r a t e d f r o m a r e c e n t l a k e p e a t a n d two s o i l s f r o m I s r a e l . T h e a v e r a g e 6 13C v a l u e f o r t h e s e i s -23.4%o. Organic matter from Upper Cretaceous massive black chert from southern I s r a e l g a v e a v a l u e of -28.6% . TABLE IV Carbon isotope ratios of organic matter and carbonate in samples from Beeri and other localities in Israel 1 Sample

613 C (%)

Organic mats, Beeri Organic mats, Beeri Organic mats, Beeri Organic mats, Beeri2 Humic acid, Beeri 2, unit BLSS Humic acid, Beeri 7a, unit BCSS Humic acid, Beeri 12, unit BLSS Benzene-methanol extract, Beeri 12, unit BLSS Benzene extract, Beeri 12, unit BLSS Humic acid (after Benzene extraetion)~ Beeri 12, unit BLSS Humic acid, from peat (HulaLake, Israel) Humic acid, from rendzina soil (Israel) Humic acid, from t e r r a r o s a soil (Israel) Kerogen from Upper Cretaceous chert (Israel) CO 2 from Beeri 2, unit BLSS CO2 from Beeri 7, unit BCSS

-82.5 -84.5 -89.3 -84.7 -78.3 -77.3 -82.7 -85.5 -83.2 -75.4 -18.6 -26.1 -25.6 -28.6 -29.3 -37.3

1Results relative to PDB carbonate. 25D for this sample (relative to S.M.O.W.) was -15%. Chem. Geol., 1 (1966) 295-316

305

T h e s i n g l e E / H v a l u e i s s i m i l a r to v a l u e s found f o r A l g a e and p l a n t s (B. S m i t h , S. E p s t e i n and I.R. K a p l a n , p e r s o n a l c o m m u n i c a t i o n ) . 5 13C v a l u e s f o r t h e CO2 r e m o v e d by a c i d i f i c a t i o n f u r t h e r i l l u s t r a t e a n o m a l i e s . C a r b o n a t e c e m e n t f r o m s i m i l a r s a n d d u n e s in the C a r i b b e a n have b e e n shown by F r i e d m a n (1965) to give 5 13C of -5%0. N o n - m a r i n e c a r b o n a t e s often y i e l d 5 13C of -10 to -20700. The two low v a l u e s shown in T a b l e IV a r e m o s t s i m i l a r to m e a s u r e m e n t s f r o m o t h e r s u l f u r r e g i o n s ( F e e l e y and Kulp, 1957; C h e n e y and J e n s e n , 1965; V i n o g r a d o v et a l . , 1964), w h e r e 12C e n r i c h e d c a r b o n a t e s h a v e b e e n m e a s u r e d . T h i s c a r b o n a t e r e p r e s e n t s a r e s i d u e , in the o r d e r of 20-100 p . p . m , a s CaCO3; m o s t of the o r i g i n a l c a r b o n a t e c e m e n t having b e e n r e m o v e d by a c i d l e a c h i n g of the s e d i m e n t .

Age of organic matter T h e K u r k a r s a n d r i d g e s of I s r a e l a r e g e n e r a l l y c o n s i d e r e d to be U p p e r P l e i s t o c e n e , a l t h o u g h no a b s o l u t e a g e d a t e h a s y e t b e e n a s c r i b e d to t h e m . In o r d e r to e s t a b l i s h the o r i g i n of the o r g a n i c m a t t e r , 14C a g e d e t e r m i n a t i o n s w e r e c a r r i e d out on two s a m p l e s of the o r g a n i c m a t s , a b e n z e n e e x t r a c t a n d s o d i u m h y d r o x i d e e x t r a c t ( h u m i c a c i d ) of t h e s e d i m e n t . R e s u l t s of T a b l e V show that the a l g a l m a t s h a v e an a v e r a g e e q u i v a l e n t a g e of a b o u t 30,000 y e a r s by two i n d e p e n d e n t m e a s u r e m e n t s , the b e n z e n e e x t r a c t a b l e o r g a n i c m a t t e r i s about the s a m e , w h e r e a s the h u m i c a c i d e x t r a c t a p p e a r s y o u n g e r . T h i s l a s t d a t e m a y be in e r r o r , s i n c e the e x t r a c t i o n by NaOH m a y h a v e r e s u l t e d in a b s o r b t i o n of r e c e n t a t m o s p h e r i c CO2, a c o n c l u s i o n a l s o c o n f i r m e d by the s o m e w h a t l o w e r 13C v a l u e f o r t h i s s a m p l e ( T a b l e IV). T h e r e s u l t s f o r the m a t s and the b e n z e n e e x t r a c t s s u g g e s t t h a t e i t h e r the e q u i v a l e n t m e a s u r e d a g e is c o r r e c t o r e l s e it r e p r e s e n t s a m i x t u r e of old c a r b o n (beyond14C m e a s u r a b i l i t y ) and c a r b o n y o u n g e r t h a n 30,000 y e a r s .

Elemental analysis of organic matter E l e m e n t a l a n a l y s e s a r e g i v e n in T a b l e VI f o r the o r g a n i c m a t s , s e v e r a l e x t r a c t s of the s e d i m e n t s f r o m B e e r i , a n d f o r c o m p a r i s o n , two s o i l a n d one p e a t h u m i c a c i d e x t r a c t f r o m e l s e w h e r e in I s r a e l . T h e r e s u l t s show that the h u m i c a c i d e x t r a c t s f r o m B e e r i h a v e a h i g h e r c a r b o n content than s i m i l a r e x t r a c t s f r o m s o i l o r f r o m Hula L a k e p e a t . T h e y a r e l o w e r in c a r b o n , h o w e v e r , t h a n the b e n z e n e e x t r a c t of the s e d i m e n t o r t h e u n d i f f e r e n t i a t e d o r g a n i c m a t s . S i m i l a r l y the b e n z e n e e x t r a c t TABLE V Radiocarbon dates of samples from Beeri Sample 1 Age (B.P.)

14C no.

1. 2. 3. 4.

NZ650 UCLA-1007 UCLA-1068 UCLA-1067

Organic mat Organic mat Benzene extract of sandstone NaOH extract of sandstone

27,700 + 500 31,370+1,400 31,200+3,500 20,000 +- 620

1Analysis 1 by T.A. Rafter, New Zealand; analyses 2-4 by R. Berger and W.F. Libby (1966,1967). 306

Chem. Geol., 1 (1966) 295-316

TABLE VI Elemental analysis of organic materials from Beeri and other samples from Israel I Sample 2 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Humic acid, Beeri unit BCSS Humie acid, Beeri unit BLSS Humie acid, Beeri unit BSS Organic mats, analysis 1 Organic mats, analysis 2 Humic acid from t e r r a rosa soil (Israel) Humic acid from rendzina soil (Israel) Humic acid from peat (Hula Lake, Israel) Humic acid, Beeri unit BLSS (after Benzene extraction) Benzene-methanol extract of sandstone, Beeri unit BLSS

C

H

N

~)

(%)

54.5 62.4 58.9 58.7 59.8

5.6 6.8 3.3 7.5 7.9

2.3 2.2 0.7 0.7

13.1 7.8 17.0 8.7 8.6

46.7

5.2

48.1

4.8

51.5

5.0

2.7

2.8

55.1

4.0

2.1

17.5

63.8

8.4

0.6

21.9

(%)

(%)

S

0.0

1Results calculated to ash-free basis. 2Analyses 1-8 by Mrs. M. Goldstein, Microanalytical Laboratories, Hebrew University, Jerusalem; analyses 9-10 by Miss H. King, Microanalytical Laboratories, U.C.L.A.

a n d the o r g a n i c m a t s showed h i g h e r h y d r o g e n and l o w e r n i t r o g e n c o n t e n t s t h a n the h u m i c a c i d e x t r a c t . T h u s , the o r g a n i c m a t s p r o b a b l y r e p r e s e n t p o l y m e r i z e d m a t e r i a l with a h i g h e r d e g r e e of s a t u r a t i o n t h a n the h u m i c e x t r a c t f r o m the s e d i m e n t . A n a l y t i c a l r e s u l t s for the h u m i c a c i d e x t r a c t s a g r e e in g e n e r a l with v a l u e s p u b l i s h e d by S w a n s o n and P a l a c a s (1964) for h u m a t e s f o r m i n g at the p r e s e n t t i m e along the F l o r i d a c o a s t .

Composition of organic matter T o help d e t e r m i n e the n a t u r e of the e n v i r o n m e n t of s u l f u r f o r m a t i o n , a t t e m p t s w e r e m a d e to c h a r a c t e r i z e the o r g a n i c m a t t e r .

Methods P r o c e d u r e s for e x t r a c t i o n a r e d e s c r i b e d in the p a r a g r a p h on c a r b o n a n d h y d r o g e n i s o t o p e s . I n f r a r e d s p e c t r o s c o p y w a s c a r r i e d out on d r i e d s a m p l e s a s p r e s s e d p e l l e t s with K B r u s i n g a P e r k i n E l m e r m o d e l 421 i n s t r u m e n t . T h e m a s s s p e c t r u m of one b e n z e n e - - m e t h a n o l e x t r a c t a n d a s o d i u m h y d r o x i d e e x t r a c t w a s c a r r i e d out on a n AEI m o d e l MS-9 i n s t r u m e n t at U . C . L . A . A s i n g l e gas c h r o m a t o g r a m w a s m e a s u r e d by P r o f e s s o r J . Or6 ( U n i v e r s i t y of Houston) u s i n g a B a r b e r C o l e m a n m o d e l 5000 i n s t r u m e n t .

Chem. Geol., 1 (1966) 295-316

307

Wavelength 2,5

(mic

5

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Results A 1.4 kg sample of sandstone from B e e r i (unit BLSS) was first extracted with the benzene--methanol mixture and then the sodium hydroxide. The weight of each extract was 3.08 g and 13.95 g respectively. Nonpolar material t h e r e f o r e only r e p r e s e n t s about 16% of the total or extractable organic m a t e r i a l in the sandstone. Because of the c h a r a c t e r i s t i c s of the NaOH soluble material, it is named "humic acid" here. The infrared s p e c t r a shown in Fig.3 are s i m i l a r to those m e a s u r e d by Ziechmann (1964) for European peat and Swanson and P a l a c a s (1965) for humate from northwest Florida. Strong peaks are m e a s ured at 2.95, 3.5, 5.85 and 6.2 # . These r e p r e s e n t -OH, - C H and -OH, - C = O , a n d - C = C - ( a r o m a t i c ) groups. Absorption peaks at 7.2, 7.8, -8.2 and 9.2# may r e p r e s e n t either (C-O-C) or a r o m a t i c s t r u c t u r e s . The peaks in the 10-15p region probably r e p r e s e n t substituted a r o m a t i c rings. The shape of the absorption curve did not change after heating the pellet for 1 h at 105 ° C, indicating that the OH groups were phenolic or alcoholic hydroxyl r a t h e r than water (confirmed by Dr. I. B r e g e r , U.S. Geological Survey). The spectrum of the intact organic mats (Fig.3d) appears m o r e complex than that of the humic acids. The peaks described above are also present in the benzene extract, (Fig.4) although the --CH and - C = C - ( a r o m a t i c ) absorption band a p p e a r s to be the strongest here; but -OH bands a r e still present. Peaks at about 7 and 8g are also strong. A m a s s spectrum was run on one benzene and one humic acid extract from Beeri 12 (unit BLSS) sandstone. The benzene extract showed m a s s e s to the range of m a s s 400. Strong peaks standing above a background were observed at m / e 137, 160, 191, 256, 258 and 369, Each of these peaks was r e m e a s u r e d at an instrument resolution of 12,000 against a known reference and the following composition has been assigned to each peak C10 H17, C12 H16, C 14H23, C19 H28 , C 19H30 and C 27H45 . The compositions show that the normal straight chain paraffins a r e minor constituents. Mass ranges of C20-C30 common in petroleum extracts and oil shales (Smith, 1966) a r e also not important, with the exception of m a s s 369. An independent n-heptane extraction of the organic mats made in P r o f e s s o r O r 6 ' s laboratory and m e a s u r e d by gas chromatography on Polysev packed capillary column demonstrated C 14-C18 alkanes and the probable p r e s e n c e of pristane and phytane. The m a s s spectrum of the humic acid extract showed peaks spread out to a m a s s of 450 without any one strong band predominating. A p r e l i m i n a r y lipid analysis on a sample of sandstone from Beeri 12 made by Dr. A. Baumann (Jet Propulsion L a b o r a t o r i e s ) indicates the predominance of neutral fatty acids and no phospholipids. The general c h a r a c t e r of the organic m a t t e r in the sandstone and mats shows a g r e a t e r similarity to peat and unconsolidated m a r i n e or fresh water sediment extracts than it does to asphalt or other petroleum derived material.

Fig.3. I n f r a r e d s p e c t r a of humic acids, a. F r o m peat, Hula Lake. b. F r o m Beeri, unit BSS. c. F r o m Beeri, unit BLSS. d. F r o m Beeri, unit BCSS. e. Organic mats, Beeri. Chem. Geol., 1 (1966) 295-316

309

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4000

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2000

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1400

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800

600

(cm -u)

Fig.4. I n f r a r e d s p e c t r a of s e d i m e n t e x t r a c t s , a. B e n z e n e - m e t h a n o l e x t r a c t of B e e r i Sandstone, unit BLSS. b. B e n z e n e - m e t h a n o l e x t r a c t of peat, Lake Hula, I s r a e l . c. Benzene e x t r a c t of B e e r i Sandstone, unit BSS.

Pollen identification In o r d e r to define m o r e c o r r e c t l y the environment of deposition, a n a l y s e s for pollen w e r e c a r r i e d out s e p a r a t e l y by A. Horowitz ( H e b r e w U n i v e r s i t y , J e r u s a l e m ) and W. Ting, (U.C.L.A.). S e v e r a l p r e p a r a t i o n s w e r e made by M r . Horowitz and Dr. Ting of the sandstone, n e a r l y a l l showing e i t h e r no pollen or e l s e s p o r e s that a p p e a r e d to be badly c o r r o d e d and beyond r e c ognition. Only one p r e p a r a t i o n from the s i l t - s a n d l a y e r BCSS (Fig.2), showed identifiable pollen. Although it is i m p o s s i b l e to i n t e r p r e t the r e s u l t s quantitatively, the 310

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f l o r a l a s s e m b l a g e a p p e a r s s i m i l a r to that found in p r e s e n t - d a y l o w - l y i n g c o a s t a l r e g i o n s of I s r a e l . A compound e n v i r o n m e n t which may r e p r e s e n t a s a l i n e m a r s h , fed by f r e s h - w a t e r s p r i n g s , is s u g g e s t e d by the p r e s e n c e of both Chenopodiacae ( b r a c k i s h w a t e r ) and Alnus ( f r e s h w a t e r ) groups.

DISCUSSION

The P l e i s t o c e n e sand r i d g e s in B e e r i a r e different from those lining the r e m a i n d e r of the M e d i t e r r a n e a n c o a s t a l s t r i p p r i m a r i l y in t h r e e ways: Ca) e x c e p t i o n a l l y high e n r i c h m e n t of e l e m e n t a l sulfur; (b) a b s e n c e of c a r b o n a t e a s a c e m e n t i n g agent; (c) high abundance of o r g a n i c m a t t e r which a l s o a c t s a s a c e m e n t between sand g r a i n s . T h e s e a n o m a l i e s p r o b a b l y a r i s e f r o m a s e r i e s of i n t e r c o n n e c t e d events. T h r e e a l t e r n a t i v e p r o c e s s e s a r e s u g g e s t e d below a s p o s s i b l e c a u s e s for the o b s e r v e d a s s o c i a t i o n of m i n e r a l s and organic matter: (1) M i n e r a l s p r i n g s . S p r i n g s a r e common in I s r a e l along the Rift Valley, extending f r o m the n o r t h e r n G a l l i l e e to the Gulf of E l i a t in the Red Sea. However, s a l i n e s p r i n g s a r e unknown f r o m the M e d i t e r r a n e a n c o a s t a l plain. S p r i n g s often contain high sulfate contents, and can o c c a s i o n a l l y be a l k a l i n e and m a y be s a t u r a t e d in sulfide (White et a l . , 1963). High s u l f i d e - c o n t a i n i n g w a t e r s p e r c o l a t i n g through sandstone could r e s u l t in f o r m a t i o n of e l e m e n t a l sulfur as is c o m m o n in s e v e r a l hot s p r i n g a r e a s . Such d e p o s i t s a r e , however, g e n e r a l l y quite l o c a l i z e d . F u r t h e r , e x t e n s i v e s p r i n g s that would be r e q u i r e d to p r o d u c e the s u l f u r d e p o s i t s , should a l s o supply a c o n s i d e r a b l e amount of opal a s a c e m e n t i n g agent for the sand g r a i n s . The p r e s e n c e of only s m a l l l e n s e s of s i l c r e t e , or p s e u d o - q u a r t z i t e , could be due to a l t e r a t i o n of q u a r t z g r a i n s by a l k a l i n e ground w a t e r s . No v e r t i c a l o r i e n t a t i o n is a p p a r ent, however, to s u g g e s t a l t e r a t i o n along an a s c e n d i n g canal of a spring. An a n a l y s i s for t e l l u r i u m , a c o m m o n component of h y d r o t h e r m a l and v o l c a n i c s u l f u r m i n e r a l s , by Dr. H.W. Lakin (U.S. G e o l o g i c a l Survey), showed s e v e r a l s a m p l e s of s u l f u r and sandstone to contain l e s s than 0.05 p . p . m . Te. T h i s f u r t h e r a r g u e s a g a i n s t the B e e r i d e p o s i t s having f o r m e d from hotspring or volcanic emanations. 34S v a l u e s of the e l e m e n t a l s u l f u r a r e quite different f r o m other v o l canic or s p r i n g s u l f i d e s (Sakai and Nagasawa, 1958; R a f t e r and Wilson, 1963; Kaplan et al., 1960). In New Z e a l a n d the a v e r a g e 534S is +3.5%o for v o l a t i l e sulfide from g e o t h e r m a l a r e a s . One p o s s i b l e o r i g i n for the sulfur could be b a c t e r i a l r e d u c t i o n of d i s s o l v e d s p r i n g sulfate, e i t h e r s u b a e r i a l l y or on the s u r f a c e . Such su'lfur should be i s o t o p i c a l l y l i g h t e r than the s t a r t i n g sulfate. T a b l e I shows that the e l e m e n t a l s u l f u r is on the a v e r a g e e n r i c h e d in 34S by 12%0, r e l a t i v e to the g r o u n d - w a t e r sulfate in that a r e a . The o r g a n i c m a t t e r could have a r i s e n f r o m Algae growing along the s t r e a m b e d s and banks of hot s p r i n g s as commonly found. In this event the 5 13C v a l u e s should be -15 to -30%0, since the c a r b o n dioxide m e t a b o l i z e d would be e i t h e r a t m o s p h e r i c (5 13C = -8%o ) or volcanic (5 13C = -4%0) (Hulston and McCabe, 1963). (2) P e t r o l e u m or gas s e e p a g e origin. S e e p a g e s of liquid or g a s e o u s h y d r o c a r b o n s a r e well-known (e.g., La B r e a T a r P i t s ) . It is t h e r e f o r e c o n c e i v a b l e that m i g r a t i o n of such p e t r o l e u m components e n r i c h e d in e l e m e n t a l s u l f u r or hydrogen sulfide, could have been the o r i g i n of both the Chem. Geol., 1 (1966) 295-316

311

sulfur and the organic m a t t e r . T h i s p r o c e s s was r e c e n t l y s u g g e s t e d for the v a s t Q u a t e r n a r y sulfur d e p o s i t of K a r a Kum by K a r a v a i k o et al. (1963). T h e r e a p p e a r s to be a m a r k e d s i m i l a r i t y between the l i t h o l o g i c a l setting of this deposit and that of B e e r i . The hydrogen sulfide r e s p o n s i b l e for the sulfur at K a r a Kum is c o n s i d e r e d to have a r i s e n from sulfate r e d u c t i o n in p e t r o l e u m - r i c h f o r m a t i o n w a t e r s of C r e t a c e o u s s t r a t a . S e v e r a l f a c t o r s a r g u e a g a i n s t such a d i r e c t o r i g i n at B e e r i . F i r s t the 14C age d a t e s (Table V) show that the organic m a t t e r contains r e l a t i v e l y young c a r b o n , which p r e cludes p e t r o l e u m as the sole c a r b o n s o u r c e . Second, the e l e m e n t a l a n a l y s i s in Table VI i n d i c a t e s that t h e r e is no s i m p l e r e l a t i o n s h i p between the o r g a n i c m a t t e r and p e t r o l e u m , since the c a r b o n content in B e e r i is too low and the nitrogen content ( e s p e c i a l l y in the humic a c i d component) is too high. T h i r d , no r e p o r t has yet been m a d e of a n o n - v o l a t i l e o r g a n i c m a t e r i a l having such an a n o m a l o u s high e n r i c h m e n t in 12C (Kaplan and N i s s e n b a u m , 1966). F o u r t h , the 5 34S is c o n s i d e r a b l y g r e a t e r than that r e p o r t e d for hydrogen sulfide in p e t r o l e u m (Thode et al., 1958) or for n a t u r a l gas (Lac gas field, southern F r a n c e , unpublished data by I.R. Kaplan). The sulfide could not have a r i s e n f r o m g r o u n d - w a t e r sulfate reduction, if the 5 34S of this sulfate was +15.3%o as it is now. Although s u r f a c e s e e p a g e s of h y d r o c a r b o n g a s e s a r e not evident n e a r the B e e r i deposit, gas has been l o c a t e d at a depth of 400 m in a well d r i l l e d 1 km f r o m the s u l f u r d e p o s i t s (Tschopp and W i e n e r , 1958). A n a l y s i s of this gas y i e l d e d 98-99% CH4, 1-2%N 2 and 0.2-0.3% H2S. (3) Lagoonal origin. The t h i r d a l t e r n a t i v e , and the one s u b s c r i b e d to by the a u t h o r s , is f o r m a t i o n of both the sulfur and o r g a n i c m a t t e r in a lagoon having r e s t r i c t e d a c c e s s to the s e a a c r o s s a b a r . The o r g a n i c m a t t e r would be d e r i v e d from both land p l a n t s and aquatic Algae. E l e m e n t a l sulfur would a r i s e through the oxidation of hydrogen sulfide f o r m e d by sulfate r e d u c t i o n at the bottom of the lagoon. B e s i d e the evidence l i s t e d above, this conclusion is f u r t h e r s u p p o r t e d by the s h a l l o w n e s s of the sulfur deposit (9-10 m) and the "bituminous" sandstone (16 m) found while d r i l l i n g a 400 m bore hole (P. Solomonica, unpublished r e p o r t , 1952) in the c e n t e r of the quarries area.

Paleoenvironrnent F r o m the above d i s c u s s i o n , it is evident that f o r m a t i o n of the sulfur f r o m s p r i n g s or p e t r o l e u m s e e p a g e is unlikely, and that the o r g a n i c m a t t e r could not have been t o t a l l y d e r i v e d f r o m "dead" p e t r o l e u m or h y d r o c a r b o n g a s e s , since a 14C age date of about 30,000 y e a r s B.P. was m e a s u r e d . The a n o m alous isotope v a l u e s for the c a r b o n compounds indicate that s e v e r a l c y c l e s p r o b a b l y took place in o r d e r to y i e l d the l a r g e f r a c t i o n a t i o n . The high c l a y - s i l t content in f o r m a t i o n BCSS (Fig.2) s t r o n g l y s u p p o r t s an aqueous e n v i r o n m e n t . Thus if a lagoon had f o r m e d , it would p r o b a b l y have s i m i l a r c h a r a c t e r i s t i c s to lagoons f r o m other a r i d zones. Sulfate in the w a t e r of such lagoons would be s u b j e c t e d to r e d u c t i o n with the f o r m a t i o n of hydrogen sulfide which would e s c a p e if the supply of i r o n was too low to bind the sulfide a s p y r i t e . The r e m a i n i n g sulfate would b e c o m e e n r i c h e d in 34S r e l a t i v e to s e a w a t e r sulfate. If t h i s lagoon, having a high sulfate content both in the f o r m of d i s s o l v e d s u l f u r and e v a p o r i t i c gypsum on the bottom of 312

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the lagoon, was physically separated from the sea, it is conceivable that almost all the sulfate could have been reduced so that no isotopic fractionation would appear in the resulting sulfur. The soluble sulfate p r e s e n t now in the B e e r i q u a r r i e s is all secondary having a r i s e n from the oxidation of elemental sulfur and a subsequent reaction of the sulfuric acid formed with the calcite cement. This is ex;ident f r o m the fact that the sulfate is enriched in 328 relative to the sulfur. This isotope relationship was also noted in a sulfur deposit now forming in a low-lying coastal strip at Kona, Bay of Bengal (Kaplan et al., 1960). Thus, intermittent flooding and filling of low-lying coastal shallow basins will allow Algae to grow in the surface water, sulfate-reducing b a c t e r i a on and in the sediment, and brackish water plants at the fringes of the lagoon. The two values of acid evolved CO2 in Table IV (average 6 13C = 32.2%0) shows that the CO2 in the carbonate was biological since it is considerably lighter than carbonate derived from evaporation of sea water or skeletal carbonate from marine o r g a n i s m s (5 13C = 0 to +4%0, Lowenstam and Epstein, 1958; Friedman, 1965) and from f r e s h water limestone (6 13C = -3-5%0, G r o s s , 1961). Carbon dioxide from most natural gas wells falls in the range of 5 13C = +3 to -9%o (Cheney and Jensen, 1965). Calcite found in association with elemental sulfur from various p a r t s of the world have yielded values ranging f r o m a v e r a g e s of 613C = -22.5%0 (Wyoming; Cheney and Jensen, 1965), -28.7%0 (Sicily, Dessau et al., 1965); -30.0%0 (Shor-su, U.S.S.R.; Vinograd0v et al., 1964), -37.9%0 (Gulf Coast; Feeley and Kulp, 1957) and -40.0~o0 (Lubaczow, Poland, Jensen, 1962). These very low values have all been a s c r i b e d to metabolic CO2 having been released by biological activity. This explanation is also supported in the Beeri deposit. Algal growths are Common to all lagoons. In low latitude s e m i - a r i d environments the Algae dry out during the dry season, giving the appearance of mud c r a c k s (De Clarke and Teichert, 1946, Australia; Fisk, 1960, Gulf Coast; Nichols, 1965, Baja California; Illing et al., 1965, P e r s i a n Gulf). Oppenheimer (1960) indicates a close relationship between the Algae and sulfate reduction o c c u r r i n g in the littoral zone and in the sand on the beaches in Laguna Madre, Gulf Coast. Smith (1954) states "The Laguna Madre algal muck sample, which was a s s o c i a t e d with a large concentration of hydrogen sulfide, contains 2.13 weight % organic carbon and 7,54 weight % of sulfur". This "algal muck" was shown by Smith to contain 3.9 times as much free hydrocarbon as well as sulfur than the clays. P. P a r k e r (personal communication, 1966) has related that the algal mats are capable of trapping gases which include CO2 and CH4 besides H2S. The v e r y low 13C Values for all the organic m a t t e r isolated, strongly suggests a common origin for this material. Since the enrichment of 12C is too great for the m a t e r i a l to have originated either directly from p e t r o leum seepage or from metabolism of CO2 in natural gas, it must have f o r m e d in one of the two following ways: (1) oxidation of methane from natural gas, which may have a high enrichment in 12C ( W a s s e r b u r g et al., 1963), to carbon dioxide and subsequent r e m e t a b o l i s m of the CO2 either photosynthetically by Algae or chemosynthetically (e.g., sulfur bacteria), or (2) the carbon was all generated in situ (as in Laguna Madre) and r e m e t a b olized, yielding sequential enrichments in 12C.

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ACKNOWLEDGEMENTS We w i s h to g r a t e f u l l y a c k n o w l e d g e the f o l l o w i n g p e o p l e f o r a s s i s t i n g us in the study. T . A . R a f t e r (New Z e a l a n d I n s t i t u t e of N u c l e a r S c i e n c e ) , S. E p s t e i n ( C a l t e c h ) , S.R. S i l v e r m a n ( C h e v r o n R e s e a r c h Co.) f o r m a s s s p e c t r o m e t r y m e a s u r e m e n t s ; R. B e r g e r and W . F . Libby ( U . C . L . A . ) f o r 14C ag e m e a s u r e m e n t s ; J . O r 6 (Houston) and A. B a u m a n ( J e t P r o p u l s i o n L a b o r a t o r i e s ) f o r a n a l y s i s of o r g a n i c m a t t e r ; H.W. L a k in (U.S. G eo l . S u r v e y ) f o r t e l l u r i u m a n a l y s i s ; W. T i n g ( U . C . L . A . ) and A. H o r o w i t z ( H e b r e w U n i v e r s i t y ) f o r p o l l e n d e t e r m i n a t i o n s ; I. Z a k f o r a c q u a i n t i n g us with the a r e a and Y. T s u r f o r g e n e r a l a s s i s t a n c e , We a r e p a r t i c u l a r l y thankful to P r o f e s s o r Y. B e n t o r f o r m a k i n g s u p p o r t a v a i l a b l e t h r o u g h the I s r a e l G e o l o g i c a l S u r v e y to i n i t i a t e the study and to NASA No.NsG 237-G2 f o r a d d i t i o n a l s u p p o r t . P a r t of t h i s study w a s c a r r i e d out w h il e one of us (I.R. Kaplan) w a s Z i s k i n d V i s i t i n g S c h o l a r at the H e b r e w U n i v e r s i t y .

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