Mineral. Deposita (Bed.) 4, 75--84 (1969)

High Strontium Contents and Sr/Ca-Ratios in Lake Constance Waters and Carbonates and their Sources in the Drainage Area o~ the Rhine River (Alpenrhein)

GERMAN MOLLER

Labora to r ium ~iir Sedimenfforschung, Mineralogisch-Petrographisches Ins t i tu t der Universit~t, Heidelberg, Ge rmany

Algal and mollusk carbonates in Lake Constance sediments proved St/Ca- ratios unusually high for fresh water environments. In most cases the observed Sr/Ca-ratios for mollusk shells fall into the range of marine mollusks. These high ratios can be attributed to a high Sr/Ca-ratio (6 -t- 0.5) in Lake Constance water. In the Alpenrhein River, the main influent of Lake Constance, St/Ca- ratios were found to vary between 4.7 (at high water discharge) and 10.7 (at low water level). High St/Ca-ratios correspond to high sulfate contents. From all tributaries of the Alpenrhein, the Ill River revealed to have the highest Sr-contents and Sr/Ca-ratios. A detailed study of its drainage area led to the detection of exceptionally high Sr-contents (up to 11.6 mg/1) and Sr/Ca-ratios (up to 116.5) in springs of the Triassic Ladinian stage of the Austroalpine nappe zone ("Ostalpine Deckenzone"). The fact that high Sr-concentrations occur together with high sulfate contents leads to the assumption that celestite is leached within Ladinian rocks. This assumption is confirmed by the evidence that celestite deposits have been reported from the same stratigraphic section ("Wettersteinkalk") from other localities in the Northern Calcareous Alps.

In Bodensee-Sedimenten auftretende biogene Carbonate zeigen ein fiir SiiB- wasserbildungen ungew6hnlich hohes Sr/Ca-Verhfiltnis; die meisten bei Mollusken gefundenen Werte fallen in den marinen Bildungsbereich. Diese hohen Sr/Ca-Verhfiltnisse k6nnen dutch das hohe Sr/Ca-Verhiilmis des Boden- seewassers (6-4-0,5) gedeutet werden, das seinerseits vom noch h/3heren Sr/ Ca-VerhSltnis des wichtigsten Zuflusses, des Alpenrheins (4,7 bei Hochwasser, 10,7 bei Niedrigwasser) geprfigt wird. Hohe Sr/Ca-Verhfilmisse fallen mit hohen Sulfatgehalten zusammen. Von allen Nebenflassen des Alpenrheins zeigt die Ill die hOchsten Sr-Gehalte und Sr/Ca-VerMltnisse. Eine Unter- suchung des Einzugsgebietes der Ill ftihrte zur Auffindung yon B~chen und Quellen mit ungew6hnlich hohen Sr-Gehalten (bis 11,6 mg/1) und Sr/Ca-Ver- Mltnissen (bis 116,5), die im Ladin der Aipinen Trias der Ostalpinen Decken- zone entspringen. Da hohe Konzentrationen mit hohen Sulfatgehalten zu- sammenfallen, kann angenommen werden, dab Coelestin aus Gesteinen des Ladins ausgelaugt wird und die hohen Sr/Ca-Verhfilmisse der Wiisser bedingt. Diese Annahme wird dutch die Tatsache erMrtet, dab Coelestin im gleichen stratigraphischen t-Iorizont (,,Wettersteinkalk") an mehreren anderen Stellen der N6rdlichen Kalkalpen beobachtet wurde.

76 G. MOLLER

I n t r o d u c t i o n

Next to sodium, magnesium, calcium, and potas- sium, strontium is the most frequently £ound cation in sea water. With a Sr-content of 8.1 p .p .m, and a Ca-content of 400 p .p .m.

atoms Sr the average St/Ca-ratio (defined as atoms Ca

1000) amounts to 9.23. In springs, rivers, and lakes the Sr/Ca-ratio is much lower. According to ODOM (1957a) the Sr/Ca-ratio of ~resh water varies between 0.5 (water from regions with consolidated carbonate rocks) and 5 and more (water from volcanic areas).

The average Sr/Ca-ratio of the representative rivers of the world is 2.2 (ODuM 1951).

In Lake Constance and its main influent, the Rhine river ("Alpenrhein") (Fig. 1), Sr/Ca- ratios are much higher than this average. In the Alpenrhein they sometimes exceed the values found in sea water and in some springs o£ tributaries of the Alfenzbach in the drainage area of the Alpenrhein they are more than ten times as high as in sea water! These extremely high St/Ca-ratios were detected in an indirect way (MOLL~i< 1968): carbonate sediments of Lake Constance mainly derived from onkolites

RHEIN

5EERHEIN ~ K O N S T A N Z • ..

f" MAIN

"J--,..-t ~ ~ / AIO

FRANCE ~ / GERMANY ~.~/~_~/; r

0 50kin CON,STANCE t I I X _

; . - ",,, ) % .-" ~AU SI~RIA ]

N / " LAN D c- r : . - - , ~ N D . f / ('-51 ' ] " ', ' ', ' c 7 , , . , l "Z[ ITALY I

x TAMINA

HINTER-/ RH EIN ] 0 km 10 20

I,, I I

S r 1 0 0 0 " < 5 Ca, o 5 - 8

LAKE CONSTANCE • > 8

I

\ 3 REG ENZ"~ "ENAU " "

\ k....~?

/

:TR-CH I

/¢"•BLU DENZ I

" I I , . , - . , . . I I "--.j.~. ~ _ L.y' Jf

N

I 30 40 50

1 I I

Fig. 1. Lake Constance and drainage area of the Alpenrhein; lpaces w h e r e water samples were taken. The numbers printed in italics follow- ing the sample designation (e. g. ]3/1) indicate the approximate St-con- tents in mg/1. Detailed data see Table 4

High Strontium Contents and St/Ca-Ratios in Lake Constance Waters 77

(calcitic algal balls) exhibited St-contents too high for normal fresh water calcite. Subse- quent studies led to the investigation of Lake Constance water and that of its main influent, the Alpenrhein, and its tributaries in the Swiss and Austrian Alps.

Analytical Methods

The analytical determination of strontium and calcium was carried out with a Perkin Elmer Atomic-Absorption-Spectrophotometer , type 303.

Hydrochemistry of the Alpenrhein and Seerhein

From former investigations (MOLLER 1964, 1965; M/2LL~R and ROPER 1966) the hydro-

chemistry of the Alpenrhein (main influent of Lake Constance, draining an area of about 6.500 km 2 of the northern Alps in Switzerland and Austria) and the Seerhein (the effluent of the so-called "Obersee" of Lake Constance into the "Untersee", Fig. 1) is well known as far as the six most important ions Na +, Ca 2+, Mg 2+, CI-, SO~-, and HCO~ are concerned. The average values for one year (October 1962 to September 1963) are shown in Table 1. The composition of the Seerhein water reflects at the same time the average composition of the "Obersee" water. In the course of a year the concentrations of the Alpenrhein vary strongly due to changing water discharge. With decreasing water dis- charge of the Alpenrhein (autumn until spring) the electrolyte content increases considerably and it decreases with increasing water discharge

Table 1. Average chemical composition of Alpenrhein- and Seer&in water (October 1, 1962, to September 30, 1963). A l l data in mg/l (after MtiLLER 1964)

Na + Ca 2+ Mg 2+ C1- HCO 7 SO4 ~-

Alpenrhein 2.00 45.32 11.03 1.38 118.10 61.27 Seerhein 3.38 45.92 8.64 2.90 137.80 41.50

Table 2. Sr-conxents and Sr/Ca-ratios in the Lake Constance Untersee- and Obersee- and the Seer&in waters

Sampling Sr Ca Sr 1000 date mg/l mg/I Ca

Seerhein, Konstanz Mettnau, Wiesenrain, 1.5 m depth Markelfinger Winkel, 5 m depth Gnadensee, between Mettnau-Reichenau, 21 m depth Reichenau-Mettnau, 4.5 m depth

7. 7.67

0.42 32.2 5.9 0.43 36.0 5.6

O.42 37.0 5.3

0.42 34.4 5.6

0.43 34.5 5.7

Seerhein Konstanz Seerhein Konstanz Seerhein Konstanz Seerhein Konstanz

7.11.67 8.12.67 3.01.68

26.02.68

38.5 6.3 42.4 6.5 44.9 6.8 48.2 6.4

Bodensee Obersee, deepest part between Langenargen-Arbon. Average of 10 samples from different depths

28.04. 65

27.05.64

0.53 42.3 6.0

0.53 45.0 5.5

78 G. MOLL=R

(mainly in early summer after melting of the snow in the Alps).

These differences are reflected chiefly in the sulfate content. On October 26, 1962, a sulfate Sampling content of 100.8 mg/1 was measured at a water date discharge of 81.0 ma/sec. On June 26, 1963, the sulfate content was only 30.0 rag/1 at a water discharge of 625.0 ma/sec (MOLLeR 1965). 27. 10.

9.11. In the Seerhein deviations f rom the average 1.12. value caused by season and water discharge 11.12. are not impor tan t and th roughout the year the hydrochemis t ry is relatively uniform due to the balancing effect of the Obersee water mass.

Strontium Content of Lake Constance Water and the Alpenrhein (see Fig. 1)

After having found high s t ront ium contents in carbonates produced by organisms in Lake Constance (see p. 77), Sr-eontents and St/Ca- ratios of the Seerhein, Alpenrhein and Lake Constance water were determined.

The values determined on July 7, 1967, in the Seerhein and Untersee are shown in Table 2. The values vary only slightly and reveal that 1. 6. at this t ime the chemical composi t ion of the 16. 6. Untersee water was more or less uniform. See- 1. 7.

16. 7. rhein samples taken in winter at low water 1. 8.

discharge show St/Ca-ratios up to 6.8. 10. 8.

Sr/Ca-ratios of ten samples, each f rom different 1. 9. water depths of the Obersee above the deepest 16. 9. part between Langenargen and Arbon , were 1.10. also determined. On Apr i l 28, 1965, an average 16. 10. St/Ca-ratio of 6.0, and on May 27, 1964, a 1.11. Sr/Ca-ratio of 5.5. was measured. 16.11.

1.12. As the hydrochemis t ry of Lake Constance is to 16. 12. a very large extent de termined by that of the Alpenrhein water, the St-content of Alpenrhein 1. 1. samples was determined. The samples were 16. 1.

1. 2. taken at regular intervals f rom October 1964 16. 2. to September 1965 and f rom June 1966 to July 1. 3. 1967 at Lustenau, Austria. The results are 16. 3. shown in Table 3 and presented graphically in 1. 4. Figs. 2 and 3. 16. 4.

Dur ing the first invest igat ion per iod the Sr- 1. 5. contents varied between 0.42 and 0.86 mg/1 16. 5.

1. 6. and the Sr/Ca-ratios between 4.8 and 8.0. F r o m 16. 6. June 1966 to July 1967 the St-contents ranged 1. 7. between 0.35 and 0.77 and the St/Ca-ratios be- 16. 7. tween 4.7 and 10.7. Thus the Sr/Ca-ratio of the

Table 3. St-contents and Sr/Ca-ralios in the Alpenrhein water at Lustenau

Highwater Sr Ca Sr level mark mg/[ mg/1 C~ 1000

c m

64 445 0.85 63.4 6.1 64 678 0.57 59.7 4.8 64 428 0.75 51.5 6.6 64 423 0.73 53.4 6.2

1. 1.65 397 0.74 47.3 7.1 16. 1.65 388 0.82 46.7 8.0

1. 2.65 398 0.77 50.9 6.9 16. 2.65 395 0.76 46.6 7.4

1. 3.65 366 0.75 47.7 7.2 16. 3.65 397 0.86 54.9 7.2

1. 4.65 468 0.65 52.3 5.7 6. 7.65 649 0.41 36.6 5.1

16. 7.65 643 0.42 34.5 5.6 1. 8.65 580 0.52 37.8 6.3

16. 8.65 532 0.58 44.8 5.9 1. 9.65 574 0.52 46.7 5.1

16. 9.65 663 0.58 45.9 5.8

66 587 0.56 45.2 5.7 66 711 0.40 35.3 5.2 66 618 0.48 40.0 5.5 66 672 0.44 37.7 5.3 66 605 0.57 41.9 6.2 66 696 0.47 39.0 5.5 66 627 0.57 43.2 6.0 66 555 0.64 44.1 6.6 66 484 0.68 47.3 6.6 66 478 0.82 44.0 8.5 66 457 0.82 51.0 7.3 66 462 0.72 37.1 8.9 66 456 0.77 38.4 9.2 66 451 0.80 41.1 8.9

67 452 0.77 42.5 8.3 67 425 0.86 30.5 12.9 67 453 0.76 46.5 7.5 67 434 0.77 29.8 11.8 67 491 0.66 31.3 9.6 67 480 0.71 30.3 10.7 67 477 0.74 32.8 10.3 67 554 0.64 33.8 8.6 67 524 0.65 44.7 6.6 67 807 0.41 40.2 4.7 67 700 0.48 39.3 5.6 67 635 0.52 43.4 5.5 67 766 0.35 31.1 5.l 67 695 0.40 31.0 5.9

High Strontium Contents and Sr/Ca-Ratios in Lake Constance Waters J9

10

9

8

7

6

5

4

h igh w a t e r level m a r k ( m )

St c gr)

~ - ~ O~ 1 go0 I f~ /I Iii ~. lA\X':~'.~ /It'

X I XI I XII ] [ I I I i I l l i IV i V i VI t VII I V i i [ l IX

1964 1965

Fig. 2. Water level, St-contents and Sr/Ca-ratios in the Alpenrhein water during the period from Oc- tober 27, 1964, to September 16, 1965

content and Sr/Ca-ratio increase; with in- creasing water discharge Sr-content and Sr/Ca- ratio decrease. Thus the strontium shows the same tendency as the sulfate content of the Alpenrhein water: high St-contents correspond to high sulfate contents. The St- and the Sr/Ca-curves run more or less parallel; this demonstrates that the changes of the Sr/Ca-ratio are mainly caused by strongly varying St-content while the Ca-content only reveals slight changes. In the Obersee the Alpenrhein water mixes with the Obersee water. The values of Table 2 indicate that an average St/Ca-ratio of about 6 ± 0.5 may be assumed for the entire Lake Constance. Values above 6 mainly appear during the low water period of the Alpenrhein and Lake Constance, and values below 6 during periods of higher water load of Alpenrhein and Lake Constance.

Alpenrhein was temporarily higher than in sea water. It is evident from Figs. 2 and 3 that a relation- ship exists between the Sr-content and the Sr/ Ca-ratio on the one hand and the water dis- charge of the Alpenrhein (high water level mark) on the other hand: with falling water level (and thus decreasing water discharge) St-

Strontium Contents in the Waters of the Alpenrhein Drainage Area, Especially the Ill River

In order to clarify the origin of the unusually high St/Ca-ratios in the Alpenrhein water, water samples were taken from the most im- portant tributaries of the Alpenrhein at the end

10

9

8

7

6

5

4

h igh w a t e r Level m a r k ( m ) / ~ / I

s r [pogr) I i

V

VI i VII t VIII h IX i X t XI t XII I I I II t Ill ~ IV I V i Vl { Vll

1 9 6 6 1967

Fig. 3. Water level, Sr-content and St/Ca-ratios in the Alpenrhein water during the period from June 1, 1966, to July 16, 1967

80 G. Mi)LLER

Table 4. Sr-contents and St~Ca-ratios in rivers of lhe Alpenrhein drainage area

Sample Sampling locality Sr Ca Sr designation mg/1 mg/1 C~ 1000

A Alpenrhein near Lustenau 0.48 37.0 5.9 B Ill near Feldkirch 0.75 38.7 8.9 C Tamina near Bad Ragaz 0.21 31.7 3.0 D Landquart near Landquart 0.29 30.4 4.4 E P1essur near Chur 0.35 32.0 5.0 F Alpenrlaein S of influx of the Plessur 0.37 29.2 5.8 G Vorderrhein S of Reichenau 0.31 26.8 5.3 H Hinterrhein S of Reichenau 0.42 29.2 6.6

of September 1967. The results (Table 4, Fig. 1) reveal that the Vorderrhein as well as Hinter- rhein, Plessur and Ill rivers have St/Ca-ratios above 5. The highest St/Ca-ratio (8.9) and by far the highest St-content (0.75 mg/1), how- ever, were found in the IlL It was already known that the sulfate content of the Ill is also higher than that of other Alpenrhein trib- utaries. Thus the search for strontium was concentrated on the Ill and its influents.

The results of the samples taken in October 1967 are shown in Fig. 4 and Table 5.

The St-contents vary between <0.01 and 11.6 mg/1, the St/Ca-ratios between < 1 and 116.5. In the waters with maximum Sr/Ca- values, the St/Ca-ratio is thus more than ten times higher than in sea water! It is evident from Fig. 4 that three zones with considerably varying St-contents and Sr/Ca-ratios can be distinguished:

A) Drainage area of the Ill river south of the mouth of the Rellsbach and the drainage area of some other southern tributaries of the Alfenzbach. St-contents are below 0.5 mg/1, the St/Ca-ratio is lower than 5. The entire area coincides with the area of crystalline rocks.

B) Drainage area of the Ill river between Rells- bach and the mouth of the Lutzbach as well as part of the southern drainage area of the Ill between Lutzbach and Feldkirch. Sr-contents are in general 1--2 mg Sr/1; in smaller tributaries of the Ill and Alfenzbach, however, they rise to 11.6 mg/1. St/Ca-ratios range chiefly between 5 and 25; they are much higher,

however, in the Mtihlbach and Schmiedtobel area. The drainage area of this zone belongs to the Austroalpine nappe zone ("Ostalpine Decken- zone") consisting mainly of Mesozoic rocks.

C) Drainage area of some northern tributaries of the Lutzbach and Ill between Lutzbach and Feldkirch. The Sr-contents are about 1 mg/1, the Sr/Ca-ratio is only slightly higher or lower than 5. The drainage area of these streams consists mainly of mostly clastic series of the Vor- arlberger Flysch (Upper Cretaceous to Terti- ary). High Sr-contents and Sr/Ca-ratios occur only in the streams heading in the Triassic of the Austroalpine nappe zone: the highest values observed until now were measured in the northern tributaries of the Alfenzbach and in two smaller tributaries of the Ill between Rellsbach and Alfenzbach. The drainage area of the Alvierbach, Meng- bach, Gallinabach, and Samina has not yet been systematically investigated. It is probable that similarly high values occur in some tributaries of these streams draining areas with Triassic sediments.

Localisation of Areas with Highest Strontium Content in Waters East and Southeast of Bludenz: Origin of the High Strontium Concentrations

Detailed investigations of the area E and SE of Bludenz revealed that high strontium con-

High Strontium Contents and Sr/Ca-Ratios in Lake Constance Waters 81

Table 5. Sr- and S04-conients and Sr/Ca-ratios of rvalers in lbe ]1] drainage area

Table 5 (Continued)

Sample Sr Ca Sr SO~ Sample Sr Ca Sr SO~ no. rag/1 rag/1 C-~ 1000 mg/l no. rag/1 rag/1 -Ca 1000 rag/1

1 1.26 50.0 11.5 25.85 2 0.45 62.6 3.3 0.0 3 1.07 61.6 7.9 22.6 4 0.54 58.8 4.2 1.62 5 0.55 57.2 4.4 1.29 6 0.54 54.4 4.3 2.42 7 0.62 54.8 5.2 6.14 8 0.56 44.4 5.8 8.24 9 0.48 45.6 4.8 19.70

10 0.80 54.4 6.7 12.92 11 0.76 40.4 8.6 50.40 12 0.17 37.0 2.1 16.15 13 0.42 45.0 4.3 33.76 14 0.77 50.0 7.0 71.87 15 0.64 47.0 6.2 36.72 16 1.64 53.6 14.0 54.91 17 0.77 35.0 10.0 55.88 18 6.92 57.0 55.4 112.09 19 2.45 43.4 26.0 57.50 20 2.20 50.0 20.1 97.23 21 0.85 35.0 11.1 60.24 22 0.02 n .b . < 1 3.23 23 2.52 61.2 18.8 158.28 24 0.61 30.6 9.1 43.61 25 0.10 13.0 3.5 47.97 26 0.03 ,a. d. <1 50.23 27 0.04 n.d. <1 62.34 28 < 0.01 n .d . < 1 54.91 29 < 0.01 n .d . < 1 56.53 30 0.04 n .d . < 1 64.28 31 0.06 n .d . < 1 61.37 32 0.09 n .d . < 1 73.23 33 0.05 n .d . < 1 59.11 34 0.01 n .d . < 1 53.14 35 < 0.01 n .d . < 1 56.53 36 < 0.01 n .d . < 1 0.00 37 0.02 n .d . < 1 0.00 38 < 0.01 n .d . < 1 0.00 39 < 0.01 n .d . < 1 0.00 40 0.02 n .d . < 1 n .b . 41 0.20 35.6 2.6 n .b . 42 1.26 36.4 15.8 36.34 43 2.92 51.2 26.0 64.12 44 2.00 61.2 14.9 137.77 45 2.20 58.0 17.3 116.28 46 0.53 53.0 4.6 0.00 47 1.44 48.0 13.7 49.75 48 1.45 41.6 13.5 76.88 49 1.45 47.6 13.9 77.36 50 7.16 57.2 57.1 119.19 51 7.00 57.2 55.8 125.01

52 0.20 27.8 3.2 3.23 53 < 0.10 25.6 < 1.8 0.00 54 < 0.1 27.8 < 1.6 0.00 55 7.16 57.6 56.7 121.13 56 0.25 30.4 3.8 20.19 57 2.62 51.6 23.2 88.51 58 3.24 36.8 40.1 29.72 59 < 0.1 38.2 < 1.2 0.0 60 < 0.1 36.8 < 1.2 0.0 61 <0.1 36.8 <1 .2 0.0 62 0.1 31.0 1.5 0.0 63 3.16 45.5 31.7 20.67 64 4.16 46.2 41.1 16.15 65 11.6 45.4 116.5 91.42 66 11.5 53.2 98.6 114.03 67 1.44 35.2 18.7 38.12 68 3.76 42.4 40.4 27.46 69 7.16 45.5 71.8 39.99 70 0.56 38.2 6.7 48.45 71 2.40 37.8 29.0 71.23 72 2.35 41.2 26.0 61.37 73 4.16 103.0 18.4 290.72 74 1.42 40.2 16.1 35.53 75 4.16 103.0 18.4 307.19 76 4.16 103.0 18.4 323.34 77 3.20 52.8 27.6 68.49 78 2.92 51.4 25.9 66.54 79 5.30 191 12.6 459.98 80 5.07 226.5 10.2 544.61 81 9.80 52.4 85.6 125.82 82 5.60 232 11.0 557.53

tents and St/Ca-ratios are found mainly in the Ladinian stage of the Alpine Triassic 1. Highest values are found in springs o£ the Ladinian clayey-marly "Partnach- and Arlberg-Schich- ten" bu t no t in the "Hauptdolomi t" -member o£ the Norian stage. Waters o~ the "Haupt- dolomit" overlying the Ladinian and Carnian do not contain much strontium. This is clearly

1 In the area studied the Alpine Triassic is subdivided in the following stages (from bottom to top): Skythian (Bunter Sandstone), Anisian (Muschelkalk), Ladinian (with Partnaeh-Schichten and Arlberg-Schichten), Carnian (with Raibler Schichten and gypsum beds) and Norian (Haupt- dolomit).

6 Mineralium Deposita, 4[1

82 G. MOLLEB.

FELDKIRCH

~ _ 210

Vorart berg FLY5CH

4/

.< . . - . . . : : - : :) ? / - . ' . " "" ,2~o . ' - "

. . . . ~ . ~ . : . " : . " . . . ' " ' ~ : . . ' " : : : : . ....:~.... n . - : . ' - . . - . . - . " - - : - . ' : " "'-" '. " . " . . . ~ . - . . . . . . . . . ~ 1 3 1 o . , " o ' ' . ' - . " . . . ' . . ~ , ;"

• " ~ P/7. . . . . . , . \ r . ~ " / . z MUHLS4CH " . " . ~ . ". • . ~ • . . ~ I L L ~ " . . 1612 " ' " " " " " ." " " ' "7~,- ~ . " "~1'; / ~ / " MASONSACH" , K . " . . . "

• . ¢5 , . . . ' . . • . " ." ", ' 7314 . " . 55 /7V ] I, - , ' " ' . ' ' " " "" "

• " ' : - ' ( ,A/S! , 1 : - : . . . . , - . . . . . . . : . .

• 7915,8015,81110,8216 " . " " " " . • " . , ~ - ~ ' "

"t'~'-: BLUDENZ" • . ~ . : , ~ / : : . - • ~/7-...

. . ' . ' . 2 " • . " . . y . : . " • " ." • . . : " ,@~. / " . . " . " . . . . 8ws .~wo .

• : . . . . " . ' ~ / . " . . . . . . : - . , : , # 5 2 / : . ' . . " . - . ' , , ~ , . - . . . . . " . " • " • " " . ~ 1 . •" " ' • • ' • " ". . " ~ ' ~ o " • " • . • " • " *, • ~ z . . ~ L ~ O R ~ V A S E R = ' • ' • - A L F E N Z B A C H "~

• " ' ' ~ 1 . ' - ' . " . ' • " " ~ / . ' . " _ ' . . ' • . " . ' ~ zu " ,Yar~'~,.~v~ • • W~E~ . ~ " ~ • : , . X . ' " " ~ 1 . • • " " . . . . . . •1 . " . - . " . . " . " . . ' l ~ 3 l S \ . " . • . . ~ ~

• ' . - " ' : ~ l , - . " - " : ' / . " - • " . " : " " " - ~ " ~ ' ~ ~ 4 ' * Y • ' " " " " ' " • " " ' " " " " " " " " ' " " " " ~41 /0 2510 ~ ' 1 . . . - . . -."; .. I " - . : 7

, ~ ' . " . " ' o " . ' . - ' ' . ' , ' , " ~ - " " " . - : ' . £ : : ~ B ~ " , ~ C H R U N S . r ~ " ~ 6 ~0 ~ \ 4010 x

- - -.. : : , ,.-, n V Ef ,.b x ' ' " \ : " " " . ' . / k j P~ ~ , g L l , / , ~ 2~b-

, < 5 ~ "-a.,: =.:. , " $ / ~ - ~ao/o o,~

o 5 - 25

2 5 - 5 0

• 5 0 - 1 0 0

~( > 1 0 0

0 5 I I I I t r

S__r 1000 Ca

N

1o, k m I

6414

pm

2210 , ~

< u

m

t4E L I T Z B A C H

'31°p'1° I F" .... x x 3810

x )61 /O

Fig. 4. Sr/Ca-ratios and Sr-contents (numbers printed in i t a l i c s following the sample designation, e.g. 5 1 / 7 , indicate the approximate Sr-contents in rag/l) of the waters of the Ill drainage area

seen from Fig. 4: the upper parts of the Mtihlbach and Schmiedtobel rivers (Haupt- dolomit) show extremely low Sr-contents and St/Ca-ratios (samples 52, 54, 59--62); spring samples taken from the Ladinian below the Hauptdolomit, however, have high Sr-values. The Gravasertobel drains an area mainly made up of " A r l b e r g - S c h i c h t e n " (Ladinian), the Gipsbach rises from the gypsum beds of the Carnian stage; thus they have the highest sul- fate contents. The relatively high strontium content of the gypsum, however, cannot sufficiently explain the high Sr-contents and Sr/Ca-ratios found in the water. Waters taken in the gypsum quarries revealed the expected Sr/Ca-ratio ok gypsum. Thus the origin of Sr cannot yet be stated directly, the less so since analyses o£ sedi-

ment samples taken from springs with high Sr-content did not reveal elevated St-contents; also in thin sections no strontium minerals could be observed.

The fact that high St-contents are observed in connection with high sulfate contents in springs of the Ladinian can best be explained in that celestite (SrSO4) is leached either in the Ladi- nian itself or in the overlying CarMan (with gypsum beds).

This explanation is supported by the fact that in many evaporitic cycles of different formations celestite occurs as an independent mineral. It forms celestite-rich rocks deposited towards the end of the carbonate stage of the evaporite sequence and immediately before the crys- tallization of gypsum (MOLLER 1962).

High Strontium Contents and Sr/Ca-Ratios in Lake Constance Waters 83

In non-evaporitic sediments, celestite is to be found in limestones which primarily contained greater amounts of aragonite (with high Sr- content). During calcitization or dolomitization by diagenetic processes, the high Sr-content of the aragonite could not be incorporated com- pletely into the lattice of calcite or dolomite and was thus liberated. In the case of sufficient sulfate ions in the pore solutions, celestite could have been formed in situ as tiny crystals scattered more or less evenly throughout the whole rock or - - after a short transport - - as layers, small veins, and nodules of a thickness up to several tens of centimeters. In the "Wettersteinkalk"-member of the Ladi- nian stage - - the stratigraphic equivalent of the Ladinian "'Arlberg-Schichten'" in the eastern continuation of our area - - larger quantities of celestite have been detected forming accumula- tions with a thickness of up to 50 cm (NEY 1957). From the northern rim of the Northern Calcareous Alps, celestite already has been found earlier in the same horizon (STEINM~TZ 1948). Thus further investigations should be concerned mainly with the occurrence of gyp- sum in the Alpine Triassic and that of possible celestite at its base, as well as with celestite beds within the carbonate rocks of the "Arlberg- Schichten".

Inf luence of the H i g h Sr]Ca-Ratio in Lake Constance Water on the Sr-Content of Biogenic Carbonates

As the Sr/Ca-ratio of Lake Constance water is very high compared to other fresh waters, the Sr/Ca-ratios and Sr-contents of biogenic car- bonates secreted in Lake Constance water are also much higher than in normal fresh water carbonates (MOLLER 1968). Fig. 5 shows St-contents (related to 100% CaCOa) and St/Ca-ratios of different Lake Constance Pelecypod and Gastropod shells (mostly aragonitic) as well as calcite aggregates produced by blue-green algae (onkolites). Similarly high St-contents are observed in shallow water sediments of the Untersee mainly made up of onkolite debris. These sediments occasionally contain fragments of mollusk shells. The SrjCa-ratios of Lake Constance carbonates are considerably higher (Table 6) when corn-

6*

0,07 0,1 0,15 0,2 0,25 0,3 °/oSr

Pis id ium

[] i [ ] l [ ] [ ] [] [ ] [ ] [ ] Sphcterium

H I [ ] Anodont '=

[] rmi

L B i thyn io

[ ] P lano rb i s

Gyrau lus

Lymneee

Vatvat 'a

B a t h y o m p h a l u s

[] [] []

~ 1 Carbonat-e- Sedim en t-s mainly derived from onko[it-es

On kolit'es i ~ CaLcite A t a g o n i t e

I ; i I i t i i i i i i ; i I I i ! I i 1

0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2/+ 2.6 2.8 3.0 3.2 3.4

5._£ 1000 Ca

Fig. 5. Sr-content (related to 100% CaCOa) and St/Ca-ratios in mollusk shells, onkolites and Lake Constance carbonate sediments mainly composed of onkolitic debris

pared with the mean values for fresh water carbonates (ODuIvi 1957b). In comparison with the mean values for marine mollusk shells, however, (THOMPSON and CHOW 1955; ODUM 1957b; W2tSKOWlAK 1962) the average Sr/Ca- ratios are lower. I t is impossible to obtain a clear differentiation in an individual case: if the "lowest marine values" indicated by THOMPSON and CHOW (1955) and OmlM (1957b) are con- sidered, the result will be that almost all individ- ual values of Lake Constance mollusks could still fall within the marine range indicated by THOMPSON and CHOW (1955). Relying on the values of ODUM (1957b), this applies to still more than half of the values, above all Pele- cypods. Only algal calcite is clearly differen- tiated. These findings reveal that St-contents and Sr/ Ca-ratios of carbonates are not indicators of salinity but of the Sr/Ca-ratio in the depositional environment. This on the other hand is to a large extent determined by the geologic and lithologic setting of the drainage area.

84 G. MOLLER, High Strontium Contents and St/Ca-Ratios in Lake Constance Waters

Table 6. Mean Sr/Ca-ratios for fresh water and marine environment calcite algae and aragon#e mollusks as compared with Lake Constance material

Fresh waters of Lake Constance Marine environment humid regions this study (ODux* 1957 b) (THomPSON and CHOW (ODuM 1957b) 1955) Number Mean Number Mean Number Mean Lowest Number Mean Lowest of cases Sr/Ca of cases St/Ca of cases St/Ca marine of cases Sr/Ca marine

value value

Calcite 3 0.58 21 1.06 9 3.96 3.60 9 3.20 2.93 algae Aragonite 33 0.75 17 1.52 14 2.34 1.70 53 1.68 1.25 Gastropods Aragonite 38 0.87 15 2.19 8 2.51 1.70 64 1.85 1.01 Pelecypods

A c k n o w l e d g e m e n t s

I wish to extend my sincere thanks to Dr. ULRICH F~SRSTNER, presently in Kabul, who took the samples in the drainage area of the Ill River and to MANFRED GASTNER who performed the analytical work. I also thank the "Deutsche Forschungsgemeinschaft" for their financial support of our work in the "Lake Constance Project".

R e f e r e n c e s

MOLL~R, G. : Zur Geochemie des Strontiums in ozeanen Evaporiten unter besonderer Bertick- sichtigung der sediment/iren Coelestinlager- stiitte yon Hemmelte-West (Stid-Oldenburg). Geologic 11, 1--90 (1962).

- - Zur Hydrochemie yon Alpenrhein und See- rhein. Ergebnisse einj/ihriger systematischer Untersuchungen. Gas-u. Wasserf. 105, 810--814 (1964).

- - E r g e b n i s s e einj/ihriger systematischer Unter- suchungen tiber die Hydrochemie yon Alpen- und Seerhein (mit Einzeluntersuchungen an weiteren Bodensee-Zufltissen). Fortschr. Was- serchem. 65, 33--99 (1965).

- - , a n d H.-P. R6PER: Erste Ergebnisse hydro- chemischer Untersuchungen am Bodensee. Gas- u. Wasserf. 107, 825--830 (1966).

- - Exceptionally High Strontium Concentrations in Fresh Water Onkolites and Mollusk Shells of Lake Constance. In: G. MOLLER and G. M. FRIEDMAN (Edits.): Recent Developments in Carbonate Sedimentology in Central Europe, 116--127. Berlin-Heidelberg-New York: Sprin- ger 1968.

NEt, P. : 13ber ein neues C61estin-Vorkommen bei Fischbaeh/Inn, Oberbayern. Aufschluss 8, 153- 156 (1957).

ODUM, H. T. : The stability of the world strontium cycle. Science 114, 407--411 (1951).

- - Strontium in Natural Waters. Inst. Marine Sci. IV, 22--37 (1957a).

- - Biogeochemical deposition of strontium. Inst. Marine Sci. IV, 38--114 (1957b).

STmNMETZ, H. : Uber zwei C61estin-Vorkommen vom n6rdlichen Alpenrand. Heiddberger Beitr. Mineral. Petrog. 1, 399--402 (1948).

THOMPSON, T, G., and T. J. CHOW: The strontium- calcium ratio in carbonate-secreting marine organisms, In: Papers in Marine Biology and Oceanography. Deep-Sea Res., Suppl. 3, 30--39 (1955).

WASKOWIAK, R.: Geochemische Untersuchungen an rezenten Molluskenschalen mariner Her- kurfft. Freiberger Forschungsh. C 136, 155 p. (1962).

Received December 12, 1968

Prof. Dr. G. Mt~LLER Laboratorium fat Sedimendorschung, Berliner StraBe 19, 69 Heidelberg, Germany