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Chemical Geology 21
Geochemical identification of fresh water sources in brackish
groundwater mixtures; the example of Lake Kinneret
(Sea of Galilee), Israel
Ofra Klein-BenDavid*, Haim Gvirtzman1, Amitai Katz1
Institute of Earth Sciences, the Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904, Israel
Received 14 January 2004; accepted 19 August 2004
Abstract
Fresh waters that dilute brines are considered to have a negligible effect on the ion ratios of the resultant mixture. We show
that the major element composition of the fresh end-member can be deduced from the chemical composition of the mixed
waters. That composition, then, can be used to differentiate between different neighboring carbonate aquifers, which supply the
water. This is demonstrated for the Fuliya and Tabgha saline springs, located on the northwestern shore of Lake Kinneret (Sea of
Galilee), Israel. At these springs, shallow fresh groundwater mixes with brines from deep aquifers. Seven saline springs and
wells located at the Fuliya and Tabgha blocks were sampled over a year, and 32 eastern Galilee fresh springs and wells were
sampled as representatives of the fresh water end-member. All samples were analyzed for major and minor ions. The saline
spring data were used to construct mixing lines, followed by their extrapolation to low concentrations in order to derive the ion/
chloride ratio characterizing the fresh component. We constructed ion/Cl vs. Cl curves; projection of the composition of fresh
water on the calculated curve was used to identify a certain fresh water source as a possible end-member. Results indicate that
the composition of the water feeding the Fuliya springs is different from that at Tabgha, reflecting interactions with different
rocks in each basin. The major fresh water end-member diluting the Fuliya brines is characterized by high Mg/Cl and low Sr/Cl
ratios, and is consistent with the composition of fresh groundwater in the dolomitic Cenomanian and Turonian aquifers widely
exposed in the Fuliya drainage basin. The major fresh water end-member diluting the Tabgha brines, on the other hand, is
characterized by low Mg/Cl and high Sr/Cl ratios, and is consistent with the composition of fresh groundwater in the chalky
Eocene Timrat Fm. and Senonian outcrops. Although the chalky formations in the Tabgha drainage basin are exposed over only
20% of the area they contribute most of the solutes to the fresh water end-member. Rain flows over the chalky formations and
then infiltrates into the Bar-Kokhba Eocene outcrops.
D 2004 Elsevier B.V. All rights reserved.
Keywords: Saline springs; Brine freshwater mixing; End-member; Fuliya; Tabgha
0009-2541/$ - s
doi:10.1016/j.ch
* Correspon
E-mail addr1 Fax: +972
4 (2005) 45–59
ee front matter D 2004 Elsevier B.V. All rights reserved.
emgeo.2004.08.025
ding author: Fax: +972 2 5662581.
esses: [email protected] (O. Klein-BenDavid)8 [email protected] (H. Gvirtzman)8 [email protected] (A. Katz).
2 5662581.
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5946
1. Introduction
Lake Kinneret is a fresh water lake located within
the Dead Sea Rift (DSR) valley at the northern part of
Israel (Fig. 1). The present (July 2003) average salinity
Fig. 1. (A) locations of springs and wells in the eastern Galilee, the num
located in the lower left corner. One hundred-meter contours are applied. Th
in the Fuliya area. (C) Locations of springs and wells at the Tabgha area.
of the lake is 250mgCl/L, an order of magnitude higher
than the concentration of the Jordan River water and
other surface waters entering the lake (Katz, 2003). The
majority of the salts are contributed from saline springs,
which supply less than 10% of the lake-water, but
bers correspond to the names in Table 4; a general location map is
e lake bathymetry contours are 5 m spaced. (B) Locations of springs
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 47
almost 90% of its salts (Simon and Mero, 1992;
Kolodny et al., 1999). Three groups of saline springs
are located on the western shore of the lake: the Tiberias
hot springs whose chloride concentration is around
18,000 mg/L (Mazor and Mero, 1969; Moise et al.,
2000) throughout the year and the Fuliya and Tabgha
springs whose chloride concentrations vary seasonally
between 500 and 3500 mg/L (Mazor and Mero, 1969).
The last two groups are the focus of this article.
The Fuliya and Tabgha springs exhibit abrupt
seasonal salinity variations (Goldschmidt et al.,
1967; Rimmer et al., 1999). At Fuliya salinity is
maximal in March, following the last rains, and at
Tabgha, salinity is maximal in November, by the end
of the dry season (Fig. 2). Mazor and Mero (1969)
plotted the concentration of various ions vs. the Cl
concentration in the Fuliya and Tabgha springs. They
showed that the springs construct linear arrays on such
diagrams indicating a two-component mixing system;
one end-member is brine and the other end-member is
a fresh water component. Extrapolating these mixing
lines to high and low concentrations can give an
estimation of the ion ratios in the end-members.
Many authors have tried to infer the composition
of the saline end-member; it is generally accepted
that the brines are residual evaporated, ancient
seawater that invaded the DSR during the Neogene,
precipitated evaporitic minerals and interacted with
the aquifers (Klein-BenDavid et al., 2004; Starinsky,
1974; Stein et al., 1997, 2000; Zak, 1997).
Fig. 2. Seasonal variation in the Cl concentration in the En Sheva spring o
Gvirtzman et al. (1997) showed that circulating
fresh water from the Galilee aquifers flushes the
brine to the surface. However, The chemical charac-
teristics of the diluting fresh water in the different
spring groups were never established in detail.
Because the fresh end-member d18O and yD is
similar in the Fuliya and Tabgha recharge areas, the
chemical composition of the water may be the only
way to distinguish between them.
Recharge water in the eastern Galilee aquifers flows
over and through different rock formations and
interacts with them. The common rock types are
dolomite, limestone, chalk, marl and basalt. The
changes in Ca, Mg, Sr and Cl concentrations are
examined as indicative of the interaction with the
different rocks. Elevated Mg/Ca and low Sr/Cl ratios
are expected in the interaction with dolomite, whereas
high Sr/Cl and low Mg/Ca ratios will be representative
of chalk-related samples. Water that interacted with
limestone would give intermediate values and water
that flows through basalts would give both high Mg/Ca
and Sr/Cl ratios (Kafri et al., 2002).
The objective of this study is to define chemical
constraints to the composition of the fresh water
end-member feeding the Fuliya and Tabgha groups
of springs through the comparison of the ion ratios
in the calculated Fuliya and Tabgha fresh end-
member and the measured eastern Galilee sources
and to relate the observed groundwater compositions
to specific eastern Galilee aquifers.
f the Tabgha group and in the Fuliya 6/2 spring of the Fuliya group.
Fig. 3. The Tabgha, Fuliya and Tiberias hot springs drainage basin drawn on the eastern Galilee geological map.
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5948
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 49
2. Hydrogeological setting
The DSR is a left-lateral transform, along which
several rhomb-shaped grabens were formed, including
the Dead Sea and Lake Kinneret (Freund et al., 1970;
Garfunkel, 1981; Ben-Avraham et al., 1996; Al-Zoubi
and Ten-Brink, 2001). This basin includes the deepest
terrestial location on Earth as well as Lake Kinneret—
the lowest fresh water lakes on Earth (Fig. 1). Lake
Kinneret drains groundwater from five surrounding
aquifers: (1) the 200-m-thick, Neogene Bashan Group
basalt (Shaliv, 1989); (2) the 350-m-thick, Eocene
Avdat Group limestone and chalk (Saltzman, 1967;
Michelson, 1975; Sneh, 1988); (3) the 600-m-thick,
Cenomanian–Turonian Judea Group of predominantly
carbonates (Bein, 1967; Kafri, 1972); (4) the 400-m-
thick, Lower Cretaceous Kurnub Group of mainly
sandstones (Eliezry, 1959; Michelson, 1975); and (5)
the 2500-m-thick, Jurassic Arad Group of mainly
carbonates (Dubertret, 1966). The recharge areas of the
first three aquifers are exposed over the eastern Galilee
Mountains (Fig. 3; Table 1), the fourth is exposed over
a small area, while the fifth is totally confined.
The subsiding rift valley is filled by a Miocene–
Quaternary sequence that is at least 4 km thick
(Marcus and Slager, 1985). On the western margin
of the graben, some faulted blocks expose the Judea
aquifer along the margins of Lake Kinneret, channel-
ing the main discharge of the system (Goldschmidt et
al., 1967; Gvirtzman et al., 1997). The faults and the
shear zone along the rift allow mixing of water from
Table 1
Recharge areas of the different formation at the Fuliya and Tabgha
drainage basins
Stratigraphy Age Fuliya Tabgha
km2 % km2 %
Fill units Miocene–Holocene 64 31 33 9
Cover Basalt Pliocene–Pleistocene 17 8 76 21
Bar Kokhba Fm. Middle Eocene 2 1 25 7
Timrat Fm. Lower–Middle Eocene 7 3 32 9
Mount Scopus Group Senonian–Paleocene 17 8 36 10
Bina Fm. Turonian 6 3 8 2
Sakhnin Fm. Cenomanian 20 10 56 15
Deir-Hanna Fm. Cenomanian 42 20 84 23
Kammon Fm. Albian–Cenomanian 19 9 17 5
Ein el Assad Fm. Lower Cretaceous 9 5 5 1
Sum 203 100 371 100
Numbers are rounded to zero decimals.
deep aquifers with shallow fresh groundwater, which
emerges as springs (Moise et al., 2000).
Groundwater drains from the eastern Galilee
Mountains toward Lake Kinneret within three subsur-
face drainage basins: Tiberias, Fuliya and Tabgha.
These basins are separated from each other by major
faults. The borders of these recharge basins are shown
in Fig. 3. The total discharge of groundwater at the
onshore springs at Tiberias, Fuliya and Tabgha is
approximately 1.2, 11 and 25 million m3/year (Bein,
1978). The total estimated discharge of the onshore
and offshore springs is 5, 20 and 40 million m3/year,
respectively (Gvirtzman, unpublished data).
3. Methods
3.1. Sampling
Three springs belonging to the Fuliya group and
four springs and one artesian well from the Tabgha
group were sampled for chemical analyses. Sampling
was performed every 2 weeks (or at shorter intervals)
between April 1997 and May 1998. In addition, 47
samples from 32 fresh water springs and wells spread
over the eastern Galilee (Table 2 and Fig. 1) were
sampled once or twice between August 1996 and May
1998. They were selected according to their geo-
graphic and stratigraphic locations to represent the
entire region’s fresh groundwater. In the Fuliya basin,
wells from the Cenomanian, Turonian and Neogene
(Yavne’el) aquifers were sampled. In Tabgha the water
was sampled from the Eocene aquifer and springs
form Neogene (Korazim), Cenomanian–Turonian,
Senonian and Eocene formations.
Samples were collected as close as possible to the
discharge point. The samples were stored in 330 mL
PET (polyethylene teraphtalate) gas-tight plastic bot-
tles. The water was refrigerated (4–5 8C) until analysis.
3.2. Chemical analysis
Water samples were filtered using Whatmank #40
filters in order to remove all insoluble particles and
were diluted with deionized water (18.3 MV/cm) to
achieve optimal analytical ranges. Each sample was
analyzed in triplicate. Na, K, Mg, Ca, Sr, Si, and S were
measured using ICP-OES by an automated Perkin-
Table 2
Calculated linear regression parameters for ion vs. Cl correlation in the Fuliya and Tabgha saline sources (full analysis in Klein-BenDavid et al.,
2004)
Water source Number
of samples
Temperature
range (C8)aMg
(mg/L)
Ca
(mg/L)
Sr
(mg/L)
Cl
(mg/L)
Fuliya Group
Fuliya 5 31 27.0–28.0 Average 65.3 156 1.45 755
S.D.b 2.95 8.07 0.14 69.6
Slopec 0.042 0.114 0.002
Interceptd 33.9 70.7 �0.066
R2e 0.963 0.960 0.965
Fuliya 6 30 18.3–27.0 Average 64.1 151 1.34 720
S.D. 2.21 7.74 0.12 54.8
Slope 0.037 0.119 0.002
Intercept 37.7 65.5 �0.138
R2 0.825 0.709 0.954
Fuliya 6/2 29 26.7–28.1 Average 73.0 178 1.78 939
S.D. 4.17 11.4 0.19 98.4
Slope 0.041 0.113 0.002
Intercept 34.3 72.1 �0.066
R2 0.942 0.954 0.986
Tabgha Group
En Sheva 35 24.8–28.0 Average 62.3 249 4.84 1112
S.D. 9.93 27.0 0.83 222
Slope 0.044 0.118 0.004
Intercept 13.3 117 0.75
R2 0.975 0.946 0.972
Druzi Springf 17 16.8–28.7 Average 69.9 249 5.00 1277
S.D. 6.98 18.2 0.53 159
Slope 0.043 0.110 0.003
Intercept 14.9 108 0.78
R2 0.958 0.926 0.966
Ma’ayan Matok 33 26.0–28.0 Average 84.8 316 7.12 1770
S.D. 7.32 19.7 0.61 166
Slope 0.044 0.115 0.004
Intercept 7.78 113 0.68
R2 0.976 0.935 0.979
Kinneret 7 33 23.9–28.0 Average 41.7 189 3.31 734
S.D. 10.2 28.3 0.87 206
Slope 0.049 0.137 0.004
Intercept 5.50 88.2 0.21
R2 0.995 0.987 0.997
a Temperatures were measured as close as possible to the spring.b Standard deviation.c a-Linear slope ( Y=aX+b).d b-Linear intercept ( Y=aX+b).e Correlation coefficient.f The Druzi spring was not sampled through the whole sampling period.
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5950
Elmer Optima-3000 radial ICP system. Chloride, Br
and NO3 were analyzed using an automated Lachat
Instruments model QE flow injection analysis (FIA)
system with colorimetric detection (Eaton et al., 1995).
Instrumental drift was monitored by analyzing calibra-
tion standards every 10 samples and corrected for by an
in-house correction program (Katz, 1997). The ICP, Cl
and Br (FIA) precision is equal to or smaller than 1%.
The NO3 precision is F2%. Bicarbonate was titrated
using 0.02 NHCl with the BDHk #4480 indicator, at a
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 51
precision ofF0.5–1%. Further analytical details can be
found in Klein-BenDavid et al. (2004).
4. Results
Ions vs. Cl diagrams were plotted for seven Fuliya
and Tabgha saline sources. The Cl content of the
Fig. 4. Magnesium, Ca and Sr vs. Cl plots for the Fuliya (left column) and T
for the Fuliya charts: Fuliya 5 o; Fuliya 6 x; Fuliya 6/2 5. Legend for t
Kinneret 7 4.
selected saline sources ranges between 500 and 2000
mg/L. Fig. 4 displays the positive linear regression
between Ca,Mg and Sr and Cl. Such a behavior reflects
mixing between a fresh water component and brine.
We calculated the linear regression equation for
these lines. As the mixing occurs between brine and
fresh water, rather than distilled water, the lines do not
extrapolate through the origin and different points
abgha (right column) sources. Linear regressions are plotted. Legend
he Tabgha charts: En Sheva x; Ma’ayan matok 5; Druzi spring ;
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5952
along the line display different ion/Cl ratios. Thus, in
order to estimate the ion/Cl ratios of the fresh water
end-member we extrapolated the line to low concen-
trations and calculated the ratios for a pre-determined
Cl concentration.
Through extrapolation, we tested Cl concentrations
between 10 and 100 mg/L. As fresh groundwater in the
recharge basin displays this concentration range we
assumed that it is representative of the fresh end-
member. Table 2 presents the regression equations for
the Ca, Mg, Sr and Cl relationships and the correlation
coefficient R2. Table 3 presents the calculated ion/Cl
ratios in the tested Cl concentration range. We
calculated the error in the equivalent ion/Cl ratio to
the extrapolation to low concentrations. The calcula-
tions were conducted according to the procedure of
Natrella (1963) sections 5-3 and 5-4.1.2.1, using a 1�afactor of 0.95. The error for the ratios calculated from
16 of the lines is smaller than F10% (mostly smaller
than F5%). Two lines yielded up to 17% error. Three
Table 3
The ion/Cl equivalent ratios calculated from the extrapolated linear re
concentrations ranging between 10 and 100 mg/La
Cl (mg/L) 10 20 30 40
Fuliya
Fuliya 5 Mg/Cl 10.01 5.07 3.42 2.5
Ca/Cl 12.70 6.45 4.37 3.3
Sr/Clb �0.0037 �0.0010 �0.0001 0.0
Fuliya 6 Mg/Cl 11.11 5.61 3.78 2.8
Ca/Cl 11.80 6.00 4.07 3.11
Sr/Clb �0.0095 �0.0039 �0.0021 �0.0
Fuliya 6/2 Mg/Cl 10.14 5.13 3.46 2.6
Ca/Cl 12.95 6.57 4.45 3.3
Sr/Clb �0.0038 �0.0011 �0.0002 0.0
Tabgha
En Sheva Mg/Cl 4.00 2.06 1.42 1.1
Ca/Cl 20.97 10.59 7.13 5.4
Sr/Cl 0.063 0.033 0.023 0.0
Druzi Spring Mg/Cl 4.48 2.30 1.58 1.2
Ca/Cl 19.36 9.78 6.58 4.9
Sr/Cl 0.066 0.034 0.024 0.0
Ma’ayan Matok Mg/Clc 2.40 1.26 0.88 0.6
Ca/Cl 20.25 10.23 6.89 5.2
Sr/Clc 0.058 0.030 0.021 0.0
Kinneret 7 Mg/Cl 1.75 0.95 0.68 0.5
Ca/Cl 15.84 8.04 5.44 4.1
Sr/Cl 0.02 0.012 0.009 0.0
a Errors are up to F10% (mostly smaller then 5%).b ~100% error (see text).c F17% error.
lines, calculated for Sr vs. Cl in the Fuliya springs, gave
errors within the range of 100%. The reason for this
large error is the fact that the regression line crosscuts
the axis very close to the origin and the value of the
ratio is in the order of 10�4. Any minor change in the
value will cause a very large relative error.
A comparison of the ion ratios in the eastern
Galilee fresh water sources to the calculated fresh end-
member may distinguish between different eastern
Galilee sources as possible fresh water feeders to the
Fuliya and Tabgha springs. Table 4 lists the chemical
composition of 32 springs and wells sampled in the
Fuliya and Tabgha drainage basins from eight differ-
ent aquifers and lithologies.
5. Discussion
In order to compare the calculated ion/Cl ratios
in the fresh end-member with the actual ion/Cl
gression equations for Fuliya and Tabgha saline sources for Cl
50 60 70 80 90 100
9 2.10 1.77 1.53 1.36 1.22 1.11
3 2.70 2.28 1.99 1.76 1.59 1.45
003 0.0006 0.0007 0.0009 0.0010 0.0010 0.0011
6 2.31 1.94 1.68 1.48 1.33 1.21
2.53 2.14 1.87 1.66 1.50 1.37
011 �0.0006 �0.0002 0.0001 0.0003 0.0004 0.0006
2 2.12 1.79 1.55 1.37 1.23 1.12
9 2.75 2.32 2.02 1.79 1.62 1.47
002 0.0005 0.0007 0.0008 0.0009 0.0010 0.0011
0 0.90 0.77 0.68 0.61 0.56 0.52
0 4.36 3.67 3.18 2.80 2.52 2.29
18 0.015 0.013 0.012 0.011 0.010 0.009
1 1.00 0.85 0.75 0.67 0.61 0.56
9 4.03 3.39 2.93 2.59 2.32 2.11
18 0.015 0.013 0.012 0.011 0.010 0.009
9 0.58 0.51 0.45 0.41 0.38 0.35
2 4.21 3.54 3.07 2.71 2.43 2.21
17 0.014 0.012 0.011 0.010 0.009 0.008
5 0.46 0.41 0.37 0.34 0.32 0.30
4 3.36 2.84 2.47 2.19 1.98 1.80
08 0.007 0.006 0.006 0.006 0.005 0.005
Table 4
Summary of chemical analyses of fresh water samples collected at springs and wells in the eastern Galileea
Source No. Unit Well
depth
(M)
Typeb Sampling
date
Na
(mg/L)
K
(mg/L)
Mg
(mg/L)
Ca
(mg/L)
Sr
(mg/L)
Si
(mg/L)
SO42�
(mg/L)
Cl
(mg/L)
NO3�
(mg/L)
HCO3�
(mg/L)
Arabe-1 1 Lower
Cenomanian
302 W 12/08/96 33.3 15.7 37.7 79.7 0.185 7.84 23.0 69.2 78.2 327
Arabe-1 W 17/03/98 33.9 16.4 38.6 81.8 0.187 8.27 19.8 61.4 69.0 329
Chazon-2 2 367 W 12/08/96 18.7 1.57 36.3 71.4 0.154 6.78 10.7 34.0 14.8 356
Chazon-2 W 17/03/98 19.0 1.61 36.9 73.0 0.157 6.92 11.1 34.9 17.7 352
Golani 1 3 502 W 12/08/96 70.0 3.78 44.1 95.1 0.358 8.83 17.5 163 24.6 352
Golani 1 W 10/03/98 70.7 3.78 44.7 96.4 0.362 8.78 17.9 166 25.4 355
Golani 2 4 647 W 12/08/96 53.5 1.89 37.1 79.3 0.307 9.76 13.6 102 16.4 349
Golani 2 W 10/03/98 50.4 1.83 36.2 78.3 0.304 10.03 13.6 96.6 16.2 339
Kalanit-1 5 540 W 12/08/96 17.2 1.51 31.9 74.2 0.183 7.19 10.6 32.8 14.5 357
Kalanit-1 W 17/03/98 18.0 1.59 34.7 78.8 0.188 7.94 9.76 33.0 14.9 365
Chazon-1 6 Upper
Cenomanian–
Turonian
300 W 12/08/96 16.6 0.98 34.8 72.4 0.117 6.08 10.4 33.2 15.4 372
Chazon-1 W 17/03/98 18.1 1.14 38.3 74.3 0.116 6.33 11.8 34.3 18.6 355
Chazon-3 7 247 W 12/08/96 19.4 1.25 40.4 73.9 0.122 6.18 13.3 37.8 23.3 392
Chazon-4 8 319 W 12/08/96 30.3 1.07 40.1 81.6 0.167 7.92 12.5 64.8 23.0 397
Chazon-4 W 17/03/98 32.2 1.12 43.5 86.2 0.175 8.69 11.5 65.3 26.2 395
Chitin 1 9 279 W 12/08/96 33.3 1.70 31.3 71.0 0.244 8.31 12.2 63.6 16.0 327
Chitin 1 W 10/03/98 34.5 1.59 30.1 73.2 0.320 10.3 17.7 57.9 14.1 334
Chitin 3 10 501 W 12/08/96 34.3 1.59 32.2 71.1 0.272 8.83 13.2 64.0 15.0 342
Chitin 4 11 374 W 12/08/96 27.8 1.66 33.1 73.3 0.216 7.99 10.4 53.0 14.6 357
Chitin 4 W 10/03/98 30.0 1.72 36.0 77.5 0.221 8.76 9.94 56.0 14.4 350
En Po’em 12 Cenomanian–
Turonian
SP 20/07/98 13.1 0.60 35.7 95.0 0.073 19.1 17.4 29.1 22.6 408
En Taron 13 SP 20/07/98 10.7 3.37 35.7 85.5 0.066 8.20 11.8 20.2 13.1 435
En Yakim 14 SP 20/07/98 10.6 2.99 35.9 85.6 0.065 20.2 12.0 19.7 13.3 408
En Hitra 15 Senonian SP 20/07/98 13.8 0.48 5.08 104 0.419 86.2 12.8 29.8 8.37 300
En Koves 16 SP 20/07/98 33.0 7.10 8.67 121 0.556 17.6 34.4 52.8 49.7 307
En Pash’hur 17 SP 20/07/98 13.4 1.10 5.62 116 0.487 22.5 10.8 39.2 17.9 320
En Zetim 18 SP 20/07/98 12.1 1.24 5.89 120 0.623 14.1 26.9 27.3 6.62 349
Ginosar 19 Eocene
Bar-Kokhba
240 W 12/08/96 18.3 1.75 33.4 72.8 0.163 7.04 9.40 34.1 11.1 382
Hakok 20 112 W 10/03/98 45.7 2.69 29.1 101 0.470 12.8 12.2 86.5 32.6 372
Hakuk W 12/08/96 27.6 1.35 32.6 79.1 0.236 8.72 11.0 46.0 16.8 387
Hakuk 2 21 150 W 12/08/96 44.8 2.56 28.0 98.4 0.462 11.9 13.5 94.1 33.8 372
En Kichli 22 Eocene
Timrat
SP 20/07/98 34.8 14.6 15.8 106 0.854 69.8 46.5 57.3 7.99 350
En Sela 23 SP 20/07/98 32.6 12.4 15.1 119 0.891 74.4 45.9 53.0 25.6 350
En Sela 2 24 SP 20/07/98 32.3 12.3 14.7 119 0.881 74.1 46.1 53.3 25.2 350
En Dovshan 25 Neogene
Basalt–
Korazim
SP 20/07/98 95.0 21.8 34.8 81.4 0.376 15.7 18.3 95.5 13.1 671
En Korazim 26 SP 20/07/98 43.4 8.12 36.5 67.7 0.394 37.3 7.39 44.8 0.45 430
En Shum 27 SP 20/07/98 23.5 2.48 24.3 72.1 0.235 20.2 21.8 39.6 11.9 271
En Tofach 28 SP 20/07/98 23.3 2.36 25.0 56.7 0.200 28.5 19.8 35.3 15.3 261
Yavne’el 1 29 Neogene
Basalt–
Yavne’el
111 W 10/03/98 118 3.07 36.8 56.7 0.585 20.5 47.8 203 45.0 200
Yavne’el 2 30 98 W 10/03/98 97.7 3.58 38.7 38.6 0.658 22.3 21.7 111 32.0 308
Yavne’el B 31 142 W 12/08/96 96.4 3.26 35.0 34.8 0.582 22.7 20.8 98.7 30.9 287
Yavne’el B W 10/03/98 97.2 3.23 38.9 31.3 0.611 21.8 18.4 120 41.7 255
Yavne’el C 32 120 W 12/08/96 93.7 3.18 37.3 30.3 0.632 21.1 20.4 119 42.8 262
(continued on next page)
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 53
Source No. Unit Well
depth
(M)
Typeb Sampling
date
Na
(mg/L)
K
(mg/L)
Mg
(mg/L)
Ca
(mg/L)
Sr
(mg/L)
Si
(mg/L)
SO42�
(mg/L)
Cl
(mg/L)
NO3�
(mg/L)
HCO3�
(mg/L)
En Bardic Eocene
Timrat
SP 23.4 36.9 13.1 127 0.566 16.4 40.4 48.0 66.7 362
Bardi runoff c RF 12.6 4.82 2.62 58.3 0.239 5.49 43.1 17.0 5.25 127
En Neriac Upper
Cenomanian–
Turonian
SP 9.70 1.48 45.1 84.0 0.064 4.15 8.9 20.9 13.7 451
Neria runoff c RF 3.29 1.55 4.79 20.6 0.019 3.65 4.97 4.41 2.53 80.6
a Br concentrations in fresh-water samples are below detection limit.b Type: Sp=Spring, W=Well.c Average composition from Burg (1998).
Table 4 (continued)
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5954
ratios in the Eastern Galilee fresh water sources we
plotted ion/Cl vs. Cl diagrams (Fig. 5). We used this
projection method because, except for dilution with
extremely pure water, a two-end-member mixing
system would result in hyperbolic curves of the
general form of Ax+Bxy+Cy+D=0 (see Appendix
A). The Eastern Galilee fresh water samples were
plotted on the hyperboles; any fresh water falling
along the hyperboles is a possible end-member
candidate.
5.1. The fresh end-member in Fuliya
Fig. 5 presents the calculated Mg/Cl and Ca/Cl
ratios plotted against Cl concentration for the Fuliya
water sources. The eastern Galilee sources plotted on
the same diagram indicate that the Cenomanian–
Turonian sources as well as the Eocene–Bar-Kokhba
waters follow the calculated curve, whereas the other
sources fall off line, indicating that these sources are
similar in their Mg/Cl and Ca/Cl ratios to the fresh
component feeding the Fuliya springs.
Because the resulting Sr/Cl ratios are negative no
plotting was attempted. Still, this indicates that the
ratio in the fresh water end-member is low. Low
values are observed in the Cenomanian–Turonian
sources.
5.2. The fresh end-member in Tabgha
We also projected Mg/Cl, Ca/Cl and Sr/Cl ratios
vs. the corresponding Cl concentration for the Tabgha
saline springs (Fig. 5). The calculated curves show
some variability due to the large variation in the
salinity of the different saline sources, ranging
between 500 mg Cl/L in the Kinneret 7 well and
2000 mg Cl/L in the Ma’ayam Matok spring. The
Eastern Galilee springs discharging from the chalky
Senonian and Eocenian–Timrat formations are the
only sources that fit the Tabgha curves.
Hence it can be calculated that the water from
Cenomanian and Turonian aquifers as well as those
from the Eocene–Bar-Kokhba Fm. are chemically
similar to the calculated fresh end-member feeding the
Fuliya springs, whereas the Senonian and Eocene–
Timrat springs fit the calculated end-member of the
Tabgha sources. The basaltic aquifers differ from
those of Fuliya and Tabgha.
Thus, the ion ratios in fresh water from carbonate
aquifers can be used to differentiate between neigh-
boring carbonate recharge areas.
5.3. Correlation with local geology
5.3.1. Fuliya basin
Cenomanian–Turonian limestones and dolomites
account for 43% of the exposure of the Fuliya
recharge area (Fig. 1 and Table 1). Smaller areas of
Senonian chalk (8%), Eocene limestone-chalk (4%)
and Neogene basalt (8%) are exposed in the Fuliya
recharge basin, and have only a minor effect on the
groundwater chemical composition. Aquiclude fill
units cover the rest of the area.
Thus, the Cenomanian–Turonian aquifers are the
major fresh water suppliers to the Fuliya springs.
Although the Eocene–Bar Kokhba water composition
is in accord with the calculated Fuliya fresh end-
member, it is not likely that this aquifer provides a
significant amount of fresh water to the Fuliya
springs.
Fig. 5. Calculated Mg/Cl, Ca/Cl and Sr/Cl equivalent ratios vs. Cl concentration (meq/L) for the Fuliya (left column) and Tabgha (right column)
sources. The gray area represents a 10% error range for the hyperbolic curves.
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 55
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5956
5.3.2. Tabgaha basin
The Tabgha recharge area displays a larger variation
in lithology than the Fuliya recharge area (Table 1).
The chemical analyses indicate that the chalky
Eocene–Timrat Formation and Senonian outcrops
Fig. 6. Calculated Mg/Ca, and Sr/Ca equivalent ratios vs. Cl concentratio
springs and wells.
exposed over 19% of the drainage basin have the
most significant contribution to the water chemical
composition. Conversely, The Cenomanian–Turonian
limestone–dolomite formations exposed over 44% of
the area and the Eocene–Bar-Kokhba limestone for-
n (mg/L) for the Fuliya and Tabgha sources and the eastern Galilee
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–59 57
mation exposed over 7% of the area have only a minor
effect on the water chemical composition. Further-
more, because of the low permeability of the chalky
Eocene–Timrat Formation and Senonian outcrops, it is
hard to explain the amount of water discharging from
the Tabgha springs only by the flow from these
formations (Gvirtzman et al., 1997).
This discrepancy requires an explanation. Conse-
quently, we compared the composition of the calcu-
lated fresh end-member for the Tabgha springs with
the composition of springs from the upper part of the
Tabgha basin discharging from the Deir Hanna and
Timrat formations (En Neria and En Bardi, respec-
tively) and with runoff water from the spring vicinity
that flows over dolomite and chalk, respectively (Burg,
1998). Fig. 6 shows Mg/Ca and Sr/Ca ratios plotted
against the Cl concentration in the En Neria and En
Bardi spring and runoff water compared to the eastern
Galilee sources and the calculated Tabgha end-
member. The Figure indicates that the Mg/Ca and Sr/
Ca ratios in the En Bardi spring water are similar to the
ratios measured in the Timrat Fm. springs and to the
calculated end-member. The runoff water displays
slightly lower ratios as well as low Cl concentrations
but they are still within the range of the calculated end-
member. On the other hand, the En Neria spring and
runoff water do not fit the calculated end-member,
displaying high Mg/Ca and low Sr/Ca ratios. This
observation indicates that the water chemical compo-
sition is acquired at a very early stage of its flow and
that runoff water flowing over the different formations
can be easily distinguished. Due to the lower perme-
ability of the chalky formations, much of the runoff
water does not infiltrate into the bedrock until
encountering more permeable rocks. Surface flow on
the chalky outcrops will finally infiltrate into the Bar-
Kokhba limestone recharging it with water with high
Sr/Ca and low Mg/Ca ratios.
Nevertheless, the Cenomanian–Turonian forma-
tions are exposed over a large part of the recharge
basin but their contribution to the solute content of the
fresh end-member seems to be minor. The Cenoma-
nian–Turonian rock column in this area is divided into
four formations (Fig. 3): Sakhnin (C1, a permeable
aquifer), Deir-Hanna (C2, aquitard), Kammon (C3, a
permeable aquifer) and Bina (t, a permeable aquifer). In
the Tabgha recharge area the Cenomanian–Turonian
rock outcrop consists mostly of the Deir-Hanna
formation (23%), whose hydraulic conductivity is
relatively small (Gvirtzman et al., 1997); moreover,
the Deir-Hanna Fm. surface flow drainage to a western
Galilee system (Kziv stream). Nevertheless, the Sakh-
nin Fm. and to a lesser degree the Kammon Fm.
(exposed over 15% and 5% of the drainage area,
respectively) can contribute water to the local aquifers.
From the observed chemical composition it is evident
that the amount of solutes contributed from these
formations is low. The solute concentration in runoff
water and fresh spring water (17 and 48 mg Cl/L,
respectively) from En Bardi (chalky Timrat formation)
carry more solutes than water interacting with lime-
stone and dolomite in the En Neria vicinity (Burg,
1998). This observation may partly explain the smaller
contribution of the Sakhnin and Kammon water to the
fresh end-member.
In summary, the fresh water end-member in
Tabgha acquires its chemical composition mainly
during its flow over the Senonian and Eocene chalky
rocks. This water flows down and infiltrates into the
Bar Kokhba aquifer and discharges at the Tabgha
springs. The solute addition from the Sakhnin and Bar
Kokhba formations is minor.
To conclude, the fresh component in the Tabgha
basin acquires its solute content from shallow depth
while the Fuliya springs are recharged by deeper
aquifers. This conclusion is consistent with an
independent hydrological model indicating that the
major fresh water recharge to the Tabgha and Fuliya
blocks comes from the Eocene aquifers and Cenoma-
nian–Turonian aquifers, respectively (Gvirtzman et
al., 1997).
6. Conclusions
(1) In two component mixing systems, linear equa-
tions constructed from the ion vs. Cl correlation
can be extrapolated to low Cl concentrations and
be used for the assessment of the ion/Cl ratio in a
fresh end-member.
(2) Hyperboles constructed by projecting ion/Cl
ratios vs. Cl can be used to estimate two end-
member mixing in an aquatic system; projecting
the composition of natural water on the calcu-
lated curve can be used to identify the fresh
water source.
O. Klein-BenDavid et al. / Chemical Geology 214 (2005) 45–5958
(3) The major fresh water end-member diluting the
Fuliya brines is characterized by high Mg/Cl and
low Sr/Cl ratios, and is consistent with the
composition of fresh groundwater in the Cen-
omanian and Turonian aquifers.
(4) The major fresh water end-member diluting the
Tabgha brines is characterized by low Mg/Cl and
high Sr/Cl ratios, and is consistent with the
composition of fresh groundwater in the Eocene
Timrat formation and Senonian outcrops.
(5) Although the chalky formations in the Tab-
gha drainage basin are exposed over only
19% of the area they contribute most of the
solutes to the fresh water end-member. There
is no significant solute contribution from the
Cenomanian–Turonian aquifers.
Acknowledgments
The Israeli Water Commission—the Ministry of
Energy and Infrastructure (account number 65/01)
supported this study. Einat Kasher, Ahuva Agranat
and Moshe Riban are thanked for technical support.
Onn Crouvi and Ittai Haviv are thanked for help in GIS
analysis, and finally we are grateful to Prof. H. Blatt
and Prof. A Starinsky for their helpful comments. [LW]
Appendix A
The equation for the hyperbolic mixing curve
between components a and b for Ca and Cl.
ACa
Cl
�mix
þ B Cl½ �mix
Ca
Cl
�mix
þ C Cl½ �mix þ D ¼ 0
��
A ¼ Cl½ �b Ca½ �a � Cl½ �a Ca½ �b
B ¼ Ca½ �b � Ca½ �a
C ¼ Ca½ �aCa
Cl
�a
� Ca½ �bCa
Cl
�b
��
D ¼ Cl½ �a Ca½ �bCa
Cl
�b
� Cl½ �b Ca½ �aCa
Cl
�a
��
This equation results will not result in a hyperbolic
curve when: B=[Ca]b�[Ca]a=0.
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