Sources of salinization of groundwater in the Lower Yarmouk Gorge, East of the River Jordan

Peter Möller 1,∗ , Marco De Lucia1 , Eliahu Rosenthal2 , Nimrod Inbar3,4 , Elias Salameh5 , Fabien Magri6,7 , Christian Siebert8 1 GFZ German Research Centre for Geosciences, Potsdam, Germany 2 The School of Earth Sciences, Tel Aviv University, Tel Aviv, Israel 3 Department of Geophysics and Space Sciences, Eastern R&D, Ariel, Israel 4 Department of Physics, Ariel University, Ariel, Israel 5 University of Jordan, Amman, Jordan 6 BfE Federal Office for the Safety of Nuclear Waste Management, Dept. FA 2, Berlin, Germany 7 Free University of Berlin, Hydrogeology, Berlin, Germany 8 Helmholtz Centre for Environmental Research UFZ, Dept. of Catchment Hydrology, Halle, Germany * Correspondence: pemoe@gfz-potsdam.de


Hydrogeological setting
The Yarmouk basin comprises the eastern Golan Heights and south-eastern flanks of the Hermon Massif, shared by Israel and Syria, the northern plunges of the Ajloun Dome (Jordan), and the Hauran Plateau including the western flank of the Jebel Druz (Syria) (Fig.1). The LYG is the major outlet of surface and groundwater from the Yarmouk basin. Morphologically, the Gorge separates the Ajloun Mountains and the Jordanian Ramta Plains from the Golan Heights and the Hauran Plateau, respectively.
The anticlinal structure of the Ajloun is built of Lower Cretaceous Kurnub sandstones and Upper Cretaceous, marine, strongly karstified, fractured and silicified lime-and dolostones forming the A7/B2 aquifer in Jordan (Fig.2), which descends northward. For easement and shortness, the Jordanian nomenclature of formations is preferred in this contribution. Groundwaters in the A7/B2 are confined by the overlying bituminous Senonian B3 aquiclude, which contains phosphorite, chert and chalk and separates the A7/B2 from the locally exploited limy B4 aquifer. The Cretaceous and Tertiary sedimentary aquifers, which crop out in the Ajloun anticline descend northward into the Golan syncline and surface later again at the foothills of the Hermon anticline, which consists of thick Jurassic lime-and dolostone aquifers with abundant basaltic intrusions [49]. As a consequence, groundwaters south and north of the Gorge migrate through the same aquiferous formations. Contrasting the Ajloun, the Golan Heights are unconformably covered by up to 700 m thick Plio-Pleistocene Cover Basalt [33,39]. A marly sequence at its base, the highly fractured basalt serves as a regional aquifer being annually directly recharged by 500-1,200 mm of precipitation [8]. During the pre-Quaternary the Golan Heights were subjected to tectonic stress documented in a highly faulted and deformed subsurface [24] with intense and deep karstification of the Upper Cretaceous and Tertiary lime-and dolostones [11]. A meridional ridge in these formations acts as subsurface water divide in the covering basalt aquifer [8], leading to groundwater drainage in the latter either W-SW to the Hula-and the Sea of Galilee basin or E-SE into the Hauran Plateau and the Upper Yarmouk Gorge. Hydraulic connections between the basaltic cover and the underlying aquiferous Cretaceous carbonate formations may exist throughout the Golan Heights [25].
The eastward continuation of the Golan Heights is the flat and southward dipping volcanic area of the Hauran Plateau, which passes in the SE into the enormous accumulation of Neogene-Quaternary basalts of the Jebel Druze [17,22]. Precipitation infiltrates directly into Upper Quaternary basalts exposed all over the Plateau and drains towards the LYG, partially feeding perennial springs in the arcuated Wadi Arram (Fig. 1) which was a major contributor to the Yarmouk River in the past [9].
Analyses of spring and well waters from the Lower Yarmouk Gorge. Grouping according the geographical and chemical proximity (code). In the two last columns the normalized Tb/Lu ratios and the fraction of basaltic-rock water, bw, in mixture with limestone water are given as derived from Fig. 4. South of the Yarmouk River the hot water from Ain (Arabic term for spring) Himma (42°C) emerges from the B3 aquitard, ascending along faults from the B2 aquifer [3]. In the nearby artesian Mukheibeh well field the groundwater is exploited from A7 and B2 discharging with temperatures of 29-46°C probably heated by volcanic intrusions at depths of 3-4 km [36]. Hot groundwater from the A7 aquifer is also known from the western Ajloun escarpment within the Lower Jordan Valley [27,28,46]. In the Ajloun the temperature of groundwater from A7/B2 is only slightly enhanced (23-31°C ) and cool if draining the shallow basaltic aquifer or the B4.  (Table 1).

Code
With few exceptions the groundwater of the LYG are saturated with respect to calcite but neither to gypsum nor halite [51]. The groundwater from Ain Himma, the springs of Hammat Gader (enclosing codes ES, EB, ER and EM in Table 1) and Mezar well 3 are seemingly mixtures of local groundwater, relic seawater evaporation brine(s) and leached evaporites and dissolved calcite from limestone [51,52].

Sampling and analytical procedure
During a synchronous sampling campaign in 2016, wells and springs on both sides of the LYG were chemically analyzed. To allow a regionally comprehensive elaboration, selected analytical results from earlier local campaigns were included (Table 1). In the field, samples were collected by filtrating (0.22 µm) water into cleaned HD-PE bottles. Cation samples have been acidified to ensure conservation.
To determine REY and U(VI), preconcentration was required. Therefore, about 4 l of sample were filtered (0.22 µm), acidified by sub-boiled (index sbb) HCl to a pH=2, and spiked with 1 ml of Tm solution. At the same day, the samples were passed through C 18 Sep-Pak cartridges, loaded with ethylhexylphosphate liquid ion exchanger. In the lab, each cartridge was eluated with HCl sbb and eluates were evaporated to incipient dryness, taken up with HNO 3sbb and the resulting solution was analyzed applying ICP-MS (Elan DRC-e). Independently, Ca 2+ and Mg 2+ were determined by similar ICP-MS. K + and Na + were analyzed by ICP-AES (Spectro Arcos) using matrix adjusted standard solution for calibration. Cl − , Br − , SO 2− 4 were determined by Dionex ICS (AS18 column). The alkalinity was titrated to pH 4.3 with H 2 SO 4 and given as HCO − 3 .

Selection of end member fluids in the Yarmouk basin
The suggested quantification of salinity contributions is based on defined end members of water types in the LYG:  (Table A1 and Table 1).
The averages of limestone water of two well waters from each the Golan Heights and the Ajloun Mts. were selected. Their Cl − concentrations range between 0.50 and 0.80 meq/l ( Table 2). This wide spread suggests that the samples with values >0.50 meq/l might have already leached either evaporites or contain seawater brines. Two particular brines have to be considered: 1. The Late Tertiary brine was generated by evaporation of intruded Tethys seawater into the Jordan-Dead Sea Rift [31]. This evaporation brine infiltrated the Cretaceous and Jurassic aquifers east and west of the Rift. This type of Mg 2+ -Cl − brine was identified at Ha'On in the 1960s [21] along the SE shore of Lake Tiberias. The variations in composition of two wells at Ha'On between 1961 and 2004 are averaged ( Table 2). For more detail refer to Table A1. 2. The Late Triassic-to Early Jurassic brine of Rosh Pinna is hosted at depths of 2,500 m in limestones of the Korazim block north of Lake Tiberias (Fig. 1). This brine represents a mixture with the Tertiary Ha'On of brine and fresh water [42].

Estimation of fractions of brine, basaltic-rock-and limestone water
The fractions of basaltic-rock water, ε bw , in mixtures of both pure basaltic-rock water and limestone water (Fig. 4a), are derived from interpretation of REY distribution patterns showing the variation of mixtures of both types of groundwater. Each of the REY patterns is characterized by C1 chondrite-normalized Tb/Lu values [1] that decrease with increasing ε bw values (Fig. 4b), which is used to approach reliable ε bw for the corresponding Tb/Lu values of each groundwater in the study area. For more information of REY patterns refer to [52]. This approach of ε bw assumes that the REY patterns are not significantly varied by dissolution of evaporites or by WRI. Applying ε bw and ε lmst = 1 − ε bw , the end member composition of basaltic-rock-and limestone water (Table 2) and the analysed concentrations of species i, c i,agw in Eq. 1 yields the sum of ε brine · c i,brine + c i,WRI of each species i. The summation of contribution of Cl − from basaltic-rock-and limestone water is given as "estimated" c Cl,est by Eq. 2. If halite is absent, the maximum fraction of ε brine is derived from Eq. 3 which probably yields an overestimation. Another way to characterize the salinization of groundwater is achieved by estimating the total dissolved equivalents TDE (in meq/l), which is independent on processes by such as ion exchange with clay minerals, albitization, dolomitization. TDE, however, varies due to dissolution and precipitation of minerals and mixing of fresh and saline waters. TDE bw and TDE lmst are estimated for the contributions of corresponding waters (Eq. 4). TDE of the analyzed groundwater, TDE agw , is given by summation over all dissolved species i (Eq. 5). The sum of TDE WRI +TDE brine is estimated according to Eq. 6.

Correlations of solutes in Yarmouk groundwater
The cross plots of dissolved species in groundwater reveal relationships between end members of saline and fresh water. The fresh water end member of basaltic-rock-and limestone water (Table 2) are implemented in Fig  . Cross plots of dissolved species in groundwater. Note that the high-salinity groundwaters are related to either basaltic or limestone water (a-e). This is not the case in (f). Averages of low Cl − containing water from the Ajloun Mts. and from the Golan Heights are used for limestone water. Average of low Cl − containing water from the Hauran Plateau are used for basaltic-rock water (Table 1).
x/yy indicates the sampling ID and the year of sampling in the 21 th century.
More details reveal the indicated trend lines in the cross plots of 1000·Br − /Cl − and Na + /Cl − (Fig. 6). For orientation the trend of evaporated seawater is given as red line [23,37]. The groundwater from springs of Hammat Gader and Himma and from well Mezar 2 define vertical trends, which are only explainable by leaching of Br − from the organic-rich limestones of the B3 aquitard. Mezar 1 and 3 and the low Br − /Cl − samples of all vertical trends suggest a mixing line between Mukheibeh groundwater and evaporated seawater such as the Ha'On brine [32]. A second mixing line is indicated by Ein (Hebrew term for spring) Sahina (ES) and the wells Mukheibeh 1 and 6. The water of Mukheibeh 9 well shows an extreme position. Applying the partitioning around medoids clustering method [38] on the groundwaters of the LYG, using the L1 norm for distance measure (=sum of the absolute distances of all components) ( Fig. 7), identifies the same distinct clusters ("code" in Table 1) based only on geographical and chemical proximity. The results of this analysis are visualized in terms of three principal components, which cumulatively explain 83 % of the variance of the samples. The spheres in Fig. 7 represent the position of samples in the vectorial space of the principal components; the similarly colored small dots indicate the corresponding projections on the three faces of the cube. In the C1/C2 plane Mukheibeh waters (code U1, U2, U3 in Table 1) yield a curve which is far away from the projection of Hammat Gader samples (codes ER and EM). ME2 waters show some relationship to ME1. The projection onto C1/C2 and C1/C3 planes reveal that ME3 waters are closely associated with code U3 in plane C1/C2. Only in the plane C2/C3 ME3 and U3 are well separated. Ain Himma is well separated from Hammat Gader and Mukheibeh (U1-U3) in the C1/C2 plane. This way, Fig. 7 visualizes different trends and groupings of waters and brines in the LYG. The different code groups form either clusters or strings in space, thereby indicating constant or variable mixtures, respectively.  (Table 1). This plot is based on concentrations in mg/l.

Mixing of basaltic-rock-and limestone water
The cross plot of ε bw and ε lmst shows the distribution of the various types of water mixtures along the diagonal line (Fig. 8). The red cross marks the arrays of either dominantly limestone-or basaltic rock groundwater. The pure limestone water is presented by Mezar 2 and Mukheibeh 8 in the year 2013; the most basaltic-rock groundwater is among the Mukheibeh ones. Hammat Gader, Ain Himma and Mezar 3 cover the range of ε bw between zero and 0.5. Most of the Mukheibeh waters (U1 and U2) are of the basaltic-water type, whereas the Mukheibeh subgroup U3 (with one exception) and the remaining groundwaters are of limestone water type.
The Mukheibeh field is characterized by mixing of basaltic rock-and Ajloun limestone water with ε brine of 0.0019-0.004 of Ha'On brine (Table 3); in Ain Himma water ε brine varies between 0.0086 and 0.015. When fitting Hammat Gader and the Mezar waters to mixtures of Golan limestone-and basaltic rock water and Ha'On brine, ε brine range between 0.019 and 0.031 for Hammat Gader and ME1 and ME 2. In contrast, ME3 reveals ε brine between 0.0022-0.0039 resembling Mukheibeh water. Substituting the Ha'on brine by Rosh Pinna brine in Hammat Gader and Mezar 1 and 2, the ε brine decline to 0.013-0.028 (Table A2a) as the result of the enhanced chlorinity of Rosh Pinna which is 36 % higher than in Ha'On brine ( Table 2). The maximum of volume of brine fraction is 0.03; The cross plots of ε bw and ε brine suggests three different trends (Fig. 9a). The low ε brine values of Mukheibeh water slightly increase with ε bw . Although Ein Sahina and Ain Saraya discharge in the area of Hammat Gader, they plot together with Mezar 3 and the Mukheibeh data. The trend of Hammat Gader and Mezar wells 1 and 2 show the highest ε brine fraction, while Ain Himma plots at slightly lower ε brine .

Contributions by water/rock interaction
Following the two suggested approaches of salinization in chapter 3.2, two results are obtained depending on the origin of Cl − either from brine (Eq. 3) or from halite in evaporites. Both ways of estimations are documented in Table A2 and Table 3 shows the main results. The approach of ε brine by Eq. 3 yields the maximum of TDE brine and the minimum of TDE brine (Table A2), whereas ε brine = 0 yields the maximum of TDE WRI+brine in Table 3. TDE WRI increases over two orders of magnitude in Mukheibeh groundwater. Contrastingly, the increase of TDE WRI in Mezar, Ain Himma and Hammat Gader is less than factor of two (Fig. 9b). The contribution of TDE from water/rock interactions (TDE WRI ) is less than by brine (TDE brine ) in Hammat Gader and Mezar and most of Ain Himma samples.
From the estimated species i of WRI or WRI+brine (Table A2) the amounts of dissolved gypsum and calcite is given by SO 2− 4 /2 and (Ca 2+ −SO 2− 4 )/2 in mmol/l in Table 3. The amount of halite equals the amount of Cl − in meq/l. (-) signs indicate precipitation; (+) values show dissolution. Calcite shows precipitation when fitting Hammat Gader and Mezar waters with Ajloun limestone water, which is not the case when using Golan limestone water. The composition of brines from Hammat Gader and groundwater from Mezar 1 and 2 is estimated for various combinations of brines and fresh waters. The results of these mixing estimates are compiled in the lower part of Table A2 and Table 3. The differences in mixing either Ajloun or Golan limestone water with either Ha'On or Rosh Pinna brines yield similar Table 3. Compilation of TDE values, brine fraction ebrine, and mineralogical composition of WRI and WRI+brine.   Table 3). The dissolution of calcite and gypsum leads to enhancement of Ca 2+ in Mukheibeh groundwater (Fig. 5e). The increase of Mg 2+ in groundwater (Fig. 5f) is caused by high Mg 2+ concentration in the admixed Ha'On brine. The cross plots of calcite and gypsum reveal that their amounts are very similar and independent on the absence or presence of brine Eq. 2. Gypsum is always dissolved but calcite is both dissolved in Hammat Gader, Mezar and part of the Muhheibeh waters and precipitated in the other part of Mukheibeh and Himma water (Fig. 10).
The cross plots of halite and gypsum dissolution only reveal two trends between Mukheibeh at one end and either Hammat Gader waters or Mezar and Himma waters at the other end (Fig. 11). Here ε brine is assumed to be zero and its contribution appear together with those of the WRI.

Saline contributions to groundwater
Although the process of estimating the contributions of basaltic-rock-and limestone water may not be as precise as the figures suggest, the volume contribution of brine is always less than 3 volume-%. Because the fractions of basaltic-rock-and limestone water are based on interpretations of REY patterns, it should be kept in mind that the limestone water may have already dissolved some gypsum and halite. This may lead to too high brine-and limestone water fractions due to which the fraction of basaltic-rock water is lowered. For similar reasons the true contribution of WRI may be slightly higher than derived in Table 3. Possible atmospheric contributions are minimized by selecting basaltic-rockand limestone water with lowest Cl − concentrations.
The triplot visualizes the differences of the various local groundwater and brines (Fig. 11). The contributions TDE WRI+brine , TDE bw and TDE lmst in groundwaters show a narrow cluster of Mezar wells 1 and 2, Hammat Gader and Ain Saraya samples, whereas water from Mukheibeh well field, Ain Himma and Mezar 3 cover a wide field between the dashed lines. The contributions in TDE from brine and WRI ranges between 10 and 70 %, 80-90 % in Mukheibeh, Ain Himma and Mezar 3 and in Hammat Gader and Mezar wells 1 and 2, respectively. These estimates do not really differ, if the sources of limestones water or brines are varied. The Mukheibeh groundwater originates from an aquifer with constant contribution of brine but increasing dissolution of gypsum (Fig. 9b). Calcite in code group U3 and Ain Himma is always precipitated (Table 3) contrasting the mixing in Hammat Gader, and Mezar wells 1 and 2. The mixture of Mt. Hermon/Golan limestone water and Ha'On brine in Mezar 2 distinctly differs from Hammat Gader by enhanced contributions by WRI (Figs. 7, 9 and 11). In assumed absence of brine the dissolution of halite amounts to about 1 mmol/l for Mukheibeh and Mezar 3, about 4-6 mmol/l in Ain Himma, and between 8 and 13 mmol/l in Hammat Gader and Mezar wells 1 and 2 (Table 3; Fig. 11). Independent on the type of estimates, the dissolution of gypsum varies between 0 and 0.5 mol/l in Mukheibeh and Mezar wells 1 and 3 waters. It ranges from 1-3.5 mmol/l in Ain Himma, Hammat Gader and Mezar 2.
In absence of deep brines, gypsum and calcite are dissolved in Hammat Gader and Mezar 1 and 3 in Golan limestone water. In the presence of Rosh Pinna brine instead of Ha'On brine, calcite often has to be precipitated making the former less reasonable because the limestone water is already saturated with respect to calcite. Mezar 3 does not dissolve gypsum but calcite particularly in the presence of Rosh Pinna brine (Table 3). Taking Ajloun limestone water and Ha'On brine calcite is precipitated from groundwater of Hammat Gader and Mezar (Table A2) suggesting that Ajloun water does not play any in these waters.
All groundwater mixes with brine being present in aquifer rocks and interact with aquifer rocks. The contribution of brine dominates the salinity of groundwater. The Tortonian Ha'On brine is identified in the study area. It is reasonable to assume that this brine infiltrated the Cretaceous (and probably Jurassic) limestone aquifers and is therefore omnipresent in the surroundings of the Yarmouk Gorge [43]. Estimates based on the contributions of Rosh Pinna brine abundantly lead to dissolution of calcite when applying Eq. 2 which is unreasonable because in limestone aquifers calcite saturation should be attained.

Groundwater divide between the Ajloun and the Golan Heights
Chemical similarities suggest that Mezar 3 on the northern Yarmouk River bank but located very near to the LYF produce groundwater of the Mukheibeh type (Fig. 3). Ein Sahina and M5, both north of LYF, produce water of the Mukheibeh type (Table 1). Ain Saraya south of the Yarmouk River just opposite of Hammat Gader but north of LYF produces water typical for Hammat Gader (Table 1). Ain Himma located southwest of the Yarmouk River but north of the LYF is seemingly related to Hammat Gader brines (Fig. 5). The thermohaline water of Hammat Gader seems to ascend along faults from greater depth. These examples of distribution of salinized groundwater indicate that probably not the Yarmouk River but the LYF delineates the groundwater divide between the Ajloun and the Golan Heights. LYF clearly separates the Mukeibeh well field with 0.002 < ε brine < 0.004 from the Mezar well field (0.02 < ε brine < 0.04), Ain Himma (0.009 < ε brine < 0.013) and Hammat Gader region (0.02 < ε brine < 0.04).
Although the LYF follows the trend of the Yarmouk River the chemical composition of local groundwater and brines is oriented according to the LYF and not to the political border between Jordan and Israel given by the Yarmouk River. According to the regional differences the transboundary flow may be influenced by local pumping on the Israeli side, the artesian outflow on the Jordanian side, and recharge of the common aquifer on both sides of the LYF.
In well and spring water of the Mezar field and Hammat Gader region significant changes in REY patterns [52] indicate variation in groundwater flow and mixing of basaltic-rock-and limestone waters (Fig. 4b). Mezar 3 in 2008 produced water with the same REY pattern of Mezar 2 which definitely originates from the deep aquifer in the Golan. In Fig. 11 (Fig. 2). In 2008, Mezar 2 and 3 showed the same type of REY patterns which do not fit into Fig. 4a [52].
Figs. 5, 6, 7, 9 and 11 suggest different aquifers. The uppermost fresh water aquifer producing the Mukheibeh type is dominantly recharged by either basaltic-rock-or limestone water. Part of the infiltrated water penetrate into deeper aquifers and leach along their flow paths evaporites and relics of brine. The deepest aquifer is that of Mezar 2. Hammat Gader originates from an aquifer which enables much less contact with gypsum but slightly more with halite, whereas Mezar 2 and Himma water had more contact with gypsum and less halite.

Conclusion
The basaltic-rock groundwaters from the Hauran Plateau mix with limestone water from either the Ajloun or the Golan Heights depending on the position of springs and wells south or north of the Lower Yarmouk fault respectively. The most basaltic-rock-dominated waters occur in the center of the Mukheibeh well field defined by wells 1, 2 and 4. The limestone-dominated waters are mainly present in the region of Mezar and Hammat Gader. Running sub-parallel to the Yarmouk River, the LYF seems to be the actual groundwater divide between the Ajloun and the Golan Heights.
Ein Sahina and Mukheihbeh 5, north and southwest of of Hammat Gader, respectively, and Mezar 3 resemble in composition the Mukeihbeh water (Table 1) but are located north of the LYF. The variability of Ain Himma composition sometimes resembles that of Mezar 2 suggesting groundwater from great depth. Ain Saraya south of the Yarmouk River and opposite of Hammat Gader produces the same type of saline water from north of the LYF. Since the Yarmouk River represents the international border between Jordan and Israel, these examples suggest only in a political sense some transboundary flow over short distances possibly through local N-S trending faults and fissures beneath the river but do not impugn the general barrier character of the LYF in respect to regional groundwater flow crossing beneath the Gorge.
The salinity of groundwater is mainly due to (i) leaching of remnants of Tertiary Rift brine but not of mixtures of relicts of the Triassic brine with the former and (ii) water/rock interaction such as dissolution of gypsum and calcite. The basaltic-rock-dominated waters show the lowest salinities, whereas the waters of Hammat Gader and Mezar 2 manifest the highest salinity. Only the basaltic-rock waters show higher TDE WRI than TDE brine . The contribution of atmospheric precipitation is considered part of the recharge water or to be negligible in water with lowest Cl − concentrations.
The uniform trend of Mg 2+ with Cl − in all groundwater excepting the Mukeheibeh ones suggest leaching of the Tertiary Ha'On brine which is of Mg 2+ -Cl − type. The different dilution trends of other dissolved species such as Na + , K + , Ca 2+ Br − and SO 2− 4 of either Hammat Gader or Mezar/Ain Himma indicate differences in occurrences of evaporite minerals in the respective aquifers.

Acknowledgments:
We thank various members of the local water authorities enabling sampling along the Yarmouk River. The assistance of Dr. M. Raggad during sampling is gratefully acknowledged.

Conflicts of Interest:
The authors declare not to have any conflict of interest.

Abbreviations
The following abbreviations are used in this manuscript:

LYG
Lower Yarmouk Gorge WRI Water/rock interaction LYF Lower Yarmouk fault ε brine Volume-fraction of brine ε bw Volume-fraction of basaltic-rock water ε lmst Volume-fraction of limestone water c i,bw Concentration of species i in basaltic-rock water c i,brine Concentration of species i in brine c i,agw Concentration of species i in analyzed groundwater c i,WRI Concentration of species i due to WRI TDE bw Total dissolved equivalents due to weathered basalt TDE lmst Total dissolved equivalents due to dissolved limestones TDE agw Total dissolved equivalents in analyzed groundwater TDE brine Total dissolved equivalents in brine TDE est Total dissolved equivalents of estimated mixture of basaltic-rock-and limestone water TDE WRI Total dissolved equivalents due to water/rock interaction TDE WRI+brine Total dissolved equivalents due to water/rock interaction and mixing with brine Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 28 February 2020 doi:10.20944/preprints202002.0414.v1 Table A1.