Mineralogy, geochemistry and genesis of the modern sediments of Seyfe Lake, Kırşehir, central Anatolia, Turkey

Journal of African Earth Sciences 102 (2015) 116–130

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Mineralogy, geochemistry and genesis of the modern sediments of Seyfe Lake, Kırsßehir, central Anatolia, Turkey Nergis Önalgil a, Selahattin Kadir a,⇑, Tacit Külah a, Muhsin Eren b, Ali Gürel c a

Eskisßehir Osmangazi University, Department of Geological Engineering, TR-26480 Eskisßehir, Turkey Mersin University, Department of Geological Engineering, TR-33343 Mersin, Turkey c Nig˘de University, Department of Geological Engineering, TR-51200 Nig˘de, Turkey b

a r t i c l e

i n f o

Article history: Received 1 August 2014 Received in revised form 7 October 2014 Accepted 20 October 2014 Available online 20 November 2014 Keywords: Calcite Gypsum Halite ± thenardite Geochemistry Mineralogy Seyfe Lake

a b s t r a c t Seyfe Lake (Kırsßehir, Turkey) is located within a depression zone extending along a NW–SE-trending fault in central Anatolia. Evaporite and carbonate sediments occur at the bottom of the lake which is fed by high-sulfate spring and well waters circulating N–S through salt domes. The recent sediments of Seyfe Lake are deposited in delta, backshore, beach, mud-flat and shallow lake environments. In the mud-flat environment, calcite, gypsum, halite, and thenardite are associated with fine-grained detrital sediments. Sediments from the margin to the lake center are distributed as calcite, gypsum and halite ± thenardite, yielding an annular distribution pattern. An increase in Na2O, SO3, and S, and a decrease in CaO toward the lake center are due to sediment distribution. On the other hand, a positive correlation of SiO2 with MgO, K2O, Na2O, Al2O3, and Fe2O3 + TiO2 is attributed to the presence of smectite, illite and feldspar. In addition, a positive correlation of Sr and Ba with CaO is related to the amount of gypsum in the sediments. Strontium is associated with in situ gypsum crystals; it increases in the intermediate and central zones of the lake as a result of a relative increase in salinity toward the lake center. The association of Sr with gypsum in the sediments suggests that Ca and Sr were derived from Sr-bearing evaporites and their carbonate host rocks, which were the likely aquifers for the brine. The S- and O-isotopic compositions of sulfate crystals range from +19.1‰ to +21.7‰ and from +16.9‰ to +20.9‰ SMOW, respectively, suggesting precipitation in a closed lake system. A relative increase of oxygen and sulfur isotope ratios toward the lake center suggests dissolution of gypsum in the host rock, with contributions from circulating groundwater and sulfate reduction (possibly by bacterial reduction). 87Sr/86Sr isotope ratios range from 0.707286 to 0.707879, suggesting a non-marine Oligo-Pliocene evaporitic host rock source for precipitation in Seyfe Lake. The concentration of Sr- and S-isotope ratios in the gypsum crystals indicates formation by precipitation/recrystallization from brine rather than from seawater. Ó 2014 Elsevier Ltd. All rights reserved.

1. Introduction Seyfe Lake occurs in a tectonic depression zone located 30 km north of Kırsßehir, central Anatolia, and it covers 10,700 ha with continuous and temporary lake cover (Fig. 1). The lake is a hydrologically closed basin fed by inflow, well, and spring waters derived from surrounding carbonate- and evaporate-bearing formations. Evaporation plays an important role in the recent sedimentation process within Seyfe Lake, producing significant evaporite minerals such as gypsum (CaSO4
2H2O), halite (NaCl), and thenardite (Na2SO4), all of which are controlled by arid climatic conditions.

⇑ Corresponding author. E-mail address: [email protected] (S. Kadir). http://dx.doi.org/10.1016/j.jafrearsci.2014.10.020 1464-343X/Ó 2014 Elsevier Ltd. All rights reserved.

Seyfe Lake and its surroundings have been examined previously for different aspects such as geology (Stchepinsky, 1942; Seymen, 1982; Kara, 1991); mining geology (Akbulut et al., 2009); neotectonics (Temiz, 2004); and hydrogeology, water quality and environmental properties (Erguvanlı, 1959; Ünsal et al., 1996; Tüfenkçi, 2005; Bolat, 2006; Çelik et al., 2007; Reis and Yılmaz, 2008). However, no study has focused on evaporite minerals in Seyfe Lake. This paper is the first study investigating carbonate and evaporate deposits in the lake; it aims to describe sedimentological, mineralogical and chemical characteristics of the sediments. Furthermore, the study investigates the process affecting the chemical composition of the brine collected in the lake and the sequence of primary saline minerals precipitated in the hydrological system. This study provides new data and interpretations that will guide future

N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130

exploration of tens of similar carbonate and evaporate lake systems in Anatolia and the Mediterranean region. 2. Geological setting The basement units in the study area are comprised of Paleozoic metamorphic rocks, such as metagabbro, amphibolite, schist, marble, and quartzite, making up the Kırsßehir crystalline massif (Figs. 1 and 2). The basement rocks are unconformably overlain by the Eocene Baraklı Formation consisting of conglomerate, sandstone and mudrock, and the Eocene Çevirme Formation comprising sandstone, limestone, and mudrock. Both formations have lateral and vertical transitions. The Upper Eocene–Oligocene Deliceırmak Formation conformably overlies the Çevirme Formation. The Deliceırmak Formation comprises conglomerate, sandstone, mudrock, and the Sekilli evaporite member, and it is unconformably overlain by the Upper Miocene–Pliocene Kızılırmak Formation consisting of alternation of red colored conglomerate, sandstone, and mudrock and also Pöhrenk evaporite, Mucur tuff, and Kozaklı limestone members. These units are discordantly overlain by Quaternary white travertine and alluvium. 3. Materials and methods A total of 86 samples were collected from the evaporite-bearing sediments within Seyfe Lake and their host rocks (Fig. 1). Approximately vertical hand drilled core samples were taken systematically along north to south, northwest to southeast, and east to west directed routes of the measured section in Seyfe Lake (Fig. 1b). Mineralogical characteristics of the samples were analyzed by polarized-light microscopy (Nikon-LV 100Pol),

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X-ray powder diffractometry (XRD; Rigaku Geigerflex), and scanning electron microscopy (SEM-EDX; JEOL JSM 84A-EDX). XRD analyses were performed using CuKa radiation and a scanning speed of 1°2h/min at the Turkish Petrolium Corporation (TPAO). Randomly oriented mounts of powdered whole-rock samples were scanned to determine the mineralogy of each bulk sample. Samples for clay analysis (<2 lm) were prepared by separating the clay fraction by sedimentation, followed by centrifugation of the suspension after overnight dispersion in distilled water. The clay particles were dispersed by ultrasonic vibration for approximately 15 min. Oriented specimens of the <2 lm fractions were prepared from each sample: air-dried, ethylene–glycol-solvated at 60 °C for 2 h, and thermally treated at 550 °C for 2 h. Semiquantitative values of rock-forming minerals were obtained with Brindley’s (1980) external standard method, whereas the relative abundances of clay-mineral fractions were determined using their basal reflections and mineral intensity factors (Moore and Reynolds, 1989). Representative clay-dominated bulk samples were prepared for SEM-EDX analyses by adhering the fresh broken surface of each rock sample onto an aluminum sample holder that had been covered with double-sided tape, followed by coating with a thin film (350 Å) of gold using a Giko ion coater at the Eskisßehir Osmangazi University. Chemical analyses of the characteristic samples were performed at the ACME Analytical Laboratories Ltd (Vancouver, Canada) using inductively coupled plasma atomic emission spectroscopy (ICPAES) for major and trace elements. The ICP-AES analyses were carried out on lithium metaborate/tetraborate fusions following dilute nitric acid digestion. Loss on ignition (LOI) is the weight difference after ignition at 1000 °C. The detection limits for the analyses were between 0.01 and 0.1 wt.% for major elements and 0.1 and 5 mg kg 1 for trace elements.

Fig. 1. Location and geological maps of Seyfe Lake area. (a) geological map of the northern section of the study area, (b) geological map and the sampling routes in Seyfe Lake (geological map modified from Kara, 1991).

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Fig. 2. Generalized stratigraphic section of the study area (modified from Kara, 1991).

In 13 representative samples of gypsum and thenardite, isotopic determinations of oxygen (d18O) and sulfur (d34S) were carried out in order to account for the origin of Seyfe Lake sediments. Gypsum and thenardite samples were purified carefully by handpicking under the binocular microscope to obtain a mass of 1500 mg of each sample. The oxygen and sulfur isotope analyses were performed in the Department of Geosciences at the University of Arizona using a MAT 261-8 mass spectrometer. d18O of sulfate was measured on CO gas in a continuous-flow gas-ratio mass spectrometer (Thermo Electron Delta V). Samples were combusted with excess C at 1350 °C using a thermal combustion elemental analyzer (ThermoQuest Finnigan) coupled to the mass spectrometer. Standardization is based on international standard OGS-1. Precision is estimated to be ±0.4 per mil or better (1d) based on repeated internal standards. d34S was measured on SO2 gas in a continuous-flow gas-ratio mass spectrometer (ThermoQuest Finnigan Delta PlusXL). Samples were combusted at 1030 °C with O2 and V2O5 using an elemental analyzer (Costech) coupled to the mass spectrometer. Standardization is based on international standards OGS-1 and NBS123, and several other sulfide and sulfate materials that have been compared between laboratories. Calibration is linear in the range 10 to +30 per mil. Precision is estimated to be ±0.15 or better (1d) based on repeated internal standards. In 5 representative samples of gypsum, isotopic determinations of strontium (87Sr/86Sr ratios) were carried out. The strontium isotopic analyses were performed in the Radiogenic Isotope

Laboratory of Middle East Technical University (METU) Central Laboratory (Ankara). The isotopic composition of the Sr sample was determined using a Triton Multi-Collector Thermal Ionization Mass Spectrometer with static multi-collection. Analytical uncertainties are given at the 2,m level, and 87Sr/86Sr data are normalized with 86 Sr/88Sr = 0.1194. During the course of the measurement, the Sr standard NIST SRM 987 was measured as 0.710245 ± 5 (n = 2). 4. Results 4.1. Facies distribution Modern sediments in the lake are deposited in delta, backshore, beach, mud-flat, and shallow lake environments (Fig. 3a–e). 4.1.1. Delta sediments These sediments are deposited at the margin of the lake, and they consist predominantly of fine grained sandy materials with angular pebbles. In the delta sediments, the grain size decreases and carbonate content gradually increases toward the delta front. The delta sediments consist mainly of quartz, calcite, and feldspar grains in addition to accessory illite and smectite (Fig. 3a and b). 4.1.2. Backshore sediments This facies, located on the northern side of the lake, is represented by greenish-beige paleosol with plant rootlets and calcrete nodules in a terrace approximately 3 meters in height. Calcrete

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Fig. 3. Field photographs showing: (a, b) general view of the delta in Seyfe Lake; (c) view of the backshore, beach, mud-flat and shallow lake; (d) calcrete nodules and powder at the lake terrace; (e) backshore, beach, mud-flat and shallow lake; (f) view of coarse gypsum rose in the margin zone; (g, h) formation of thin halite crystals in shallow small pan in the intermediate and center zones; (i, j) close-up view of halite crystals; (k) formation of needle form thenardite on gypsum and halite deposit in the center zone; (i) close-up view of (k); (m) hand drilled core showing evaporite and organic matter bearing mudrock in the intermediate zone.

nodules are beige to pale brown in color1 and 10–15 cm in diameter (SK-1, SK-5; Fig. 3c–e). 4.1.3. Beach sediments This facies outcrops exclusively at the coast of the lake, and it is comprised of pebbly sands of quartz, schist and marble (Fig. 3c and e). 1 For interpretation of color in Figs. 3 and 4, the reader is referred to the web version of this article.

4.1.4. Mud-flat sediments This facies is comprised mainly of beige to gray colored mudstone, on which desiccation cracks and small closed depressions (pans) rich with halite crystals are often observed. In some places, large surface areas are covered by evaporate minerals, such as gypsum, halite and rarely thenardite. The facies appears at the lake margin and also in the intermediate zones. The carbonate and partially detrital materials increase at the margin, whereas evaporate and clayey materials increase basinward (Fig. 3c and e). Mud-flat sediments consist of calcite, gypsum, halite, and thenardite

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Fig. 3 (continued)

associated with fine-grained detrital sediments and locally enclose gypsum roses of ±7 cm in size (Fig. 3f–l). 4.1.5. Shallow lake sediments This facies consists of beige colored mudstone having a plastic character. The upper level of this facies includes black colored organic intercalations. This facies dominates at the inner zone of the lake and consists of gypsum, clay, and accessory calcite, locally covered by thenardite needles (Fig. 3k–m).

rite ± smectite ± illite, quartz and locally feldspar. The gypsum and halite bearing central zone is also associated with thenardite crystals (Table 1; Fig. 5). Calcite was identified by diffraction peaks at 3.86, 3.04, 2.49, and 2.28 Å; gypsum was identified by peaks at 7.56, 4.27, 3.79, 3.06, and 2.87 Å. The halite is characterized by reflections at 2.82 and 1.99 Å, whereas thenardite peaks are located at 4.66, 3.84, 3.18, 3.08, 2.78, and 2.65 Å. 4.4. SEM-EDX analysis

4.2. Petrography The marble type basement rocks consist of calcite exhibiting rhombohedral cleavage (Fig. 4a). The Dulkadirli limestone is composed of micritic and microsparitic calcite enclosing nummulites, relics of coralline alga and gastropoda, as well as organic material (Fig. 4b–d). Gypsum crystals exhibit acicular crystal forms, parallel lineation, polysynthetic twins, well developed cleavage and a colorless character (Fig. 4e–h). The gypsum in the Kızılırmak Formation is almost pure having flattened and sheet-like crystal forms (Fig. 4e), and it occurs within microsparitic calcite crystals and clay fractions (Fig. 4f and h). Gypsum also encloses relics of calcite crystals having a displacive contact (Fig. 4g and h). 4.3. XRD determinations The results of X-ray diffraction analyses of the samples collected from the Pöhrenk evaporite, the Kızılırmak Formation and Seyfe Lake sediments are presented in Table 1 and Fig. 5. The host rock samples consist of gypsum, calcite, quartz, feldspar, chlorite, and locally accessory illite, smectite, and halite. The non-clastic sediment in the lake is characterized by abundant calcite at the margin associated with small amounts of halite, accessory gypsum, locally chlorite and palygorskite. Intermediate sediments consist of calcite + gypsum, small amounts of halite accompanied by accessory chlorite ± smectite ± illite, quartz, and feldspar. The center zone sediments are composed primarily of gypsum and locally concentrated halite, associated with calcite, accessory chlo-

Scanning electron microscope analyses were carried out on samples dominated by gypsum, halite, thenardite, and calcite and representing both Seyfe Lake sediment and their host rocks. The SEM images indicate that gypsum samples of the host rock exhibit prismatic laths arranged in orientated form and locally have dissolution voids (Fig. 6a–c). In contrast, gypsum from the lake sediment is associated with calcite crystals, and it exhibits irregular anhedral crystals 1–4 lm in size (Fig. 6d). The halite samples consist of euhedral or subhedral cubic crystals 1–6 lm in size (Fig. 6e–g) showing a concentric zonation and increase of the hole centerward (Fig. 6e and f), or compact subhedral cubic form (Fig. 6g). The thenardite occurs in block-, rose- and needle-like forms (Fig. 6h–j). Blocky thenardite crystals are either well-developed euhedral or highly altered and coexist with accumulated subrounded thenardite crystals (Fig. 6j). Thenardite occurs as blocks that are 5–18 lm in size, rose-like forms (maximum 25 lm diameter), and needle-like forms with a maximum diameter of 30 lm and less than 1 lm in thickness. Calcite crystals are 5–10 lm size, exhibit anhedral forms, are associated with quartz and altered feldspar and are cemented with smectite–illite flaky crystals (Fig. 6k–m). Flaky smectite locally encloses relicts of barite crystals (Fig. 6n and o). 4.5. Geochemistry Chemical analyses were conducted on representative evaporite samples from Seyfe Lake and their host rocks (Table 2). The evaporite samples in Seyfe Lake and host rock samples are characterized

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Fig. 4. Photomicrographs of: (a) calcite exhibiting rhombohedral cleavage in marble type basement rocks; (b, c) foraminifera-bearing micritic limestone of the Dulkadirli member, Discocyclina sp. in (b) and Nummulites sp. in (c); (d) micritic mudrock in the Kozaklı limestone showing organic (black) and microsparitic (white) mottlings; (e) sheet-like gypsum in the Kızılırmak Formation; (f) gypsum and calcite mottlings in the mudrock; (g, h) calcite relics in gypsum (the Kızılırmak Formation).

by high CaO (0.69–43.47% and 25.73–32.32%), especially the Pöhrenk evaporite member, in which the gypsum-dominated PM-5 sample is distinguished by 32.32% CaO and 35.18% SO3. The lake sediments exhibit elemental zonation, such as an increase of Na2O from 0.94% to 10.42% and a decrease of CaO from 25.78% to 22.96% from margin to center. SO3 + S increase from the lake margin toward the center (from 2.26% + 1.17% to 10.98% + 5.13%) (Fig. 7a). Both CaO and Na2O exhibit a positive correlation with SO3 + S (Fig. 7a). Furthermore, Sr (0.043–1.236 ppm) and Ba (3–467 ppm) have a positive correlation with CaO (0.69–43.47%) in calcite and gypsum (Fig. 7b and c). Sr values in the lake sediments range

from 1062 to 3106 ppm, and averages 1120 ppm in host rock samples. The presence of SiO2 is related to quartz and feldspar; a positive correlation of SiO2 content with Al2O3, Fe2O3, MgO, TiO2, and K2O suggests the presence of accessory chlorite, smectite and illite (Fig. 7d–h). 4.6. Isotope geochemistry of sulfur and oxygen The sulfur and oxygen isotope ratios of sulfate were determined in representative gypsum and thenardite samples from Seyfe Lake

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Table 1 Mineralogical composition, abundance and distribution within the Pöhrenk evaporite, the Kızılırmak Formation, and Seyfe Lake. Sample

Location

cal

gp

hl

Host rock SK-1 SK-5 M3-2 M3-8 PM-1 PM-2 PM-3 PM-4 PM-5 PM-6 PM-7

N-Terrace N-Terrace N N N N N N N N N

+ acc ++ + +++ + +

++++ +++++

acc

Marginal zone YB-1 KC-1 KC-3 S2-1 S2-3 S2-5

N E E W W W

+ ++++ ++++ ++ ++++ ++++

++++ acc acc acc acc

acc + + acc + +

Intermediate zone Y1-1 S Y1-3 S Y1-5 S Y1-7 S Y1-9 S KC-5 E KC-7 E KC-8 E KC-9 E KC-10 E KC-11 E S2-7 W S2-9 W

++++ +++ +++ +++ ++ ++ +++ ++++ ++++ +++ ++ +++ +++

acc ++ + + +++ ++ acc + + acc ++ + ++

+ + + + + + + acc + + + + acc

+

+++++ +++++ +++++ +++++ +++++

+++

+

acc acc + ++ acc +

+++++ acc + ++ +++++ ++++

++

+++

acc acc acc acc acc +++++ + +++++ +++++ acc ++ ++ + acc acc +++++ acc

Central zone YB-5 YB-6 YB-8 YB-10 YB-12 YTUZ-2 S2-10 S2-TUZ STUZO-2 SO-2 KCTUZ-1 KCTUZ-2 KC-13 KC-15 KCO-1 Y1-TUZ Y10-2

N N N N N N W W W W E E E E E S S

tn

chl

+ + acc + + acc

acc

+++++ +++++ +++++ ++

sme

acc acc acc acc

+

ilt

plg

+

+ acc

+

acc + +

acc

+ acc

acc acc acc + + + acc acc + acc acc acc

acc

acc acc

acc

acc

acc

acc

acc acc

acc acc

acc acc

acc acc

acc acc

acc

acc

acc

acc

acc acc acc

acc

acc

acc

+++ ++

qz

fsp

acc acc + + + + + acc

acc acc + +++ ++ + ++ acc

+

+

acc acc acc + acc acc

acc

acc acc acc acc acc acc acc acc acc

acc

acc acc acc

acc acc acc acc

amp

acc

acc acc acc

acc acc

acc acc

acc acc acc

acc acc acc acc acc

acc

acc acc acc acc

acc

acc

acc

cal: calcite, gp: gypsum, hl: halite, tn: thenardite, chl: chlorite, sme: smectite, ilt: illite, plg: palygorskite, qz: quartz, fsp: feldspar, amp: amphibole, acc: accessory, +: relative abundance of mineral. N: north, S: south, E: east, W: west.

sediments and gypsum from the Kızılırmak Formation representing host rock; these data are shown in Table 3 and plotted in Fig. 8a. The sulfur and oxygen isotope ratios range from 19.1‰ to 21.7‰ and 16.9‰ to 20.9‰, respectively. The d34S vs. d18O values concentrate in two regions related to Seyfe Lake and their host rocks (Fig. 8a). The isotope ratios are larger in the lake sulfate samples compared to the gypsum samples of the host rocks. On the other hand, both isotope ratios increase centerward of the lake. 4.7.

87

Sr/86Sr Isotope geochemistry

The 87Sr/86Sr isotope geochemistry was conducted on representative gypsum samples from Seyfe Lake as shown in Table 3 and plotted in Fig. 8b. The 87Sr/86Sr ratio ranges from 0.707286 to 0.707879.

5. Discussion Seyfe Lake developed within a depression zone, which extends along a NW–SE-trending fault in the central Anatolia. It is a hydrologically closed and starved lake where evaporation exceeds inflow and there is a lack of clastic sediment supply from the carbonateand gypsum-bearing catchment source host rocks (Hardie and Eugster, 1970; Eugster, 1980a,b). The recent sediments of Seyfe Lake are characteristic of deposition in delta, beach, mud-flat and shallow lake environments. The Quaternary evaporitic deposits of the lake display three concentric zonations for both calcite and gypsum at the margin and intermediate zones representing mudflat sediments and halite ± gypsum ± thenardite in the center zone representing shallow lake sediments, yielding an annular deposition and distribution (bull’s eye) pattern (Cohen, 2003; Fig. 9).

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Fig. 5. X-ray diffraction patterns of the samples collected from the Pöhrenk evaporite, the Kızılırmak Formation, and Seyfe Lake. gp: gypsum, cal: calcite, hl: halite, tn: thenardite, chl: chlorite, ilt: illite, plg: palygorskite, qz: quartz, fsp: feldspar, and amp: amphibole.

Therefore, calcite precipitated at the first stage following concentration of CaCO3 at the base of Seyfe Lake. Subsequently, gypsum and halite precipitation continued upward and lakeward following a decrease of Ca/Na and increase of Cl under control of seasonal climatic conditions. Furthermore, a positive correlation between Na2O and SO3 + S, a local increase of Sr values in the lake sediments (1062 and 3106 ppm) and increase of SO3 + S + Cl from the lake margin to the center also support this hypothesis (Borchert and

Muir, 1964; Braitsch, 1971; Krauskopf, 1979). Thus, carbonate, sulfate and chlorite minerals are controlled by the relative concentrations of Ca, Na, Cl, SO4 and climatic conditions (Sinha and Raymahashay, 2004). Furthermore, the enrichment of inflow water in the Pöhrenk evaporite and carbonate units with Ca, HCO3, SO3, S, and Cl; high concentrations of sulfate in spring and well water (0.168– 10.278 g/l); and K in circulating groundwater through salt ‘‘domes’’

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Fig. 6. SEM images showing: (a–c) euhedral crystals to subhedral prismatic laths of gypsum showing dissolution voids (arrow) (PM-6); (d) calcite relics in anhedral gypsum crystal from Seyfe Lake sediment (Y1-3) with a compact subhedral cubic form; (e, f) euhedral or subhedral cubic halite crystal exhibiting zonation and centralward holes (S2TUZ-1, YTUZ-2); (g) compact subhedral cubic halite crystal (YTUZ-2); (h–j) well-crystallized blocky, rody and rose-like thenardite (KCTUZ-1, KCTUZ-2); (k) anhedral calcite crystals (S2-9); (l) calcite crystals cemented with flaky smectite crystals (S2-9); (m) calcite crystals associated with feldspar and quartz in Seyfe Lake sediment (M3-8); (n, o) close-up view of smectite–illite crystal encloses relict of barite (M3-8).

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130 Table 2 Chemical composition of Seyfe Lake sediments and surrounding host rocks. Major oxide (wt.%)

Host rock

Lake sediment Marginal zone

SK-1

M3-2

PM-5

PM-7

Avg.

YD1-1

YD1-8

S1-1

S2-1

S2-5

KC-1

YB-1

Avg.

SiO2 Al2O3 RFe2O3 CaO MgO Na2O K2O MnO TiO2 P2O5 Cr2O3 LOl Total TOT/C TOT/S SO3

16 4.64 2.10 25.73 1.59 0.91 0.54 0.03 0.20 0.04 0.011 23.79 75.58 1.74 9.43 16.64

47.9 14.13 7.22 6.87 4.90 1.10 2.68 0.12 0.78 0.22 0.021 14.49 100.47 1.2 – –

– 0.02 – 32.32 – – – – – 0.03 – 20.77 53.14 0.69 17.52 35.18

48.8 13.93 6.42 6.95 4.63 1.19 3.10 0.11 0.71 0.20 0.020 13.61 99.65 1.29 – 0.008

28.18 8.18 3.94 17.97 2.78 0.80 1.58 0.07 0.42 0.12 0.01 18.17 82.21 1.23 6.74 12.96

36.9 8.75 3.99 16.27 4.04 1.82 0.55 0.08 0.41 0.08 0.018 26.68 99.58 3.91 0.25 0.551

35.1 9.06 4.19 17.16 4.58 1.36 0.72 0.09 0.42 0.10 0.018 26.86 99.68 4.11 0.25 0.409

18.1 3.76 1.68 33.90 4.38 0.35 0.07 0.04 0.19 0.07 0.009 36.11 98.61 8.03 0.4 0.937

33.6 8.09 3.49 10.90 3.05 1.31 1.27 0.03 0.44 0.22 0.021 37.66 100.06 12.99 0.46 0.12

8.2 1.90 0.87 43.47 2.03 0.04 – 0.02 0.09 0.05 0.004 42.15 98.87 10.70 0.47 1.027

15.9 3.09 1.36 33.98 5.48 0.15 0.02 0.03 0.15 0.11 0.008 38.46 98.72 8.92 0.44 0.984

24.8 4.48 1.60 24.77 2.83 1.56 0.65 0.03 0.23 0.08 0.017 23.67 84.74 3.26 5.89 11.822

24.66 5.59 2.45 25.78 3.77 0.94 0.47 0.05 0.28 0.10 0.01 33.08 97.18 7.42 1.17 2.26

Trace elements (ppm) Ba Be Co Cs Ga Hf Nb Rb Sn Sr Ta Th U V W Zr Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Mo Cu Pb Zn Ni As Cd Sb Bi Ag Au (ppb) Hg Tl Se

184 2 6.9 3.0 4.5 1.3 5.0 33.3 – 2045.1 0.4 5.8 2.3 49 1.4 46.5 8.4 13.1 23.6 2.65 9.9 1.96 0.40 1.78 0.24 1.51 0.28 0.69 0.13 0.87 0.12 0.4 10.8 6.6 21 30.0 24.1 0.1 0.3 – – – – – –

287 2 24.8 5.6 14.3 3.3 9.6 74.1 – 272.5 0.7 8.5 2.4 129 1.2 119.6 19.4 23.1 45.1 5.16 20 4.04 1.05 3.96 0.58 3.54 0.69 1.97 0.31 2.08 0.30 0.3 17.8 14.9 60 96.5 16.0 – – 0.2 – 1.0 – 0.2 –

3 – – – – – – – – 1709 – – – – – 0.3 0.1 0.2 0.3 0.02 – – – – – 0.06 – – – – – – 27.4 1.4 – 0.8 – – – – – – – – –

467 3 22.1 5.8 13.0 2.9 9.5 82.2 1 454.2 0.8 8.0 2.1 127 1.5 115.9 18.9 25.5 47.5 5.11 20.9 4.06 1.03 3.86 0.55 3.09 0.56 1.95 0.27 1.72 0.28 0.3 21.2 15.0 64 90.6 6.4 – – 0.2 – 3.1 – 0.2 –

235.25 1.75 13.45 3.60 7.95 1.88 6.03 47.40 0.25 1120.20 0.48 5.58 1.70 76.25 1.03 70.58 11.70 15.48 29.13 3.24 12.70 2.52 0.62 2.40 0.34 2.05 0.38 1.15 0.18 1.17 0.18 0.25 19.30 9.48 36.25 54.48 11.63 0.03 0.08 0.10 – 1.03 – 0.10 –

284 – 12.8 4.5 9.3 2.2 9.6 62.9 1 590.2 0.8 8.4 2.5 64 1.5 89.8 14.7 24.0 41.7 4.97 18.9 3.23 0.72 3.10 0.45 2.80 0.51 1.44 0.21 1.56 0.23 0.9 24.1 15.3 51 67.9 26.8 0.2 0.4 0.2 – 4.7 – 0.3 –

312 2 13.5 5.3 9.6 2.2 8.7 64.3 2 672.3 0.6 9.1 4.0 75 1.5 85.9 14.6 24.2 43.6 5.05 18.2 3.31 0.71 3.04 0.47 2.68 0.54 1.50 0.20 1.22 0.22 0.7 24.9 17.3 57 72.8 38.8 0.3 0.4 0.2 – 7.6 – 0.3 –

275 1 5.8 3.2 3.3 1.2 4.4 31.5 – 1331 0.3 3.8 6.8 36 0.9 41.1 6.4 10.0 19.2 2.15 7.4 1.38 0.31 1.32 0.20 1.17 0.26 0.63 0.09 0.75 0.10 0.4 12.4 7.0 20 31.2 19.7 0.1 0.7 – – 2.4 – 0.1 –

336 6 10.5 16.1 8.2 2.4 10.2 62.2 3 475.5 0.8 8.1 8.2 107 2.3 87.3 14.8 22.8 45.2 4.74 16.5 3.15 0.73 2.89 0.46 2.40 0.49 1.65 0.26 1.20 0.23 1.0 30.8 18.5 69 60.1 17.6 0.4 1.1 0.4 – 8.8 0.12 0.5 2.0

243 1 3.3 2.3 1.5 0.5 2.5 16.8 – 1246.7 0.2 1.8 5.1 13 – 22.6 3.4 5 10 1.04 4.4 0.68 0.19 0.69 0.09 0.54 0.09 0.30 0.06 0.29 0.04 0.4 9.0 4.1 10 17.8 12.1 – 0.4 – – 1.8 – – –

378 – 3.9 8.9 2.2 0.9 2.6 40.6 – 1442 0.2 2.8 4.0 28 – 33.0 5.3 8.6 15.2 1.72 6.6 1.16 0.25 1.08 0.15 0.87 0.15 0.45 0.07 0.37 0.06 2.5 9.2 5.8 19 20.3 12.3 0.1 0.2 – – – – – –

353 2 5.1 1.9 4.2 1.9 4.9 32.2 – 1677.8 0.4 4.1 6.1 28 1.3 78.4 7.9 14.1 26.3 3 10.6 1.91 0.48 1.76 0.25 1.61 0.28 0.72 0.11 0.83 0.12 1.0 9.0 6.2 17 24.7 25.8 – 0.4 – – – – – –

311.57 1.71 7.84 6.03 5.47 1.61 6.13 44.36 0.86 1062.21 0.47 5.44 5.24 50.14 1.07 62.59 9.59 15.53 28.74 3.24 11.80 2.12 0.48 1.98 0.30 1.72 0.33 0.96 0.14 0.89 0.14 0.99 17.06 10.60 34.71 42.11 21.87 0.16 0.51 0.11 – 3.61 0.02 0.17 0.29

Major oxide (wt.%)

SiO2 Al2O3 RFe2O3 CaO MgO Na2O

Lake sediment Intermediate zone S2-9

KC-5

KC-8

KC-11

Y1-1

Y1-3

Y1-9

Avg.

16.5 3.72 1.67 30.81 5.65 1.03

19.4 4.29 1.90 27.85 9.38 0.90

16.6 3.55 1.55 31.80 6.75 0.97

18.7 4.23 1.94 26.69 7.28 1.93

21.6 5.07 2.32 28.27 7.12 0.87

18.8 4.32 1.99 27.38 7.51 1.55

15.2 3.50 1.57 27.97 5.23 2.55

18.11 4.10 1.85 28.68 6.99 1.40

(continued on next page)

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130

Table 2 (continued) Major oxide (wt.%)

Lake sediment Intermediate zone S2-9

KC-5

KC-8

KC-11

Y1-1

Y1-3

Y1-9

Avg.

K2O MnO TiO2 P2O5 Cr2O3 LOl Total TOT/C TOT/S SO3

0.16 0.04 0.18 0.07 0.010 36.13 95.94 7.19 1.03 2.251

0.20 0.04 0.21 0.10 0.008 32.93 97.22 6.45 1.09 2.395

0.20 0.04 0.19 0.10 0.009 34.57 96.31 7.21 1.19 2.483

0.45 0.04 0.19 0.08 0.008 31.97 93.56 5.68 2.01 4.359

0.22 0.05 0.23 0.10 0.011 33.19 99.07 6.77 0.51 1.035

0.26 0.04 0.19 0.08 0.008 33.95 96.10 6.22 1.45 2.863

0.64 0.03 0.15 0.06 0.006 32.03 88.89 5.57 3.39 6.800

0.30 0.04 0.19 0.08 0.01 33.54 95.30 6.44 1.52 3.17

Trace elements (ppm) Ba Be Co Cs Ga Hf Nb Rb Sn Sr Ta Th U V W Zr Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Mo Cu Pb Zn Ni As Cd Sb Bi Ag Au (ppb) Hg Tl Se

310 – 6.0 2.4 3.7 1.0 3.9 31.1 – 3401 0.4 3.3 24.3 44 1.0 43.2 6.2 9.1 16.7 1.98 6.9 1.32 0.32 1.33 0.19 1.28 0.22 0.56 0.10 0.66 0.08 0.6 11.7 6.4 20 26.1 37.0 – 0.6 – – 0.7 – 0.1 –

264 – 5.9 3.2 4.0 1.3 4.8 36.8 – 1571 0.5 4.0 10.1 42 1.0 44 8.0 9.1 11.3 2.45 8.4 1.72 0.35 1.49 0.21 1.38 0.26 0.71 0.11 0.62 0.11 1.1 12.3 7.3 25 33.6 40.4 – 0.2 0.2 – 0.9 – 0.1 –

249 – 5.8 2.8 3.2 0.9 4.1 30.6 – 1270 0.4 4.1 10.3 40 0.9 40.4 6.6 9.1 10.9 2.31 7.7 1.54 0.34 1.48 0.22 1.20 0.24 0.67 0.11 0.67 0.11 0.7 11.1 6.3 21 26.2 47.3 – 0.4 – – 1.0 – 0.1 –

288 2 6.6 3.0 4.2 1.1 3.6 36.1 – 2131 0.3 3.7 21.7 51 1.1 45.7 6.4 10.3 18.6 2.13 8.2 1.36 0.31 1.26 0.19 1.10 0.21 0.68 0.09 0.78 0.09 0.6 13.6 6.7 25 32.6 59.9 – 0.5 – – 1.8 – 0.1 –

314 – 7.4 3.4 4.7 1.2 4.3 41.0 – 1369.2 0.4 4.3 12.2 54 1.1 45.7 8.0 11.8 23.4 2.57 9.5 1.81 0.39 1.59 0.23 1.38 0.29 0.76 0.12 0.92 0.13 0.8 14.8 8.7 30 40.1 59.4 0.1 0.5 – – 0.5 – 0.1 –

299 – 6.4 2.8 4.1 1.1 3.8 34.5 – 2352 0.3 3.7 23.9 46 0.8 41.1 6.7 10.7 19.4 2.16 9.9 1.55 0.35 1.36 0.19 1.36 0.22 0.59 0.09 0.60 0.09 0.8 14.2 7.9 25 32.2 63.2 – 0.5 – – 1.6 – 0.1 –

285 – 5.5 2.3 3.1 1.0 3.5 27.4 – 3163 0.2 3.5 19.7 75 0.6 34.5 5.5 9.4 17.7 1.95 7.2 1.28 0.28 1.23 0.16 1.17 0.17 0.67 0.09 0.50 0.10 1.3 11.5 6.3 20 27.1 36.3 0.1 0.6 – – 3.8 – 0.1 –

287.00 0.29 6.23 2.84 3.86 1.09 4.00 33.93 – 2179.57 0.36 3.80 17.46 50.29 0.93 42.09 6.77 10.50 19.60 2.22 8.26 1.51 0.33 1.39 0.20 1.27 0.23 0.66 0.10 0.68 0.10 0.84 12.74 7.09 23.71 31.13 49.07 0.03 0.47 0.03 – 1.47 – 0.10 –

Major oxide (wt.%)

Lake sediment Central zone S2-11

SO-2

KC-15

KCO-1

YB-5

YB-8

YB-10

YB-12

YTUZ-2

KCTUZ-1

Avg.

SiO2 Al2O3 RFe2O3 CaO MgO Na2O K2O MnO TiO2 P2O5 Cr2O3

12.7 2.75 1.22 29.09 4.39 2.62 0.60 0.03 0.12 0.04 0.004

16.9 3.90 1.75 27.34 5.81 3.03 0.61 0.03 0.18 0.07 0.008

8.8 1.98 0.86 29.80 2.87 1.39 0.26 0.02 0.08 0.03 0.018

18.6 4.23 1.92 26.88 7.15 2.24 0.56 0.04 0.18 0.08 0.006

9.2 2.36 0.87 26.02 0.87 1.59 0.51 – 0.10 0.02 0.009

11 2.27 1.02 29.81 4.28 1.75 0.38 0.02 0.10 0.03 0.005

13.6 2.79 1.21 29.44 4.93 1.78 0.50 0.02 0.13 0.04 0.005

13.9 2.92 1.30 29.66 5.14 2.11 0.54 0.03 0.13 0.05 0.007

0.40 0.09 0.04 0.69 1.61 45.53 0.16 – – – 0.003

– – – 0.90 1.27 42.12 – – – – –

10.51 2.33 1.02 22.96 3.83 10.42 0.41 0.02 0.10 0.04 0.01

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130 Table 2 (continued) Major oxide (wt.%)

Lake sediment Central zone S2-11

SO-2

KC-15

KCO-1

YB-5

YB-8

YB-10

YB-12

YTUZ-2

KCTUZ-1

Avg.

LOl Total TOT/C TOT/S SO3

28.80 82.36 5.04 5.85 13.47

31.03 90.61 6.10 2.33 5.768

26.94 73.05 2.88 9.85 20.21

31.42 93.34 6.03 2.00 4.412

22.33 63.87 0.14 14.09 26.4

28.10 78.76 4.34 7.25 16.33

29.61 84.04 5.18 5.23 13.35

30.04 85.84 5.67 3.90 9.835

95.6 53.36 0.07 0.79 –

– – – – –

32.39 70.52 3.55 5.13 10.98

Trace elements (ppm) Ba Be Co Cs Ga Hf Nb Rb Sn Sr Ta Th U V W Zr Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Mo Cu Pb Zn Ni As Cd Sb Bi Ag Au (ppb) Hg Tl Se

226 – 4.0 2.0 2.6 1.0 5.2 23.9 – 2984 0.5 2.0 14.6 36 1.0 45.2 4.2 5.8 12.0 1.51 4.3 0.94 0.24 1.15 0.14 0.87 0.16 0.52 0.05 0.39 0.04 2.2 10.4 5.0 16 21.2 37.6 0.1 0.9 – – – – – –

280 – 5.3 2.7 4.1 1.9 8.8 30.8 – 2530 0.8 3.5 20.4 46 1.5 71.8 6.7 8.5 17.3 1.94 5.9 1.65 0.31 1.59 0.24 1.46 0.28 0.82 0.09 0.81 0.08 0.8 13.3 7.2 22 28.6 45.7 – 0.9 – – 1.0 – 0.1 –

157 – 2.9 1.1 1.0 0.4 2.1 15.9 – 2626 0.2 1.9 8.1 18 0.5 20.9 3.1 4.8 9.7 1.07 2.6 0.72 0.15 0.68 0.10 0.66 0.13 0.34 0.05 0.20 0.05 0.6 6.6 3.3 11 13.9 18.4 – 0.5 – – – – – –

272 – 6.1 3.0 4.0 1.3 5.5 33.3 – 2015 0.5 3.3 20.4 52 1.5 46.6 5.7 9.0 17.8 2.03 7.0 1.32 0.28 1.26 0.15 0.99 0.20 0.54 0.06 0.61 0.07 0.7 13.7 7.2 25 30.6 63.9 – 0.8 – – – – 0.1 –

226 – 2.2 1.6 1.7 0.8 2.5 16.7 – 10,359 0.2 2.0 1.2 19 0.6 31.8 3.5 6.9 12.9 1.46 5.3 0.92 0.22 0.77 0.12 0.71 0.13 0.36 0.06 0.33 0.06 0.8 5.7 2.8 10 12 4.8 – 0.6 – – – – – –

192 – 3.2 1.5 1.7 1.2 4.2 17.2 – 3222 0.5 1.9 12.0 25 2.4 50.4 3.6 5.0 9.1 1.14 3.7 0.85 0.16 0.84 0.12 0.71 0.14 0.49 0.04 0.38 0.04 0.6 8.0 3.7 12 15.9 34.2 – 0.8 – – – – – –

235 – 3.8 1.9 2.9 0.8 3.2 21.9 – 3488 0.2 2.2 46.6 29 3.3 33.4 3.9 6.7 13.1 1.48 5.3 0.85 0.23 0.84 0.13 0.47 0.06 0.44 0.06 0.44 0.05 0.6 9.4 4.6 14 19.7 40.6 – 0.9 – – – – – –

241 – 3.9 2.1 2.3 0.7 3.1 23.1 – 3538 0.3 2.4 15.8 30 1.5 28.7 4.4 6.6 12.7 1.48 4.9 0.91 0.21 0.83 0.12 0.87 0.13 0.44 0.05 0.37 0.07 0.7 10.0 5.2 17 23.2 43.1 – 0.8 – – – – – –

– – – – – – – – – 204.5 – – 0.4 – – 1.6 – – – 0.05 – – – – – – – – – – – 0.2 6.8 0.1 – 0.5 1.3 – – – – 1.4 – – –

– – – – – – – – – 94.30 – – 0.68 – – – – – – – – – – – – – – – – – – – – 7.73 3.3 – – – – – – – – – –

182.90 – 3.14 1.59 2.03 0.81 3.46 18.28 – 3106.08 0.32 1.92 14.02 25.50 1.23 33.04 3.51 5.33 10.46 1.22 3.9 0.82 0.18 0.80 0.11 0.67 0.12 0.40 0.05 0.35 0.05 0.72 8.39 4.68 13.03 16.56 28.96 0.01 0.62 – – 0.24 – 0.02 –

_ sources located NE of the lake also support this suggestion (DSI, 1990). The positive correlation of Sr ± Ba with CaO content may also suggest that Sr and Ba are associated with gypsum. Thus, Sr and CaO concentrations decrease with an increase in total C, S, and gypsum, and a decrease in calcite, toward the center of Seyfe Lake (Sonnenfeld, 1984; Warren, 2006). On the other hand, the presence of barite (BaSO4) was also observed in the mudrock samples via SEM-EDX observations, but it is not detected by XRD because its concentration is below the detection limit. The consumption of Ca, S, and SO4, and a relative increase of Cl/ SO4 resulted in rapid crystallization of euhedral hopper halite in a minimum wind mixing environment in the mud-flat sediment where desiccation cracks are common. Local precipitation of thenardite (Na2SO4) as small restricted pan (having diameter of 1– 1.5 m) of thin crusts on halite prevalent lacustrine sediments in the middle of Seyfe Lake surface may suggest formation either

through direct precipitation under high temperatures or by conversion from possibly pre-existing mirabilite. Mineralogically and micromorphologically, the lack of mirabilite in well-developed, euhedral, blocky, rody and rose-like thenardite crystals suggests seasonal direct precipitation of thenardite in a modern depositional environment similar to that which is reported for thenardite precipitation in the playa lakes of the Great Plains in the United States (Last, 1994). Micromorphologically, the development of gypsum within calcite suggests conversion of calcite to gypsum via an increase in the concentration of SO3 + S toward the lake center. In contrast, the lack of a relationship between gypsum and halite may reveal direct precipitation of both rather than conversion of one to the other (Schreiber and Walker, 1992). The relative increase in d34S and d18O values of gypsum in the host rock samples (from 12.2‰ to 18.0‰ and from 8.7‰ to 11.6‰) compared to gypsum in the lake sediments (from 19.1‰ to 23.0‰ and from 16.5‰ to 20.9‰) also suggests that both S

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130

Fig. 7. Elemental variation diagrams for major oxides and trace elements of Seyfe Lake sediment samples. (a) Lateral distribution of CaO, Na2O and SO3 + S; (b) Sr vs. CaO; (c) Ba vs. CaO; (d) Al2O3 vs. SiO2; (e) Fe2O3 vs. SiO2; (f) MgO vs. SiO2; (g) TiO2 vs. SiO2; (h) K2O vs. SiO2.

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130 Table 3 Isotopic composition of Seyfe Lake sediments and surrounding sulfate host rocks. Sample

Mineral

d34S

d18Osulphate

87

Host rock SK-1 SK-5 GYP-1 PM-4 PM-5 PM-6

Gypsum Gypsum Gypsum Gypsum Gypsum Gypsum

21.6 21.8 23.0 12.2 18.0 16.3

20.0 19.2 16.5 11.6 8.7 9.9

0.707836 – – – – 0.707286

Lake sediment KCTUZ-1 KCTUZ-2 KC-15 SO-2 YB-1 YB-5 YB-8

Thenardite Thenardite Gypsum Gypsum Gypsum Gypsum Gypsum

19.1 19.4 21.3 21.7 21.0 21.7 21.2

18.3 20.9 16.9 20.7 19.2 20.5 20.2

– – 0.707873 0.707879 – – 0.707826

Sr/86Sr

and O isotopes increase with an increase in evaporation in the closed Seyfe Lake system; this may be controlled by paleoclimatical conditions of the central Anatolia following the Messinean salinity crisis (Palmer et al., 2004; Bates et al., 1970; Matano et al., 2005). This may also indicate that fractionation of the host rock gypsum by bacterial reduction resulted in an increase the S isotope ratios. Furthermore, a relative increase in the 87Sr/86Sr ratio from the host rock (0.707286–0.707836) to the lake center (0.707826– 0.707879) is controlled by an increase in salinity relative to an increase of NaO, SO3 + S, Cl and decrease of CaO. This also suggests that gypsum in the lake environment was derived from the gypsum-bearing catchment source host rocks and is consistent with the 87Sr/86Sr ratio of gypsum from the Bigadiç borate deposit, but different from the Sultançayır and Emet that have various sources (Palmer et al., 2004; Palmer and Helvacı, 1997; Orti et al., 2002).

Fig. 8. (a) A cross plot of stable isotope values (d34S and d18O) of Seyfe Lake gypsum and thenardite samples. (b) Relationship between d34S and isotope from nonmarine evaporites of Seyfe Lake and host rock.

Fig. 9. General modeling of Seyfe Lake showing chemical and mineralogical distributions.

87

Sr/86Sr of gypsum

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N. Önalgil et al. / Journal of African Earth Sciences 102 (2015) 116–130

6. Conclusion In Seyfe Lake, sedimentation takes place in delta, beach, mudflat, and shallow lake environments. Sediments exhibit a zonation with calcite and gypsum predominantly in mud-flats at the lake margin and intermediate zones, and halite ± gypsum ± thenardite in the center zone. This zonation is due to seasonal climatic conditions. This zonation results from an increase in the Na/Ca ratio, SO3 + S, Cl and salinity centerward of the lake. The high concentration of Na and Cl at the lake center caused the precipitation of halite, and the increase in the SO3 + S/Cl ratio resulted in local precipitation of thenardite on halite crystals in pans at the advance stage of evaporation resulting from high temperature conditions. The 87Sr/86Sr ratio, high Na2O, CaO, SO3, Sr and Ba values suggest that the gypsum, halite and thenardite in Seyfe Lake sediments precipitated in a shallow saline lake system from chemical and physical weathering of carbonate- and gypsum-bearing catchment source host rocks. The presence of coarse euhedral halite crystals having concentric (hopper aggregate) form suggests rapid water lost and crystallization of halite by evaporation and an increase in salinity.

Acknowledgments This study was financially supported by the Scientific Research Projects Fund of Eskisßehir Osmangazi University in the framework of Project 201015030, and it comprises a part of the first author’s MSc thesis. This study was conducted based on a special permission from the Ministry of Forestry and Water Affairs of Turkey. The authors are much indebted to Professor Cahit Helvacı (Dokuz Eylül University, Turkey) and an anonymous reviewer for their extremely careful and constructive reviews that significantly improved the quality of the paper. We are also extremely grateful to Professor Patrick G. Eriksson (University of Pretoria, South Africa) for his insightful editorial comments and suggestions.

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