Palaeogeographical zonation of gypsum facies:Middle Miocene Badenian of Central Paratethys(Carpathian Foredeep in Europe)

Tadeusz Marek Peryt

Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland

Abstract Studies on Middle Miocene Badenian gypsum in various parts of Central Paratethys, the oldest widespread primary marine gypsum, in western Ukraine, southern Poland and Moravia (Czech Republic) indicate that there are three principal gypsum facies: crystalline gypsum, stromatolitic gypsum and clastic gypsum. The latter typically occurs between crystalline and stromatolitic gypsum and between stromatolitic gypsum and the land. In addition, it is common in channels within gypsum microbialites, and is the main facies during the deposition of the upper part of Badenian gypsum when important bathymetric differences existed within the marginal part of the Carpathian Fore deep Basin, the largest foredeep basin in Europe.Within crystalline gypsum facies, it is observed the overall size of the crystals increases and that the layering declines towards the permanent, stabilized brine body, and thus the giant gypsum inter growths–non-layered coarse-crystalline selenite – is the end-member of gypsum facies continuum. Typically it passes into layered selenites although owing to fluctuations of pycnocline level, some transitional gypsum subfacies may be missing both in the vertical section as well as in particular outcrops. The following important controls on the development of gypsum facies have been identified: pycnocline level fluctuations, brine level fluctuations including brine sheets and floods, rare marine transgressions, pedogenesis leading to “alabastrine” gypsum development, and rate of inflow of continental water.

Key words gypsum, depositional environments, facies, Badenian, palaeogeography

1 lntroduction＊

One of major problems encountered during the palaeogeographic interpretation of ancient big evaporite basins is the lack of their proper analogs and hence the reasoning based on the study of modern counterparts, limited in size,has to be applied. Modern small salina-type evaporite basins are well studied (e.g., Arakel, 1980; Warren, 1982; Orti Caboet al., 1984; Logan, 1987) and have been successfully applied in the past to interpret the palaeogeography and sedimentary history of the Middle Miocene mid-Badenian gypsum (initiated to form 13.81 Ma ago) of the Carpathian Foredeep Basin, the largest foredeep basin in Europe, a part of the Paratethys-an epicontinental sea that developed as a relic of the Tethys , which existed between the Early Oligocene and late Middle Miocene times. This gypsum is the oldest widespread primary gypsum facies and hence it is important for interpretation of older sulphate deposits,also because its facies have been studied in great detail by a number of workers in the past (e.g., Kwiatkowski,1972; Bąbel, 1987, 1991, 2004, 2005a, 2005b; Kasprzyk,1989, 1991, 1993a, 1993b, 1999; Peryt, 1996, 2001, 2006;Petrichenkoet al., 1997; Bąbel and Bogucki, 2007). Previous studies indicated that Badenian gypsum was mostly deposited, particularly in the lower part of the stratigraphic section, in a vast brine pan, and although individual depositional features and facies types in the Badenian may be explained by comparison with modern salinas, the lateral persistence of thin beds over large areas with only minor changes in thickness and facies indicates that they formed on broad, very low relief areas which could be affected by rapid transgressions (Peryt, 2001, 2006). In this paper the newest results on a selected site, Młyny (Busko) PIG1 borehole section, in southern Poland are reported and their implications for the interpretation of the gypsum section in southern Poland as well as in other parts of the Carpathian Foredeep basin are discussed; those gypsum sections are ca. 700 km apart (Fig. 1).

2 Geological setting

The Badenian evaporites of Central Paratethys have been subjected to studies for almost two centuries. During the last decades the research was focused on the Carpathian Foredeep Basin system and thus this basin, the largest of the Badenian evaporite basins has become the best studied, and known, evaporite basin of the Central Paratethys (Peryt, 2006). The Carpathian Foredeep basin stretches for more than 1300 km from the environs of Vienna to the NW part of Bulgaria. The Badenian evaporites are mainly underlain by usually deep-marine siliciclastics and carbonates (several tens to several hundreds of metres thick) although in the Carpathian foreland area (as well as in some parts of the Foredeep) gypsum deposits overlie the Mesozoic or Paleozoic rocks. The evaporites are overlain by thick deep-marine to brackish siliciclastic deposits(Neyet al., 1974; Porębskiet al., 2003) that attain up to 5 km in thickness (Kurovetset al., 2004).

Fig. 1 Location map. A-Palaeogeographic reconstruction of the Central Paratethys (Early Badenian marine sedimentation; after Rögl, 1998); B-Carpathian Foredeep Basin in Poland (grey); C-The northern part of the Połaniec Trough showing the occurrence of gypsum (grey) and the location of sections studied (after Kasprzyk, 1993a; modified by Gonera et al., 2012: figure 1)

Badenian evaporites in the northern part of Carpathian Foredeep show a regular spatial facies pattern (Peryt,2006). In the northern and northeastern parts of the Carpathian Foredeep primary gypsum (Krzyżanowice Formation in Poland and Tyras Suite in Ukraine; Fig. 2) forms a wide (up to 100 km in Ukraine) marginal Ca-sulfate platform (several tens of meters thick). They are covered by the Ratyn Limestone (e.g., Peryt and Kasprzyk, 1992a;Peryt and Peryt, 1994; Perytet al., 2012) or fine siliciclastic facies (e.g., Peryt and Peryt, 2009; Gedl and Peryt,2011). The sulphate platform passes basinward into the Ca-sulfate basin where anhydrite deposits are 10-20 m thick (Kasprzyk and Ortí, 1998; Peryt, 2000). Kasprzyk and Ortí (1998) and Kasprzyk (2003) indicated a complex and long-lasting nature of anhydritization processes within Badenian gypsum deposits. The processes started under synsedimentary conditions and continued in burial(Kasprzyk, 2003). In the narrow axial part of the basin,halite deposits occur in local salt basins (Bukowski, 2011).

The entire marginal gypsum platform is typically composed of giant gypsum intergrowths in the lower part and overlain successively by stromatolitic gypsum, sabre gypsum and clastic gypsum units (Fig. 3) that can be traced over a distance of 700 km. Kasprzyk (1993a) recognized 18 units (units a-r) in the complete gypsum section south of the Holy Cross Mts (Poland). Many of these units can be traced throughout the northern Carpathian Foredeep from the Czech Republic to western Ukraine, although there are differences in the succession, thickness and component lithofacies of these gypsum units (Peryt, 1996; Perytet al., 1997a, 1997b; Bąbel, 2005a, 2005b). In addition, in western Ukraine other types of gypsum bearing sections occur, and have been characterized by Peryt (2001) and Perytet al.(2004). In the deeper subsurface, gypsum is partly or completely replaced by anhydrite (and associated secondary gypsum) and it is possible to relate particular anhydrite lithofacies to their parent gypsum lithofacies(Kubica, 1992; Kasprzyk and Ortí, 1998; Jasionowski and Peryt, 2010).

Fig. 2 Stratigraphic position of mid-Badenian gypsum. The Miocene time scale after Hilgen et al. (2009), partly recalibrated and correlated to regional stages of the central Paratethys. The lower limit of Badenian evaporites after de Leeuw et al. (2010);calcareous nannoplankton zones after Peryt (1997); NN5 Sph.het. Z = NN5 Sphenolites heteromorphous Zone; lithostratigraphy after Andreyeva-Grigorovich et al. (1997), Jasionowski(1997) and Oszczypko-Clowes et al. (2012).

The gypsum section in the marginal Ca-sulfate platform can be divided into two parts: lower autochthonous(mostly crystalline and stromatolitic gypsum) and upper allochthonous (clastic). Autochthonous gypsum facies(crystalline gypsum, stromatolitic and massive alabastrine gypsum) were deposited in two main environments (Peryt,1996). One variety of crystalline gypsum (giant gypsum intergrowths) precipitated from highly concentrated brines at the initial stage of gypsum precipitation, whereas other varieties of autochthonous gypsum facies (i.e., sabre gypsum, “grass-like” gypsum, stromatolitic and massive alabastrine gypsum) were deposited in a vast brine pan characterized by a mosaic of facies. In the most marginal part of the gypsum platform in western Ukraine, the entire gypsum sequence consists of stromatolitic gypsum, and it passes landwards into the siliciclastic facies (Peryt, 2001;Perytet al., 2004). Basinwards of the Facies Zone I of the entirely stromatolitic development, stromatolitic gypsum occurs in the lower part of the gypsum section and sabre gypsum (occasionally with a clastic gypsum unit above the sabre gypsum) in its upper part. The width of this facies zone (Facies Zone II) may exceed 40 km (Fig. 4).

In southern Poland and in Moravia, the peripheral platform is much smaller and only Facies Zone III is noted(Kasprzyk, 1991, 1993a; Perytet al., 1997b).

3 Gypsum facies in studied regions

3.1 The Wschodnia River region (southern Poland)

The Wschodnia River region is located in the northern part of the Carpathian Foredeep Basin, within the Połaniec Trough, east of the classical outcrops Borków and Leszcze that are extensively described in the literature (e.g., Bąbel,1991, 1999a, 1999b; Kasprzyk, 1993a, 1999; Peryt and Jasionowski, 1994; Hałaset al., 1996; Peryt, 2013a, 2013b;with references therein). The Badenian deposits in the northern part of the Carpathian Foredeep Basin in Poland lie transgressively on eroded Cretaceous and Jurassic strata, and owing to the occurrence of gypsum deposits of the Krzyżanowice Formation, the Badenian section is tripartite. Below the gypsum various carbonate and siliciclastic rock units (up to several tens of metres thick) occur in the Pińczów Formation, containing in its upper part marls of the Baranów Beds which are several metres thick in the Borków area (Peryt and Gedl, 2010). But in the northern part of the Połaniec Trough, they attain thickness of 100 m (Wilczyński,1984). The gypsum is covered by the Upper Badenian siliciclastic facies of the Machów Formation (Fig. 2).

Fig. 3 Badenian gypsum sequence in Borków Quarry (after Peryt and Jasionowski, 1994) and in boreholes of the northern Połaniec Trough. Sections other than Młyny (Busko) PIG 1 are after Kasprzyk (1993a).

Fig. 4 Badenian evaporite facies in the northern Carpathian Foredeep Basin (simplified after Peryt, 2006). The location of the map is shown on the map of Europe. I-IV indicate gypsum facies (in the case of IV, gypsum and/or anhydrite facies), numbers 1-5 indicate localities shown in Fig. 8; Ko-Kobeřice, PT-Połaniec Trough, Z-Zalyshchyky, MO-Moldova, RO-Romania. Solid black line is the present limit of evaporite facies.

Kasprzyk (1993a) recognized fifteen gypsum units (a to n) in the Borków quarry section, which is 32 m thick(Fig. 3). The lower member contains the unit of giant gypsum intergrowths (up to 3-5 m high) overlain by bedded(banded) selenites (grass-like gypsum) with intercalations of alabastrine and stromatolitic gypsum (Fig. 3). Further up in the section, skeletal gypsum passing upwards into sabre gypsum occurs (Fig. 3). Sabre-like gypsum forms units g and i and are separated by fine-grained laminated gypsum (unit h) (Kasprzyk, 1993a). The upper member of the gypsum sequence (units j-n) consists primarily of gypsum-arenites, gypsum-rudites and laminated gypsum(Bąbel, 1991, 1999a, 1999b; Peryt and Kasprzyk, 1992b;Kasprzyk, 1993a, 1999; Peryt and Jasionowski, 1994).They contain an intercalation (unit ) of marly clay (10-25 cm thick) with benthic foraminiferal assemblages dominated by infaunal forms preferring muddy or clayey sediments, with normal marine salinity, at inner shelf depths,and scarce planktonic foraminifers which indicate a major marine flooding event (Peryt, 2013a).

In the Staszów area, located east of the Połaniec Trough,giant gypsum intergrowths are locally underlain by a thin(4-55 cm) layer of bituminous clay or by algal laminites with gypsum nodules and nodular layers (Kasprzyk,1989). In several borehole sections located in the Połaniec Trough, such as Żerniki 1 and Strzelce 1 (Fig. 3; Kasprzyk,1991, 1993a; Peryt and Kasprzyk, 1992b) nodular gypsum was recorded in the lowermost part of the gypsum section and was interpreted to have formed in sabkha environment at the initial stage of evaporite sedimentation.

Another borehole (M yny (Busko) PIG1) was recently drilled between the Borków Quarry and the Przyborów 1 borehole section. The gypsum section is roughly of the same thickness as in Borków Quarry and Przyborów 1 borehole section (Fig. 3). Although the layer thickness for the lower part of this section composed mostly of crystalline gypsum is reduced in the Młyny (Busko) PIG1 borehole section compared to the Borków Quarry section(Fig. 3). This lower part, however, has thickness similar to Przyborów 1 and other sections in the northern Połaniec Trough (Fig. 3).

Fig. 5 Gypsum facies in the Młyny (Busko) PIG 1 borehole; the location of photos is shown in Fig. 3. Scale bar is 1 cm. A-Giant gypsum intergrowths (partly distorted); B and C-Sabre gypsum; D-Skeletal gypsum, with elongate rod-like and chaotically arranged selenite crystals in a matrix of granular gypsum. Between the gypsum crystals clay and carbonate grains forming distinct partings and pockets occur; E-Laminated, distorted gypsum above sabre gypsum (lower right corner); F-Clastic gypsum composed on intercalated gypsum breccia and laminated gypsum.

The gypsum section of the Młyny (Busko) PIG1 borehole begins with gypsum nodules embedded in clayey matrix (and accompanied by native sulphur accumulations),the gypsum resembles smaller, chaotically arranged giant gypsum intergrowths despite its nodular nature (Fig. 5A),which is characteristic for the upper part of the giant gypsum intergrowths unit elsewhere (e.g., Bąbel, 1987; Peryt,1996). The bottom part is followed by a complex of inter-calated bedded selenite and alabastrine gypsum, with one thicker (20 cm) bed of alabastrine gypsum in the middle of this complex. Higher up in the section, stromatolitic gypsum occurs, which passes into selenitic gypsum that composed of elongate rod-like and chaotically arranged selenite crystals in a matrix of granular gypsum (Fig. 5D).Such development is characteristic for skeletal gypsum(Kwiatkowski, 1974)-a variety characteristically occurring in the lower part of sabre gypsum unit elsewhere in the basin (e.g., Kasprzyk, 1993a; Peryt, 1996). Then, typical sabre gypsum occurs (Figs. 3, 5B, 5C) and it is covered by contorted laminated gypsum (Fig. 5E). The upper part of the gypsum section of Młyny (Busko) PIG1 borehole section is composed of intercalated gypsum breccia and laminated gypsum, which is often contorted (Fig. 5F).

3.2 Moravia (Czech Republic)

The gypsum section in Kobeřice (Moravia, Czech Republic) was characterized by Perytet al.(1997a, 1997b).The section is shown in Figure 6. Several (although not all) gypsum units known from Borków can be recognized.In the lower part of the gypsum section, a giant gypsum intergrowths unit occurs (3.3 to 4.2 m thick) and is covered by clays containing clasts (as much as 50 cm across in places) of giant gypsum intergrowths (Fig. 6; Perytet al.,1997b), as well as abundant planktonic foraminifers. The thickness of clays varies as the upper surface of giant gypsum intergrowths unit is very irregular and furrowed (Fig.6; see also Perytet al., 1997b: Fig. 2a). The clay unit (up to 1.7 m thick) is overlain by alabastrine gypsum unit (10-32 cm thick) that is regarded as equivalent to the marker bed(unit c of Kasprzyk, 1993a) in the entire Carpathian Foredeep Basin (cf. Petrichenkoet al., 1997). The alabastrine gypsum unit is followed by the unit built of sabre gypsum crystals embedded in clay-gypsum matrix (Fig. 6; Perytet al., 1997b), and the thickness of sabre gypsum unit at-tains 10 m. Higher up in the section, laminated gypsum,gypsiferous claystones with breccia intercalations, and massive breccias, all forming the clastic gypsum unit, occur (Fig. 6).

Fig. 6 Gypsum section in Kobeřice (after Peryt et al., 1997a, 1997b) showing photos of the lowermost part of gypsum sequence in Kobeřice. Field photos (length of hammer handle, arrowed in B: 29 cm; width of hammer handle: 4 cm); a-Alabastrine gypsum; c-Clay; fr-Clast of giant gypsum intergrowth; ggi-Giant gypsum intergrowth.

3.3 Western Ukraine

As already mentioned, in western Ukraine, a continual facies record from the most marginal facies characterized by stromatolitic gypsum with intercalations of siliciclastic deposits, to the more outer gypsum platform facies characterized by the occurrence of giant gypsum intergrowths in the lowest gypsum unit is observed. Eventually, a nodular gypsum with clear pseudomorphs after giant gypsum intergrowths occurs (Peryt, 1996, 2001). The giant gypsum intergrowth unit is covered, in the outer gypsum facies, by stromatolitic gypsum with intercalations of selenitic gypsum (lower part of Fig. 7A) passing into the intercalated alabastrine and selenitic gypsum (Fig. 7B, middle part of Fig. 7A), followed by a regional marker bed of cryptocrystalline massive “alabastrine” gypsum (upper part of Fig. 7A; Turchinov, 1999). Such a gypsum section characteristic of Facies III Zone is replaced, towards the basin margins, by stromatolitic gypsum and then by interbeded crystalline and stromatolitic and/or alabastrine gypsum occurring below the regional marker bed in Facies Zone II.Between the towns of Horodenka and Zalyshchyky, with the stromatolitic gypsum overlying the Zhuriv Formation,an intercalation of crystalline gypsum (0.5-1.0 m thick;Fig. 7C, 7D) was recorded ca. 1.5 m above the base of the gypsum succession (Fig. 8; Peryt, 2001; Perytet al.,2004). Such a facies was not recorded in the sections located further towards the basin margin (Fig. 8).

Fig. 7 Aspects of the lowermost part of gypsum sequence in western Ukraine. A-Oleshiv (stromatolitic gypsum unit overlain by intercalated stromatolitic and selenitic gypsum and then the alabastrine gypsum of the regional marker bed 1); B-Dubivtsi (intercalations of stromatolitic and selenitic gypsum showing flat laminations of selenite clusters); C and D-Blocky crystalline gypsum (C-Babyn,D-Horodnytsya) within the unit of stromatolitic gypsum. Length of hammer in A and D: 33 cm; length of hammer face in C: 18 cm;pen cap (black) is 4 cm long.

4 lnterpretation and discussion

The development of the lowest part of the gypsum section in the Młyny (Busko) PIG1 borehole combined with the results of study of the Borków Quarry and Przyborów 1 borehole indicate that the area located south of the Holy Cross Mts (so called Wschodnia River region), which was previously characterized as an island, at the beginning of the gypsum deposition, with the nodular gypsum interpreted as sabkha deposits (Kasprzyk, 1991, 1993a), in fact was formed in a slightly deeper zone than that characterized by giant gypsum growth formation. Such a palaeogeographical position resulted in the rudimentary development of facies characteristic for the lower part of the gypsum section in the peripheral sulphate platform zone in general (cf.Fig.3) and for the giant gypsum intergrowths unit in particular.In any case, also in other parts of the basin there is a clear reduction in thickness of the basal gypsum units (or their anhydrite equivalents) towards the basin (e.g., Jasionowski and Peryt, 2010). This in turn has important implications so far for the enigmatic correlation of sections from the marginal gypsum platform and the basinal sections (cf.Kasprzyk and Ortí, 1998).

The Badenian autochthonous gypsum facies indicate the deposition was in a salina-type basin, at a depth of no more than a few metres (e.g., Kasprzyk, 1993a, 1993b;Bąbel, 1999a; Schreiberet al., 2007). The nature of giant gypsum intergrowths and the way for the occurrence of impurities in gypsum suggests that giant gypsum intergrowth facies occurring at the base of gypsum section originated from density-stratified brines (Pawlikowski,1982). Bąbel (1999b) presented a more detailed interpretation of this facies assuming the existence of a relatively permanent pycnocline, with the salinity of the upper bed of brine not allowing the gypsum to precipitate. In turn,stromatolitic gypsum occurring in the lower part of the gypsum section seems to have originated from diluted brines in a shallower part of the brine pool (Peryt, 1996).Hence the temporary establishment of crystalline gypsum facies in the shallower part of the basin in western Ukraine indicates storm-induced flooding of the brine pan and the evaporite flat (Peryt, 2001).

Fig. 8 Gypsum sections between Potochyshche (located 18 km NW of Zalyshchyky) and Mamalyga (located 75 km SE of Zalyshchyky) (after Peryt et al., 2004).

The occurrence of large clasts of giant gypsum intergrowths within clays recorded at Kobeřice above the giant gypsum intergrowths seems to be related to important storm activity. The stromatolitic and selenitic (grass-like)gypsum varieties, characteristic for the lower part of gypsum section in the marginal gypsum platform (Facies Zone III of Peryt, 2006) in Poland and Ukraine are missing in Kobeřice. The clays containing abundant planktonic foraminifers may be the equivalent of unit b elsewhere. It is suggested by the occurrence in Kobeřice, that a characteristic marker bed (marker bed 1 of Peryt, 2001, 2006) consists of cryptocrystalline “alabastrine” massive gypsum with a distinctive finely crenulated lamination and has a dome-like to cauliflower-like top occurring, typically in Zone III, a few tens of centimetres to several metres above the giant gypsum intergrowths unit (Petrichenkoet al.,1997; Bąbel, 2005a; Peryt, 2006) in Zone III. This marker bed reflects an event that may be related to sudden and widespread changes in water chemistry, which in turn imply major changes in basin hydrology. It records a major phase of subaerial exposure of the entire marginal Ca-sulfate platform, and the lack of the marker bed 1 in the more marginal, and northeastern parts of the platform in western Ukraine (Fig. 8) is related to the lack of evaporite deposition there prior to the origin of the marker bed 1. This in turn is related to the general transgressive trend (and at the same time brining-up trend) with evaporite deposition and migration of facies zones toward the northeast. Accordingly, the base of sabre gypsum facies in the Facies Zone II is strongly diachronous (cf.Fig. 8; Peryt, 2006),but the Kobeřice section suggests that also within the Facies Zone III the sabre gypsum facies started to form at various times. In Moravia (Czech Republic) the gypsum sequence is transitional between the classical gypsum sequence of the Nida Trough (southern Poland). The type III in western Ukraine is on the one hand and the Wschodnia River region is on the other.

Cendónet al.(2004) indicated that geochemical data such as fluid inclusion composition of primary halites, Br content in halite and sulphate isotopic trends (δ34S and δ18O) combined with petrographic, mineralogic and sedimentological observations and all together compared with model calculations indicate recycling of evaporites during most of the period of evaporite deposition. The recycling became an especially important mechanism during the deposition of the upper part of evaporites, both for the halite and Ca-sulfate facies, which was accompanied by the block tectonics that resulted in the creation of bathymetric differences (Peryt, 2006). The upper part of the gypsum section was deposited in a basin with bottom topography of at least a few tens of metres and consists of thick redeposited gypsum in Facies Zone III. The source of this gypsum was the Facies Zone III itself as well as more marginal gypsum facies zones (i.e., II and I in the case of western Ukraine).

As already mentioned, the known depositional facies within a modern salt works (e.g., Ortíet al., 1984) permits to interpret particular facies of the Badenian gypsum (e.g.,Kasprzyk, 1993a; Peryt, 1996). Schreiberet al.(2007)commented that salinas represent only a partial working model because they are restricted to very shallow water bodies, and thus they suggested the need to apply the physical conditions known from deeper lakes, and they have been applied to Badenian evaporites (e.g., Bąbel and Bogucki, 2007). In addition, Schreiberet al.(2007) noticed that there exists a difference in the typical Badenian selenite and gypsum environments and facies in the Carpathian Foredeep Basin in Ukraine (“dry shore” model)and Poland (“wet shore” model). The difference is laid up in that continental water appears to be the important controlling factor in Poland, and probably its impact is even bigger in Moravia.

Figure 9 summarizes palaeogeographic zonation of Badenian gypsum facies which is based on observations reported in this paper as well as on previously published detailed (Peryt, 1996; Babel, 2005b; and references therein) and general (Schreiberet al., 2007) models. There are three principal gypsum facies: crystalline gypsum and stromatolitic gypsum as well as clastic gypsum that typically occurs in conditions of relatively smooth bathymetrical conditions, between crystalline and stromatolitic gypsum as well as between stromatolitic gypsum and the land (cf.Fig. 9); in addition, clastic gypsum is common in channels within gypsum microbialites (e.g., Bąbel, 2007),and it is the main facies later during the Badenian gypsum sedimentation when the bathymetric differences within the marginal part of the Carpathian Foredeep Basin have constrained the crystalline and stromatolitic gypsum occur only locally. Within crystalline gypsum facies the increase of crystal size is observed (which are schematically shown in Fig. 9) and the decline of layering towards the permanent, stabilized brine body, and thus the giant gypsum intergrowths, non-layered coarse-crystalline selenite,is the end-member of gypsum facies continuum. Typically it passes into layered selenites (Bąbel, 2005a), however,as exemplified by the occurrence of selenite intercalation within stromatolitic gypsum complex of western Ukraine(Fig. 8), owing to fluctuations of the pycnocline level,some transitional gypsum subfacies may be missing both in vertical section as well as in particular outcrops. The importance of pycnocline level fluctuations on the development of some gypsum facies have been addressed by Schreiberet al.(2007). Brine sheets and floods; rare marine transgressions (e.g., Peryt, 2013a); and pedogenesis leading to “alabastrine” gypsum development resulted in a correlation potential of particular strata in the Badenian over vast distances.

Fig. 9 Scheme showing the palaeogeographical zonation of main types of Badenian gypsum (after Peryt, 1996; Bąbel, 2005a;Schreiber et al., 2007).

5 Conclusions

1) The Middle Miocene Badenian primary gypsum facies in northern part of Central Paratethys show a distinct palaeogeographical zonation.

2) In particular, characteristic gypsum facies (such as giant gypsum intergrowths or sabre gypsum) and their frequency in the vertical section are useful environmental indicators. Some gypsum units (in particular, “alabastrine”gypsum beds) as well as intercalations of fine siliciclastic deposits register important environmental changes such as the subaerial exposure of vast part of the basin or increased supply of clay materials, which could be climatically-driven.

3) In addition to pycnocline level fluctuations which were an important control on the development of gypsum facies and the appearance of incipient giant gypsum intergrowths within the stromatolitic gypsum unit in western Ukraine, the following factors exerted the control on the development and the correlation potential of gypsum units: brine level fluctuations including brine sheets and floods; rare marine transgressions; pedogenesis leading to“alabastrine” gypsum development; rate of inflow of continental water.

4) There were two main phases of gypsum basin development. During the first phase autochthonous gypsum types (mostly crystalline and stromatolitic) were dominant, and the second phase was dominated by allochthonous gypsum deposition.

5) In southern Poland, a distinct basinward trend for the decrease of sharing autochthonous gypsum and the increase of sharing allochthonous gypsum in the vertical section is observed. This implies that during their major part the sulphates in the basin zone were coeval with allochthonous, later part of the gypsum section in the marginal part of the Badenian Basin.

Acknowledgements

I am grateful to Prof. He Qixiang and Prof. Kong Weigang for their valuable comments on an earlier version of this manuscript. The study was partly supported by National Fund for Environmental Protection and Water Management.