The deep record of the Messinian salinity crisis: Evidence of a non-desiccated Mediterranean Sea

of the very thick successions that lay below the floor of the Mediterranean, these short cores are pivotal for the understanding of the crisis evolution. On the other hand, no modern evaporite facies analysis have been performed on most of the few meters of evaporites recovered from ODP-DSDP wells, the only descriptions being those compiled during the recovery or shortly thereafter. Important exception is the work of Hardie and Lowenstein


The Messinian salinity crisis: a facies problem
The Messinian salinity crisis is one of the most complex geological events that happened on our planet.The degree of complexity of this event that turned the Mediterranean into a giant salina producing a biological-catastrophy for most marine species is well represented by the many different alternative hypotheses that have been proposed to unravel its origin and evolution.The consequence has been a scientific controversy that lasted since the discovery of the evaporite sequences buried below the Mediterranean floor (see Rouchy and Caruso, 2006).
One potentially comprehensive approach for the understanding this crisis is to unravel the intricate evaporite facies array that was deposited in the different Mediterranean areas (Fig. 1).
Although we are aware that no modern analogues are available to compare all the Messinian facies architecture, at a first glance the evaporite products are surprisingly similar to what one would expect just by simple evaporation of seawater.
Evaporite deposits range from carbonate (the first to precipitate from seawater) to gypsum (CaSO 4 •2H 2 O), halite (NaCl), kainite (MgSO 4 •KCl•3H 2 O) and finally bishofite (MgCl 2 •6H 2 O; the last to precipitate), a rather rare very soluble salt that has an extremely low potential of preservation in the rock record and yet is present in the Messinian succession in Sicily.
Yet a simple facies comparison with modern evaporites forming in the Mediterranean, both natural (sabkhas and associated salinas in North Africa) and artificial (commercial solar works), reveals many profound differences, suggesting that still other mechanisms may have influenced precipitation and sediment preservation, to some degree, in the past.One of these processes is probably the vast input of freshwater into the basin during gypsum deposition, as revealed by the Sr isotope geochemistry (Flecker and Ellam 2006;Lugli et al., 2010;Roveri et al., 2014b) and fluid inclusion data (Natalicchio et al., 2014).Another important factor may be the organic matter associated with the sediments, as accumulations of cyanobacteria and archea are included in most of the evaporite products, especially gypsum (Panieri et al., 2010) and argillaceous sediments (Dela Pierre et al., 2014).These important aspects still need to be fully explored.
Even more different and unexpected is the facies association and architecture of these deposits that are arranged in a fashion that exclude the reasonable, but in a way simplistic, view that different evaporite mineral facies should tend to form lateral equivalent deposits ("Walther''s Law"), one adjacent to the other, as in a modern solar works.This disparity exists because the deposition of gypsum is strongly influenced by anoxia, bacterial activity and, in turn, by brine depth (De Lange and Krijgsman, 2010;Lugli et al., 2010;Dela Pierre et al., 2012) and deposition and attendant preservation was probably limited to relatively shallow settings (less than 200 m).The lateral equivalent of gypsum in deep basinal settings is not necessarily halite but, as indicated by cyclostratigraphy, the shale and carbonate deposits also formed in the first salinity phase (Manzi et al. 2007(Manzi et al. , 2011(Manzi et al. , 2013)).Adding to the complexity of evaporite interpretation, some of the biological remains are contradictory, as we see that both marine and brackish fossils are documented in the same sequences (see for example Carnevale et al., 2008).

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The architectural facies approach is based on a few concepts that were applied to the Messinian crisis for the first time: a) the concept of an "evaporite event" (Hardie, 1984), indicating that dm-scale layers of halite and m-scale gypsum layers represent a complete evaporite cycle that may be independent from the previous and the following layer; b) the diverse cyclicity of the evaporite bodies that range from precession (21 21 kyrs; Krijgsman et al., 1999) to very high frequency (annual to pluriannual in gypsum and halite; Manzi et al., 2012); c) the widespread and thick clastic evaporite facies are not very common in the rock record elsewhere, but are essential for the understanding of the sedimentary evolution here (Manzi et al., 2005;Lugli et al., 2013); d) the strong possibility that some of the evaporite deposits were formed by brine mixing (Raup, 1970) and not only by simple evaporation, as brine saturation was possibly reached by downslope flows of hypersaline, dense waters, in a process similar to present-day "dense shelf water cascading" (Roveri et al., 2014c).
According to the above criteria and waiting for the possibility of a more complete drilling program through the entire sequence in the deep Mediterranean settings, the most complete stratigraphic frameworks for the salinity crisis taking into account all the observed sedimentary facies is the three-steps model proposed by CIESM (2008) and recently refined by Roveri et al. (2008Roveri et al. ( , 2014a) ) and Manzi et al. (2013): 1) the first stage of deposition (5.97--5.6Ma; Manzi et al., 2013) is dominated by massive bottom-grown selenite (Primary Lower Gypsum; Lugli et al., 2010) in semi-isolated sub-basins, whereas only organic-rich shale and dolomitic limestone accumulated in deeper and/or more open settings (Manzi et al., 2007).
2) the second stage is the salinity crisis acme (5.6--5.55Ma) with the deposition of carbonates (Manzi et al., 2011) and halite and K-bearing salts (Lugli et al., 1999) during a phase of erosion and tectonic activity producing clastic deposits (Resedimented Lower Gypsum;Manzi et al., 2005;Roveri et al., 2008) from erosion and resedimentation of previous deposits; huge primary halite bodies (not reworked) were mainly deposited in the deeper basinal settings.This is the only stage where it was possible to demonstrate that local desiccation was achieved in some peripheral salt basins in Sicily (Lugli et al., 1999), probably as a result of the complete filling of intermediate basins (400 to 600 m depth) due to tremendous depositional rate of halite (Manzi et al., 2012).
All the cores were cut with a diamond saw to document the sedimentary features.Part of the segments were trimmed to obtain large standard thin and thick sections (4.5x6 cm and up to 100 µm in thickness for halite) for the examination under the optical polarizing microscope in transmitted light.

Evaporite facies in the drill cores
The ODP and DSDP cruise recovered evaporites that were formerly grouped into the Upper Evaporite (Hsü et al., 1973a) or Upper Unit of Lofi et al. (2005) on the basis of seismic stratigraphy.According to our Sr-isotope stratigraphic reinterpretation of the Mediterranean Messinian evaporites (Roveri et al., 2014b), the drillings reached mostly sediments belonging to stages 3 (Upper Gypsum) and 2 (Resedimented Lower Gypsum and halite) of the salinity crisis (see previous chapter).Only at site 378a the drilled sequence is from stage 1 (Primary Lower Gypsum).
The evaporite sediments consist of gypsum, anhydrite and halite rocks that show evidence of primary, clastic and secondary facies modified by diagenesis and tectonics.

In situ primary evaporites
These rocks originated by subaqueous chemical precipitation from concentrated brines.

Selenite gypsum
Massive selenite (facies EF3, Lugli et al., 2010) consists of bottom-grown vertically aligned swallow-tail gypsum crystals up to about 10 cm tall.A local limited transition to layers of banded selenite (facies EF4, Lugli et al., 2010) is also visible (site 375) showing thin layers consisting of vertical crystals about 1 cm-thick with corroded terminations draped by sand-size gypsum grains (gypsarenite).The massive selenite has been drilled only at sites 375 SW of Cyprus and 378a in the Aegean Sea (Fig. 1).At site 378a the massive selenite form an apparently continuous 40 m-thick interval, but at site 375 it is present as blocks included in a clastic unit consisting of gypsrudite and gypsarenite.

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The laminar gypsum is a millimeter-scale rhythmic succession of gypsum laminae.There are two main types: the equigranular, which is inversely graded (Figs.2C and 3C), and the acicular gypsum, which is directly graded (Figs.2D and 3D).The gypsum laminae consist of inversely graded (i.e., with crystal size increasing toward the top of each lamina) cumulates of fine-grained equigranular crystals separated by very thin veneers of organic matter (less than 1 mm).The inverse gradation resemble that described in the Sicilian evaporites (Ogniben, 1957;Schreiber et al., 1976;Manzi et al., 2012).Small-scale cross-lamination is occasionally present (Figs. 2 E and 3L).Fig. 2 A) Core slab of halite rock from Site 134 showing sandy silt (light greay at the top) and fine-grained halite cube cumulate (light greay at the bottom).The clastic layer is composed of corroded cubic halite, planktonic forams, quartz, feldspar and glauconite grains.The white nodules consist of felted displacive anhydrite.This sample is 10 cm below the core section cut by a crack originally interpreted as a desiccation feature by Hsü et al. (1973a and b) and displays the same facies association (see also Fig. 4).A thin section of the core is shown in Figs.3A and 4G and F. B) Core slab of halite rock made up of clear blocky and elongated crystals.This rock appears to have recrystallized during tectonic flow (see Fig. 3B for a thin section of a similar rock).Relict of the original layering is the dark banding appearing on the top of the sample and consisting of scattered argillaceous material.Site 376.
C) Core slab of a laminar rock consisting of fine-grained graded granular gypsum with a clastic gypsum intercalation (at center of picture).A thin section of a similar cumulite rock is shown in Fig. 3C.Site 654.

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ELSEVIER_PALAEO_7285 D) Core slab of a undulate coarse gypsum laminite consisting of mm-size granular crystals (light gray beds) draped by fine-grained gypsum cumulate (dark laminae).A thin section of a similar cumulite rock is shown in Fig. 3E.Site 975.E) Core slab of a deformed undulate coarse gypsum laminite consisting of mm-size granular crystals (light gray beds) draped by fine-grained gypsum cumulate (dark laminae).Site 653.F) Core slab of an anhydrite rock consisting of large elongated nodules possibly partially modified by pressure solution, but showing some pseudomorphs after swallow tail selenite crystals.Arrow is pointing to the re-entrant angle of a swallow tail crystal.Site 124.G) Core slab of graded gypsarenite--gypsrudite rock consisting of corroded selenite fragments.A thin section of this rock is shown in Fig. 3I.Site 654.
H) Core slab of a cross bedded clastic gypsum rock consisting of reworked granular cumulate gypsum.A thin section of this rock is shown in Fig. 3L.Site 654.

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The graded equigranular gypsum facies may display undulate laminae and deformation.The undulations are related to the presence of bottom-grown coarser granular crystals, up to a few cm across, that are draped by the subsequent fine-grained gypsum laminae (Fig. 2D).The deformation appears to be the consequence of early diagenetic overgrowth of the selenite nodules (Fig. 2E).
The graded and laminated rock may contain locally small vertical bottom-grown selenite crystals onlapped, draped and drowned by the cumulate crystals (Fig. 3F).Some samples show minor displacive growth of gypsum prisms into carbonate mud associated with laminar gypsum (Fig. 3H).

Laminar halite
The laminar halite has been recognized exclusively at site 374 and consists of thin-bedded accumulations of fine-grained halite cube crystals (up to 0.3 mm across) showing primary fluid inclusions along growth bands (Fig. 3A).The cubic halite cumulate layers are 5 to 10 cm-thick and are separated by tiny (less than 0.1 mm) sheets of argillaceous mud and white coalescent displacive nodules of fine-grained acicular (felted) anhydrite (Fig. 4E and G).The mud appears to drape and rim some of the halite crystals downward.In these areas the halite crystals show slightly corroded and rounded corners suggesting that the mud penetrated downward along narrow dissolution pits developed at intercrystalline positions (Fig. 4F).Polyhalite needles less than 0.1 mm in size are scattered throughout the rock and commonly radiate out from the areas where mud is concentrated.A few cross-bedded clastic layers a few cm-thick are intercalated in the cumulate halite (Fig. 4d and E).The clastic layers are normally graded and contain grains composed of partly corroded and slightly rounded cubic halite crystals, planktonic foraminifera tests and fragments, quartz, feldspar and glauconite (Fig. 4F).The clastic grains are also partly displaced by white nodules of felted anhydrite up to a few mm in size (Fig. 4D   and G).This clastic facies contains a single crack, up to 2 mm-wide, filled by clear, fluid inclusion-free halite, which is described in detail in the discussion chapter (Fig. 4D).
F) Thin section photomicrograph of laminated rock containing small vertical bottom-grown selenite crystals (light gray at right).The selenite crystals are onlapped, draped and drowned by the cumulate crystals which settled from the water column.The selenite boundaries are also corroded suggesting that the crystal was probably standing free above the brine--sediment interface during the winter dilution which is marked by the very fine grained dark laminae containing organic matter and fine-grained carbonate.Crossed polars, transmitted light.Site 654.G) Thin section photomicrograph of an anhydrite laminite rock consisting of felted crystals.The original rock was probably a laminated gypsum cumulite very similar to Fig. 3C.Crossed polars, transmitted light.Site 975.
The coarser sediments are composed of corroded fragments of twinned crystals indicating erosion and redeposition of primary massive and banded selenite.The sedimentary features include graded laminae of gypsum granules and carbonate clasts and commonly exhibit cross-lamination (Figs. 2G and H and 3I,L and M).

Diagenetic/tectonic modified evaporites
Some of the evaporite facies show the evidence of complex post-depositional modifications related to burial diagenesis and tectonic deformation.

Blocky halite
This facies consists of large halite crystals up to a few mm across that are blocky or elongated along the main layering (Fig. 2B).The crystals are clear and show only rare primary fluid inclusions banding.Most of the visible fluid inclusions are and grouped at intra-crystalline positions as secondary irregular vermicular structures (Fig. 3B).These characteristics indicate recrystallization by halite deformation, as migrating grain boundaries consume the fluid-inclusion-rich parts of the crystals transferring the brine into the grain boundaries and providing conditions for pressure solution creep (Schléder and Urai, 2005) 4.3.2Anhydrite rocks formed from gypsum dehydration 4.3.2.1 Massive anhydrite Massive anhydrite consists of fine-grained whitish rocks composed of fine-grained acicular and interlocking anhydrite crystals and may contain large anhydrite porphyrotopes.

Elongated flat nodular anhydrite
Anhydrite rock containing flat elongated nodules may form massive or graded beds.The anhydrite fragments are aligned with their long axes parallel to bedding and in some cases show a distinctive swallow-tail shapes suggesting pseudomorphs after selenite, as demonstrated by the presence of the re-entrant angle of the former twin morphology (Fig. 2F).
Petrographically the clasts consist of polycrystalline intersecting lath-shaped anhydrite and the original shape of the clastic sulfate fragments is commonly outlined by argillaceous or fine-grained carbonate material.

Equant nodular anhydrite
This type of rock is composed of equant anhydrite nodules, made up of fine-grained acicular crystals, that grew displacively and are separated by thin veneers of organic-rich mud.

Laminar anhydrite with minor nodules
Laminar anhydrite consists of thin laminae, up to a few mm-thick, composed of felted (Fig. 3G) and lath-shaped anhydrite separated by argillaceous laminae containing organic matter.No pseudomorphs are visible within the sulfate laminae.

Entherolithic anhydrite
Entherolitic structures consist entirely of fine-grained acicular anhydrite and affect deformed undulate laminar anhydrite rocks with the maximum deformation at the margin of large displacive nodules.The entherolitic structures appear to have formed by the coalescence of anhydrite nodules grown into layers of laminated sulfate facies and deforming them to various extents.

Porphyroblastic laminar gypsum
This facies consists of large cloudy-ameboid and xenotopic gypsum (as described in Lugli, 2001;after Ciarapica et al., 1985) containing small relicts of anhydrite crystals and parallel laminae of argillaceous material.These characteristics suggest an origin by hydration of fine-grained acicular and lath anhydrite laminites.

Porphyroblastic gypsum
This porphyroblastic gypsum is made up of cloudy-ameboid and xenotopic gypsum containing anhydrite relicts.These rock probably originated by gypsification of massive anhydrite.

Porphyroblastic gypsrudite and gypsarenite
This facies consists of cloudy-ameboid and xenotopic gypsum containing small relicts of anhydrite.The rock is crossed by a network of curved argillaceous laminae cross-cutting each other.these characteristics indicate an origin by hydration of former nodular anhydrite in turn formed by burial of gypsrudite and gypsarenite rocks.

Marl with anhydrite nodules
This facies is represented by scattered displacive nodules of fine-grained acicular anhydrite that grew within mudstones.

Marl with gypsum rosettes and calcite mudstone with gypsum prisms
This facies is characterized by displacive rosettes composed of interlocking gypsum lenses and hexagonal gypsum prisms grown within marls and calcitic mudstones, respectively.

Discussion and interpretation of the evaporite facies
Previous studies of Messinian evaporites during the ODP-DSDP cruises pointed out the presence of shallow water to supra-tidal evaporitic deposits that became pivotal evidence for the definition of the "deep basin shallow water" model implying the deep desiccation of the Mediterranean (Hsü et al., 1973a,b).
Our analyses of the "deep" Messinian evaporites suggest that some evaporite facies may have a different interpretation than originally given (see Table 1 for interpretations comparison).In the next sections we briefly discuss our review of the original evaporitic facies interpretations.Marsaglia and Tribble (1999) 75c/34 Gypsiferous chalk Shallow water lacustrine, in situ diagenetic growth Marsaglia and Tribble (1999)

Halite
Based on the original interpretation (Table 1), the halite deposits were described as chevron, laminar and displacive (Hsü et al., 1973a,b;Garrison et al., 1978) and were sedimented in brine-pools or sabkhas.A shallow water origin for these halite deposits was also proposed for sites 374 and 376 (Garrison et al., 1978), based on the presence of chevron crystals (Kuehn and Hsü, 1973).
Hardie and Lowenstein ( 2004) provided a different interpretation suggesting that the halite rocks were actually cumulate deposits formed in subaqueous conditions at any water depth.
Our observations suggest that most of the halite rocks recovered by the drilled cores show evidence of recrystallization by halite deformation and flow that partially obliterated the original texture preventing or misdirecting the reconstruction of the depositional environment.The only unequivocal primary features come from DSDP site 134 and indicate deposition of fine-grained cumulate halite.From this site comes one of the sedimentary features that became famous after the enunciation of the "deep basin shallow water" model (Hsü et al., 1973b): a "desiccation crack" cutting through a sandy silt layer interbedded with unaffected laminated halite (Fig. 4).The interpretation was confirmed in another paper (Hsü et al., 1973a; their Fig. 5) although the same core sample was pictured in the opposite orientation (upside down).In our opinion the orientation shown in Hsü et al. (1973b) may be the correct one because the sand--silt layer appears to be a normal graded bed possibly deposited by a unidirectional gravity flow capped by cubic cumulate halite crystals settled at the bottom from the surface or the brine column (Fig. 4).

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The presence of the primary cubic cumulate points to subaqueous deposition in a relatively deep water environment; differently to what is observed in shallow water settings, where chevron halite is the most common sedimentary feature for the Messinian sections, especially for those layers that are affected by exposure features such as meteoric dissolution pipes and large contraction polygons in the Sicilian mines of Realmonte (Lugli, 1999;Lugli et al., 1999) and Racalmuto.The white anhydrite nodules displace the cube cumulate and the clastic layer and thus, appear to have grown in situ.Such type of growth is not exclusive of supratidal environments (as originally proposed by Hsü et al., 1973b), but may occur also in subaqueous deposits during late diagenesis (Shearman, 1985).Furthermore, the clastic layer cut by the crack that contains a large number of planktonic foraminiferal tests appears to have been deposited under subaqueous conditions instead of representing an aeolian deposit (Hsü et al., 1973b).This is because the halite cubes are only slightly corroded and rounded and the carbonate-siliciclastic fraction is relatively coarse and poorly sorted (silt--sand grain size; Fig. 4F).Moreover no exposure features have been recognized in the core section at any scale.The only dissolution features are characteristic of subaqueous environments and are very limited to the tiny mud veneers that represent annual winter and/pluriannual dilution by refreshment of the brine column that may have occurred at the winter of annual and pluriannual cycles (Fig. 4F).
Our observations on a new cut of the original core demonstrate that the crack extends further in the cumulitic halite layer above and below the sandy bed (see also Roveri et al., 2014c) and does not start from an horizon showing exposure features, such as Fig. 5 Facies association for the cores that crossed evaporite sediments in the ODP and DSDP legs in the Western Mediterranean Sea.

Annotations:
A1. this is fig 8 dissolution pipes (Fig. 4D).All these features suggest that the crack can be more properly interpreted as a late post-depositional fracture probably because of its different mechanical proprieties with respect to the sand and does not represent evidence of subaerial exposure.

Laminar gypsum
The large part of the gypsum deposits recovered from the depth has been described as laminar gypsum with or without nodules.The laminar gypsum was interpreted as a sabkha deposit (see Table 1; Garrison et al., 1978;Borsetti et al., 1990), whereas the presence of nodules was related to cumulate below wave-base (Marsaglia and Tribble, 1999), shallow- (Garrison et al., 1978;Borsetti et al., 1990) to deep-subaqueous (Hardie and Lowenstein, 2004) and clastic deposits (Pierre and Rouchy, 1990).
We do not have a clear explanation for the formation of equigranular versus.needle-gypsum laminate (cumulate) and direct versus.inversely grading more generally seen in these deposits.The sedimentation of such facies appears to be the result of accumulation of crystals settled from the brine air interface or from the brine column (in agreement with Marsaglia and Tribble, 1999;Hardie and Lowenstein, 2004) and the different cumulate facies may be the complex result of salinity, temperature and organic matter content.Each lamina appears to be a discrete seasonal episode occurring throughout the basin in a relatively deep environment.As for the example of Sicily, statistics can be successfully applied to the study of these annual deposits, revealing the influence of climatic forcings which are active today, such as ENSO oscillation, soli-lunar cycles, etc. (Manzi et al., 2012).
Our observations led to the identification of a facies association formed by alternation of primary cumulate and clastic gypsum layers.The clastic portion is provided by reworking of cumulate sediments that were resedimented downslope by low-density gravity flows, as suggested by normal grading and unidirectional ripples.This facies association has been previously described only in the deeper depocenters of Sicily (Manzi et al., 2011;2012) and Cyprus (Robertson et al., 1995;Manzi et al., in press).
The very early diagenetic overgrowth of the crystals settled at the bottom also created the undulate and nodular facies; however, the growth of these new overgrowth crystals was rapidly drowned by the continuous rain of other settling crystals (Fig. 3E and F).
In our opinion the sulfate nodules that are present in these deposits are diagenetic features and do not indicate supratidal environment.Moreover, cumulate gypsum deposits were not described in modern and ancient sabkha cycles.

Massive selenite
The only massive selenite beds at site 378A was were interpreted as shallow subaqueous by Garrison et al. (1978).They show a strontium isotope signature usually present in the field of the Primary Lower Gypsum (Roveri et al., 2014b).In particular, the described crystal facies and the presence of microbial inclusions (Panieri et al., 2010) are indicative of selenite facies EF3 and EF4 (Lugli et al., 2010).Such selenite sedimentation, seen elsewhere, was restricted to permanent marginal silled, shallow water (less that 200 m deep) subaqueous environments periodically affected by brine dilution which partially dissolved the crystal terminations but with no evidence of desiccation, as no dissolution pits are present.Generally large scale mass-wasting during the second stage of the salinity crisis were responsible or the displacement of selenite blocks downslope and their association to clastic selenite at site 375, as described for Sicily (Roveri et al., 2008;Lugli et al., 2010), Cyprus (Manzi et al., in press) and onshore Israel (Lugli et al., 2013).
We recognized a large variety of clastic gypsum deposits ranging from gypsrudites to gypsiltites, some of them modified by burial diagenesis (Figs. 2F,G and H;3I,L and M).They formed from the dismantlement of previous cumulate or bottom grown selenite deposits and subsequent resedimentation by gravity flows in a subaqueous environment (as suggested by Borsetti et al., 1990).Nevertheless, the absence of shallow to subaerial depositional features such as wave ripples, paleosoil or karstification point to deposition in relatively deep environments (Hardie and Lowenstein, 2004;Manzi et al., 2005;Roveri et al., 2008).
The studied sediments extend down to a maximum depth of 673 m below the seabed (site 652) in areas with a relatively high heat flow and are thus partially within the stability field of anhydrite that forms at the expenses of gypsum by burial diagenesis.
Anhydrite rocks are present in the cores portions buried more than 350 m below the seabed (site 371; see Fig. 5), but some anhydrite rocks have been also rehydrated back to gypsum (see next section).
In agreement with what proposed by Hardie and Lowenstein (2004), all the anhydrite deposits show no evidence of primary sabkha deposits and may be interpreted as related to diagenetic changes induced by lithostatic burial.The lithology of the original gypsum deposits, cannot be always determined, but could have been primary selenite, gypsrudite or laminar gypsum.The amount of matrix (carbonate or shale) and the sedimentary structures seems to control the shape and size of the anhydrite nodules that grew at the expenses of the original gypsum rock. ELSEVIER_PALAEO_7285

Massive and equant nodular anhydrite
The original deposits from which the massive or equant nodular anhydrite formed was probably a massive selenite with very little matrix; gypsum, both primary (massive and banded selenite) or clastic (gypsrudite and gypsarenite) may have been the original protoliths.

Elongated flat nodular anhydrite
The deposits from which this facies originated was probably a gypsrudite (clastic reworking) with a relatively abundant matrix content.This hypothesis is also supported by the bed gradation commonly associated with these deposits.

Laminar and entherolithic anhydrite
This facies formed from laminar gypsum that could have been either cumulate or clastic in origin.Despite the mesoscale undulate lamination, no clear evidence of algal structures have been recognized under the microsope; thus, in our opinion, the undulate to entherolithic appearances may be related to progressively stronger diagenetic deformations rather than any primary structure.

Gypsum after anhydrite
All the porphroblastic gypsum facies include anhydrite relicts or are characterized by hydration textures.These features indicate re-hydration of burial-diagenetic anhydrite.As stated for the anhydrite facies, no sabkha features have been recognized.For the definition of the original gypsum rock from which these facies originated see description of corresponding anhydrite facies.

Mudstone with sulfate
As illustrated in Table 1, isolated gypsum crystals within mudstones were interpreted as shallow water primary selenite (Pierre and Rouchy, 1990), sabkha porphyrotopes (Friedman, 1973), turbidite and diagenetic deposits (Borsetti et al., 1990), in situ diagenetic growth (Marsaglia and Tribble, 1999).Our observations suggest that the crystals and nodules are the result of early to late diagenetic displacive growth within a soft mud, in agreement to what proposed by Marsaglia and Tribble (1999).

Implications for the salinity crisis
The result of our review and the facies associations for all the drillcores are shown in Figs. 5, 6 and 7.These new facies associations suggest different perspective for the salinity crisis compared to the previous interpretations (see also Table 1).We have already discussed some of the features that were considered to support a deep desiccation of the Mediterranean such as "subaerial canyons", "fluvial deposits", "shallow water fossils" and "subaerial carbonate dissolution".They have also a different explanation, not exclusively related to desiccation (see Roveri et al., 2014a,b,c).The paradigmatic deep basin shallow water model (Hsü et al., 1973a) that envisaged the total desiccation of the Mediterranean Sea is built upon the fundamental pillar that the recognition of features present in supratidal deposits, interpreted to have deposited in a coastal sabkha environment, also are in the deepest portion of the basin.According to the previous suggestions of Hardie and Lowenstein (2004), who first challenged the shallow water-desiccation hypothesis, a thorough re-examination of the DSDP and ODP cores drilled in the deep Messinian evaporites reveals that: i) no unequivocal evidence of the presence of shallow-water or even supratidal environment can be inferred; ii) the largest part of the evaporites consists of cumulate or clastic deposits; iii) the coarse clastic evaporites cannot provide clear paleobathymetric constraints, but can be exclusively associated with subaqueous environments.

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Fig. 6 Facies association for the cores that crossed evaporite sediments in the ODP and DSDP legs in the Tyrrhenian Sea.

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A1.This is figure 2 (not 6) and appears to have an extremely low resolution and strongly modified colors.I am attaching a new file A1 ELSEVIER_PALAEO_7285 Fig. 7 Facies association for the cores that crossed evaporite sediments in the ODP and DSDP legs in the Eastern Mediterranean Sea.

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The evaporites share many similarities with the onshore deposits accumulated in the deeper basins of the peri-Mediterranean areas that have been included in the Resedimented Lower Gypsum unit (Roveri et al., 2008).Clastic evaporites similar to those recovered during the ODP-DSDP cores have been recognized in several geological settings, e.g., Apennines (Parea and Ricci Lucchi, 1972;Manzi et al., 2005), Sicily (Manzi et al., 2011), Spain (Fortuin and Krijgsman, 2003;Martinez del Olmo, 1996;Omodeo Salè et al., 2012), Greece (Kontopoulos et al., 1997;Karakitios et al., 2013) and Cyprus (Manzi et al., in press).These sediments have been interpreted as gravity flow deposits derived from the dismantlement of the primary gypsum deposits of the 1 st stage of the salinity crisis.Primary cumulate gypsum and halite are also intercalated within clastic deposits in Sicily (Manzi et al., 2012) and Cyprus (Robertson, 1995;Manzi et al., in press).
Clastic evaporite deposits have been recently discovered in the onshore heads of the canyons excavated along the Levant margin (Israel; Lugli et al., 2013).These deposits lie unconformably atop an erosional surface that could be correlated to the base of the Lower Evaporite unit in the Eastern Mediterranean.
Although the large part of the cored deposits discussed here represents only the uppermost portion of the seismic Upper Evaporites unit and our observations can notcannot be extrapolated for the entire Messinian suite, our findings suggest that the deposition of the late deep evaporites occurred in a persistent water body.This permanent basin was dominated by resedimentation of evaporite previously accumulated in shallow settings and by the formation of cumulate primary evaporites from supersaturated brine likely formed at the water surface or a density boundary (pycnocline) and have moved downslope by gravity, as suggested by Manzi et al. (2012).Although the ODP-DSDP core record is fragmentary and limited to the topmost part of the Messinian evaporite sequences, a modern sedimentologic and petrographic study of all the available cores has been the only possible source of direct data on the sedimentary products of the salinity crisis lying at depth below the floor of the Mediterranean Sea.This has been possible even though some of the rocks have been modified by a complex array of diagenetic processes.
This study provided us with some significant clues: a) understanding of the read-through factors useful for the interpretation of some of the diagenetic overprints, that have modified the original evaporite facies; b) recognition of the significance of the widespread clastic and cumulate evaporites facies similar to the laminar gypsum in Sicily (Manzi et al., 2012); c) rule out the presence of sabkha environment and of desiccation features, including the famous "desiccation crack" (Hsü et al., 1973a,b).
The major portion of the evaporites collected by ODP and DSDP cruises are clastic or cumulate deposits that cannot provide clear bathymetric indications but do help us to exclude shallow-water and supratidal depositional environments and a total basinal desiccation.Conversely, our data suggest that the deeper portion of the Mediterranean Sea was characterized by a permanent water body during the last phase of evaporite deposition.

Fig. 1
Fig. 1 Messinian evaporite lithological associations in the Mediterranean.ODP and DSDP drilling sites are also shown (black dots).

Fig. 3
Fig. 3 A) Thin section photomicrograph of a cumulite rock consisting of fine-grained cubic halite crystals.The crystals show trails of primary fluid inclusions and may have formed at the brine--air interface or in the water column and sunk to the bottom of the basin.Plane polarized, transmitted light.Site 134.B) Thin section photomicrograph of a blocky halite rock showing evidence of recrystallization by grain boundary migration.The large crystals contain a few cubic fluid inclusions, possible relict of primary fluid inclusions trails or secondary in origin, whereas most of the visible fluid inclusions are secondary and grouped at intra-crystalline positions as irregular vermicular structures.Plane polarized, transmitted light.Site 374.C) Thin section photomicrograph of a laminite rock consisting of cumulate graded granular gypsum crystals.These laminae probably represent annual cyclicity Crossed polars, transmitted light.Site 372.D) Thin section photomicrograph of a laminite rock consisting of cumulate graded prismatic gypsum crystals.These laminae probably represent annual cyclicity Crossed polars, transmitted light.Site 654.E) Thin section photomicrograph of a undulate laminated rock consisting of partially reworked cumulate graded granular gypsum crystals.The finer upper laminae are draping the undulate upper boundary of the coarser laminae.The laminae probably represent annual cyclicity.Crossed polars, transmitted light.Site 975.

Fig. 4
Fig. 4 Halite sedimentology and petrography from site 134.A) Halite core section 10 from Site 134 as re-photographed in 1984.B) The crack cutting through a clastic layer as depicted in Hsü et al., 1973b.C) The same core section of the previous picture as shown in a reverse orientation in Hsü et al., 1973a.D) A new cut surface of the same core from the opposite slab shows that the crack is actually extends above and below the clastic layer into the subaqueous cumulate halite rock and is thus more consistent with a post depositional fracture filled with clear halite.E) Core slab of halite cumulite and halite sandy siltstone described in FigFig.2A.F) Thin section photomicrograph of a portion of Fig. E showing the graded halite sandy siltstone (top) and the fine halite cube cumulite (bottom); the lower center part contain very thn veneers of mud (black) draping slightly corroded halite cubes; the mud also penetrates down for a couple of millimeters forming small dissolution pits located at intercrystalline position of corroded halite cubes; transmitted, plane light.G) The same thin section of Fig. F shown at crossed polars; halite is black and the felted anhydrite nodules appears as bright spots; bright tiny polyhalite needles are also common.

Fig. 8
Fig. 8 a) Relationship between primary evaporites facies associations.b) relationships between primary and diagenetic facies.