Messinian salinity crisis and its paleogeographical implications

Ruggieri, G.; Sprovieri, Rodolfo

doi:10.1016/0031-0182(76)90022-5

Cited by 38 publications

(13 citation statements)

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“…On the flank of the Strabo Mountains, an assemblage of ostracods ( Cyprideis pannonica ) and benthonic foraminifera ( Ammonia beccarii tepida ) adaptive to the hypohaline milieu (Benson, 1973a,b) was discovered. An identical assemblage appears in the topmost Gessoso Solfifera Series in Sicily where it has been correlated to the ‘lac mer’ fauna of the Paratethys (Decima, 1964; Ruggieri, 1967; Ruggieri & Sprovieri, 1974, 1976). Conclusive evidence of the abrupt drowning of lakes and exposed land at the conclusion of the MSC was obtained during drilling in the Tyrrhenian Sea where silty clay rich in pollen and spores and mud with freshwater fauna were covered abruptly by deep‐sea marine oozes.…”

Section: Discoveries From the First Deep‐sea Drillingmentioning

confidence: 87%

Decoding the Mediterranean salinity crisis

2008

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This historical narrative traces the steps to unravel, over a span of 40 years, an extraordinary event in which 5% of the dissolved salt of the oceans of the world was extracted in a fraction of a million years to form a deposit more than 1 million km 3 in volume. A buried abyssal salt layer was identified with reflection profiling and sampled during the Deep Sea Drilling Project, Leg 13. The dolomite, gypsum, anhydrite and halite in the drill cores paint a surprising picture of a Mediterranean desert lying more than 3 km below the Atlantic Ocean with brine pools that shrank and expanded by the evaporative power of the sun. The desert drowned suddenly when the Gibraltar barrier gave way. The explanation of 'deep-basin, shallow-water' desiccation and the notion of a catastrophic Zanclean flood had a mixed reception. However, the hypothesis became broadly accepted following subsequent drilling expeditions. Nevertheless, as experts examined the evaporate facies and sequences of equivalent age in the terrestrial outcrops, weaknesses appeared in the concept of repeated flooding and drying to account for the magnitude of the deposits. The 'Rosetta Stone', used to decipher conflicting interpretations, turns out not to be the deposits but the erosion surfaces that enclose them. These surfaces and their detritus -formed in response to the drop in base level during evaporative drawdown -extend to the basin floor. Evaporative drawdown began halfway through the salinity crisis when influx from the Atlantic no longer kept up with evaporation. Prior to that time, a million years passed as a sea of brine concentrated towards halite precipitation. During the later part of this interval, more than 14 cyclic beds of gypsum accumulated along shallow margins, modulated by orbital forcing. The thick salt on the deep seabed precipitated in just the next few cycles when drawdown commenced and the brine volume shrank. Upon closure of the Atlantic spillway, the remnants of the briny sea transformed into salt pans and endorheic lakes fed from watersheds of Eurasia and Africa. The revised model of evaporative concentration now has shallow-margin, shallow-water and deep-basin, deep-water precursors to desiccation.

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Section: Discoveries From the First Deep‐sea Drillingmentioning

confidence: 87%

Decoding the Mediterranean salinity crisis

2008

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“…References: Bandy (1973), Van Couvering et al (1976), Ruggieri (1958Ruggieri ( , 1967, Ruggieri and Sprovieri (1976), Debenedetti (1976), Rouchy (1982a,b).…”

Section: The Deep-basin/ Deep-water Modelmentioning

confidence: 99%

“…It has been foundassociatedwithother caspi-brackishostracodes as mentioned above, especially Euxin ocythere, Tyrrhenocythere, and Loxoconcha djaffarovi (L hodonica of Sissingh, 1972) and fresher water ostracodes like Limnocythere.As stated above, it is often found withother fossilforms, including the lagoonal foraminifer Ammonia beccarii tepida, the mollusks Congeria, Melanopsis, Melanoides, and also oligohaline diatoms (notably Sites 375 and 124; Schrader and Gersonde, 1978), and with charaphytes (in Spain; a nodose form was found with bird tracks and dragonfly larvae; Roep and van Harten, 1979;see alsoPagoier,1978;Decimaand Sprovieri,1973;Sturani. 1973;Ruggieri and Sprovieri, 1976;Geerlings et al;. Cypndeis first evolvedin the middle Miocene and spread through lagoons, estuaries and hyperalkaline or saline lakes all over the world.…”

Section: The Caspi-bracldsh Faunasmentioning

confidence: 99%

Biodynamics, saline giants and late miocene catastrophism

Benson

1991

Carbonates Evaporites

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and Krona Rakic-EI Bied 12Avenue deFrance Rabat, MoroccoABSfRAcr: The Messinian Salinity Crisis is several crises that fit the context of catastrophic modeling of the history of a Mediterranean "saline giant." Ofthe explanations available, we prefer the deep-basin/deep-water precipitation model for the early, deep-basin, massive gypsums and halites, contemporaneous with marginal, lagoonal gypsums; and the deep-basin/shallow-water desiccation theory to explain the later, shallow cyclic gypsums with associated logo mare faunas. The western basins before and after the Crisiswere deepenough to maintain intermediate oceanicwater-masses, which is not possible today because ofshallowthresholds.Early Pliocene mean paleodepths ofthe western basinswere at least in the order of than 1500m, which is the mean depth of the present Mediterranean. Tectonic changes in the threshold to the Atlantic were responsible for the isolation of the Paleo-Mediterranean during a eustatic high stand, followed by regression consequent to the evaporite precipitation phases.The context of Messinian stratigraphy has changed to include more events leading up to the Crisis. It began with evaporite deposition in the eastern basins during the Tortonian, and served to concentrate saline bottom-waters that later overflowed across the Pelagian Sea toward the west. In the western basins, it started at 6.4 Ma with a general water-budget deficit that altered the inflow over the threshold in the Rifian Corridor. A time of unusually high organic productivity and water-mass stratification followed, contemporaneous with evaporite deposition in some of the marginal seas and lagoons.Massive gypsum and halite deposition took place in the deep western basin in Chron 5 between 5.4 and 53 Ma. Our studies in Morocco and Spain indicate that passages to the Atlantic were closed during the cyclicgypsum and "lago mare" deposition, which took place during the long negative polarity reversal ofChron Gilbert from 53 to 4.9 Ma. We doubt that there were multiple marine inundations from the Atlantic into the Mediterranean after the first drawdown. The Rifian Corridor was closed by olistostromes at about 5.5 Ma. The last "leak" through the Gibraltar Barrier probably occurred in a passage through Oued Laou in northern Morocco at 5.4 Ma. The Oued Laou valley, which now forms a gorge through the Rif Mountains, could have furnished the influx of enough marine water in 27,000 years to furnish the nearly kilometer thick salt deposits of the deep Mediterranen basins.Gypsum deposits associated with shallow Paratethyan caspi-brackish (less than 8 0/00 salinity) ostracode and mollusk faunas, in the lower parts of both the Tyrrhenian and Algero-Provencal Basins, show that water depths in the deep basins changed from more than 1000 m to in the order of 100 m or less. However, faunal alternations typical of playa deposition are missing. The chemical composition of both gypsum and fossil shells indicate significant meteoric water, signaling a "fresh-water crisis." It is probable that phreati...

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“…The laminated gypsum passes upwards into massive beds of crystalline gypsum of the form termed 'cavoli'. Ruggieri & Sprovieri (1976) suggested the Pasquasia member formed in a 'lago mare' in which the waters were entirely meteoric in their origin, the marine fauna were entirely reworked and the sulphate originated from the dissolution of the underlying Cattolica member. Alternatively, this cycle may be interpreted as having formed as a result of a largescale marine inundation (refreshment) and consequent evaporation and concentration.…”

Section: Subtidal To Intertidal Environmental Cyclementioning

confidence: 99%

Depositional environments of Upper Miocene (Messinian) evaporite deposits of the Sicilian Basin*

et al. 1976

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In Sicily, Messinian evaporitic sedimentary deposits are developed under a wide variety of hypersaline conditions and in environments ranging from continental margin (subaerial), to basin‐margin supratidal, to intertidal, to subtidal and out into the hypersaline basin proper. The actual water depth at the time of deposition is indeterminate; however, relative terms such as ‘wave base’ and ‘photic zone’ are utilized. The inter‐fingering relationships of specific evaporitic facies having clear and recognizable physical characteristics are presented. These include sub‐aerial deposits of nodular calcium sulphate formed displacively within clastic sediments; gypsiferous rudites, arenites and arenitic marls, all of which are reworked sediments and are mixed in varying degrees with other clastic materials (subaerial, supratidal, and intertidal to deep basinal deposits). Laminated calcium sulphate alternating with very thin carbonate interlaminae and having two different aspects; one being even and continuous and the other of a wavy, irregular appearance (subtidal, intertidal, and supratidal deposits). Nodular calcium sulphate beds, usually associated with wavy, irregular laminated beds (supratidal, sabkha deposits); very coarsely crystalline gypsum beds (selenite), associated with more even, laminated beds (subaqueous, intertidal to subtidal deposits); wavy anastomozing gypsum beds, composed of very fine, often broken crystals (subaqueous, current‐swept deposits); halite having hopper and chevron structures (supratidal to intertidal); and halite, potash salts, etc. having continuous laminated structure (subaqueous, possibly basinal). Evidence for diagenetic changes is observed in the calcium sulphate deposits which apparently formed by tectonic stress and also by migrating hypersaline waters. These observations suggest that the common, massive form of alabastrine gypsum (or anhydrite, in the subsurface) may not always be ascribed to original depositional features, to syndiagenesis or to early diagenesis but may be the result of late diagenesis.

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Messinian salinity crisis and its paleogeographical implications

Cited by 38 publications

References 1 publication

Decoding the Mediterranean salinity crisis

Decoding the Mediterranean salinity crisis

Biodynamics, saline giants and late miocene catastrophism

Depositional environments of Upper Miocene (Messinian) evaporite deposits of the Sicilian Basin*

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