The Messinian Salinity Crisis caused global climate and ecological effects
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Peer-reviewed literature indicates that the Messinian salinity crisis drove major biological and ecological reorganizations in marine life, while the deposition of massive salt quantities impacted global carbon cycles, atmospheric carbon dioxide levels, and global cooling.
Salt giants are massive salt deposits (hundreds of metres thick) that form during the evaporation of semi-enclosed seas. The drivers of salt giant formation and their feedbacks on global and regional environmental change remain debated. In this Review, we summarize the boundary conditions, causes and consequences of the Mediterranean Messinian salinity crisis (MSC; 5.97–5.33 million years ago). Salt giant formation is more complex than the simple evaporation of an enclosed sea. Instead, the tectonic setting of an evaporative basin largely determines the timing and mode of salt formation, with superimposed impacts of orbital-scale climate and sea-level fluctuations. These drivers triggered precipitation of carbonates, gypsum, halite and bittern salts, with well-defined orbital cyclicities in carbonate and gypsum phases. Removal of Ca2+ during salt giant deposition decouples the oceanic Ca2+ and HCO3− sinks, causing reduced CaCO3 burial and, consequently, increased ocean pH, lower atmospheric partial pressure of CO2, and global cooling. Salt giants, which reflect a net evaporite-ion extraction of ~7–10% from oceans and persist over million-year timescales, could therefore be an important climate driver but are currently underconsidered in long-term carbon cycle models. Future research should use advanced hydrogeochemical models of water–ocean exchange to further explore interactions between salt giants and environmental change. Tectonic processes can lead to the formation of semi-enclosed seas and the deposition of extensive salt deposits. This Review explores the drivers and impacts of the Mediterranean Messinian salinity crisis, including previously underconsidered impacts on the global carbon cycle. Giant salt deposits (gypsum and halite) formed in the Mediterranean during the Messinian salinity crisis (MSC), and their timing and mode depended on tectonic impacts on the evaporative basin. Geodynamic and eustatic sea-level forcing are crucial for initiating and terminating salt giant formation with a subsidiary role for regional climate. The main controls on evaporitic mineral precipitation are the magnitude of freshwater deficit and the extent to which water exchange between basin and ocean is limited. Evaluation of an updated sea-level record for the time interval 6.4 to 5.0 million years ago demonstrates that sea level is a viable driver of the prominent MSC sedimentary cyclicity, in addition to orbital variation in the freshwater budget. The formation and dissolution of giant calcium sulfate (gypsum and anhydrite) deposits can have global consequences as an episodic driver of carbon cycle changes. Oceanic Ca2+ removal via CaSO4 deposition decouples the oceanic Ca2+ and HCO3− sinks, causing a decrease in CaCO3 burial and, consequently, increased ocean pH, lower atmospheric partial pressure of CO2, and global cooling. Most biogeochemical models assume that evaporite precipitation and weathering are balanced over timescales of more than 100 kyr. However, salt giants can reflect about a 7–10% net extraction of evaporite ions from ocean water that persists over million-year timescales, suggesting that current carbon cycle models could be missing an important long-term climate driver. Giant salt deposits (gypsum and halite) formed in the Mediterranean during the Messinian salinity crisis (MSC), and their timing and mode depended on tectonic impacts on the evaporative basin. Geodynamic and eustatic sea-level forcing are crucial for initiating and terminating salt giant formation with a subsidiary role for regional climate. The main controls on evaporitic mineral precipitation are the magnitude of freshwater deficit and the extent to which water exchange between basin and ocean is limited. Evaluation of an updated sea-level record for the time interval 6.4 to 5.0 million years ago demonstrates that sea level is a viable driver of the prominent MSC sedimentary cyclicity, in addition to orbital variation in the freshwater budget. Th
Understanding deep-time marine biodiversity change under the combined effects of climate and connectivity changes is fundamental for predicting the impacts of modern climate change in semi-enclosed seas. We quantify the Late Miocene-Early Pliocene [11.63 to 3.6 million years (Ma)] taxonomic diversity of the Mediterranean Sea for calcareous nannoplankton, dinocysts, foraminifera, ostracods, corals, molluscs, bryozoans, echinoids, fishes, and marine mammals. During this time, marine biota was affected by global climate cooling and the restriction of the Mediterranean's connection to the Atlantic Ocean that peaked with the Messinian salinity crisis. Although the net change in species richness from the Tortonian to the Zanclean varies by group, species turnover is greater than 30% in all cases, reflecting a high degree of reorganization of the marine ecosystem after the crisis. The results show a clear perturbation already in the pre-evaporitic Messinian (7.25 to 5.97 Ma), with patterns differing among groups and subbasins.
The Messinian salinity crisis (MSC) was a short period of isolation of the Mediterranean Sea that caused the precipitation of a million cubic kilometers of salt. The puzzling sedimentary record that formed after this deposition yields conflicting values of the extent of desiccation. Estimations range from a full exposure of most of the Mediterranean seafloor based on shallow fossil fauna found in the abyss to a nearly full Mediterranean scenario as suggested by similar, fresher-water deposits ubiquitous along the coastline: the so-called Lago-Mare formation. Using a landscape evolution model of the drawdown stage constrained with paleoclimate and sediment budgets, we show that the propagation of an erosional wave into the surrounding continents added a gradual sea level rise superimposed on the climatic oscillations of the Mediterranean. This retrogressive river incision along the spillways of the Paratethys and the Pannonian basins also explains the Mediterranean transition to fresher-water conditions during the last stage of the MSC.
Stratigraphic and geochemical evidence suggests that the Mediterranean Sea underwent widespread salinization and a kilometer-scale evaporative drawdown between 5.97 to 5.33 million years ago, during the period known as the Messinian salinity crisis (MSC). The mechanisms responsible for the accumulation of one million cubic kilometers of salt on the sea floor and the impact on terrestrial and marine fauna and on climate are being better understood in the last decades. However, the presence of relatively fresh water sediment containing fossil fauna of eastern (Paratethyan) provenance in the last stages of the MSC poses severe problems to understand the ending of the crisis. These brackish-water deposits, known as the Lago-Mare unit, are sometimes found at elevations close to the present sea level, in apparent contradiction with the coetaneous evaporitic sediment found in deeper, central parts of the Mediterranean. We make use of landscape evolution models calibrated with sediment transport and river incision data to explore plausible scenarios of climate and sea level changes during the MSC. The results show that, upon full isolation, the large initial evaporative sea level fall of the Mediterranean leads to a progressive capture of the waters from nearby lacustrine basins such as the Black Sea or the Pannonian Basin. This drainage area expansion triggers a gradual sea level rise in the Mediterranean. Milankovic climate oscillations superimposed to this trend lead to large-amplitude (500-1000 m) harmonic sea level variations reaching ever-higher levels. This is consistent with the salt precipitation in deeper areas during lowstands and Lago-Mare deposition during highstands in marginal areas. This model may also explain the seemingly contradiction between the high-level Lago-Mare deposits and the km-scale sea level drop estimated from erosion markers and implicit in the Zanclean cataclysmic reflooding model.
About 5.5 million years ago the Mediterranean Sea underwent a dramatic hydrological, environmental and biological crisis, as its connection to the global ocean and water supply was disrupted. This Messinian Salinity Crisis (MSC) left a salt deposit of thousands of cubic kilometers on the basin floor, and caused deep incision of rivers on its margins as they adjusted to a lowered water level. This makes it one of the largest salt deposits on earth, and by far the youngest, least affected by subsequent tectonic events. After 50 years of scientific effort by geologists, geochemists, geophysicists and others some of the large controversies surrounding the MSC remain unresolved. In this talk I will discuss the advances in MSC research since its discovery during the first oceanic drilling campaign in the Mediterranean in 1970, and illustrate how the vast amount of data gathered in these efforts now allow us to use modelling to decipher some of its mysteries.
The latest Miocene (5.96 to 5.33 Ma) is characterised by an outstanding event: the desiccation of the Mediterranean Sea (Messinian salinity crisis). It has been suggested that this was caused by a tectonic event, with no climatic change playing a role in desiccation. Quantifying the climate of the region during this period will help support or refute this hypothesis. An effective method for reconstructing the climate from Neogene pollen data is the “Climatic Amplitude Method” based on the modern climatic requirements of plants to interpret fossil data. It has been conceived especially for peri
The Mediterranean Sea ( MED-ih-tə-RAY-nee-ən) is an intercontinental sea situated between Europe, Asia, and Africa. It is surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Europe, and on the south by North Africa. To its west it is connected to the Atlantic Ocean via the Strait of
The Mediterranean Sea ( MED-ih-tə-RAY-nee-ən) is an intercontinental sea situated between Europe, Asia, and Africa. It is surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Europe, and on the south by North Africa. To its west it is connected to the Atlantic Ocean via the Strait of Gibraltar that separates the Iberian Peninsula in Europe from Morocco in Africa by only 14 km (9 mi); additionally, it is connected to the Black Sea through the Bosporus strait that intersects Turkey in the northeast and the Red Sea via the Suez Canal in the southeast.
The Mediterranean Sea covers an area of about 2,500,000 km2 (970,000 sq mi), representing 0.7% of the global ocean surface; it includes fifteen marginal seas, including the Aegean, Adriatic, Tyrrhenian, and Marmara. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago.
The history of the Mediterranean region is crucial to understanding the origins and development of many modern societies; it is sometimes described as an "incubator of Western civilization" and saw the emergence of some of the earliest and most advanced civilisations, including those of Egypt, Greece, and the Fertile Crescent. The Levant in the Eastern Mediterranean was among the first regions in the world to display permanent human habitation as early as 12,000 BC. The Mediterranean Sea was an important route for merchants, travellers, and migrants in antiquity, facilitating trade and cultural exchange between various peoples as well as colonisation and conquest. The Roman Empire maintained nautical hegemony over the sea for centuries and is the only state to have ever controlled all of its coast.
The Mediterranean Sea has an average depth of 1,500 m (4,900 ft) and the deepest recorded point is 5,109 ± 1 m (16,762 ± 3 ft) in the Calypso Deep in the Ionian Sea. It lies between latitudes 30° and 46°…
Many aquatic plant and seagrass species are widespread and the origin of their continent-wide ranges might result from high gene flow levels. The response of species when extending northwards since the Last Glacial Maximum can be opposed to the structuring of their populations that survived glaciation cycles in southern regions. The peri-Mediterranean is a complex series of sea basins, coastlines, islands and river deltas with a unique history since the Messinian Crisis that potentially influenced allopatric processes of aquatic life. We tested whether vast ranges across Europe and the peri-Me
Figure 6. Schematic representation of three alternative dating scenarios for the Mediterranean clade. A, a tree calibrated by setting the mean uncorrelated relaxed clock rate to 0.02 substitutions per site per million years; B, C, alternative palaeogeographic calibrations based on the Messinian Salinity Crisis with the associated marine regression. Full black circles mark the nodes used as calibration; in B multiple nodes are marked since the dating scenario assumes all of these splits to occur during the shaded period at the latest. The shaded ranges depict (part of) the uncertainty associate
region and a global fall in sea levels combined to cause a temporary drying up of the Mediterranean Sea (known as the Messinian salinity crisis) near the end
The Miocene ( MY-ə-seen, -oh-) is the first geological epoch of the Neogene Period and extends from about 23.04 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell and comes from Ancient Greek μείων (meíōn), lit. 'less', and καινός (kainós), lit. 'new' or 'recent', and thus means "less recent", because it has 18% fewer modern marine invertebrates than the
The Miocene ( MY-ə-seen, -oh-) is the first geological epoch of the Neogene Period and extends from about 23.04 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell and comes from Ancient Greek…
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