Talk:Messinian salinity crisis

Hydrothermal Salt

There's a new theory for salt formation . This theory is in development by a research group headed by Martin Hovland called "Hydrothermal salt theory", of salt formation was proposed recently. Salt rocks also form by replacement of carbonate rocks by salts. This new theory of salt deposition is related to deep origin where supercritical water loss molecular polarity and capacity of dissolution of salts and then salt from brines are deposited by hydrothermal processes in deep water, carried by non-polar water, mainly during early opening ocean after processes of rift systems. Salt rocks is frequently associated with volcanism. Based on Hydrothermal Salt, it's not necessary dry Mediterranean Sea to form salt deposits. —Preceding unsigned comment added by 186.205.173.212 (talk) 01:39, 12 December 2010 (UTC)

Effects on Black Sea

Does anyone have any further information about its effect upon the Black Sea? I recently read a book by David Gibbins (Called "Atlantis") in which he proposes that the Black sea would have had a different shoreline a lower level with it being isolated by the Bosporous. Just wondered if there was any evidence of this and whether it would make a useful addition to this page?

The Black Sea doesn't get most of its water from the Mediterranean, and the closing off and reopening of the Bosphorus happened most recently thousands of years ago (not millions, as with the Strait of Gibraltar). AnonMoos 07:35, 9 July 2006 (UTC)

Factual errors

I'd just like to point out for the interested reader that there are numerous factual errors in this article. These are not really substantial to the casual reader though. It is now estimated that sealevel only dropped 1500 m [1], though some articles suggest 2000 m. Also, DSDP leg 13 did not recover evaporites beyond a small piece of halite. This evidence came later. Hopefully I will be able to come back and modify the article soon, but there are quite a few facts that I would need to verify that are currently in this article. --129.173.105.28 15:57, 14 November 2005 (UTC)

• The Med sea level was likely at different levels at different times. At some times the Med was receiving much water from a lake called Lac Mer in the Hungary area, until the flow was cut off when the mountains of ex-Yugoslavia (Dinaric) arose. The buried Nile canyon found under Cairo (by deep drilling) proves at least 2400 meters depth at some times. Without the salt and silt that has accumulated, sometimes the depth was likely even deeper than if the Med dried out now. To alter a poem that Coleridge wrote: When Nile the sacred river ran / through canyons measureless to man / down to a hot dry sink. Anthony Appleyard 23:03, 10 December 2005 (UTC)

Autochthony writes. '. . . limit of the Labours of Hercules' - I suggest that this refers to the Pillars of Hercules. Autochthony wrote 2155z 7th November 2009. 86.151.60.238 (talk) 21:55, 7 November 2009 (UTC)

Capitalisation

Is there any reason why this is at Messinian Salinity Crisis rather than Messinian salinity crisis? Neither of the quoted references uses capital letters. --OpenToppedBus - Talk to the driver 12:17, 1 February 2006 (UTC)

OK, I decided to be bold and just move it. --OpenToppedBus - Talk to the driver 09:52, 2 February 2006 (UTC)

Fascinating

This is extremely interesting. Thanks to those who took the time to create this article. Well done...wish they taught more of this stuff in school! CoachMcGuirk 20:35, 14 April 2006 (UTC)

When did it fill back up?

• It was not clear from the article when the basin filled back up again. 06:46, 15 January 2007 User:24.6.103.21
• Answer inserted. Anthony Appleyard 07:36, 15 January 2007 (UTC)

Sahara expansion

I have chosen to withdraw the conjecture that evaporation from the Mediterranean has a significant effect upon the extent of the Sahara in central (latitudinal) Africa. Any effect would have been subtle, and the the area has had at most a slight influence upon human history. I have chosen instead to suggest that pre-modern civilizations in the Mediterranean basin would have been far different even had they existed. Ancient Egypt would have had a deep hot canyon that could have pushed human habitability beyond its capacity. All parts of the eastern Mediterranean would have been drier and with harsher extremes of temperature, and the economic basis of any intellectual or religious life would not have existed, and the absence of any sea to allow access over a wide area of disparate lands would have left all of them, especially the islands of the region, extremely isolated instead of connected. Paul from Michigan 03:34, 6 February 2007 (UTC)

Source citations needed. (SEWilco 06:20, 6 February 2007 (UTC))

The World Turn'd Upside Down

I use Arnold Toynbee's model of civilizations to connect physical geography to connect large-scale history to environmental shaping of human activity. All that I can do is to paraphrase Toynbee's voluminous A Study of History, a work not yet in the public domain. Toynbee suggests as a rule that civilization arises most readily at an optimal level of challenge and reward to those who live in an area. The Mediterranean basin to this day provides adequate foodstuffs in good variety to large populations, as it did in antiquity, but not without requiring some adjustments to circumstances. Farming is possible if one adjusts to the summer droughts of the region, which means that people must store enough foodstuffs to last through a long dry summer. (Egypt has the opposite situation; its floods occur in summer and they allow food production). Fishing is possible as a supplement, but the Mediterranean Sea has relatively sparse fishing, so fish must be a supplement. Trees are large but scattered, and enough variety of trees exist to allow the addition of nutritious fruits and nuts to a diet; they rarely form dense forests that must be cleared for agriculture. Ranching is possible, in contrast to nomadic herding that characterises steppes and the milder deserts; ranching requires law and record-keeping. The Mediterranean world requires trade, seafaring, record keeping, and law, clear characteristics of civilization. Literacy becomes a necessity, at least among elites.

Civilization could appear elsewhere in ancient times (east Asia and South Asia, the Yucatan Peninsula, the highlands of Mexico and Peru, Persia, and the Tigris-Euphrates valley with little or no influence from Mediterranean civilizations, but not in any world of large enclosed waterways. The Black Sea area was an adjunct to the civilizations of the Mediterranean region, and the Caspian Sea abuts steppes to the north and west and harsh desert to the east, and the Elburz Mountains cut it off from Persia. If one ignores the terrain and the climate, the Baltic Sea looks much like the Mediterranean -- but the terrain is relatively homogeneous, and until the Middle Ages it was surrounded by dense forests that had to be cleared if agriculture was to occur. Civilization appeared in the Baltic region only during the Middle Ages when large-scale forest-cutting became possible, and without doubt under the influence of Mediterranean cultures. The Great Lakes of North America (note what I call myself) also have some superficial similarity to the Mediterranean region as large bodies of water, but as in the Baltic basin the terrain is remarkably uniform. The region was populated by hunter-gatherers until modern times, when people whose culture clearly derived from Mediterranean civilizations (the Dutch, French, and English) began to clear dense forests for farmland and started exploiting the lakes as inland seas.

Toynbee suggests that conditions can soft enough for hunter-gatherers to persist indefinitely, as in the African "Great Lakes" region in which temperatures are uniform and foodstuffs are plentiful for small populations.

To be sure, the highest material and intellectual achievements reflect the refined geniuses of the likes of Euclid -- but some environments make such a person irrelevant despite his potential. I can see Euclid as one that conditions made necessary (he was as much a master of logic as of mathematics), but someone who would have been irrelevant in most places. If you are to discuss classical Greece, one recognizes that trade and foodstuff storage made record-keeping and architecture necessary, and that legal disputes and political debates that required shrewd argumentation were best made by those who had well honed their skills in formal logic before becoming lawyers and politicians, something that Euclid's Elements did very well.

Intellectual greatness as a rule requires extreme refinement of technique -- but the technique as a rule requires an economic foundation. No marble -- no Michelangelo. No patrons (for the lack of economic surpluses) -- no Michelangelo. No heritage of technique -- no Michelangelo. One can say much the same of Isaac Newton and Johann Sebastian Bach.

If the Mediterranean Sea basin had continued to be blocked off from Atlantic waters to this day, then not only would the physical world be wildly different to now, but so would the intellectual world. The classical civilizations from Egypt to Greece, Rome, and Carthage would ever have existed. Even if the ice sheets had retreated and opened the lands of northern Europe to human settlement (a dessicated Mediterranean might have made the Ice Age more severe), civilization would have formed later than otherwise in the lands around the Baltic and North Seas; Irish, English, German, Scandinavian, Polish, and Russian civilization owe much to Rome and Greece. Perhaps the Chinese and Japanese would have reached the New World instead of Europeans -- but not with any heritage of Athenian or Icelandic democracy. Perhaps the Aztecs would have successfully expanded their civilization into the temperate regions of North America... and the area around the southwestern shore of Lake Michigan would look far different from the Chicago and Milwaukee that we know, and with far-different institutions. Even the Italian Renaissance might not have occurred, as there would have been no ancient culture to exploit.

In religion? Monotheism appeared for a short time in Egypt and took deep root in Judea. Monotheism requires some intellectual sophistication, something unlikely to arise in the Levant. The absence of Abraham implies neither Moses, Jesus, nor Mohammed. Maybe we would have some fusion of Zoroastrianism and Buddhism throughout the world. Who knows?

If anything, the responsibility to prove that the world would be much the same lies upon anyone who seeks to claim that the world, materially and intellectually, would be much the same except in the areas around the Mediterranean Sea. I have my doubts that we would be having this discussion if the Mediterranean basin were permanently emptied of water; the knowledge and technology would probably not exist.

To be sure, Wikipedia has an invariable bias toward humanity for the simple reason that only members of Homo sapiens make contributions. It also has a bias toward literate, civilized persons because any remaining pre-literary and pre-technological persons make no contributions. That said, I prefer humanity to whatever low life might thrive in a saline pressure cooker utterly unsuited to humanity. --Paul from Michigan 19:00, 10 February 2007 (UTC)

yikes, that was a rant :) the best thing to do in a situation like this is to either question speculative statements, demand a source, or even remove them completely. 131.111.8.97 16:01, 12 February 2007 (UTC)

I use convection and circulation around a candle as a model for the hot Mediterranean desert causing a plume of upward air flow which draws in air across all the surrounding continents, producing rain forests all around it. Explorers from the Inca empire would have lined the Sahara rain forest cliff tops with stepped stone pyramids. (SEWilco 20:12, 12 February 2007 (UTC))

Truly, SEWilco, you must be joking, and I concede that you have a great punchline -- but poor history and science. The Incas were not a seafaring people. The heating of air upon the dried seabed would have been entirely adiabatic. Adiabatic heating is entirely reversible, and it would not lead to convectional flow of air masses. As air is changed in pressure with no change in chemical composition it becomes hotter in proportion to pressure in absolute temperature.

No evidence exists of any tropical rainforests in the Mediterranean basin at any time during the Pleistocene era (I will cite Jonathan Adams' Pleistocene Atlas when I find it) and his vegetation maps show that the northern Sahara at its moistest was "mere" grassland away from the coast and Mediterranean dry forest no more than a couple hundred kilometers away from the coast in a time in which summers were warmer and winters were cooler than now due to different points of apohelion and perihelion during the year. Thus if you take air at the freezing point of water (the pressure relates to absolute temperature in degrees Kelvin), then the temperature rises from 273°K (0°C) to 546°K (273°K), and if you reduce the pressure by a half, then the temperature goes down to 137°K or -137°C if you don't account for phase changes within the gas. In meteorology, air masses are observed to obey the perfect gas law very well.

So suppose that some cold air funnels down through the valley of the Rhone or the Po from near the glacial front of the Alps at a temperature at modern sea level of the freezing point for water, 273°K (0°C). Even without added heat from any other source, for example if the Mediterranean seabed is completely shrouded in thick clouds (which I have no cause to assume) so that the air cannot be heated by the sun or be heated by warm sun-baked rocks or water, exposed volcanic vents, or a localized greenhouse effect, an increased pressure of 25% raises the absolute temperature by 25%, or about 68°K to 68°C, which is quite unpleasantly hot for mammalian life. Proteins gelatinize at lower temperatures. That's slightly more than 150° F, which is higher than the record land temperature in modern times. Water at such a temperature would scald one. The pressurized air would warm the rocks and any water even without sunlight reaching the sea floor.

But adiabatic heating is reversible, so once some other flow of air pushes pressure-heated air out of the Mediterranean basin the air forced aside itself chills to temperatures normal for the time and place -- much chillier than they are now.

Jonathan Adams[2] has a series of maps of Europe and northern Africa that show the sorts of vegetation characteristic of various times duting the Ice Age. All times of lower seashores correlate to greater volumes of ice sheets, and all such times correspond with drier conditions throughout the Mediterranean basin. Although Adams does not treat the dessication of the Mediterranean as essential to his model, any time of lowered sea shores implies the expansion of deserts into places where deserts are not to be found now and not only into lowered sea shores. The lands to the north of the Mediterranean Sea and such islands as Corsica, Sardinia, Sicily, and Crete become dry grassland comparable to the American High Plains today. At some times the eastern part of the Mediterranean -- the Levant and most of Turkey -- basin becomes 'semidesert', which may or may not imply the disappearance of the Mediterranean Sea.

It can be safely said that when the Mediterranean Sea was dried out in whole (due to the closing of the Straits of Gibraltar) or in part (due to glacial-era lowering of sea levels), the region was always less pleasant for human life, less suitable for dense settlement characteristic of ant classical civilization, and less easily (if at all) traversible. Jonathan Adams has the great sources that I don't.

As for the rise of civiliaztion in the Mediterranean basin: we know the general timeline, and even the earliest civilization in the region (Egypt) apears after the retreat of the glaciers. The other civilizations of the Fertile Crescent (especially Judea, Phoenicia, Sumer, and Mesopotamia) appear later, as do Greece and Persia. Mesopotamia, Sumer, and Persia apparently appeared independently of Egypt, but without doubt ancient Greece, Judea, and in turn Rome and we moderns can trace our heritage of civilization more to Egypt than to either Sumer, Mesopotamia, or Persia.

Does anyone question that without a water-filled Mediterranean Sea, even without the expanded glaciers of glacial maxima, that the world would be very different, at least in its history? Even if civilization had spread to western Europe from Persia and Mesopotamia instead of from Egypt through Greece it would have been very different, and would have spread with greater difficulty without the milder climates and easy transportation that the Mediteranean provides. --Paul from Michigan 00:46, 20 February 2007 (UTC)

"If the Mediterranean hadn't reflooded"

The list of possible effects if the Mediterranean hadn't reflooded is pure speculation, with no references cited. The entire course of human history would have been altered beyond recognition, and picking a few random changes that might have occurred around its coast is completely arbitrary. I'm going to remove the whole list unless someone provides a citation. Hiding it in the "Popular culture" section (which also ought the be removed entirely, but that's another debate) is no excuse for not citing sources.James A. Stewart 01:05, 21 April 2007 (UTC)

I deleted it several times. Sink it again. (SEWilco 04:56, 21 April 2007 (UTC))

• Which text are you referring to?

  Messinian salinity crisis#Dehydrated geography is about real-time-line conditions in late Miocene times, except perhaps the last sentence of paragraph 6.

  Messinian salinity crisis#In popular culture does not take up much space, and very many Wikipedia pages have "In popular culture" sections. Leave it alone. Can we have a discussion or vote on this?

  Anthony Appleyard 05:26, 21 April 2007 (UTC)

I'm referring to the items marked by "citation needed" which are speculation with no references cited. (SEWilco 05:39, 21 April 2007 (UTC))

The text involved is here:

---

In popular culture

There had been speculations about a possible dehydration of the Mediterranean Sea in the distant past, even before geology developed.

• In the first century, Pliny the Elder recounted a popular story in his Natural History according to which the Mediterranean Sea was created when the Atlantic ocean gained admission through the Strait of Gibraltar:

At the narrowest part of the Straits, there are mountains placed to form barriers to the entrance on either side, Abyla in Africa, and Calpe in Europe, the boundaries formerly of the Labours of Hercules. Hence it is that the inhabitants have called them the Columns of that god; they also believe that they were dug through by him; upon which the sea, which was before excluded, gained admission, and so changed the face of nature.

• 

  Wells' 1920s speculative map of 50,000 years ago

  In 1920, H. G. Wells published a popular history book in which it was suggested that the Mediterranean basin had in the past been cut off from the Atlantic. One piece of physical evidence, a deep channel past Gibraltar, had been noticed. Wells estimated that the basin had refilled roughly between 30,000 and 10,000 BCE. The theory he printed was that:
  • In the last Ice Age, so much ocean water was taken into the icecaps that world ocean level dropped below the sill in the Strait of Gibraltar.
  • Without the inflow from the Atlantic, the Mediterranean would evaporate much more water than it receives, and would evaporate down to two large lakes, one on the Balearic Abyssal Plain, the other further east.
  • The east lake would receive most of the incoming river water, and may have overflowed into the west lake.
  • All or some of this seabed may have had a human population, where it was watered from the incoming rivers.
  • There is a long deep submerged valley running from the Mediterranean out into the Atlantic.
  • (Modern research has shown that Wells' theory is incorrect. All the geological and plant-fossil evidence shows that the Mediterranean did not dry out during the last ice age. Sea levels were 120m lower than today, resulting in a shallower Strait of Gibraltar and a reduced water exchange with the Atlantic, but there was no cut-off.)
• Atlantropa, also referred to as Panropa, was a gigantic engineering and colonization project devised by the German architect Herman Sörgel in the 1920s and promulgated by him until his death in 1952. Its central feature was a hydroelectric dam to be built across the Strait of Gibraltar, and the lowering of the surface of the Mediterranean Sea by up to 200 metres. Similar projects have appeared in fiction.
• Poul Anderson's Time Patrol story "Gibraltar Falls" (1975) takes place while the Atlantic begins to fill the Mediterranean Sea; here "falls" means "waterfall".
• Harry Turtledove's novella "Down in the Bottomlands," which takes place on an alternate Earth where the Mediterranean Sea stayed empty, and void of water, and part of it is a national park to the countries around it, none of which are nations that we are familiar with in the real world.
• An early Dan Dare science fiction comic story says as a side remark that (in its time line) the Mediterranean stayed dry until Neolithic times and was flooded by alien spaceships exploding, breaking the Strait of Gibraltar open.
• The episode "The Vanished Sea" of the Animal Planet/ORF/ZDF-produced television series The Future Is Wild posits a world 5 million years in the future where the Mediterranean Basin has again dried up, and explores what kind of life could survive the new climate.
• Julian May's 1980s science fiction books The Many Colored Land and The Golden Torc are set in Europe just before and during the rupture at Gibraltar. The rupture and the rapid filling of the Mediterranean form a Wagnerian climax to The Golden Torc, in which aliens and time-traveling humans are caught up in the cataclysm.
• The Gandalara Cycle by Randall Garrett and Vicki Ann Heydron chronicles the adventures of Ricardo, a modern earth man, sent into the past, where he discovers an entire civilization at the bottom of the dry Mediterranean.
• Wolfgang Jeschke's time-travel novel, The Last Day of Creation, happens 5 million years ago, while the Mediterranean bed was dry.
• xkcd webcomic number 1190, Time, constitutes time lapse frames of a story, with the comic's image updating every 30 minutes initially, and later every hour. The story began with a male and female building a sandcastle on a beach, and later going on a quest to find why their sea was rising. After over three months of regular updates to the story, the story's author revealed that he based the story in a world where the Mediterranean Sea has dried off over long period of time, but recently started refilling.

---

References

40 year gap

There presently is a gap of about 40 years (1920-1961) in the discovery of clues of the crisis. I think I still have one source on the topic which I'll check again. (SEWilco 18:44, 6 June 2007 (UTC))

H.G. Wells

As much as I like his novels, I think it is inappropriate that this article should have an entire (lengthy) paragraph almost solely devoted to speculations on the part of H.G. Wells before even starting to treat the subject itself. Wells was not a scientist and his thoughts on this phenomenon are indeed speculative, and as such they lack relevancy. This way we could include entire sections of similar speculative thought by lay individuals about natural phenomena in lots of other articles, which we don't. The connection with the actual Messinian Salinity Crisis is weak; Wells speculates about an event which he thought might have taken place during the last Ice Age (not the Miocene), when nothing happened that may come close to a drying up of the Mediterranean, and he thought the Mediterranean plains would have been fertile, which they obviously weren't. In my opinion, Wells' views, if they are to be mentioned, should be much less prominently featured than they are now. Iblardi 19:41, 6 June 2007 (UTC)

It's a non-fiction history book, which is why I used phrases such as "thought" and "believed". He shows that there was awareness that the basin might have dried up, and at least one clue had been noticed before 1961. (SEWilco 01:50, 7 June 2007 (UTC))

Gibraltar strait "permanently" open?

On serveral places in the article it is said that the Gibraltar strait is now permanently open. Given evidence that the Mediterranean has dried up several times in the past, is it not realistic to think it will happen again? Drhex 21:23, 30 July 2007 (UTC)

Possibly, but an open Strait of Gibraltar has been present for the last 5.odd million years, which can count as "permanent". The Messinian Crisis was only of short duration compared to that time span. Iblardi 21:45, 30 July 2007 (UTC)

Check out Pangaea Ultima. I know it's only hypothetical, as it is a projected future, but is most likely that Gibralter will close off again. It is not contested that Africa is moving north into Europe. There's an illustration at [3]. Of course, if the sea levels rise much, it may be a moot point. samwaltz 23:10, 30 July 2007 (UTC)

Sure, given the general pattern of plate tectonics in that region it is more than likely that it will happen again. Go ahead and mention it. "Permanently" in this context is only relative of course, i.e. counting from ~5 million years ago up to our present day. Iblardi 10:35, 31 July 2007 (UTC)

Pressure and temperature at the dried-up abyssal plain

I wonder about the temperature and pressure at the lowest bottom of the dried-up Mediterranean basin. Can anyone calculate it? I assume an “altitude” similar to the deepest places in the Mediterranean Sea today. Also, global temperatures where higher 5 – 6 million years ago. So present-day Spain, Portugal and Morocco might have been tropical. Could liquid water exist on the bottom of the dried-up abyssal plain? Even if it could temperatures might have been above 150°C. If so the area would have been lifeless since no known cellular mechanisms would work properly at such temperatures. In other words not even the hardiest of heat-loving bacteria would had survived.

2007-12-08 Lena Synnerholm, Märsta, Sweden. —Preceding unsigned comment added by 85.229.19.152 (talk) 17:33, 8 December 2007 (UTC)

I was probably too generalising about the climate at the time. The time span of tried-up Mediterranean episodes is 700,000 years. With an ice-age cycle of 96,000 years this equels to 7 1/3 cycle. During interglacials the climate in the regions where probaly as I described them. During ice-ages global climate might have been as today or even colder. Still, I wounder if anyone can calculate the temperature and preasure on the bottom of the dried-up abyssal plain.

2008-01-19 Lena Synnerholm, Märsta, Sweden. —Preceding unsigned comment added by 85.229.19.152 (talk) 18:21, 19 January 2008 (UTC)

It wouldnt be that hot. The most you could hope for would be about 70°C in the summer, with 80°C on some very extraordinarily hot days. And the fact that the Earth was warmer then would have little effect, because the tropics dont usually warm as much when that happens (with some exceptions, e.g. the Permio-Trassic extinction event.) I am going to write in this article soon, but all I will say is that the answer is unknown. Soap ^Talk/_{Contributions} 19:33, 30 July 2008 (UTC)

Can you please calculate the pressure too? The combination of heat and pressure may not had allowed for liquid water.

2008-10-04 Lena Synnerholm, Märsta, Sweden. 11:04, 26 August 2009 User:212.247.167.70

the higher pressure the more likely water is liquid (just high school physics:). But i like a section about climate condition during time 5 Mya when the hot climate was essential to human evolution. One of theory is that the extreme hot temperature was critical to our prehistory. On the beaches of drying sea there should be a lot of well preserved (salted) herrings or other kind of fish. The monkey may get reason to go deep in the hot zone to become human. TN 76.16.176.166 (talk) 02:20, 27 May 2009 (UTC)

• As the sea retreated, any fish would swim to deeper water, and die when the water got too salty. Thus would not happen often enough to support a population of monkeys. Anthony Appleyard (talk) 04:19, 27 May 2009 (UTC)

I don’t think the drying-up of the Mediterranean Sea has anything to do with human evolution. First, at the time in question our ancestors still lived in forest and open woodland. Secondly, the northernmost fossil from the period – nicknamed Toumaï – was found in Chad. Thirdly, the genus of humans (Homo) evolved 2.6 million years ago. Until then, our ancestors had had brains about the size of a chimp’s. On the other hand it is true that higher pressure means higher boiling point for water. What I originally wondered was: could there have been any pools of liquid water on the dried-up ocean floor? If so thermophilic bacteria may have survived down there but probably nor other life.

2009-08-25 Lena Synnerholm, Märsta, Sweden. 11:04, 26 August 2009 User:212.247.167.70

This is a comment rather than a direct edit. I am not a meteorologist, so do not claim expertise. I am simply commenting based on my general knowledge of physics and simple mass-balance and energy-balance considerations. I will leave it to the original author to respond to my comments appropriately if they are judged accurate.

The ground temperatures at the bottom of the dry basin cannot be determined by the adiabatic calculation because the air masses you are moving will gain or lose heat (are not adiabatic) and the basin is already filled with air at the final pressure. You are not continually delivering newly-compressed air with its heat content into the bottom of the basin without displacing an equivalent amount of air elsewhere in the basin that will be removing nearly the same amount of heat. It is not the same amount of heat, of course, because the older air has lost some of its heat by radiating some of that into the atmosphere as a result of its higher temperature. The heat content of air masses change due to warming effects from the sunlight-warmed ground surface below and cooling effects due to direct radiation into space. Water vapor effects in heat transmssion are also great, but we will ignore that for the hypothesized dry air. If the air in the basin were stagnant, such that no adiabatic effects would be present at all, the temperature at the floor of the dry Mediterranean would be whatever the surface albedo and atmospheric conditions produced. As you begin moving in new air, you will have the adiabatic effect but have to also include the effects of mixing of this with the existing, lower temperature air already there and the increased radiation loss rate of higher temperature air. A meteorologist would have to address this to clarify the proportions, but the temperatures at the bottom of the basin, while probably affected by this adiabatic heating, may well be more affected by the heat loss and gain from the air masses than by simply converting a hypothetical constant air-mass heat content to temperature based on the increase in pressure.

An additional factor is related to the fact that air density is related to temperature as well as the pressure. Warmer air at any particular elevation is less dense than cooler air at that elevation. While the air pressures may balance at a particular elevation, if you go upwards within adjacent air masses of different temperatures, the pressure exerted by the denser mass will decrease faster than the pressure exerted by the less dense mass. This causes the less dense air (with greater pressure at the greater height) to move above the denser and the denser under the less dense, so the less dense air becomes buoyant and moves upwards.

Now consider the Mediterranean Basin. It will be filled with air at some temperature and have an air column with pressures reflecting both elevation and temperature of the air within the column. Assume a continental wind brings a dry air mass laterally across the boundary of the basin. There may be viscous effects by which flowing air masses can entrain air below to make space for descending air, but for now I will look at it purely hydrostatically. For this air mass to quiescently descend into and displace the air already there, that air would have to be more dense on reaching the floor of the basin than the air already there. However, the increasing density of the descending air is partially counteracted by the adiabatically increasing temperature of that air. If the air already on the basin floor is hotter than the descending air will be when it arrives, buoyancy will make space for it. This might be the case for air warmed due to overlying a dark land surface. Alternately, if it is cooler, the upper air would have to descend against the buoyancy effect. Only by considering fluid flow effects to force movements of air against the tendency for lighter air to rise might you get the upper air to displace the lower air in these conditions. The question then becomes a question of the relative strength of these effects and is no longer a strictly adiabatic effect anyway.

Adiabatic cooling occurs at mountain ranges as the moving air masses have to rise because they can't pass through the rock. However, air masses moving across a depression do not have to descend into the depression. They could simply pass over it if there is no buoyancy difference to cause the air to descend. This is a simplified concept as it does not include entrainment effects of high level winds on lower air masses. While not a meteorologist, I suspect this effect is not generally enough to overwhelm the buoyancy effect.

As a final comment, you do also have to consider the heat transfer effects of the evaporation of the water inflowing from the rivers of Europe and the Nile. Even during dry periods, these will be contributing significant amounts of water to be evaporated as their catchment areas extend well beyond the immediate area of the Mediterranean.

Tony Cooley (talk) 04:48, 16 May 2011 (UTC)

I think youve got upslope and downslope winds the wrong way around. A downslope wind obeys the adiabatic equations perfectly, but an upslope will only do so until it reaches 100% saturation. Therefore, any winds descending into the dry seabed will indeed warm up at a very high rate. —Soap— 20:44, 5 June 2022 (UTC)

"In Popular culture"

I don't see that this section refers to the Messinian salinity crisis at all - hence my removal of it. Certainly none of the works refer to the Messinian period. A list of works of fiction about the Mediterranean sea has any place in an encyclopaedia article about a specific event at a specific time. At worst, the map leads to great confusion, suggesting at first blush that the crisis may have occurred alongside neolithic man. The Dinosaur article does not have an extensive list of books about cavemen eating dinosaurs, etc. If the material must remain, it could be reduced to a passing comment that "some people have written about the Med drying out", and if absolutely necessary an article "Fictional works about the desiccation of the Mediterranean sea" could be created. But no long list please. Verisimilus T 17:08, 4 April 2008 (UTC)

Yes, it does seem to have acquired a lot of fluff which is not particularly relevant nor likely to be useful in the rest of the article. I agree with its removal. -- SEWilco (talk) 20:17, 4 April 2008 (UTC)

Atlantic pouring in through the breach

This is probably a bit off-topic, but Re: the 'Replenishment' section, about the time when the Strait of Gibraltar was ultimately breached, and the Atlantic poured in through a relatively small gap - see the video of the 1993 Pantai Remis landslide when the sea broke through a narrow land barrier between an open cast tin mine (right next to the sea - yes, really) to get an idea of what this might have been like (on a somewhat smaller scale ...) Roisterdoister (talk) 11:44, 20 September 2008 (UTC)

the Suez canal?

• I don't understand geology that well, and maybe someone who does can answer a question. If the Strait of Gibraltar closed off, and the Mediterranean dropped some thousands of feet, what would keep the Suez isthmus from eroding to the point that a connection with the Red Sea opened up? AFAIK the land between the Red Sea and Mediterranean isn't more than 30 feet high -- the Suez Canal was built without any locks. It seems to me that, if there were a huge steep drop down from the current coast of Africa to the much lower Med. Sea, rain falling would quickly erode deep channels all along the coast (and the rain shadow effect would mean more rain than currently), and I can easily imagine one of those channels expanding to the point that it cut across the Suez isthmus. (Perhaps the isthmus was much higher then, or the Red Sea itself was blocked?) Benwing (talk) 03:54, 1 April 2009 (UTC)
  • There is not enough rain in the area for that to happen. And, sometimes the Bab el Mandeb was closed and the Red Sea also was an empty hot dry salt-floored sink. Anthony Appleyard (talk) 04:22, 27 May 2009 (UTC)
• If the sea dry out the bottom will rise up - rising up the coastline. Read about Archimedes and his bath. TN 76.16.176.166 (talk) 02:23, 27 May 2009 (UTC)
  • Due to isostasy. And see Red Sea#Geology. Anthony Appleyard (talk) 04:22, 27 May 2009 (UTC)

Coincidence of timing

The dramatic dry period, 6.0 to 5.3 Mya, closely coincides, with the evolutionary split, between forest-dwelling Chimpanzees, and savanna-dwelling proto-humans. Could there be some kind of closer connection ? 66.235.26.150 (talk) 22:04, 24 August 2010 (UTC)

Hutton's observation

James Hutton, speculating about the origin of salt deposits, wrote in his 'THEORY of the EARTH; or an INVESTIGATION of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe' that "THE formation of salt at the bottom of the sea, without the assistance of subterranean fire, is not a thing unsupposable, as at first sight it might be. Let us but suppose a rock place across the gut of Gibraltar, (a case nowise unnatural), and the bottom of the Mediterranean would be certainly filled with salt, because the evaporation from the surface of that sea exceeds the measure of its supply" [4]. I'm not sure that this has any place in the article, but it's quite a thought experiment for 1785. Mikenorton (talk) 22:37, 24 August 2010 (UTC)

HG Wells cleanup - help needed

There's a section on H.G. Wells' comment on this ("In 1920, H. G. Wells published a popular history book...") and it looks like someone may have added a comment on the article ("The previous statement is a logical fallacy because it assumes...")

Needs someone with more background to figure out what's H. G. Wells' view and what's modern research views on that, and what (if any) is "reader comment" or "metacomment" needing to be merged into the article or removed. Basically needs minor cleanup. FT2 ^{(Talk | email)} 16:02, 22 February 2011 (UTC)

I think the comment is nonsense, to be honest. It is generally agreed on that the Messinian salinity crisis, which ended 5.33 million years ago, was the last time when the Mediterranean dried out. There were no later dry periods. You won't find a single reputable scholar who claims that the Mediterranean was dry during the last ice age (the period Wells is theorizing about), because all the geological and plant-fossil evidence we have today shows that it wasn't.

I have changed the passage about Wells accordingly. Generally speaking, I am not sure about the benefit of having the "in popular culture" section in the article. The Messinian salinity crisis is a scientific topic. The "in popular culture" section does not really contain anything relevant to that, all it is liable to do is add confusion and pseudo-science. I suggest removing it entirely. Godagast (talk) 13:05, 5 March 2011 (UTC)

The problem with the "in popular culture" section at the moment is that mix together "popular culture" with "past beliefs". Maybe separating the section under different headings could make it a bit more encyclopaedic. In principle I'm for keeping the information that are at the moment in the section. --Dia^ (talk) 16:12, 5 March 2011 (UTC)

After further examination, I think that the sections "Evidence", "Scholarship", "Chronology" and some parts of "in popular culture" should be worked together in a "Discovery history" section. What do you think? --Dia^ (talk) 17:20, 5 March 2011 (UTC)

Illogical "Causes"

"Changes in climate must almost certainly be invoked to explain the periodic nature of the events. They occur during cool periods of Milankovic cycles, when less solar energy reached the Earth. This led to less evaporation of the North Atlantic, hence less rainfall over the Mediterranean. This would have starved the basin of water supply from rivers and allowed its desiccation.

Contrary to many people's instincts, there is now a scientific consensus that global sea level fluctuations cannot have been the major cause, although it may have played a role. The lack of ice caps at the time means there was no realistic mechanism to cause significant changes in sea level - there was nowhere for the water to go, and the morphology of ocean basins cannot change on such a short timescale.[citation needed]..."

-- These last two paragraphs (already affixed with a cite tag) ought be nuked for failing simple tests of logic. Given a setting in which the Strait of Gibraltar is open (however shallow, but open), a lowering on either side would result in increased flow and resultant erosion (continually keeping the channel open). Were the climate of the Med arid to the point of the sea level declining greatly, even the least active trickle from the Atlantic would quickly back-build erosively, resulting in a canyon and re-filled Mediterranean.

In the absence of any hard evidence, the most logical theory is one in which uplift and closure of the Strait occurred during a local climatic regime which was wet enough (i.e., wetter than at present) that the Mediterranean's fresh-water input almost exactly matched its evaporation (i.e., the level of the sea relative to the Atlantic would neither quickly fall nor rise in the event of damming). Only after the dam is well established (laterally thick) could the sea level drop without the dam almost immediately collapsing or eroding.

The following sentences: "They occur during cool periods of Milankovic cycles, when less solar energy reached the Earth. This led to less evaporation of the North Atlantic, hence less rainfall over the Mediterranean" ...are climatologically specious. First, colder climates result in a lower latitude orientation of the jet streams as bolstered Arctic airmasses invade farther south, i.e., increased wind and storminess in the temperate zones (in other words, more rain in the Mediterranean region, supporting my thesis above). Secondly, and in confirmation, the sea region as well as Saharan Africa were significantly wetter during the most recent advances of the Quaternary glaciations when the mid-latitude Westerlies descended into the region, dislodging the "Saharan high" (a permanent fixture today) responsible for desertification.--66.41.95.121 (talk) 05:12, 15 August 2012 (UTC)

Crisis

Since there were no humans around during this "crisis", why is it called a crisis? Seems to be more of a event than a crisis. — Preceding unsigned comment added by 60.241.37.187 (talk) 22:48, 18 March 2013 (UTC)

Header

I propose removing the following from the first sentence: ", also referred to as the Messinian Event, and in its latest stage as the Lago Mare event, ". Messinian Event is not frequently used, and Lago-Mare refers to only a part of the period. Gaianauta (talk) 12:49, 27 May 2014 (UTC)

I'd go ahead with the latter. But with the former, maybe say "infrequently referred to as Messinian Event." If by not frequently, you mean you haven't heard it in 20 years, then it doesn't matter I suppose. Just be bold. I think maybe 5 people watch this article. SkepticalRaptor (talk) 19:46, 31 May 2014 (UTC)

I'd been meaning to reply - I've seen "Messinian event" used quite often, although less than the "Messinian salinity crisis". Looking on Google Scholar and Google Books gives plenty of examples [5], [6]. I would keep it as an alternative. Mikenorton (talk) 20:31, 31 May 2014 (UTC)

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