Slashdot Mirror
Mediterranean Might Have Filled In Months
An anonymous reader writes "A new model suggests that the Mediterranean Sea was filled in a gigantic flood some 5.3 million years ago. According to Daniel Garcia-Castellanos' paper in Nature, the sill at the Straight of Gibraltar gave way rather suddenly, with 40 cm of rock eroding and the water level rising by 10 m per day at its peak. They imagine a shallow, fast-moving stream of water (around 100 km/hr) several kilometers wide pouring into the basin with a flow greater than a thousand Amazon rivers — that's about 100,000,000 cubic meters per second." The flood would have dropped worldwide sea levels by 9.5 meters, probably triggering climate changes. In this model the Mediterranean filled in anywhere from a few months to two years at the outside.
Julian May already wrote about it in The Golden Torc back in the '80s and her story is way more interesting than this one :-)
Ok, just once, giving you the benefit of doubt concerning trolling:
The mediterrean doesnt have that many rivers flowing into it, but is in a relatively hot climate.
This means that much more water evaporates than it recieves.
Several times in history, the connection of the mediterrean with the other oceans (i.e. the atlantic) was closed by the way of plate tectonics,ice age, etc (plate of africa going north and forming the alps...)).
During these times, the entire sea evaporated away. IIRC, it was once MUCH deeper, but at the ground there are a few km of salt and sediments from those times.
But such things cannot last. Thousands (if an ice age) or millions of years later there was a breach somewhere to let water enter (be it by way of an earthquake, rising water level of the outside oceans, etc). And after that, erosion had its way.
It must have been an unimagineable awesome display ...
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
The Mediterranean flood hypothesis is not new - these authors have just done more work on the geology. They lean against the giant waterfall idea ("We do not envisage a waterfall..."), which is a shame - I always liked the idea of a supersonic waterfall.
Also the much quoted Biblical age of the Earth was calculated in 1650.
Untrue. The belief the earth is 6000 years old goes back at least to 200 CE : "The majority of classical Rabbis hold that the Earth was created around 6,000 years ago.[10] This view is based on a chronology developed in a midrash, Seder Olam, which was based on a literal reading of the book of Genesis. It is considered to have been written by the Tanna Yose ben Halafta and covers history from the creation of the universe to the construction of the Second Temple in Jerusalem."
I know because saint Augustine (400 CE) referred to this timetable too : "They are deceived, too, by those highly mendacious documents which profess to give the history of many thousand years, though, reckoning by the sacred writings, we find that not 6000 years have yet passed."
If all else fails, immortality can always be assured by spectacular error.
I'm a geology grad student doing a thesis on tectonic geomorphology. I read this article with great interest; my research is on mountain rivers/streams so I know a bit about this kind of thing.
Your alternate theories don't really work, for a variety of reasons. I'm not an expert on all these topics, but I'll explain as best I can and hopefully anyone that might know better will correct me :)
The glacier theory doesn't work because glaciation did not, in fact, reach that far south. The area has stayed at a relatively stable latitude for the past 250 million years at the least (check out a plate reconstruction for 30 Ma compared to the present - the site has earlier reconstructions as well). Even during ice ages, glaciation never got that close to the equator. This is beside the fact that you can actually distinguish between a glacial valley and the kind of thing they're saying this is - based on the shape, type of sediments, and so on.
Tectonic movement doesn't operate on the same time scale as erosional and stream processes. Tectonics has a major influence on the way rivers operate - in fact that's what my research is about - but not in the way you're speculating. You might be surprised how well preserved rock formations are compared to when they originally formed - it sounds like this one is more or less the same as when it was deposited, which is common in most areas. Tectonics is constantly shifting the crust, yes, but not as much or as fast as you're supposing, and even then this is a relatively inactive area.
Now, your final theory is actually about right, but if you change it to follow how river erosion actually works, then you're basically saying what the researchers here are saying. Their description is a bit misleading, depending on how long you think this took to occur (and I would lean more towards it taking longer - two years as they say, or even a little more, but I don't know the specifics of where they came up with that figure).
The valley shape and sediment type suggest a braided river system, with multiple small, fast streams covering a broad area, constantly shifting left and right. As they drop sediment and fill in depressions, the areas where water is not flowing become the new depressions, so the streams shift back and forth, filling the area with sediment evenly. The coarse of meandering rivers (which are more mature and have slower flow rates) can change on sub-decade time scales, and braided rivers are constantly shifting. Now, the important thing is that these braided streams don't carve v-shaped valleys - they spread themselves out broadly, eroding laterally.
Thus, the initial break would have carved a v-shape valley, but it would quickly erode laterally. Most of the initial deluge would not be recorded - it simply wiped everything away. What's left is the wide valley that got flushed out, and the coarse deposits that filled the valley from the braided streams that existed near the end of the deluge, when flow rate was still high but not enough to wipe away absolutely everything.
One of the most interesting things about this research is that it supports the idea that these things can happen catastrophically. In the 1800's, during the early days of geology, there was a huge debate surrounding whether geology happened catastrophically or gradually. Now, the theories those guys were pushing were ridiculous (although a lot of fun), but the question of time scales is still relevant. It became clear by the early 1900's that gradualism is more realistic, and all of geology is essentially based on that - almost anything can happen if you give it enough time. It's the same conceptual leap that you need to understand biology and evolution, but with geology there is even more time to play with, and physics can easily explain how rocks are affected by forces over long time periods.
This led eventuall