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| From Popular Mechanics, some science reporting that I'm not going to get too skeptical about this time, promise. Scientists Found Evidence of a Megaflood that Shaped Earth’s Geologic History  The flood may have refilled the entire Mediterranean Basin in just two years. Not that it shouldn't be approached with a level of skepticism; it's just that I don't know enough about the subject to know what questions to ask. However, I do question the headline: certain people see that headline and immediately think of one particular story involving rain, animals, and an ark. Hopefully the subhead is enough to disabuse one of any such notions, not to mention the article itself. Ages, epochs, periods, and even eras are often defined by some sort of geologic trauma. The Chicxulub asteroid, for example, pushed the Earth into the Cenozoic Era, and 65 million years later, experts are pondering if we’ve entered a new geologic age induced by modern humans (and their predilection for greenhouse gasses). If you ever look at a geologic time scale (here's one from Wiki),  you might note that geologic ages, eras, epochs, and so on proliferate more in relatively recent times than they did way back when. I've often wondered how much of this is observational and/or recency bias.As for the "new geologic age induced by modern humans," I don't know for sure, but I thought they discarded the concept of the Anthropocene. Of course, "they" aren't a monolith and there might still be debate. Around 6 million years ago, between the Miocene and Pliocene epochs—or more specifically, the Messinian and Zanclean ages—the Mediterranean Sea was cut off from the Atlantic Ocean and formed a vast, desiccated salt plain between the European and African continents. If there's no ocean or sea between the continents, are they separate continents? By ancient convention, Europe and Asia are considered different continents, so I suppose so. Until, that is, this roughly 600,000-year-long period known as the Messinian Salinity Crisis suddenly came to an end. Messinian Salinity Crisis would make an excellent name for a 70s prog-rock band. At first, scientists believed that the water’s return to the Mediterranean took roughly 10,000 years. I have a bit of an objection to this wording. It's not like scientists took it on faith; there was evidence. It's entirely possible that the evidence was misinterpreted, but, as this article shows, scientists change their views when new or reinterpreted evidence shows up. But the discovery of erosion channels stretching from the Gulf of Cadiz to the Alboran Sea in 2009 challenged this idea, suggesting instead that a powerful megaflood may have refilled the Mediterranean Basin in as little as two to 16 years. Other than wondering why the author didn't just say "Straits of Gibraltar," which is probably better-known globally than "Alboran Sea" and "Gulf of Cadiz," there's a really, really big difference between 10,000 years and something on the order of a decade. Specifically, 1000 orders of magnitude. Quite a few discoveries move whatever needle by a tiny amount, like if there's evidence that the Sun is 5 billion years old but new evidence comes in that suggests 5.1 billion (I'm not saying this happened, just an example my head came up with). But this difference is a major shift. So I'd be looking for lots of evidence to back it up. Extraordinary claims require extraordinary evidence, and I call a 1000 orders of magnitude change extraordinary. But, again, I'm not saying it's not true; I just don't know much about this subject. That likely means this flooding event—now known as the Zanclean megaflood—featured discharge rates of roughly 68 to 100 Sverdrups (one Sverdrup equals one million cubic meters per second). Case in point: I'd never heard of the Sverdrup. So of course I looked it Sverdr-up. Turns out it's used in oceanography. From that Wiki link: "One sverdrup is about five times what is carried at the estuary by the world's largest river, the Amazon."It shouldn't be surprising that they came up with a larger unit. This is analogous to how star masses are reported in terms of solar masses, or interstellar distances in light-years or parsecs. It keeps us from dealing mathematically with huge numbers, like billions or trillions, or having to use exponents. At any rate (that's a pun there), even if the numbers (68 to 100 in this case) are comprehensible, the amount of water flow is almost certainly not. The article goes into a discussion of the evidence that led to this extraordinary conclusion. I don't know enough o say whether it's compelling or not, but I did find it an interesting read. But then: This model shows that flooding could have reached speeds of 72 miles per hour, carving deep channels as observed in the seismic data. Look, I get using nonstandard units to make enormous quantities somewhat manageable in calculations, but switching from metric/SI to "miles per hour?" That, I cannot abide. Pick one. (It's about 115 km/h.) Now, let's see if I can find a lead singer for Messinian Salinity Crisis. And some musicians. Because I have no talent, either. |
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