Today, the Black Sea is a brackish inland sea, fed by fresh water from European rivers and saltier, Mediterranean seawater flowing in through the Bosporus strait. In the 1970s and 1980s, cores through nowsubmerged sediments off the northern and western coasts revealed the remains of a coastal plain that was exposed late in the last ice age and into the interglacial warmth of the past 10,000 years. Long after glacial melt waters began raising world sea levels, it seems, the Black Sea was a freshwater lake, much smaller and lower than todays sea; it was cut off from the Mediterranean because the level of that sea was even lower than the Bosporus.
Evidence that a rising Mediterranean suddenly refilled this lowered Black Sea emerged from a joint RussianUS expedition in 1993, during which researchers used seismic waves to image the layers of sediment at the bottom of the Black Sea. If rising waters had crept slowly across the coastal plain, they would have deposited a wedge of sediment as they went. But as Ryan, Pitman, and colleagues wholesale ugg boots on sale reported in Marine Geology last year, they saw no sign of that. Instead they found a thin, uniform dusting of sediment, consistent with a geologically instantaneous refilling of the Black Sea.
In addition, radiocarbon dating of the shells of the first salttolerant molluscan invaders from the Mediterranean yielded the same age—7550 years before present, plus or minus 100 years—regardless of whether the shells came from deep, permanently flooded sediments or from the shallow shelf. If the refilling had been gradual, the team reasoned, the shells in deeper water would have been laid down first.
Finally, seismic probing has shown that the hardrock basement beneath the sediments filling the Bosporus channel lies at a depth of nearly 100 meters, rather than 35 meters, as had been thought. So the floodwaters could have cut a very deep channel through the sediments and down to bedrock, letting the water spill through ugg boots far faster
Evidence that a rising Mediterranean suddenly refilled this lowered Black Sea emerged from a joint RussianUS expedition in 1993, during which researchers used seismic waves to image the layers of sediment at the bottom of the Black Sea. If rising waters had crept slowly across the coastal plain, they would have deposited a wedge of sediment as they went. But as Ryan, Pitman, and colleagues wholesale ugg boots on sale reported in Marine Geology last year, they saw no sign of that. Instead they found a thin, uniform dusting of sediment, consistent with a geologically instantaneous refilling of the Black Sea.
In addition, radiocarbon dating of the shells of the first salttolerant molluscan invaders from the Mediterranean yielded the same age—7550 years before present, plus or minus 100 years—regardless of whether the shells came from deep, permanently flooded sediments or from the shallow shelf. If the refilling had been gradual, the team reasoned, the shells in deeper water would have been laid down first.
Finally, seismic probing has shown that the hardrock basement beneath the sediments filling the Bosporus channel lies at a depth of nearly 100 meters, rather than 35 meters, as had been thought. So the floodwaters could have cut a very deep channel through the sediments and down to bedrock, letting the water spill through ugg boots far faster
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