What is the Zanclean flood?
The Zanclean flood is a theory that explains how the modern-day Mediterranean Sea became the body of water it is today. The Zanclean flood (or Zanclean deluge) is a theory proposed by scientists to explain how the Atlantic Ocean filled the Mediterranean basin. This massive event would have been the start of the Zanclean age and meant the likely extermination of any animals or plant life that happened to be in the region at the time. Although this theory isn’t totally accepted, it is still regarded as a potential solution to the filling of the basin. In its essence, the theory states that the event was caused by the Strait of Gibraltar’s opening, whether by tectonic subsidence, erosion from a stream, or sea level rise. The most commonly held belief is that a stream slowly eroded the Strait until the Atlantic Ocean finally punched through, allowing the massive region to be filled with water.
When did the Zanclean flood potentially happen?
The current estimates for when the Zanclean flood occurred place the event around 5.33 million years ago. No humans were alive during that time, although many animals and plants were likely killed during this great deluge. If humans had been around during the catastrophic event, it’s like that many ancient myths would have been created to explain this one-of-a-kind moment. Regardless, there were no ancient humans around during this period, although the last common ancestor between humans and chimpanzees was potentially living during this period.
What were the consequences of the Zanclean flood?
Although the Zanclean flood happened before human existence, the regional consequences were still monumental. Before the flood, animals could cross the basin from Europe into Africa. After the flood, the passageway was effectively cut off, segmenting and isolating the once-transitional region, allowing speciation on either side of the sea. An example of this can be seen in Psammophis odysseus, an ancient species of snake that once lived in Africa and the southern region of Europe. The snake lived around 5.5 million years ago, going extinct in Europe soon after the flood. Its relatives in Africa, however, lived on and continued to evolve. While the flood stopped some animal migration, it did encourage others, especially in the ocean. When the waters settled, there was a massive new landscape for animal migration into the Mediterranean Sea. Once the water region was established, animals like cetaceans (whales) and pinnipeds (seals) inhabited the area. Aside from animal migration interference, the flood also changed the resulting region’s weather. Records show that a significantly smaller flood in ancient times triggered a cold period, making it very likely that the massive flood had far-reaching temperature impacts. Estimates show that the potential cooling region reached all the way to modern-day New Caledonia near Australia.
Did animals die during the Zanclean flood?
Things probably weren’t good for any animals in the Mediterranean basin at the time. Due to the amount of water, seismic activity was triggered, causing landslides and tsunamis over 330 feet tall. Additionally, any sea life initially shot into the basin would have been killed as the water was still shallow and mixed with a lot of sediment.
Have other large-scale floods occurred on the Earth?
Although the Zanclean flood is one of the largest, other similar floods have existed throughout history. In North America, the Bonneville flood overflowed through the Snake River Basin near the last ice age, and it is known as the second largest flood in geologic history. The Black Sea deluge hypothesis is similar to the Zanclean flood hypothesis and examines the possibility of the Mediterranean Sea flooding into the Black Sea through the Bosporus Strait.
