The bearing land bridge, which once connected Asia and Alaska, possibly appeared much later in the last ice age than previously expected, narrowing the time window during which people could migrate to America, indicate the calculation.
A new study found that the land bridge probably existed about 35,000 years ago, until the coldest part of the last ice age, known as the last glacial maximum (LGM). This is a mockery with one of the oldest, respected places of human activity in America – 23,000-year-old traces Found in the National White Sands in New Mexico.
Cycles of the ice age
The earth is regularly subjected to cycles in which More or less icy covers the surface of the worldThe field at the height of each ice age is the global sea level falls when the water of the planet is frozen in massive ice shields. At the end of these ice times, when the temperature rises, ice shields are melted and sea levels increase.
The previous study showed that in LGM the Bering -Waiting bridge allowed animals, such as Mammoth And horses Wandering between Asia and America. The best understanding when this land bridge was recently above the sea level can help shed light on when and how people first migrated into the new world.
Previous work He suggested that the global sea level was about 425 feet (130 meters) lower on LGM between 26,500 and 19,000 years ago, Jesse FarmerAccording to Live Science, an assistant professor at the Environment School at the University of Massachusetts Boston and co -author of the new study on the ground bridge. This forced scientists to evaluate that the Bering land bridge was higher than the sea level, starting from 70,000 years ago, he noted.
Nevertheless, there were two signs that perhaps there were even more in the full picture of the Bering land bridge. Firstly, “it is impossible to recognize sea levels very accurately from that time,” said the farmer. “With our existing tools, uncertainty from 10 to 20 meters (from 33 to 66 feet) would be very good.”
Secondly, “in this case, we are not concerned about the average worldwide, but in particular, the Bering Strait,” said the farmer. High latitudes, for example, where the Bering Strait is located, were relatively close to the place where ice shields would grow. The weight of ice would press to the ground, raising the local level of the sea.
Indeed, in PNS paper 2023The farmer and his colleagues showed that the Bering land bridge could be actually flooded between them 46,000 years ago and 35 700 years agoThis means that this was not found for land transitions until after that. Data on the Ocean of the draft suggests that the nutrients typical of the Pacific Ocean began to invade the Arctic Ocean during this time, with the most probable explanation that the strait of the Bering Strait was open.
These conclusions indicate that the Bering land bridge may have again discovered only about 10,000 years to the height of the last ice age, much later than previously expected. One question that helps to solve is what human lines – ours or our extinct relatives – could go to the new world.
“Later, the appearance will support the idea that completely modern people first traveled to the North American continent.” Jan ButitAn independent archaeologist who did not take part in this study told Live Science. “Neanderthals And DenisovanTwo other hominids, who, as you know, occupied parts of Siberia, have already died out or on the verge of disappearance, throughout the North -Eastern Asia by this time. ”
In addition, the analysis of the fossils of ancient animals under the age of 46,000 in Eurasia and America, such as mammoths, bison, lions and a bear, confirmed the likelihood that the Bering land bridge was opened later than before – much closer to LGM. Computer models of migration of these creatures based on fossil deposits suggested that the land bridge was closed during the flight. The document of 2023 suggested that it was.
“You have two completely different sets of data telling the same story,” said Farmer.
Although the Bering land bridge, perhaps, did not open until I thought before, Farmer noted that the knowledge of mipping, demonstrated The ancestors of modern Inuite He suggested that it was still possible that ancient people could break into America in a boat, just as ancient people migrated across the sea to Australia and New Guinea.
“Any human migration to America up to 40,000 to 35,000 years ago would demand a water court and the ability to navigate the open ocean,” Butov said. “As far as we know, this was achieved only by anatomically modern people.”
