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Last Glacial Maximum (27,000 to 20,000 years ago) Previous Page Previous Page Previous Next Previous Next Previous New analytics for the first time Great Barrier Reef samples covering the time 22,000 years ago to 19,000 years ago
The research team, led by Professor Yusuke Yokoyama of the University of Tokyo, now divides the Last Glacial Maximum into two distinct periods:
- period A-30,000 to 21,500 years ago, the sea level was relatively stable
- period B-21,000 to 17,000 years ago, the sea level was unstable with large, rapid fluctuations
The rapid drop in sea level observed 21,000 years ago is particularly striking because it contradicts current understanding of this period.
"This challenges the paradigm that glacier size can not change slowly, "said Yokoyama, lead author of the paper published in Nature on 26 July 2018.
These possibilities of glaciers are important in the context of modern climate change and its associated impacts.
"The current models of glacier dynamics can be too conservative. These predictions are likely to be considered, "said Yokoyama.
Future climate prediction models are tested by their ability to accurately calculate their climate.
"Research teams like bear collect data about how the earth is used," said Yokoyama.
"It's really important to understand the For more information, please visit the website http://www.youtube.com/watch?v=ZZQ&utm_source=aluminium&utm_source=aluminium&utm_source=aluminium&utm_source=alberta&utm_source=a&url=http%3A%2F%2Fwww%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F "Yokoyama"
In 1945, Yokoyama was the co-chief scientist of the International Ocean Expedition 325: Great Barrier Reef Environmental Changes. Associate Professor Jody Webster from the University of Sydney, School of Geosciences was also co-chief scientist on the expedition. The research team spent two months on the 93.6-meter-long (102-yard-long) research vessel Greatship Maya Collecting fossil coral reef samples. Hydrographers Offshore Passage of Mackay and Noggin Offshore Pass of Cairns, both on the East Coast of the Australian State of Queensland.
Collecting fossil corals from the Last Glacial Maximum is technically and logistically challenging.
"We sampled coral from 90 meters to 130 meters (98 to 142 yards) It's difficult to collect data anywhere between 50 and 200 meters (55 and 219 yards) underwater; 't go below 30 meters (33 yards) and ship more than 200 meters, "said Yokoyama.
The Great Barrier Reef past ice cream ice sheet behavior. The reef's tropical position of the glacier ice sheets, the so-called "tectonic plate" of the Great Barrier Reefs.
additional, the Australian tectonic plate has minimal seismic activity, so earthquakes did not change the position of the reef. The Great Barrier Reefs (19659013) The Greatship Maya (19659013) The Greatship Maya center of the Great Barrier Reef, now submerged in deep water. In the distance, waves break the modern Great Barrier Reef in shallow waters. University of Tokyo Professor Yusuke Yokoyama was co-chief scientist on the expedition to collect coral fossil core samples in 2010. Credit: Yusuke Yokoyama
"Sites close to the ice sheets can not provide accurate sea level histories because they are overwritten by large deformations of the Earth," said Yokoyama.
Studying reef samples
Researchers The structure of coral and algae layers within the core samples to determine the depth of water. Advanced radiocarbon and uranium-thorium dating results provided by the team at the University of Tokyo. Researchers combines time and depth with global depths of certain depths.
"Two death events of the reefs are very clear in the coral cores we examined," said Yokoyama.
When the ice sheets grew , coral in deeper waters survived. If the water becomes too deep, sunlight and nutrients become unavailable and the reef can drown.
"1965-1900" Webster led the team of reef scientists from Spain, Japan, and the US account manager for interpreting ecological data was used to track reef habitat depth, and therefore relative sea level, over time. That information was then combined with radiometric data and used by Yokoyama and his team to model fluctuations in the vertical position of the seafloor caused by changes in water or ice volume. The Last Glacial Maximum Period.
"Fossil coral reefs were very sensitive to environmental changes, so by examining the biological assemblages in the cores we were able to reconstruct how ancient water depths changed. time, "said Webster.
Explore further:
Landmark international study examines reef's ability to recover from abrupt environmental change over millennia
More information:
Rapid glaciation and a two-step sea level plunge into the Last Glacial Maximum, Nature (2018). DOI: 10.1038 / s41586-018-0335-4, https://www.nature.com/articles/s41586-018-0335-4
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