An international team of researchers has found an 80-meter-thick sedimentary record in the Charyn Canyon in Kazakhstan documenting the interactions of climate change between land, atmosphere and ocean over the past 5 million years.
This unearthed sedimentary record is the first reliable evidence in one place of the long-term interactions between the major climate systems of the Eurasian continent, presented by the alternating layers of dust and soil preserved as sediments in Charyn Canyon, which enabled the researchers to validate the hypothesis Fresh water flows into the Arctic Ocean. Read also Conserves the soil and combats climate change.. the ant hedgehog moves tons of soil components annually Rare microscopic magnetic fossils produced by bacteria reveal the history of Earth’s climate It may be too late to save the world’s largest closed sea due to climate change Climate change led to the collapse of Oman’s mangrove wealth 6,000 years ago
Between climate and land systems
The land surfaces of Eurasia seem to have contributed significantly to the water cycle of the land, atmosphere, and oceans over the past 5 million years.
The researchers chose the location of the study to be in central Central Asia, in an inland place as far from the ocean as possible, and they examined the sedimentary record, which is 80 meters thick, and took soil samples at different altitudes to ensure a comprehensive survey.
Then they measured the relative concentrations of isotopes within soil carbonates, and re-modeled the change in soil moisture over time, in addition to dating uranium and lead to soil carbonates and their accumulation rates in the sediment record.
Soil samples analyzed revealed an area characterized by increased aridity over the past 5 million years, and the researchers found that the soil was wetter in the early Pliocene than in later eras, or than it is today.
And then the drought began, but the process of its drying was not of a regular nature in its change, but rather was variable due to short-term climatic fluctuations, which we can mainly attribute to the interaction between the westerly winds on the middle latitudes and the high pressure system in Siberia.
The Pliocene era represents the last geological time period in which the concentration of carbon dioxide in the atmosphere was similar to what it is today, i.e. an estimated 400 parts per million, and this time period lasted from 5 to 2.6 million years.
Siberian westerly wind
Research in the Charine Canyon enabled scientists to investigate the long-term interaction between the Siberian highlands and the rain-laden westerly winds.
The team found that the watery climate of the Charyn Canyon mirrors that of the steppes to the north, where a number of large Siberian rivers that are influenced by the movement of high and western air masses flow there. Thus the activity of the Siberian River in the north could be a major cause of soil moisture changes at the Charyn Canyon site.
The results of this study provide an integrated archive of the terrestrial climate over the past 5 million years, which is a valuable basis for future climate models.