雅思閱讀:Amazon River shaped by see-saw tilt of continent
SOUTH AMERICA'S AMAZON RIVER Basin was a vast wetland for millions of years. That was until tectonic processes deep in the Earth transformed it into the world's largest drainage system, new research suggests.
Geoscientists from the University of Sydney and the California Institute of Technology believe a process called 'continental tilting', which began about 30 million years ago and continued for about 16 million years, tipped South America like a see-saw and drained its wetlands.
The event, funnelled water over 6400 km east to the Atlantic Ocean in what the team describes as the world's largest water slide. "What we're describing involves the whole continent," lead author Grace Shephard told Australian Geographic. "This tilting led to the formation of the Amazon River as we know it today."
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