Like the veins of the Earth, rivers flow throughout the planet, bringing both life and destruction.
Scientists for more than half a century have thought that rivers were relatively recent phenomena because with most modern rivers, vegetation provides the structure that holds river banks in place.
How, then, would have deep rivers existed prior to the emergence of land plants? After all, land plants did not emerge until the Silurian period about 450 million years ago, a period that occurred not long ago considering the earth’s age of 4.5 billion years.
UCSB professor Vamsi Ganti and his team have found evidence that deep rivers did exist before the Silurian period. They measured the depths of pre-Silurian river deposits in northwest Scotland and compiled data from other pre-Silurian river deposits around the world.
Dr. Ganti and his colleagues found that these rivers were about 13 to 50 feet deep on average.
The findings shocked him.
“Those are really deep rivers to exist in the absence of vegetation,” he said, “and that was actually a really surprising result for us.”
The team had to double check its findings, so members returned to the study site at the Torridonian sandstone deposits in the Scottish Highlands.
“I spent two summers there saying, ‘This can’t be true. I should go and collect more data,’ ” said Dr. Ganti.
He and his team ended up collecting roughly 2,000 measurements at the location, and the field data collection cost about $9,000. The project was funded with Dr. Ganti’s fellowship money from Imperial College London, where he was a research fellow. The native of Hyderabad, India earned his undergraduate degree in civil engineering at the Indian Institute of Technology in Delhi. He left India to attain his Ph.D. in civil engineering at the University of Minnesota.
He now teaches and researches at UCSB, where he’s building a flume lab to simulate rivers and deltas to continue his study.
“Rivers are interesting to me because they’re not only important for more than livelihood but also because they leave behind clues about how ancient earth would have been,” Dr. Ganti said.
On his research challenging a long-accepted hypothesis that deep rivers did not exist until 450 million years ago, Dr. Ganti replied, “It is exciting definitely.” To him, his study is not one that answers a question but instead raises further questions.
With these additional questions, Dr. Vanti hopes to understand how rivers evolved over time and how they will change, trying to speculate their implications for the planet’s future.
