Machupuchare in the Annapurna Range of the Himalaya in central Nepal is a mountain influenced by monsoons.
Click on image for full size
Courtesy of Kip Hodges
Storms Shaped the Himalayan Mountains
News story originally written on November 9, 2008
Rain is important for many reasons. It can even impact the world’s largest mountains.
New research suggests that strong storms called monsoons shaped the development of the Himalayan Mountains over millions of years.
In Asia, where the Himalayan Mountains are located, the climate is affected by seasonal winds that carry moist air over the Pacific Ocean into East Asia and over the Indian Ocean into South Asia. These moist winds make monsoons. Scientists don’t know when this pattern first started, but evidence suggests that it was at least 24 million years ago.
To figure out how monsoons have changed high in the Himalayas over the past 24 million years, scientists looked to the bottom of the ocean. They studied the chemistry of layers of sediments from the seafloor of the South China Sea. The sediments were weathered from mountains, and then transported in the Pearl River system in China before settling down on the seafloor.
The chemistry of the seafloor sediments shows how much of the mountain rock weathered away over time. The scientists found that more monsoons lead to more weathering of rocks.
The Tibetan Plateau, where the Himalayas are located, is the largest high-altitude place on Earth. Many scientists believe that when the Tibetan Plateau uplifted, the monsoons became more intense. However, the information that scientists found in the sediments does not support that idea.
The chemistry of the sediments suggests that there was an increase in East Asian monsoon intensity from 23 to 10 million years ago, then monsoons became weaker until about 4 million years ago. After that, monsoons became more intense again.
"Earth is a complex system," said Kip Hodges, one of the scientists who worked on this research. "We cannot begin to fully understand mountain building without appreciating the roles of the hydrosphere and atmosphere in the evolution of mountain ranges."
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
Rain is precipitation that falls to the Earth in drops of 5mm or more in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more
Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates different pressures in the atmosphere which creates the winds around the globe. Since the Earth spins,...more
If you sneeze into a pile of dust, the little particles fly everywhere. But if you sneeze into a pile of rocks, they will stay put. It takes more force than a sneeze to move those rocks. Winds and water...more
When water or wind loses energy and slows down, sediment can no longer be carried in it. The particles fall through the water or air and form a blanket of sediment on the bottom of a river, a lake, ocean,...more
The first time people got a glimpse of the whole Earth was December 1968. Apollo 8 astronauts took pictures of the Earth as they traveled to and from the Moon. In their photographs, the Earth looks like...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more