Researchers at Brigham Young University report that the Hawaiian Islands are dissolving. In fact, researchers contend that Oahu’s Koolau and Waianae mountains will someday shrink down to nothing more than a flat, low-lying island like Midway.
Although erosion is an issue for the Hawaiian Islands, researchers argue that it isn’t the primary offender. They believe that the mountains of Oahu are almost certainly dissolving from within.
“We tried to figure out how fast the island is going away and what the influence of climate is on that rate,” said Steve Nelson, a geologist at Brigham Young University, in a statement. “More material is dissolving from those islands than what is being carried off through erosion.”
Mr. Nelson and his colleagues sampled both groundwater and stream water for two months to determine which source removed more mineral material. They also used ground and surface water estimates from the U.S. Geological Survey to calculate the total quantity of mass that vanished from the Hawaiian Islands each year.
“All of the Hawaiian Islands are made of just one kind of rock,” Mr. Nelson posited. “The weathering rates are variable, too, because rainfall is so variable, so it’s a great natural laboratory.”
In order to forecast the island’s future, researchers have to consider plate tectonics. They point out that Oahu actually rises in elevation at a steady rate as it is pushed northwest.
Researchers believe that Oahu will continue to grow for as long as 1.5 million years, but that the force of groundwater will eventually win and the island will begin its transformation to a flat, low-lying island like Midway.
Oahu is the second oldest of the six Islands of Aloha and is positioned between Kauai and Maui. Oahu’s two major mountain ranges, the Waianae and Koolau ranges, run almost parallel to each other. More than one hundred ridges extend from the spines of each range, creating stunning mountain vistas.
Check out the pictures posted by Unreal Hawaii to see the beautiful mountain vistas offered by the Waianae mountains.
Co-author Brian Selck joined the project after the field work in Hawaii was completed.
However, Mr. Selck analyzed soil samples in the lab back in Provo, Utah.
“The main thing that surprised me on the way was the appearance of a large amount of quartz in a saprolite taken from a 1-meter depth,” Mr. Selck said.
The study’s findings are described in detail in the journal Geochimica et Cosmochimica Acta.