Groundwater is causing Oahu’s mountains to dissolve, new study says
A new study carried out by scientists working with the Birgham Young University claims that the Hawaiian islands are dissolving, and that at some point in the future they might fall off the map completely.More precisely, they discovered that the mountains found on Oahu (Koolau and Waianae), Hawaii's third largest island, are being eroded from within by groundwater. Thus, they are quite likely to shrink as the years go by, and ultimately turn into plains.
In all fairness, it must be made clear that soil erosion also has a say in this, yet it seems that said groundwater must be listed as the major culprit, Science Daily explains.
The scientists reached this conclusion after comparing and contrasting the chemical makeup of Oahu's groundwater and its water streams. The process of collecting samples and analyzing them took about two months, yet the researchers believe that is was all worthwhile.
Thus, they found that the former contained significantly more minerals than the latter, which basically means that groundwater is wearing down these mountains much faster than the streams flowing on their surface are.
However, it will be about 1.5 million years before these mountains begin their descent, seeing how, for the time being at least, plate tectonics are making sure that the island's elevation is increasing by pushing it towards the northwest.
“We tried to figure out how fast the island is going away and what the influence of climate is on that rate. More material is dissolving from those islands than what is being carried off through erosion,” explained geologist Steve Nelson from said university.
Furthermore, “All of the Hawaiian Islands are made of just one kind of rock. The weathering rates are variable, too, because rainfall is so variable, so it's a great natural laboratory.”
The study was published in the Journal Geochimica et Cosmochimica Acta.