By Timothy Hurley
Advertiser Maui County Bureau
Molokini Islet, that crescent-shaped mecca for snorkelers three miles off the southern coast of Maui, apparently is much older than previously believed.
A graduate student from Kyoto University has determined that Molokini erupted 230,000 years ago — give or take 90,000 years, the Hawaiian Volcano Observatory reported recently.
Geologists had assumed Molokini was a fairly young volcanic formation, because of its location along Haleakala's southwest rift zone, which erupted within the past 50,000 years.
But the new research suggests Molokini is probably even older than Haleakala Crater itself, which is believed to have been formed 50,000 to 300,000 years ago.
Yoshitomo Nishimitsu, working with colleagues at the Big Island’s Hawaiian Volcano Observatory, used a potassium-argon method of dating to measure ages from 60 lava flows on Haleakala. The ages will help to clarify Haleakala's volcanic history and the likelihood of future eruption along its rift zones, according to the observatory’s geologists.
Molokini Islet is a bird sanctuary off-limits to the public. The northern rim and the crater is below sea level, creating a popular destination for snorkeling tours.
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