Mauna Loa for Dummies - The Freelance Files MMCIII

1984 eruption of Mauna Loa

If we've learned one tiny thing from our years of skewering greedy freelancers, it's that a little knowledge can be a bad thing. We were reminded of that recently when one of the staffers came across a handful of puzzling statements in a post written by someone who claims to be a science writer (but has a BA in Fine Arts). While Phil Whitmer did a fair job of rewording content from more authoritative material for his Sciencing.com post, "Volcanic Rock Types by Mauna Loa," a few of his statements made it pretty obvious that he was just performing a copy-reword-paste job.

The answer to the question is quite simple: basalt. There may be a little pumice and some obsidian, but the vast majority of the rock is basalt. Whitmer prattled briefly about different names (aa and pahoehoe) without saying much about the textures those two Hawaiian words reference (blocky and ropey). The rest of his text is a mishmash of factoids and mistakes. We're talking mistakes like,

• "The volcano bubbles and spews red-hot molten rock from its summit crater on a regular cycle." – No one says the eruptions are "on a regular cycle": the average time between historic eruptions is about six years, but there has been none since 1984. Not "regular" at all...
• "About 98 percent of the volcano's surface is covered with basaltic rock lava flows that are radio-carbon dated at less than 10,000 years old." – You can't radiocarbon date basalt because it contains no carbon. The most likely radiometric dating method is Uranium-Thorium.
• "Tholeiites are a type of basalt generated by subduction of the Earth's tectonic plates underneath Mauna Loa." – No, Phil, Tholeiites are generated from melted mantle and occur in two places: rift zones and hot spots. The Hawaiian Islands lie over a mantle hotspot in the middle of the Pacific Ocean. There is no subduction taking place within about 2,000 miles.
• "Tholeiitic basalt has a fine-grained intergranular groundmass lacking olivine." – Sorry, Phil, but "fine-grained intergranular groundmass" means not a darned thing.

Clearly Whitmer cobbled together his post by alternating chunks of disparate information from different sources and then rewording it. Had Phil actually understood what he was writing, he might have done a better job. Since he didn't understand it but published it anyway, he's now the proud owner of a Dumbass of the Day award. Go, Phil...

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