Jargon Battles!

So Ron and Callan are having a good-natured discussion about the term "xenobomb." This is a good example of how we as scientists use language. For use in the study of the natural world, the words we use to describe objects and processes must refer to something specific (not vague) and also be accurate (reasonably).

Although I have nothing more specific to add to their web discussion. The general thought on twitter is that some kind of "xenolith-cored bomb" term is most specific and accurate. Either way, the sample in Callan's lab is a gorgeous olivine peridotite. You don't often get such lovely chunks of the mantle brought near the surface for us to see.

There is an excellent surfing location on Kauai where the large beach boulders are almost all cored by these olivine xenoliths. Though if you go, don't walk around with your big telephoto lens like I did - the surfers value the secluded, private nature of this beach. Fortunately, I was forewarned by a local and kept myself as inconspicuous as possible. (Can that be done with a 400mm lens?)

Here's an example - Hawaiian quarter for scale. Note also, the rusty-colored surface of the olivine crystals. Olivine is an iron-magnesium silicate and weathers into iron, magnesium oxides and silica (SiO₂ in solution).

Olivine Sand

All this talk of Hawai'ian volcanoes has reminded me that I have some photographs of olivine sand (from somewhere near South Point, I suspect). I suppose I could talk about the mineralogy, or the grain shape and rounding. Or I could describe the method I use to stack multiple images together to increase apparent depth of field in the image. For now, I'll just post the image:

(click to embiggen)