Any geologists out there?

[harryopal1]

I wonder if there are any geologist followers of this website? The reason I ask relates to a post i just made on an an Australian fossicking webdsite remarking on the lovely specimen volcanic, olivine bombs sprinkled with peridot that used to be found (maybe still found) at a place called Mt Shadwell in Victoria.

Mt Agung keeps venting every now and then which makes me wonder if it is reasonable to suppose that one might find similar volcanic, olivine bombs around the flanks of Mt Agung? Are olivine bombs a feature of all erupting volcanoes or does it require a particular type of geological formation.?

 

[snpark]

Don't ask me, I'm too stoned

 

[harryopal1]

Don't ask me, I'm too stoned

"Stoned" or bombed?

 

[Minuteman]

Sorry, I don't have a clue what you are talking about.

 

[snpark]

Rock on Tommy

 

[harryopal1]

Well i response to my searching I got these two replies:

This one from a lapidary forum:
Hi Harryopal, just a quick spot of research on this one, I doubt that you would find olivine bombs near Mt Agung the chemistry isn't quite right. You would typically only see olivine bombs in mafic to ultramafic rocks whereas Mt Agung appears to be more of an Intermediary composition.

And another from a Peter Rendevouz on Facebook:
you'd have greater success looking in hawaii .. there is no olavine bombs as you call them at Agung. Olivine is made up primarily of magnesium, iron, silicon, and oxygen, and the combination of the latter three creates a class of mineral known as an iron silicate. It doesn't come raining from the sky or eruptions.... it can be found in old lava having formed after ejection.
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[Puspawarna]

Well i response to my searching I got these two replies:

...
you'd have greater success looking in hawaii ..

Absolutely. I have a lot of olivine-studded rocks in the house that I picked up on hikes around the lava fields.

 

[harryopal1]

Do they have peridot spirnkled through the olivine?

 

[Puspawarna]

Do they have peridot spirnkled through the olivine?

Not that I know of. The stuff I have looks like this: this.

I'm about to start researching peridot though. You have made me curious.