by ibelieveindevil » Sat Dec 01, 2012 5:46 pm
by Baarb » Sun Dec 02, 2012 1:55 am
by WillP » Wed Dec 19, 2012 3:26 am
by ibelieveindevil » Fri Dec 28, 2012 5:34 pm
by dadndave » Fri Dec 28, 2012 7:45 pm
by ibelieveindevil » Sun Dec 30, 2012 11:14 am
by dadndave » Mon Dec 31, 2012 11:46 am
by nartreb » Thu Jan 03, 2013 7:32 pm
In reality all rocks are ultimately volcanic in origin
by ibelieveindevil » Fri Jan 04, 2013 4:08 pm
nartreb wrote:In reality all rocks are ultimately volcanic in origin
Nope. Lots of rock is sedimentary in origin. The sediment is often biological in origin - calcium-rich shells of dead plankton, for example. (I suppose the calcium was mostly in magma during the formation of the Earth....)
edit: I think you meant "all mountains are ulitmately volcanic in origin". I think that's basically right, if extremely indirect: the himalaya, for example, are pretty far from any expanding mid-ocean ridges (definitely volcanic) that are indirectly pushing India into Asia. And for certain definitions of "mountain", I could point to peaks formed by meteor impact or a few other non-volcanic processes.
Re the "side peak": Wikipedia mentions a "bogong volcano" and maps it to a small bump in the middle of a slope, tens of miles from the summit of Mt Bogong. It's possible that's simply an incorrect set of coordinates for Mt Bogong, or it could be that "bogong volcano" means something different from "mt bogong". (Or maybe there is a "bogong volcano" that's distinct from Mt bogong, AND wikipedia has its coordinates wrong ) Wikipedia doesn't cite useful sources in this case, and I know nothing about Australian geography.
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