Virginia's volcanic past: Mole Hill and Trimble Knob
Virginia has two extinct volcanoes, Mole Hill and Trimble Knob. What are the odds of us Virginians dying in a pyroclastic flow? Rest assured that Virginia's two best-known volcanoes - Mole Hill in Rockingham County and Trimble Knob in Highland County - are in no danger of blowing their tops.Full Story
“Geologist [I'm Climate Change]”
Since: Mar 07
#1 Dec 19, 2012
Nice little article about 2 nice little volcanoes.
may be related to the random ocean island volcano and seamount volcanoes where a small hotspot creates a magma disc which sits at the base of the crust for several million years before it finally erupts due to a tectionic flexure or a concentration of gas imbalances the system.
A similar one in the UK is the cretaceous "wolf rock" S. of Cornwall on the edge of a basin in the English Channel; A continental flexure example.
A 2nd which is more to the liking of the USA is the Leucite hills of Wyoming (formed ahead of the arrival of the Yellowstone hotspot in the outflow bow shock); A gas imbalance example. That last one (Leucite hills) is famous for the vast variety of rick named coined for the ultramafic nodules found in the alkali basalt. It is also infamous for the number of ul-tramafic word breaks issued by cal-tech in the igneous petrology papers on the nodules.
The host alkali basalt has apparently throughout the time only been mentioned in passing.
Will like to hear more of the basalt composition.
Have a nice day: Ag
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