The Brief but Violent Life of Monogenetic Volcanoes
A new study in the journal Geology is shedding light on the brief but violent lives of maar-diatreme volcanoes, which erupt when magma and water meet in an explosive marriage below the surface of the earth.
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“Geologist [I'm Climate Change]”
Since: Mar 07
#1 Oct 3, 2012
From the info it seems that the main driving force of the Maar eruption is internal magmatic gas which initially cores out the maar pipe vent.
To remain as a Maar, the magma initially coreing out the pipe must then be fed by hydrothermal explosions into the pipe from the water rich walls which form the Maar when the walls cave in and seal the vent.
Likely explains the occasional cinder cone in the floor of the Maar occuring after the vent collapse.
To form the Maar the magma held in the base crustal fracture must therefore remain at the base of the crust long enough to crystallise out a few mafic minerals and exsolve enough gas to be vigorously explosive when near the surface.
The volcanoes of the basin & range backarc basin would fit the bill rather well as megathrust eventas are ~500 years apart here. The volcanoes of the Mogollon rim & grand canyon area would be even more fit for the bill as their magma would have originated in fractures in the Mexican basin & range (with megathrust crustal relaxation events ~2000-3000 years apart) betwen Sierra Madre & the Rivera plate E. of the Gulf of california rift.
Have a nice day: Ag
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