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Author Topic: Do Geysers Rock your world ?  (Read 3809 times)

Offline neilep

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Do Geysers Rock your world ?
« on: 02/02/2008 18:57:29 »
Dear Geyserologists,

Like my geyser ?




It's being delivered next Tuesday !! I can't wait...because I have a ping pong ball that I want to float on top of it !

I am also informed that geysers only form where certain rock conditions exist ...is this true ?...is this because of the water ?.....or is it because of what provides the heat and the then Orgeyserm ? ;D





 

Offline JimBob

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Do Geysers Rock your world ?
« Reply #1 on: 02/02/2008 21:35:38 »
it is the magmatic heat flow and the continual supply of ground water that forms them.
 

Offline neilep

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Do Geysers Rock your world ?
« Reply #2 on: 02/02/2008 22:32:53 »
it is the magmatic heat flow and the continual supply of ground water that forms them.


Hang On !!...Magmatic ?...you mean .....molten liquid Rock ?......

So, the rock structure conditions at near surface temperature doesn't matter ?
 

Offline opus

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Do Geysers Rock your world ?
« Reply #3 on: 02/02/2008 23:24:14 »
Diamond geyser!
 

Offline Bass

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« Reply #4 on: 02/02/2008 23:35:03 »
I'm gone two weeks and look at the mess I have to clean up!  (That'll teach me for leaving) ::)

With my years of work in Yellowstone, I'm probably the closest thing to a "geezerospecialist".

Geysers require 3 things:
        1. Heat source- most commonly magmatic (but not always!)
        2. Water- lots of it
        3. most critical- a unique plumbing system (we used to stand around Old Faithful a moments before an eruption and shout into the radios- "Flush all the toilets in the lodges" just to watch the reaction of the hordes of tourists as the geyser would erupt shortly thereafter).

Heat source- Like JimBob said, this is most commonly magmatic heat- which is why 75% of the world's geysers are located in Yellowstone Park, and most of the rest in Iceland, New Zealand or on the flanks of other volcanoes.  But, there are a few that tap other sources of heat, caused by faults or in areas where the geothermal gradient is unusually high (a couple of small isolated geysers in Nevada come to mind).

Water- almost all geysers are located in basins adjacent to rivers/creeks or lakes.  Steamboat Geyser in Yellowstone can expel millions of gallons of water in a single eruption.  Large geysers expel thousands of gallons.   Lots of water is required to replenish the system.  If the system is water-starved, mudpots and fumaroles develop instead of geysers and hot springs.

Plumbing system- for a geyser to erupt, the plumbing system must be fairly open at depth (to collect enough water and steam) but it MUST be restricted at the surface (a single small vent or pipe).  The restriction allows the hot water and steam to be forcefully ejected into the air.  If not restricted, the hot water merely bubbles up to the surface as a hot spring.  Excelsior Geyser in the Midway Geyser Basin, Yellowstone, erupted with such force several decades ago, that it blew the surface plumbing system apart.  No longer a geyser, it is now a hot spring that emits something like 4 million gallons of hot water a day.

Geysers have a cycle, which is why some geysers are so predictable.  After an eruption, cool groundwater flows back into all the cracks and crevices deep below geyser.  The water heats up- and because of the high pressures (remember, hundreds of feet of water is fairly heavy), the water becomes superheated (the temperature is greater than the boiling point).  The superheated water is less dense than the overlying cooler water, so it gradually begins to rise, usually pushing water out of the top of the geyser.  Eventually the superheated water rises high enough to overcoming the confining pressure and flashes into steam- expanding significantly.  The expanding steam rushes towards the surface, pushing the remaining  water out of the vent creating the spectacular eruptions we all love.  As the steam rushes out, pressures are further decreased and more superheated water flashes into steam- continuing until the "resorvoir" of water is exhausted.  Virtually all geysers begin with an eruption of water and end with steam eruptions- then the cycle begins anew.

If every geyser were a simple closed system, they would all be predictable.  Because they are open systems, they can lose energy to other parts of the system (like other geysers), or may require more heat to overcome the confining pressures (some geysers only erupt when the water table drops).

In the early days of Yellowstone, a chinese laundry used to use one of the geyser/hot springs to wash the dirty linens.  While washing one day, he added a bit too much soap, causing the spring to bubble up then erupt furiously.  The soap bubbles displaced water and lowered the confining pressure enough to cause an eruption.  Sure enough, during the next Presidential visit to the park, one the rangers had the job of pouring soap into geyser vents just before the President (Harding?) would show up so he wouldn't have to wait too long for an eruption.  I believe it worked for about 60% of the geysers.
 

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Do Geysers Rock your world ?
« Reply #4 on: 02/02/2008 23:35:03 »

 

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