I recently learned that ice is considered to be a rock by Geologists.

[Fort Fun Indiana]

I'm not a geologist ... but I think if you put that much pressure on granite, an igneous rock, it changes into gneiss, a metamorphic species ... I haven't tumbled either so I don't know ...

Yes, past a certain pressure, it will flow like liquid. But over large time scales, solid rock can also slowly "flow". As can ice (obviously).

 

[westwall]

I'm not a geologist ... but I think if you put that much pressure on granite, an igneous rock, it changes into gneiss, a metamorphic species ... I haven't tumbled either so I don't know ...

No, gneiss is a product of sedimentary rock being put under high pressure and heat.

 

[ReinyDays]

Yes, past a certain pressure, it will flow like liquid. But over large time scales, solid rock can also slowly "flow". As can ice (obviously).

I can tell you right now ice will not tumble, it will melt ... and besides, it's soft enough to cut with a wood saw ...

I don't know enough about geology to say why it would be useful to consider ice as a rock ... it certainly doesn't explain the exotic properties, far from it ...

Water is special ... in almost every way ... and she's given special treatment in just about every scientific discipline I've explored ... especially meteorology ... paradoxically exotic for the fourth most common substance in the universe ...

 

[ReinyDays]

No, gneiss is a product of sedimentary rock being put under high pressure and heat.

Both ... gneiss has to do with temperature and pressure ... er, sedimentary rock can be composed of granite ... then metamorphed into gneiss ...

Granite is specifically iron-rich lava cooled very very slowly ... so that each individual mineral crystalizes in order ... forming the crystals we see in the granite matrix ... temperature and/or pressure changes this into the "slate to gneiss" spectrum ...

1,000 minerals under 10,000 different conditions produces many types of metamorphic rock ... all I care about is if they tumble well ... I picked gneiss because I didn't think lower temperatures and pressures would affect granite ... that's some hard stuff ... tumbles well ...

 

[westwall]

Both ... gneiss has to do with temperature and pressure ... er, sedimentary rock can be composed of granite ... then metamorphed into gneiss ...

Granite is specifically iron-rich lava cooled very very slowly ... so that each individual mineral crystalizes in order ... forming the crystals we see in the granite matrix ... temperature and/or pressure changes this into the "slate to gneiss" spectrum ...

1,000 minerals under 10,000 different conditions produces many types of metamorphic rock ... all I care about is if they tumble well ... I picked gneiss because I didn't think lower temperatures and pressures would affect granite ... that's some hard stuff ... tumbles well ...

No, granite is an igneous rock. If you melt a gneiss you will end up with either diorite, granodiorite, monzanite, quartz monzanite, or granite, depending on what the mineral content was. If you melt granite, you get granite.

 

[ReinyDays]

No, granite is an igneous rock. If you melt a gneiss you will end up with either diorite, granodiorite, monzanite, quartz monzanite, or granite, depending on what the mineral content was. If you melt granite, you get granite.

If you melt granite ... and let it cool on the surface ... you get rhyolite ... the extruded form of silica-rich magma ...

Or do you mean fractionally melting granite ... and if we melt all the quartz do we still have granite? ... like you say, granite is igneous and formed from cooled magma coming up from below ... if we re-melt the rock and let it change form, then it's not igneous anymore, it's metamorphic ... maybe not gneiss, but it's not igneous ...

 

[westwall]

If you melt granite ... and let it cool on the surface ... you get rhyolite ... the extruded form of silica-rich magma ...

Or do you mean fractionally melting granite ... and if we melt all the quartz do we still have granite? ... like you say, granite is igneous and formed from cooled magma coming up from below ... if we re-melt the rock and let it change form, then it's not igneous anymore, it's metamorphic ... maybe not gneiss, but it's not igneous ...

Correct, the grain size has to do with the time taken to cool the melt. Diorite and its host of derivatives creates andesite. Any rock that COMES from a melt is igneous. Metamorphic rocks never completely melt. That's why they are metamorphic. The path to become a gneiss starts with mud. Which alters to mudstone, which alters to a slate, which alters to a phyllite, which alters to a schist, which alters to a gneiss, which then finally melts again to start the process all over again


I AM a geologist.

 

[Vastator]

On Pluto, ice is as hard as granite.
Technically, I believe that glass is also a "highly viscous fluid" that merely acts like a solid at room temperature, and very old windows are often seen to develop sags and things in them.

Glass can be widely defined as an amorphous solid. An amorphous solid can be considered to have a random arrangement of atoms, such as observed in a gas, but more realistically can considered to only lack long-range order such as those found in crystalline solids.

Glass (Amorphous Solids)

Qualitative introduction to glasses (silica, metallic, etc.) and their role as materials optically, electrically, and thermally.

search.app

 

[ReinyDays]

Correct, the grain size has to do with the time taken to cool the melt. Diorite and its host of derivatives creates andesite. Any rock that COMES from a melt is igneous. Metamorphic rocks never completely melt. That's why they are metamorphic. The path to become a gneiss starts with mud. Which alters to mudstone, which alters to a slate, which alters to a phyllite, which alters to a schist, which alters to a gneiss, which then finally melts again to start the process all over again


I AM a geologist.

I'm learning geology through Wikipedia ... so major gaps everywhere with my knowledge ... but I'm not completely clueless down in the river's gravel bed looking for agates ... not completely ...

I have a sharp piece of quartz ... if I can't scratch the rock, it's worth tumbling ... which means only two types of metamorphic rocks ... [giggle] ... extruded materials are full of gas bubbles and never seem to take a polish ... pumice is a good example, they float in water they have so many air pockets ...

 

[westwall]

I'm learning geology through Wikipedia ... so major gaps everywhere with my knowledge ... but I'm not completely clueless down in the river's gravel bed looking for agates ... not completely ...

I have a sharp piece of quartz ... if I can't scratch the rock, it's worth tumbling ... which means only two types of metamorphic rocks ... [giggle] ... extruded materials are full of gas bubbles and never seem to take a polish ... pumice is a good example, they float in water they have so many air pockets ...

Ohhhhh, wiki is terrible for geology. Try Britannica. Or better yet look through the material online from The Mackey School of Mines, or any other Earth Sciences departments out there.

As far as the gas issue goes, the spectrum runs from basalt/gabbro on the low end of gas to rhyolite/granite on the high end. You can see the difference in the types of volcanic eruptions.

Low gas basalt is quite moderate and flows easily. You can get very close to magma on the surface and be quite safe, so long as you're not a moron.

Rhyolitic eruptions are tremendously destructive most of the time. They are the creators of the giant volcanic caldera's such as made Yellowstone and Mammoth.

Rarely they erupt as a plug of magma forced up out of the ground like a tube of toothpaste. Mt. Lassen is an example of that.

 

[ReinyDays]

Ohhhhh, wiki is terrible for geology. Try Britannica. Or better yet look through the material online from The Mackey School of Mines, or any other Earth Sciences departments out there.

As far as the gas issue goes, the spectrum runs from basalt/gabbro on the low end of gas to rhyolite/granite on the high end. You can see the difference in the types of volcanic eruptions.

Low gas basalt is quite moderate and flows easily. You can get very close to magma on the surface and be quite safe, so long as you're not a moron.

Rhyolitic eruptions are tremendously destructive most of the time. They are the creators of the giant volcanic caldera's such as made Yellowstone and Mammoth.

Rarely they erupt as a plug of magma forced up out of the ground like a tube of toothpaste. Mt. Lassen is an example of that.

I'll look into that ... or just buy a damn textbook ...

Rhyolite is what we have here to the east ... ocean floor scrapings to the west ... arch-typical volcanic arc ... Cascadia Rain Forest ... must be 100 sq miles of pumice near Crater Lake ...

Technically it's not true there's an active volcano inside Portland city limits ... it's a cinder cone ... so it's safe until the next 9.8 M earthquake ...

 

[westwall]

I'll look into that ... or just buy a damn textbook ...

Rhyolite is what we have here to the east ... ocean floor scrapings to the west ... arch-typical volcanic arc ... Cascadia Rain Forest ... must be 100 sq miles of pumice near Crater Lake ...

Technically it's not true there's an active volcano inside Portland city limits ... it's a cinder cone ... so it's safe until the next 9.8 M earthquake ...

I'll look into that ... or just buy a damn textbook ...

Rhyolite is what we have here to the east ... ocean floor scrapings to the west ... arch-typical volcanic arc ... Cascadia Rain Forest ... must be 100 sq miles of pumice near Crater Lake ...

Technically it's not true there's an active volcano inside Portland city limits ... it's a cinder cone ... so it's safe until the next 9.8 M earthquake ...

Yeah you're referring to Mt. Tabor correct? That's a part of the Boring Lava Field, I think it's classified as dormant, not extinct, though I could be wrong about that. IIRC the last eruption in that area was around 50,000 years ago.

 

[ReinyDays]

Yeah you're referring to Mt. Tabor correct? That's a part of the Boring Lava Field, I think it's classified as dormant, not extinct, though I could be wrong about that. IIRC the last eruption in that area was around 50,000 years ago.

Cinder cones are usually one-and-done ... part of the plumbing under Mount Hood ... and Mount Hood is "active" ... I think I have my terminology correct to say this is a rhyolite producing system ... melts from the mid-lithosphere mixed with the surface basalts from the subducting plate ... I guess ... so "active" meaning thousands of years ...

Like Pinatubo ... not Krakatoa ...

 

[westwall]

Cinder cones are usually one-and-done ... part of the plumbing under Mount Hood ... and Mount Hood is "active" ... I think I have my terminology correct to say this is a rhyolite producing system ... melts from the mid-lithosphere mixed with the surface basalts from the subducting plate ... I guess ...

Pinatubo ... not Krakatoa ...

Actually that whole region is a series of volcanic island arcs, so the dominant volcanic material is andesitic. Midway along the gas content, so you can have mild or violent eruptions. The flood basalt areas, like Boring, are the stitching that hold the region together.

Pinatubo and Krakatoa are both stratovolcanoes, Krakatoa just happens to have a bit more silica in it's melt which makes it more dangerous. That and it is right on the ocean. So the major explosions have been phreatomagmatic. Big big big booms with those.

Same thing happened with Mt. St. Helen's. Earthquake dislodged a large slab of material which brought the glacier in direct contact with the magma body, and BOOM.

 

[ReinyDays]

Actually that whole region is a series of volcanic island arcs, so the dominant volcanic material is andesitic. Midway along the gas content, so you can have mild or violent eruptions. The flood basalt areas, like Boring, are the stitching that hold the region together.

Pinatubo and Krakatoa are both stratovolcanoes, Krakatoa just happens to have a bit more silica in it's melt which makes it more dangerous. That and it is right on the ocean. So the major explosions have been phreatomagmatic. Big big big booms with those.

Same thing happened with Mt. St. Helen's. Earthquake dislodged a large slab of material which brought the glacier in direct contact with the magma body, and BOOM.

The May of 1883 eruption at Krakatoa was a classic Plinian eruption ... it was all the sea water that seeped into the magma chamber afterward that caused the violent eruption in November of the year ... I think we'll find the same mechanic for the second eruption at Tonga Tonga ...

The Cascade volcanoes are too far inland to get much sea water intrusion ... we just get normal pyroclastic flows, thank goodness [giggle] ... 700ºC at 700 mph winds are enough to ruin the day ... sure don't want steam explosions at the same time ...

Nothing a few mega-thrust earthquakes can't fix ...

 

[westwall]

The May of 1883 eruption at Krakatoa was a classic Plinian eruption ... it was all the sea water that seeped into the magma chamber afterward that caused the violent eruption in November of the year ... I think we'll find the same mechanic for the second eruption at Tonga Tonga ...

The Cascade volcanoes are too far inland to get much sea water intrusion ... we just get normal pyroclastic flows, thank goodness [giggle] ... 700ºC at 700 mph winds are enough to ruin the day ... sure don't want steam explosions at the same time ...

Nothing a few mega-thrust earthquakes can't fix ...

Or cause.....that's the thing about thrust faults, they give, and they take.

 

[ReinyDays]

Or cause.....that's the thing about thrust faults, they give, and they take.

I'm a bit of a gardener ... boy, do these volcanoes give ... these clay soil grows anything ... I understand why Vesuvius is covered in vineyards ...

 

[westwall]

I'm a bit of a gardener ... boy, do these volcanoes give ... these clay soil grows anything ... I understand why Vesuvius is covered in vineyards ...

Yup. Some of the richest soils on Earth.

 

[RetiredGySgt]

Yup. Some of the richest soils on Earth.

did you all see the story a while ago about how scientists dropped Gophers on mount Saint Helens and how it was just a day thing then they removed them and years later got striking results?

 

[westwall]

did you all see the story a while ago about how scientists dropped Gophers on mount Saint Helens and how it was just a day thing then they removed them and years later got striking results?

I have no idea to what you are referring!