Rock Cycle for Alex

[LewisWildermuth]

Since there seems to be too much shouting in the other thread I've moved this here...

quote:

Originally posted by alexgb00


A science contibutes something to mankind. As far as i know, darwinists haven't contributed anything to society.

Cures for genetic diseases, Gene therapy, a myriad of new drugs, les rejection in transplants, less problems with insulin for diabetics, etc... etc...

Nope can't think of one good thing, a few thousand good things, but just one is hard...

quote:

Think about it carefully. You believe that the earth's surface is slowly getting thicker as dust settles over time. In a couple billion years, the crust has grown a certain thickness, right? It is still piling up. OK, from where did all this sediment come? It doesn't make any sense to me. I can understand layers forming in a sudden catastrophe, like a volcanic eruption, or a flood.

Did you skip all of your high school science classes?

Let's introduce you to one concept... The Rock Cycle...

http://www.science.ubc.ca/~geol202/.../rockcycle.html

http://www.bbc.co.uk/education/rocks/rockcycle.shtml

http://www.rocksandminerals.com/rockcycle.htm

But becareful, you might learn something if you click these links...

And you know the danger of learning the truth... It might just set you free you know...

 

[alexgb00]

Alex... Me? Hey hey! I have a thread dedicated to me! Cool.

Lewis, i'm kind of sleepy now. But i'll be back.

 

[LewisWildermuth]

Yes sir, i did. Sorry i didn't reply right away.

I have seen this before, but i still don't understand how the thickness of the crust can always increase. Unless the crust sinks under our feet into the magma underneath, slowly moving down, i don't get how the sediment can increase continuously forever. I hope you know what i mean, because it's difficult to explain.

God bless you!

Basicly yes. Once you get so deep the rocks remelt.

I just noticed you live in Oregon, I'm just a bit north of you in Washington, we sit right on top of one of the pacific subduction zones, the volcanos around here are caused by the pacific plate that is being pushed benieth us and melting. Every once in a while some of it bubbles up and one of the volcanos blow.

Neat huh?

 

[alexgb00]

Yeah, it's interesting stuff. By the way, i live in Portland Oregon, which is right across the river from Washington. I see you live in Tacoma. I've been past there last week when i went to SeaTac to meet some people.

When i talk to someone online, i imagine them far away, like in Texas. But sometimes they are pretty near.


OK, i'm asleep now. I'll talk to you later. God bless you, Lew!
Alex

 

[alexgb00]

Good morning, Lewis!

I wanted to ask you, do you remember that earthquake around February 2001? We felt it here, but not much. I heard that it was a lot closer to Tacoma.

By "remelt," do you mean that the crust itself cycles downward? I haven't heard that. I read that the plates slide sideways and the oceanic ones come under the continents. Do you know how long it takes for a surface layer to sink down to the melting place? Probably a longer time than we can imagine, but this would destroy all the fossils underground.

Excuse me for the simple vocabulary -- i'm not a geologist, you see.

 

[LewisWildermuth]

Well, niether am I, but I was curious so I read a lot of books.

Yes, it seems that as rocks get burried deeper and deeper they remelt. That, combined with gravity keeps the mountians from poking into space.

Yes it destroies the fosils that may have been in that rock, but it can make some cool things.

Marble is one of those cool things. Marble is limestone that either got burried so deep that it started to melt and then was pushed back up or had a magma plume come close to it. All the fosils in the limestone are destroyed, but we now have a neat new type of rock.

 

[LewisWildermuth]

Oh and yes I remember it well, Tacoma was close but Seattle got hit harder, go figure...

 

[euphoric]

Originally posted by alexgb00
Good morning, Lewis!

I wanted to ask you, do you remember that earthquake around February 2001? We felt it here, but not much. I heard that it was a lot closer to Tacoma.

By "remelt," do you mean that the crust itself cycles downward? I haven't heard that. I read that the plates slide sideways and the oceanic ones come under the continents. Do you know how long it takes for a surface layer to sink down to the melting place? Probably a longer time than we can imagine, but this would destroy all the fossils underground.

Excuse me for the simple vocabulary -- i'm not a geologist, you see.

The idea you're describing does occur and it's called subduction.  To find a graphical description of the process click here.  I'm sure those around here who are better versed in geology than I can offer you resources for detailed information if you want.

-brett

 

[Late_Cretaceous]

Oceanic plates do indeed cycle. Of all the ocean floors in the world, all are less then 250 MY old. Not very old in a 4.5 billion year old world. COntinental landmasses are slightly different. Contintents are composed of lighter, more bouyant materials then the basalt of the ocean floor. Imagine, if you will, a small wier in a stream. The water flows over the wier but the froth on top stays in place. A good place to see this is at a sewage treatment plant. As crustal plates colide one will be pushed underneath the other to melt in the mantle (recyled), if there is continental land mass on one of the two colliding plates it will stay afloat. This is happening on the west coast of south america. Volcanoes are produced because of the titanic heat and chuning magma. Continents are the only places where very old rocks are preserved.

BTW, rock can and does flow on large scales. Take a look at a world map (especially one that depicts the ocean floor). Along some of the ocean trenches you will see strings is islands. The aleutians, the windward and leeward islands of the carribean, the south sandwich islands, the kiril islands and others. They all have a trench on the ocean floor. YOu will notice somehting else, they are all arc shaped! AS one plate slides over the other it bulges out, flowing like pancake batter. This is what is predicted in mathematical models of crustal movements.

The recycling of oceanic floor cools the earth's interior. Lubricated by the oceans themselves, the plates plunge into the magma, heating melting as they cool the magma (like ice cubes in coffee). Most of the heat comes from radioactive decay, some of it is left over from the formation of the earth. WIthout this long term cycle the world would look very different. Take Venus for example. It has basalt crust, but without water to soften it and lubricate it, it is too brittle and bouyant to cycle like here on earth. It is beleived that the whole crust undergoes a massive meltdown as the heat from beneath builds up without an outlet. The entire crust of the planet Venus is the same age (300MY). Here on earth, you will find very young crust along the mid atlantic ridge, in some cases less then a million years old. Go out to the eastern edge of the pacific, and the bedrock is much much older.