Geological dating techniques

[Loudmouth]

It is true. You were not there. Comparing forensics with the distant past is apples and oranges.

That would be apples to apples. If events in the past create evidence that we can observe in the present, then we can use that evidence to reconstruct the events that happened in the past.

 

[TBDude65]

Not fully understood. How deep is the issue, what makes it happen, - not whether there are zones of subduction. To claim zones of subduction mean that it is understood is wrong.

Another example is the fermi bubbles. (mysterious structures that emanate from the Milky Ways center and extend roughly 20,000 light-years above and below the galactic plane). -NOT understood.
Then there is the recently discovered rectangular galaxy. NOT understood. (The galaxy LEDA 074886 is shaped more or less like a rectangle)

By the way. let's do a fact heck on you. Show the source for plates going deep into the mantle.

Is your issue with imaging the mantle and finding the subducted slabs? Or with currently subjecting slabs?

Subducted slab "graveyards" citations: Seismic evidence for slab graveyards atop the Core Mantle Boundary beneath the Indian Ocean Geoid Low - ScienceDirect
http://www.nature.com/ngeo/journal/v3/n6/full/ngeo855.html?foxtrotcallback=true

Papers on current slab subduction in South America (as an example):
Tectonic implications of tomographic images of subducted lithosphere beneath northwestern South America | Geology | GeoScienceWorld
Geodynamics of flat subduction: Seismicity and tomographic constraints from the Andean margin

The neat thing about the subduction beneath South America is that to there are multiple plates subducting along the east Pacific of SA and Latin America, and also that the angle of subduction changes (which causes corresponding changes, such as the distance the volcanic arc is from the trench)

 

[TBDude65]

It is true. You were not there. Comparing forensics with the distant past is apples and oranges.

No, it really isn't. We still have the physical (not only the rocks, but structures associated with conditions of formation. For sed rocks that includes sedimentary structures like ripples and graded bedding. For igneous and metamorphic rocks, that means the size of the crystals, foliation for mm rx and flow structures for Ig rx) and chemical records.

We use modern observational and experimental (laboratory experiments and/or computer simulations) studies to calibrate how rocks form, how long it takes for them to form, and what the conditions are under which they can and do form.

 

[TBDude65]

Did someone deny plate tectonics? I think the issue is what makes plates move, not whether they do. Science doesn't understand. Like to pretend you do?

There are 2 mechanisms that cause plate motion and both are a consequence of mantle convection.

1) Ridge push: Mid-Ocean Ridges (and Continental Rifts too) are elevated with respect to the sea floor around them, because they rest on a geothermal high as a consequence of mantle up-welling between two adjacent slabs that are diverging away from one another. The mantle convects beneath the ridge, pushing it up. As the elevation increases, the mass at the higher elevation pushes down on the rest of the slab due to gravity (basically the same thing as a glacier pushing itself downslope into the ocean).
2) Slab Pull: the subducting slab beneath an over-riding plate is colder than the mantle into which it subducts. Because it is cold, it is also denser. The subducting slab is being pushed by the Ridge Push, and the cold slab is also being pulled downwards by gravity. Think of it like the video below of a ball chain coming out of a container. Once it starts accelerating downwards, the weight of the subducting portion (the ball chain thrown out of the cup) pulls the rest of the slab with it

 

[time]

That would be apples to apples. If events in the past create evidence that we can observe in the present, then we can use that evidence to reconstruct the events that happened in the past.

Only if you know how things were then.

 

[time]

Is your issue with imaging the mantle and finding the subducted slabs? Or with currently subjecting slabs?

Subducted slab "graveyards" citations: Seismic evidence for slab graveyards atop the Core Mantle Boundary beneath the Indian Ocean Geoid Low - ScienceDirect
http://www.nature.com/ngeo/journal/v3/n6/full/ngeo855.html?foxtrotcallback=true

From your link
" feature on the Earth, whose origin still remains ambiguous...

We attribute these high velocities to the presence of dehydrated high density slab graveyards atop the Core Mantle Boundary beneath the Indian Ocean. Release of water at the mid-to-upper mantle depths due to the dehydration of subducted slabs causing a reduction in density and velocity of the ambient mantle, could be responsible for--"

I think the issue is that they do not fully understand. As some have pointed out here in the past, the inner earth may be heterogeneous from the surface in ways we have no idea about. For example some spiritual feature to the inner earth. One cannot just say something like...the waves took longer, so there must be water slowing them down...or a cold zone..or etc. That is all very well and good as far as speculation goes, but when we realize they admit not fully understanding, it should give us pause to reevaluate conclusions.

The neat thing about the subduction beneath South America is that to there are multiple plates subducting along the east Pacific of SA and Latin America, and also that the angle of subduction changes (which causes corresponding changes, such as the distance the volcanic arc is from the trench)

That may be neat but it doesn't address the issue of them not knowing what really is at work under there and causing the plate movement.

 

[time]

..

 

[time]

There are 2 mechanisms that cause plate motion and both are a consequence of mantle convection.

1) Ridge push: Mid-Ocean Ridges (and Continental Rifts too) are elevated with respect to the sea floor around them, because they rest on a geothermal high as a consequence of mantle up-welling between two adjacent slabs that are diverging away from one another. The mantle convects beneath the ridge, pushing it up. As the elevation increases, the mass at the higher elevation pushes down on the rest of the slab due to gravity (basically the same thing as a glacier pushing itself downslope into the ocean).

NO. That is the general theory. Look at the link where they admitted not knowing. In your explanation, you have the ridge doing something for untold ages. The reality could be that a rapid event in the past was the main factor, and subsequent spreading was just a comparatively minor recent after the fact event. You do not know.

2) Slab Pull: the subducting slab beneath an over-riding plate is colder than the mantle into which it subducts. Because it is cold, it is also denser.

Maybe. But merely relying on seismic waves is not sufficient evidence to reach such sweeping conclusions.

The subducting slab is being pushed by the Ridge Push, and the cold slab is also being pulled downwards by gravity.

Or maybe a rapid event rammed the plates causing subduction, in which case, your conclusion would need revisiting.

Think of it like the video below of a ball chain coming out of a container. Once it starts accelerating downwards, the weight of the subducting portion (the ball chain thrown out of the cup) pulls the rest of the slab with it

Do we know what gravity is like down there? If so, what are the tests? Do we know what the consistency of the crust and mantle and rock was at the time of the rapid event? (or do you insist on a narrow view and looking at it only as if it was a great ages event?) Do we know that thermodynamics is at work there as it is on the surface, and if so, how? You would be best to say you just don't really know.

 

[Job 33:6]

NO. That is the general theory. Look at the link where they admitted not knowing. In your explanation, you have the ridge doing something for untold ages. The reality could be that a rapid event in the past was the main factor, and subsequent spreading was just a comparatively minor recent after the fact event. You do not know.


Maybe. But merely relying on seismic waves is not sufficient evidence to reach such sweeping conclusions.


Or maybe a rapid event rammed the plates causing subduction, in which case, your conclusion would need revisiting.



Do we know what gravity is like down there? If so, what are the tests? Do we know what the consistency of the crust and mantle and rock was at the time of the rapid event? (or do you insist on a narrow view and looking at it only as if it was a great ages event?) Do we know that thermodynamics is at work there as it is on the surface, and if so, how? You would be best to say you just don't really know.

Its more than just temperatures that cause one slab to move beneath another. Mafic rocks are heavier than felsic. Diamond formation is also caused by subducting carbonaceous material.

@time Do you not believe subduction is real or?

 

[time]

Its more than just temperatures that cause one slab to move beneath another. Mafic rocks are heavier than felsic. Diamond formation is also caused by subducting carbonaceous material.

@time Do you not believe subduction is real or?

A lot of area did get subducted. Today, in slow motion we also have some suducting action. That does not mean the hole theory of PT is correct. That does not mean we know when or how it got that way. That does not mean science fully (to say the least) understands what goes on down there.

 

[Subduction Zone]

A lot of area did get subducted. Today, in slow motion we also have some suducting action. That does not mean the hole theory of PT is correct. That does not mean we know when or how it got that way. That does not mean science fully (to say the least) understands what goes on down there.

Actually it does. We can measure how fast plates move. We can see that they have always moved at roughly the same rate.

 

[TBDude65]

NO. That is the general theory. Look at the link where they admitted not knowing. In your explanation, you have the ridge doing something for untold ages. The reality could be that a rapid event in the past was the main factor, and subsequent spreading was just a comparatively minor recent after the fact event. You do not know.


Maybe. But merely relying on seismic waves is not sufficient evidence to reach such sweeping conclusions.


Or maybe a rapid event rammed the plates causing subduction, in which case, your conclusion would need revisiting.



Do we know what gravity is like down there? If so, what are the tests? Do we know what the consistency of the crust and mantle and rock was at the time of the rapid event? (or do you insist on a narrow view and looking at it only as if it was a great ages event?) Do we know that thermodynamics is at work there as it is on the surface, and if so, how? You would be best to say you just don't really know.

I can see now that there is a larger void of ignorance on geology than I had anticipated. You speak as if you know what you're talking about, but your words betray you and indicate a profound ignorance of the subject. You shouldn't parade about ignorance as knowledge, it makes you an obvious fraud to those of us that know what we are talking about

 

[Loudmouth]

Only if you know how things were then.

The evidence in the present tells us how things were then.

 

[time]

Actually it does. We can measure how fast plates move. We can see that they have always moved at roughly the same rate.

Yes and that measure is --slow! So what?

 

[time]

I can see now that there is a larger void of ignorance on geology than I had anticipated. You speak as if you know what you're talking about, but your words betray you and indicate a profound ignorance of the subject. You shouldn't parade about ignorance as knowledge, it makes you an obvious fraud to those of us that know what we are talking about

Not believing the whole package offered by the speculation of science equals ignorance in your mind. You see, not using the parts of science they are admittedly ignorant about is a very good thing actually. Yes, there WAS subduction, and areas that are subducted. Yes, we see a slow rate of subduction today. The rest, basically is your invention. Rather than resort to name calling and childish behavior, I would suggest you try to support your invented stories, and maybe try to address the OP.

 

[Loudmouth]

Yes and that measure is --slow! So what?

We can also find evidence that plate movements were the same in the past. For example, we can measure the age of the islands and seamounts in the Hawaiian archipelago and Emperor seamounts which were produced by the Pacific plate moving over a nearly stationary mantle plume in the Pacific ocean.

When we measure the age of those mountains and compare their age to their current distance from the hotspot that is currently pushing out lava, we get this graph:

As you can see, there is nearly a straight line. This indicates that the speed of the plate has been nearly constant for the last 70 million years.

 

[Subduction Zone]

Yes and that measure is --slow! So what?

The topic of this thread is geological dating techniques. You also brought up the subject trying to imply that plate tectonics was not understood.

Sadly you just can't admit that you are wrong.

 

[TBDude65]

Not believing the whole package offered by the speculation of science equals ignorance in your mind. You see, not using the parts of science they are admittedly ignorant about is a very good thing actually. Yes, there WAS subduction, and areas that are subducted. Yes, we see a slow rate of subduction today. The rest, basically is your invention. Rather than resort to name calling and childish behavior, I would suggest you try to support your invented stories, and maybe try to address the OP.

I've addressed the OP in an earlier post.

And no, it isn't that you reject something from geology, it's your use of language that tells me you don't know what you're talking about.

 

[time]

The evidence in the present tells us how things were then.

No doubt it tells you things. I think dad pointed out here for years that the present is not actually the key to the past. I have pointed out even longer than that, how time possibly does not exist beyond the bubble of earth. I really don't want to argue about it. I do not accept beliefs about the unknown that you offer.

The evidence says man was here more than twice the time you have believed. That evidence is not in the form of fossils. Dad pointed out that there was no fossils for man in the days of Noah. The evidence I see in recent news is footprints!

"Fossil footprints challenge established theories of human evolution
The footprints are approximately 5.7 million years old and were made at a time when previous research puts our ancestors in Africa -- with ape-like feet."
https://www.sciencedaily.com/releases/2017/08/170831134221.htm
Your story was wrong. Now if you could actually go deep down and observe how things actually are and actually work under the earth, I have no doubt that your stories would be blown to kingdom come there as well. Science preys on ignorance.

 

[Subduction Zone]

Not believing the whole package offered by the speculation of science equals ignorance in your mind. You see, not using the parts of science they are admittedly ignorant about is a very good thing actually. Yes, there WAS subduction, and areas that are subducted. Yes, we see a slow rate of subduction today. The rest, basically is your invention. Rather than resort to name calling and childish behavior, I would suggest you try to support your invented stories, and maybe try to address the OP.

We can also "see" slow rates of subduction in the past. There has never been the rapid subduction of the hydroplate theory of Brown.