The great breadths of time.

It's been commented on several times but it looks like you haven't picked up on it: there are chemical processes involed in forming rock too. It is not all a heating and cooling issue.Sedimentary rocks "lithify" through various chemical processes which I don't know anything about.

It does (without all the details) answer the "Why not?". The physics tells us that it takes time for magma to cool. What we've been given so far is a simplified way to approximate how long. It should be obvious that cooling in nature is a LOT more complicated in it's details than Fick's law covers. All the processes you've given would, I think, lengthen the process. We should then consider processes which would shorten it. For example, it water could perculate into it that might cool it faster.I don't recall that we ever applied Fick's law to the Kilehua cooling.

This site explains that the heat in the Earth is trying to escape into space. For us, that would equate "the heat is rising", i.e., from the cores and mantle.I have an old Discover Magazine with an article about a diamond mind (the deepest one on Earth at the time of the article, I believe.) and some scientists took a trip to the bottom and noted how hot it was. I do believe there was some molten material below them (they were in a series of natural caves of some sort with some chasms/cliffs). My point being that, the further down you travel, the hotter it gets, and that heat wants out. So it makes sense to me that the heat is traveling "up" until it disperses to a point that appears cool to us.Obviously I'm in no position to tell you you're wrong, but this is currently where I stand on the subject.

I never said it didn't get hotter as you go deeper. The question is "why".It does not get hotter JUST because you do deeper. The depth doesn't create any heat. It is hotter because you are under a thicker layer of insulation and therefore that level can't cool as fast.At a mile down there is a huge mass of earth underneath you with lots of radioactivity generating heat and modest amount of insulation above you so it is hotter than the surface. Down much deeper and there is a LOT of insulation above you and the heat generated is trapped there so it is much hotter.

I am working my way to there. Wanted to get several my misconceptions taken care of first, and some things clarified. If we can, I would like to wait a little longer before discussing things that could increase the cooling rate. I think that point treads dangerously close to Creationist ideas, and want stay neutral for the purpose of the discussion.

Maybe I'm miss-understanding one of you, but what you wrote here... ...doesn't seem to mean quite the same as what JonF said earlier in the thread when I brought up insulation; Is there a difference between the two statements or is it just the wording?

They are almost the same:We both talk about the temperature lower in the earth but JonF is taking about the cooling of a 'lump' of rock. I'm talking about the earth as a whole.If you are looking at the cooling of a 'lump' then if it is better insulated OR immersed in a hotter environment then it would cool more slowly. The environment lower down is hotter for the reasons we have been discussion.Again, JonF is talking about the individual lump and I am taking about the earth as a whole bulk.Same things being said though.

Whew! I had let the insulation point drop earlier because JonF's statement had me thinking I was wrong. I think we agree here, although my wording may not have implied it; There is some "old" heat trapped in the rock due to insulation of surrounding rock. And while it is a slow process, that heat does escape.Would it be proper to say that this insulation process occurs in "pocket" regions within the Earth, or is it uniform throughout?Also, is it proper to say that the surrounding rock will also remain "warm" while the insulated "pocket" is cooling?Are the above statements a description of conduction {convection being heat transfer within a fluid)?

And I didn't start out 100% certain. yes. Uniform -- in general. However there must be some variation in the insultation from place to place. It is, in the details, messy and complicated. Yes. In fact, I would think that, since the bulk of the Earth is much bigger than even a large pluton and the heat flow is about constant the temperature of the surronding rock will, in the long term remain steady (some temporary local heating because of the hot rock in it). This is ALL to do with conduction. When you get lower down (below the crust) then we start to consider convection. We are talking about surface (or near to it) rock formation so there is, I think, more conduction that convection.

Ned has brought up chemical processes once or twice. I'm not avoiding, just putting it on pause. I think I'm ready to go there now.By chemical process, are we describing creation of the layers/rocks or the creation of heat. If we're just describing "stuff", then I think we can skip it, since I would like to remain with heating and cooling.

"Hampered" is not really the right word. Fick's law still applies and works just as well as long as you properly account for what's happening in and around the region of interest. The process of cooling is the process of cooling and is described by Fick's law but to get the right answer you have to dump in all the data. Sometimes we leave out some of the complicating data and calculate a simpler problem and get a "wrong" answer, but we can often predict how the answer is wrong; that is, we often can tell whether the time we calculated is too short or too long. So a simpler calculation can still be usefulFor example, radioactive decay and heat rising from the depths below add heat to the system. Radioactive decay inside the system adds heat directly; radioactive decay from outside the system and heat rising from the depths below add heat to the system by conduction across the boundary of the system. That extra heat slows down cooling. That is, if you calculate the cooling of a pluton without accounting for radioactivity and heat rising from the depths below, the answer you get will be shorter than the time it will actually take a real pluton to cool. So radioactivity and heat rising from the depths don't help the creationists at all; it just makes things worse for them. (The calculations we do usually do include the external heat but do not include the heat generated by radioactivity inside the pluton).Pressure doesn't have much (if any) effect on cooling ... it is possible for pressure to force the material to change state to a different form that conducts heat differently, but that's rare.The only YEC "discussions" I've seen on how plutons cool involve water, which is an excellent conductor of heat and can absorb quite a bit of heat. Unfortunately for the YECs, water on the outside of the pluton isn't enough, because you would still have to transfer all that heat from the middle of the pluton to the edge, and that takes time. Lots of time. So you need an extensive network of magically formed cracks (don't forget the pluton starts out as liwuid and is under tremendous compressive pressure ... what opens up cracks?), a source of relatively cool water (the magical flood? But we need this water underground ...) and, after the pluton cools, some more magic to close up the cracks and weld the material together, 'cause we don't see those cracks today.Yet another problem with YEC scenarios is the grain size in the plutons. Grains are little chunks of individual minerals in rocks. Crudely put, fast cooling means small grain size, slow cooling means big grain size, and very slow cooling means very big grain size. Plutons have very big grain size. That means very slow cooling. There have been a few experiments that show that fast cooling can occasionally produce large grains under special circumstances, and maybe those circumstances actaully apply "in the wild" once in a while, but they don't always apply in the wild; at least some (if not all) plutons with very large grain sizes cooled very slowly.

Chemical processes are involved in creating solid sedimentary rock from un-consoldiated material, and in creating the particular minerals that form in igneous rock. Although the chemical processes always absorb or release heat (depending on the particula process), in practice the amount of heat is small compared to other sources and can safely be ignored.

It's pretty much just the wording. "Insulation", to most people, means something that is a really horrible conductor of heat. Rocks aren't great conductors of heat, but they're not really horrible at it.If you look back to Fick's law on the first page, there are two things involved; how well the material conducts heat ("K") and the "thermal gradient" (d²T/dx²). If K is very small, heat flows slowly. That's insulation.If d²T/dx² is small, heat also flows slowly. That's not necessaarily insulation, depending on what K is.In the case of the entire Earth, K is sort of middlin'-size and d²T/dx² is very small because of the long distance (dx) from the center of the Earth to the surface. In the case of the upper layers of the Earth, K is still sort of middlin'-size and d²T/dx² is still small, but now it's because the distance (dx) is middlin' and the difference in temperature (dT) is relatively small.

How likely is it that some rock has cooled and reheated in cycles before being disconnected from it's heat source?Can we determine how long a rock has been hot before it began cooling?Is there a "line" that determines when a rock is considered hot?...Does it have to be hot throughout or is the outer region enough?Can we duplicate the heating process in a lab? For instance, can we seal a rock in a container and record an increase in temperature from the readioactive decay? Can we detect an increase in the temperature of the container?

Cyclic cooling and heating largely doesn't happen. "Being disconnected from its heat source" is "physically rising out of the hot interior to nearer the cooler exterior". Then it cools. It doesn't get heated again until it gets sent down to the hotter interior again by subduction, millions of years later. Of course it might get eroded before the subduction happens. Not really.For igneous rocks, no; before they began cooling they weren't rocks, they were molten rock materials. The dating methods we have start the clock ticking when the rock solidifies.For sedimentary rocks, your question is meaningless; cooling is not involved.For metamorphic rocks, we can sometimes find a time that is longer than the time the rock was hot but not molten. Under some circumstances we can look at two radiometric clocks in metamorphic rocks, one of which tells us when the metamorphosis ended (the rock cooled) and the other of which tells us when the parent igneous rock formed (which is obviously before the rock was subducted and reheated). Not a solid one. Depends on what you are looking for. Melting is almost certainly hot. Different minerals melt at very different temperatures. Rocks metamorphose at temperatures significantly under melting, and different minerals start metamorphising at very different temperatures. Enough for what?Just the outer region is enough to burn your fingers if you try to pick it up.Melting requires that all the minerals reach thier melting point, throughout the rock.Re-setting the radiometric clock so the rock looks new to dating methods requires getting the entire rock to some significant percentage of its complete melting temperature. Yes, and yes, and yes. The only thing we can't do in a lab is subject it to high temperature and pressure for a million years or therabouts. Look at the links I posted in Message 18. I think you need to spend more time reading the links and studying the material.