Continental Drift Contradictions (CDC)

If the mantle is solid where does lava come from? Lava is a liquid is itt not? and it comes from the mantle so how does lava get liquified if the mantle is solid? It seems to me the mantle is liquid and the data from "S"&"P" wave research is modeled incorrectly as is usually the case with modeling. The models are done wrong.

Magma is the liquid silicate rock that you are referring to. It is called lava once it is discharged from the earth. Magma exists in the asthenosphere which is border layer between the crust (lithosphere) and mantle. The asthenosphere is sometimes called the upper mantle. Being the least dense portions of the mantle, magma can be solid floating due to bouyancy upon the more solid mantle. Eruptibility completes the conversion to the liquid phase. While under great pressure, the magma is a super-heated solid, take the pressure off due to faulting and the magma melts and quickly rises up through cracks in the more dense lithosphere. The magma may collect in pockets (or magma chambers). The intense heat of the magma then melts volatiles and crust materials which add to its total volume. The amount of magma in the chamber is what is available to become lava in the event of an eruption.

As is the case with many of the post I have read in the last two weeks or so. Folks bash models. The S and P wave model is not the result of a whim. Volumes of research support it. Continental Drift is an evolving process that can be extrapolated. The present day continents could have been predicted before formation, just as future land forms are being predicted now. Subduction zones in the seafloor are also easily incorporated into the general continental drift theories that are currently supported by most geologists. Chain island formation over hotspots (weak crust that leads straight down to the asthenosphere) is also good evidence. Visit Hawaii. They have subduction, tiki torches, hula girls, and pina coladas......



Mark Vitrone

If rocks remain solid as the pressure increases they behave differently than anything else does. There is a thermodynamic point all matter(except your magna/lava rocks) seems to have called the triple point. Most of what has been done in geology is good but the modeling is as bad as any in this field too. The "P""S" data is good but how it is modeled is pathetic do to the fact it needs to ideas such as MV states about the pressure effecting the triple point of matter.

Sorry Jim. Mark nailed it and you muffed it.

As usual.

LB

Jim, the triple point is the place where a substance is at the solid, liquid and gaseous states simultaneously as a result of clever manipulations of temperature and pressure. I do not understand what evidence leads you to believe that a bad model exists for this topic. The model does not seem to me to be poor as it allows for some predictions to be made. Predicting THAT a volcano will erupt is easy, a few weeks training allows anyone to take the measurements that allow for this. Predicting WHEN a volcano will erupt is difficult. Making tests of hypotheses is also tricky as it is difficult to hold variables constant. Super computers make this job easier because of the models geologists use. Now, every eruption we observe and record adds to the body of evidence because the geological models are evolving with new observations. Since it is not easy to make a volcano erupt we have to be patient and try to make predictions unhindered by politics and money. Oil drilling and natural gas exploration has also helped us understand these things better.

But listen fellas, who knows, we have drilled very deep and still not reached the mantle so far as I last read. But I do need to come to the defense of the current model of the earth not because it is right but because it is very clever and repeatable, everytime there is an earthquake it is further supported.
As for CD, look at a map, you can see where the bloody continents used to be attached, print off a map of the earth get some round tipped scissors, some elmer's glue and some construction paper. Cut out each continent and island and play puzzle. It is fun and instructional. CD is happening!



Mark Vitrone

MV, I agree with most of this but not the modeling part. As for the triple point-if one were to plot this on a T-S diagram(something I don't think has been done) I think you would see it is a horizonal line from the triple point to the liquid/solid phase change. This line is a temperature and whatever the pressure it remains the same. The shell game is when the liquid/vapor phase gets put in the place where the liquid/solid phase is. It would be a good thing to plot this from data rather than shout about it and if I'm wrong so be it. But, I think these phase changes are solid proof the model is wrong and this will be established someday. There are other lines of reasoning indicating this is so. It is too bad poor models are used to replace thinking in the modern world.