Reply To: Quartz CAN Form in a Melt!

Home Forums General Discussion Quartz CAN Form in a Melt! Reply To: Quartz CAN Form in a Melt!

#31258
Barry
Participant

The Universal Model (UM) relies very heavily on the claim that the quartz found in nature cannot possibly have formed from molten material. In a recent post, “Quartz is Not Glass. So What?”, I debunked their assertion that only glass, and never minerals like quartz, can form from molten rock. I even provided an example where Dean Sessions had quoted a geology textbook to support his argument, but ignored part of the same paragraph that said experimental petrologists have grown quartz and other minerals from hydrous granitic melts.

I brought this up in the discussion forum on the UM website, but to no avail. The UM Team insists that because it was a “hydrous” granitic melt, that means that it must be just like growing it in a hot, pressurized vat of water like they do in Dean Sessions’ garage. And plus the petrologist must not have really meant “melt” in a literal sense, and besides that the quartz they grew from the… some OTHER thing than a melt that they nevertheless called a melt… didn’t have as big crystals as natural granites. Oh, and there was a lot of stuff about how great the UM is, and how if I would just stop being so stubborn and open my mind to their glorious new vision of science, I could step with them into a triumphant future…. You get the idea.

So anyway, the UM Team is still stuck on the whole “only glass can come from a melt” thing. Because I am a helpful sort of guy, however, I’m going to give their metaphorical pot another stir. That is, even if the UM Team were right that only glass could form from a melt, they would still have a problem. Quartz and other crystals can form from glass.

Yep. It’s called “devitrification,” and I found a really great example for the UM Team to mull over. In 1997, a couple scientists from Stanford and the U.S. Geological Survey published a paper called, “Kinetics of the Coesite to Quartz Transformation” in Earth and Planetary Science Letters. First, they obtained some essentially pure silica glass from Corning, and baked it at 1000 °C and 3.6 GPa pressure for 24 hours. This produced coesite, which is a high-pressure polymorph (same chemical formula, different molecular-scale structure) of quartz. Then they adjusted the conditions to 700–1000°C at pressures of 190–410 MPa, which caused some of the coesite to transform into quartz. There was no water present, although the atoms in the original glass were about 0.1% hydrogen.

Now let’s review a couple of the demonstrably false statements in the UM that this information contradicts.

We know the physical properties of coesite and other high pressure. high temperature, silica-based minerals depicted in the Silica Phase Diagram, because of laboratory experiments conducted by scientists who were able to produce these minerals. After mineral formation, temperature and pressure return to normalized conditions and researchers observe and measure the physical properties of the minerals, such as density and crystal structure. Once heated, the minerals do not revert to natural quartz after they cool and/or with pressure reduction; the properties and crystalline structure of the minerals arc preserved, remaining as they were when formed. (UM, Vol. 1, pp. 102-103)
FALSE. In the experiments I described, coesite was produced from glass, the temperature and pressure were reduced (just not all the way to Earth surface conditions) and quartz formed.

The Moon and other planets, Mars and Mercury, must show the telltale signs of a glass-like crust if they originated from a magmatic melt. (UM, Vol. 1, p. 105)
FALSE. Even if glass were the only possible product of a cooling melt (and it isn’t), the glass could still transform to a crystalline state under the right conditions.