If I may, I would like to restate some of TC's problems in fleshing out his 'theory' of rapid plate tectonics.
TC's 'model' requires very low volatiles in mantle derived upwelling magma at mid ocean ridges. Otherwise, the SO2, CO2 and H2O would have poisoned, greenhoused, and steamed Noah and company.
Unfortunately, low volatiles in the mantle also greatly increases viscosity and melt temperatures. So mantle convection, subduction and oceanic plate formation could never have gotten started in the first place.
The only way out is to postulate vastly higher mantle temperatures to lower the viscosity and facilitate melting. But that doesn't work either... a higher starting temp for the mantle means we have to get rid of that heat very quickly to arrive at today's lower value. The only way to get rid of heat is to increase the amount radiated into space. To do that, we must raise the effective surface temperature of the Earth. That's very hard to do when the surface is blanketed by greenhouse gasses (there had to be SOME volatiles released). Even ignoring greenhouse effects, the surface and atmosphere would have to be thousands of degrees higher (that's my initial guess, anyway) to get rid of all that heat.
I will leave confirmation of my guess to TC. He should calulate the mantle temperature required to lower viscosity by many orders of magnitude while keeping volatiles low, then calculate the black-body temperature required to get rid of that heat in a year or so. The best part is, this calculation requires little or no calculus to get a pretty good approximation.
On a related subject, I came across a useful piece of data that TC has absolutely NO hope of ever reconciling with his mythology...
http://earth.agu.org/revgeophys/sleep00/node9.html
At this site we find a very interesting overview of the effects of water and other volatiles in driving plate tectonics. Near the end is a section on cosmogenic beryllium - 10Be:
quote:
Studies of the cosmogenic isotope 10Be in arc lavas provide strong evidence that water from the slabs is derived in part from subducted sediments and that some sediments are subducted to great depths [ Morris et al., 1990; Edwards et al., 1993; Gill et al., 1993; Leeman et al., 1994]. The half life of 10Be, 1.5 million years is short enough that the isotope is present in young sediments but not in other crust and mantle reservoirs that might enter the magma. The 10Be in sediments needs to be subducted and reach the source region within a few million years to be present in the observed concentrations. The concentration of 10Be, normalized to the concentration of the stable isotope 9Be, shows the variations implied by the geometry of subduction. The ratio 10Be/9Be is low for lavas derived from young hot slabs which dehydrate at depths shallower than the source region compared with lavas derived from old cold slabs that dehydrate at source region depths [ Leeman et al., 1994] and decreases for volcanoes further from the trench. As expected, detectable 10Be is absent in mid-ocean ridge and oceanic island lavas where no slab is present.
So we have evidence that the magmas erupting at MORs and oceanic islands are either older than a few dozen million years, or are derived from primordial mantle material (in the context of TC's model). Which do you prefer, TC?
Either way, to form 10Be at the concentrations found on the surface of the earth requires either a very long time (tens of millions of years), or a cosmic ray flux that was higher by about 10 million times during TC's period of rapid plate teconics. That means Noah and family received about 26 millirems(annual dosage today) times 10 million = 260,000 rems. That's nearly a thousand times the lethal dose. Noah was poached, steamed and
FRIED -
extra cripsy.
After several years of reading the standard creationist debunking material, I do not recall seeing this particular argument. Has anyone else seen this idea before? Or can I claim credit for an additional YEC-bashing tool? (as if we needed any more)
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