'16-10-16, 11:26 '16-10-16, 11:33   Lloyd St. Louis area	Since the present rate of erosion of continents would erode them all to or below sea level within 20 million years, and since the continents were split off the supercontinent that came along with the oceans from an asteroid like Ceres, and since there is very little eroded sediments on the seafloors, the LHB must have occurred much less than 20 million years ago.
'16-10-28, 16:45 '16-10-28, 18:34   Lloyd St. Louis area	Do you have an estimate of how fast hydrogen would have dissociated from water in the stratosphere? And could ozone have formed above the remaining water vapor to protect it from further dissociation?
'16-10-28, 18:30 '16-10-28, 18:32   Charles Chandler Baltimore, MD	I don't have an estimate for how long it would take, but any ozone that might get formed will be heavier than water vapor, and thus the water vapor will percolate above it.