1. This was “Assumption 1” on page 120. It now reads 60 miles.
As a first approximation, the volume of rock removed was the length of the rupture (46,000 miles) times its average width (about 1400 miles as seen in Figure 54 on page 121), times the unknown depth to the subterranean chamber. Much more difficult to estimate, and not included, was another source of rock removed by the escaping, subterranean water: crushed pillars and rock eroded from the chamber’s floor and ceiling. During the flood, sediments deposited on the continents averaged slightly more than a mile in depth. Fewer sediment were deposited on today’s ocean floors, because they opened up late in the flood, just before the floodwaters drained at the end of the rapid continental-drift phase.
2. T. A. Stern et al., “A Seismic Reflection Image for the Base of a Tectonic Plate,” Nature, Vol. 518, 5 February 2015, pp. 85–88.
3. “The layer contains an estimated 2 percent molten rock, enough to drastically reduce the strength of the rock and essentially grease the overlying plate, like a layer of melted water beneath an ice skater’s blades. Because it is sandwiched between the plate and the mantle, the layer also forms a barrier between the two. That separation challenges the prevailing view that flowing material in the mantle drives plate tectonics, says the geophysicist who let the study, Tim Stern of Victoria University of Wellington in New Zealand.” Thomas Sumner, “Pacific Plate Slides Over Slick Layer: Mantle Might Not Drive Movements After All,” Science News, Vol. 188, 26 December 2015, p. 27.
4. “The existence of such a localized channel probably has implications for the driving forces of plate tectonics and mantle dynamics.” Catherine A. Rychert, “The Slippery Base of a Tectonic Plate,” Nature, Vol 518, 5 February 2015, pp. 39–40.