SHEPARD (POST-) VINDICATED
re Subaerial Formation of Submarine Canyons
(Google Links on January 25, 2005:
"Mediterranean dry" = 989K; "Mediterranean dry" + Hsu = 3,710)
In the first edition of his book "Submarine Geology" , Francis P. Shepard, nicknamed 'the father of Marine Geology' , attributed the origin of submarine canyons
- usually V-shaped valleys cutting into the continental shelf and slope, in contrast to much deeper trenches
and troughs commonly parallel to the coast and shelf-edge - to subaerial erosion, meaning that they were cut as
terrestrial canyons before being submerged.
Thus, these canyons were supposed to have been cut during low sealevel stands associated with Ice Ages.
In the 1950's, the Dutch father of Marine Geology, Philip Kuenen, attributed canyons to submarine erosion
effected by turbidity currents.
Probably it was Jacques Cousteau who gave the death-blow to Shepard's hypothesis when he pointed out that he had discovered Mediterranean
submarine canyos at depths well beyond the 100 to 200 m of lowered eustatic sealevels
during the last few glacial epochs. Shepard graciously admitted defeat and joined the turbidity current crew.
Then came the astonishing discovery described by Kenneth Hsu of the fact that the Mediterranean had been "dry",
not just once but several times!
|In my lectures, I used to make a chalk-board sketch of the moment that 3 potential counterparts of Sem, Cham and Japhet alerted their dad Noah to the fact that
water had started cascading down through a gap
please click to enlarge
|(the present Strait of Gibraltar)
up there in the 3,000 m high mountain range
separating the (dry) Mediterranean from the (overflowing) Atlantic Ocean; indeed, a seminal moment in Earth's history!
But our four fathers living on the dry desert "floor" of the future Mediterranean Sea might have looked up at the
spectacular canyons cut into Mount Corsica and Mount Sardinia at that time - subaerially. BLO fecit 20050125 - stories
No need for turbidity currents, even though admittedly they explain away abyssal plains!
Question: does your Professor believe in: (a) seafloor spreading ..
(b) subaerial origin of submarine canyons ..
(c) turbidity currents ..(d) all of the above ..(e) none of the above..
Perhaps we should have as much of an open mind about such other possible effects of this "Salinity Crisis" as described in
Discovery of Atlantis by Robert Sarmast (in press? 2005): Excerpts of Chapters:
8. More later, d.v.