[Fred Nerks]

...The one truly puzzling thing I've run across about the "spreading" seafloors is that layers of sediment are thicker by several orders of magnitude on the newer seafloor than older seafloor. Something else I can't wrap my brain around.

CRUSTAL AGES should do it for you, the oldest crust is at the margins.

[ForGod'sSake]

...the oldest crust is at the margins.

AND the thickest sediment is nearer the mid ocean ridges(NEWEST seafloor), AND possibly on the margins but haven't looked into that. The sediment is very thin to almost non existent on the plains. Go figger...