From Message 831 we see 35 meters deposited over 42,000 years at Lake Suigetsu. That's 0.8333 mm per year, and over a million years that would result in sediment 833.33 km thick. We know this time because of the annual layers of the diatom/clay varves, confirmed by 14C dating calibrations.
35 meters in 42,00o years is 0.833 mm per year fine. But 1 million times that is only 833,300 mm which is 833
meters not kms.