Published 09/2019- updated 09/2026
Every year, erosion removes enormous quantities of rock and soil from the continents. Rivers then transport billions of tons of this material toward the oceans, where much of it is deposited along continental margins, deltas, and the seafloor. Modern scientific estimates indicate that rivers transport enormous quantities of sediment toward the world’s coastal regions each year.¹
This raises an interesting question: If erosion and sedimentation have been operating for immense periods of geological time, why isn’t there vastly more sediment covering the ocean floor?
The sediment covering the ocean basins is not uniformly distributed. It can be extremely thick near continental margins and major deltas, while large areas of the deep-ocean floor contain comparatively thin sedimentary deposits. This is significant because the continents are continually being eroded while rivers continue transporting sediment toward the oceans.
Simply projecting today’s sediment-delivery rates backward produces a timescale far shorter than billions of years. From a young-earth perspective, this is exactly what we would expect. The oceans have simply not had billions of years to accumulate sediment at anything resembling observed rates.
THE MAINSTREAM EXPLANATION
Geologists do not claim that sediment has been accumulating uninterrupted on the same ocean floor for billions of years. Plate tectonics provides an important part of the conventional explanation. Oceanic crust is continually created at mid-ocean ridges, moves across the ocean basins, and is eventually recycled into Earth’s interior at many subduction zones. Sediment can therefore be scraped from descending plates, incorporated into continental margins, transported into trenches, or carried into subduction zones.
Sediment delivery is also not constant. Climate, erosion rates, sea level, tectonic uplift, glaciation, dams, and changes in river systems can dramatically alter how much sediment reaches the oceans. Modern research demonstrates just how variable this process can be.²
These processes must therefore be considered before simply dividing the amount of sediment presently on the ocean floor by today’s sedimentation rate.
BUT THE OBSERVATION REMAINS
The empirical observation is nevertheless striking: enormous quantities of sediment are being eroded from the continents and transported toward the oceans today, yet the ocean basins do not contain anything approaching billions of years of sediment accumulated at comparable rates.
The biblical Flood model offers another explanation. Much of the sedimentary record would have been produced catastrophically during the Flood and its aftermath, when enormous volumes of water eroded, transported, sorted, and redeposited material on a scale far beyond ordinary modern river systems. After that catastrophe, continued erosion of the continents added more sediment to the relatively young ocean basins.
The amount of sediment on the seafloor does not by itself prove a young Earth because sediment recycling, subduction, and changing erosion rates must be considered. But today’s enormous sediment flux should not be ignored. The comparatively limited sediment cover of the ocean basins deserves consideration when evaluating competing models of Earth’s history.
Sources
- Darby, S. E., et al., “Fluvial sediment supply to a mega-delta reduced by shifting tropical-cyclone activity,” Nature 539 (2016): 276–279. The paper notes an estimated global river sediment delivery to coastal regions of approximately 19 billion tonnes annually.
- Syvitski, J., et al., “Earth’s sediment cycle during the Anthropocene,” Nature Reviews Earth & Environment 3 (2022): 179–196. This review discusses sediment production, transport, sequestration, dam trapping, and the complexity of the global sediment cycle.
