Are Most Fossils Forever Lost Due to Tectonic Plate Movements?

The question whether most fossils have been or will be destroyed due to tectonic plate movements is a complex one that involves geology, paleontology, and the nature of fossilization. While the answer is not absolutely definitive, the evidence suggests that a significant portion of the fossil record has indeed been lost, irrevocably.

Global Geological Struggles

The Earth's crust is in a constant state of flux, with tectonic plates moving, colliding, and subducting. This process means that vast amounts of seabottom sediment, including potential fossil sites, can be eroded and lost to deep-ocean trenches. According to geologists, the subduction zones responsible for this erosion are particularly destructive to fossil records, leading to loss over millions of years.

For example, any fossils embedded in subducted sediment are likely subjected to metamorphism, a process that subjects rocks to intense heat and pressure, heavily altering, and often destroying the original organic structures. Moreover, due to tectonic activity, there is almost no sedimentary record older than 120 million years currently available on the ocean floor.

Escaped Subduction and Preservation

Despite the destruction in some areas, there are also instances where fossils managed to survive. In subduction zones, the subducting plate's bottom edge often undergoes a scraping action, known as the accretion of terrains. This scraping action can cause material to become scraped off and deposited onto the overriding plate, forming terrains like those found in western North America.

These terrains contain fossils from subducted material, making them valuable sites for paleontologists. However, the complex geological processes mean that many of these fossils are often destroyed before they can be discovered. For instance, even well-preserved fossils of larger organisms are exceptionally rare, with most remains being broken down into sand-sized particles that blend into sedimentary rocks or dissolve away.

The Fate of Shallow-Water Fossils

The reality of fossil discovery diminishes further when we consider the vast majority of fossil organisms lived in shallow waters near coastlines. The bones and shells in these areas are frequently broken down by waves and currents, breaking them into tiny, unidentifiable grains. However, there are exceptions. Tiny organisms that are already sand-sized can sometimes be identified as specific species, given that they aren’t too battered.

It's important to note that even the well-preserved fossils that do get discovered are often confined to regions where fossil-bearing sedimentary rocks are exposed at the Earth's surface. This exposure is a rare event, as much of the Earth’s crust is buried under vast amounts of sediment or is locked deep within the Earth’s crust.

Conclusion

In summary, it is highly likely that the vast majority of fossils will never be discovered due to tectonic plate movements. While some fossils manage to survive and be discovered, the geological processes that ensure the gradual destruction and burial of fossilized remains are extensive and often defeating. This underscores the importance of every fossil discovery in reconstructing the Earth's deep history.

Related Keywords

Fossils, tectonic plate movement, fossil discovery