The discovery of dinosaur bones buried deep within the Earth sparks curiosity about how these ancient remains ended up so far beneath the surface. These relics are found underground, a testament to geological processes spanning millions of years. Understanding their journey involves exploring the natural forces that lead to their burial, transformation, and eventual exposure.
Why Dinosaur Bones Are Found Underground
Dinosaur bones are found underground due to specific conditions required for their preservation, primarily rapid burial. After a dinosaur died, its remains needed quick coverage by sediment like mud, sand, or volcanic ash. This protected them from scavengers and decomposition, preventing the bones from being scattered or destroyed on the surface.
Over time, layers of new sediment accumulated on top of the buried remains. This pressure, combined with natural cementing agents, transformed the soft sediments into hard sedimentary rock, encasing the bones. As water rich in minerals, like silica or calcite, seeped into the porous bones, these minerals filled the empty spaces and gradually replaced the original bone material, a process called permineralization. This transformation turned the bones into dense, decay-resistant rock, embedding them deep within the Earth’s crust.
Factors Influencing Current Depth and Exposure
While initial burial places dinosaur bones at considerable depths, their current location and accessibility are influenced by ongoing geological forces. Tectonic uplift, a process where Earth’s crust pushes rock layers upwards, can raise deeply buried sedimentary rock formations containing fossils closer to the surface.
Erosion, caused by wind, water, and ice, gradually wears away overlying rock layers. This continuous removal exposes ancient strata and their contained fossils, making them visible to paleontologists. Faulting, involving breaks and shifts in the Earth’s crust, can also bring deeply buried rock units and their fossils closer to the surface or expose them at different angles. The type of sedimentary rock, such as sandstone or shale, and the rate of erosion in a particular region also determine how quickly fossils become accessible or how deeply they remain buried.
How Deep Dinosaur Bones Are Discovered
Paleontologists employ strategies to locate and uncover dinosaur bones. They begin by identifying promising geological formations, typically sedimentary rock layers from the Mesozoic Era. These rock layers are often exposed in areas with significant erosion, like badlands, where the landscape has been carved away, revealing ancient strata.
Once a potential site is identified, paleontologists conduct surveys, often by walking across the terrain and looking for small fragments of bone weathering out of the ground. Finding even a small fragment can indicate a more complete skeleton buried nearby. Excavation involves carefully removing the surrounding rock, known as overburden, using tools from heavy equipment to smaller tools like awls, chisels, and paintbrushes for delicate work. This meticulous process protects the fragile bones, which are stabilized with glue before being encased in plaster jackets for safe transport to a laboratory for further study.