Preservation of Ancient Human Bones in Africa: Fossilisation and Modern Methods
Over the past century, archaeology has made incredible discoveries that have shed light on our understanding of human evolution. Among these discoveries are the remains of early humans, some dating back more than 100,000 years. How have these bones managed to survive for such an extended period, and what methods are used to preserve them?
Fossilisation: Nature's Preservation Process
When studying ancient human bones in Africa that span over 100,000 years, one cannot ignore the process of fossilisation. This natural preservation method involves the mineralisation of organic materials over time. During fossilisation, minerals replace the original bone structure, effectively "locking" the bone in place and preventing it from decomposing. This process can last for thousands or even millions of years, providing invaluable insights into our past.
Natural Fossilisation Process
The fossilisation process typically begins when an organism's remains are buried quickly in sediment. This prevents the rapid decomposition that would otherwise occur. Over time, minerals in the surrounding sediment gradually replace the original organic material. This transformation can happen over a very long period, often taking millions of years, but can also occur more quickly in certain environments.
Factors Influencing Fossilisation
The preservation of human bones is influenced by several factors, including the chemical composition of the sediment, the surrounding environment, and the depth at which the remains are buried. Bones in arid environments, for instance, have a higher chance of preservation due to the low levels of moisture and the presence of minerals that can aid in the fossilisation process.
Modern Preservation Techniques: A Case Study
While natural fossilisation is a crucial factor in the preservation of ancient human bones, modern preservation techniques have also played a significant role. One such technique involves the consolidation of bones, a process that can restore the integrity of fractured or crumbling bones.
A Case Study: The Fossil Cow Bone Process
A notable example of modern preservation methods is the process used on a 350,000-year-old fossil cow bone from Boxgrove, England. In 1985, researchers employed a technique using Paraloid B72, a methyl methacrylate co polymer. This material was dissolved in acetone and then applied under vacuum to ensure that every pore of the bone was consolidated. The use of Paraloid B72 helps to stabilize the bone and prevent further deterioration.
Consolidation Process
Begin by ensuring the bone is clean and dry.
Prepare a solution of Paraloid B72 in acetone. The ratio of Paraloid to acetone can vary, but a commonly used ratio is 1:10.
Apply the solution under a vacuum to ensure that it penetrates every pore of the bone.
Allow the bone to dry thoroughly before placing it in a controlled environment.
Conclusion
The preservation of ancient human bones from over 100,000 years ago is a complex process that combines natural fossilisation with modern conservation techniques. Whether it be the millions of years of sedimentary processes or the careful consolidation of crumbling bones, these methods have allowed us to uncover the secrets of our past. As technology continues to advance, these preservation methods will undoubtedly become even more sophisticated, providing future generations with a clearer picture of humanity's deep history.