5:15 PM - 7:15 PM
[BPT04-P07] Early diagenesis during fossilization process of whalebone by fossilization experiments in shallow marine environment
Keywords:taphonomy, whalebone, diagenesis
Fossilization processes are mainly studied by observation of fossil assemblages and chemical analysis. There are also some experimental studies using living organisms, but are limited to small-scale, short-term studies. It is difficult to understand the entire process of fossilization at such an experimental scale, and large-scale and long-term studies are needed to comprehensively understand the fossilization process, especially for large organisms. Experiments conducted in natural environments are effective in overcoming these research challenges.
This study aims to clarify the initial fossilization process of whale remains through long-term fossilization experiments over a period of about four years in a natural environment.
In this study, three whale carcasses were submerged in Tsukumo Bay, Noto Peninsula, Ishikawa Prefecture in 2020. Stereomicroscopic and scanning electron microscopic observations, thin section observations, and Raman spectroscopic analysis were conducted to clarify the changes within the whalebone after submergence.
White substance composed of carbon, oxygen, and calcium was formed in the whalebone. This white material is believed to be organic crystals bound to calcium. It is also thought to from by anaerobic decomposition of organic matter in the whalebone, and was observed to develop from near the surface of the bone approximately at least one year after deposition.
The Ca-bonded organic crystals resembled carbonate minerals found in fossil bones in both shape and elemental composition. This suggests that Ca-bonded organic matter crystals serve as precursors to carbonate minerals such as those found in fossil bones.
Conventionally, carbonate minerals have been thought to precipitate directly upon decomposition of the remains. However, no mineral precipitation was observed within the whale bones in this study, and Ca-bonded organic matter crystals were formed. This raises the possibility that Ca-bonded organic matter crystals form as the organic matter in the bone decomposes, and eventually mineralize into carbonate minerals.
This study successfully elucidated a previously overlooked aspect of the bone fossilization process through long-term in vivo experiments in natural environments.
This study aims to clarify the initial fossilization process of whale remains through long-term fossilization experiments over a period of about four years in a natural environment.
In this study, three whale carcasses were submerged in Tsukumo Bay, Noto Peninsula, Ishikawa Prefecture in 2020. Stereomicroscopic and scanning electron microscopic observations, thin section observations, and Raman spectroscopic analysis were conducted to clarify the changes within the whalebone after submergence.
White substance composed of carbon, oxygen, and calcium was formed in the whalebone. This white material is believed to be organic crystals bound to calcium. It is also thought to from by anaerobic decomposition of organic matter in the whalebone, and was observed to develop from near the surface of the bone approximately at least one year after deposition.
The Ca-bonded organic crystals resembled carbonate minerals found in fossil bones in both shape and elemental composition. This suggests that Ca-bonded organic matter crystals serve as precursors to carbonate minerals such as those found in fossil bones.
Conventionally, carbonate minerals have been thought to precipitate directly upon decomposition of the remains. However, no mineral precipitation was observed within the whale bones in this study, and Ca-bonded organic matter crystals were formed. This raises the possibility that Ca-bonded organic matter crystals form as the organic matter in the bone decomposes, and eventually mineralize into carbonate minerals.
This study successfully elucidated a previously overlooked aspect of the bone fossilization process through long-term in vivo experiments in natural environments.