Where has amino acid racemization dating been used, posts navigation
Unlike radioactivity, which is extremely predictable, there are a lot of factors that can affect the rate that amino acids transform from one form to another. The side chain is what allows all the different Amino Acids to have their own specific characteristic.
In these circumstances, it can tell you the last time the rock was heated. Depurination, a hydrolytic reaction, is the primary cause of nucleic acid degradation, and racemization is affected by some of the factors that influence this process.
Chronological information may be conveyed by the presence, absence and form of the bones from one or more animal groups, which were known to have fixed periods of existence, found in a strata at an archaeological site.
In addition to the above limitations of science, historical science is limited by the fragmentary nature of the artifacts it is able to find. Researchers turned to Jeffrey Bada and his colleagues at the Scripps Institution of Oceanography in La Jolla, CA, who are considered experts in the field of racemization analysis.
This might be a very good clue to the existence of a real evolutionary pathway, but not necessarily.
Many decades later, these explorers where found and various studies where done on their bodies. These blocks may result in Demon dating change to the viral protein coat. Paleontological finds from which DNA sequences purportedly millions of years old have been reported show extensive racemization, and the amino acids present are mainly contaminates.
The presence of L-amino acids could indicate contamination, evidence for life, or both. Dethlefsen who applied the methodology to tombstones from 18th and 19th century New England and demonstrated that the popularity of the decorative motifs on the headstones did follow a battleship-shaped distribution over time.
Have a look at my two pages on these issues. They stick together in pairs. The forward Racemization reaction is running at the same rate as the reverse Racemization reaction.
It almost looks like the racemization rate could be independent of the assumed ages of the fossils. Assumptions throughout the scientific process are extremely important because they must hold the facts together. As such, these methods are all relative: When the rate of conversion is known, racemization provides a clock that can be used to determine the time of death.
The non-linear kinetics of Asp racemization have prompted a number of suggestions as to the underlying mechanism s and have led to the use of mathematical transformations which linearize the increase in D-Asp with respect to time.