The ratio for the PDB is .0112372
What I want to know is the actual abundance of each carbon isotope in the PDB and not their ratio.
According to Columbia University the normal carbon isotope abundances are
Carbon-12 .9893 Carbon13 .0107
If I use these normal values to calculate the abundances in Pee Dee Belemnite I get these two possibilities.
Carbon-12=0.9893 Carbon-13=0.0111(normalized)
Carbon-12=0.9522(normalized) Carbon-13=0.0107
Either example shows that the Pee Dee Belemnite is isotope heavy. This carbon was processed by an interstellar flare and the lighter Carbon-12 was preferentially lost to space.
The Pee Dee formation is found directly at the K/T boundary. They found the most isotopically heavy sample of carbon they could (from an interstellar impact) to use as their scientific standard! The Pee Dee Belemnite proves that the K/T boundary is an interstellar impact event.
Had they used the normal isotopic abundance as the standard all of the impact boundaries would show up as positive numbers. That negative or positive sign giving away the impact boundaries must have really annoyed somebody. The PDB standard and their way of calculating it made everything a negative number so that the impact heavy isotope enrichment at extinction boundaries would not stand out so clearly.
Search for (delta c thirteen) or (delta c 13) or carbon isotope ratios to see the calculation.
Does anyone have the directly measured carbon isotopic abundances for the Pee Dee Belemnite carbon standard?
Can anyone explain why this basic information about a “Scientific Standard” is missing or unavailable?
What I want to know is the actual abundance of each carbon isotope in the PDB and not their ratio.
According to Columbia University the normal carbon isotope abundances are
Carbon-12 .9893 Carbon13 .0107
If I use these normal values to calculate the abundances in Pee Dee Belemnite I get these two possibilities.
Carbon-12=0.9893 Carbon-13=0.0111(normalized)
Carbon-12=0.9522(normalized) Carbon-13=0.0107
Either example shows that the Pee Dee Belemnite is isotope heavy. This carbon was processed by an interstellar flare and the lighter Carbon-12 was preferentially lost to space.
The Pee Dee formation is found directly at the K/T boundary. They found the most isotopically heavy sample of carbon they could (from an interstellar impact) to use as their scientific standard! The Pee Dee Belemnite proves that the K/T boundary is an interstellar impact event.
Had they used the normal isotopic abundance as the standard all of the impact boundaries would show up as positive numbers. That negative or positive sign giving away the impact boundaries must have really annoyed somebody. The PDB standard and their way of calculating it made everything a negative number so that the impact heavy isotope enrichment at extinction boundaries would not stand out so clearly.
Search for (delta c thirteen) or (delta c 13) or carbon isotope ratios to see the calculation.
Does anyone have the directly measured carbon isotopic abundances for the Pee Dee Belemnite carbon standard?
Can anyone explain why this basic information about a “Scientific Standard” is missing or unavailable?