Radiocarbon dating bone collagen

Carbon-14 is produced in the upper atmosphere when cosmic rays bombard nitrogen atoms.The ensuing atomic interactions create a steady supply of c14 that rapidly diffuses throughout the atmosphere.The objective of pre-treatment is to ensure that the carbon being analyzed is native to the sample submitted for dating.

The collagen fraction usually yields more reliable dates than the apatite fraction (see Dates on bones).Plants take up c14 along with other carbon isotopes during photosynthesis in the proportions that occur in the atmosphere; animals acquire c14 by eating the plants (or other animals).During the lifetime of an organism, the amount of c14 in the tissues remains at an equilibrium since the loss (through radioactive decay) is balanced by the gain (through uptake via photosynthesis or consumption of organically fixed carbon).Acids may be used to eliminate contaminating carbonates.Bases may be used to remove contaminating humic acids.

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