Which dating technique would you use to determine the age of a fossil believed to be petrified wood?

Which dating technique would you use to determine the age of a fossil believed to be petrified wood?

• A. Relative dating: superposition
• B. Relative dating: fossil succession
• C. Absolute dating: carbon dating
• D. Absolute dating: potassium-argon (K-AR) dating

Answer: (C)

Dating fossils often relies on radiometric methods that target the material of the fossil itself. For petrified wood, the fossil originated from once-living plant tissue, so it can contain carbon from that original material. Radiocarbon dating measures the decay of carbon-14 in organic material, giving an age estimate for samples up to about 50,000 years. Because this method analyzes the fossil’s own carbon, it provides a direct age for the petrified wood rather than guessing from surrounding rocks. Relative dating methods, like superposition or fossil succession, only tell whether something is older or younger than another layer or fossil — they don’t provide an exact numerical age. Potassium-argon dating, on the other hand, is used to date volcanic rocks or minerals containing potassium and is most informative for much older samples; it dates the rock, not the fossil’s organic matter itself, and is not as direct for dating petrified wood.

Dating fossils often relies on radiometric methods that target the material of the fossil itself. For petrified wood, the fossil originated from once-living plant tissue, so it can contain carbon from that original material. Radiocarbon dating measures the decay of carbon-14 in organic material, giving an age estimate for samples up to about 50,000 years. Because this method analyzes the fossil’s own carbon, it provides a direct age for the petrified wood rather than guessing from surrounding rocks.

Relative dating methods, like superposition or fossil succession, only tell whether something is older or younger than another layer or fossil — they don’t provide an exact numerical age. Potassium-argon dating, on the other hand, is used to date volcanic rocks or minerals containing potassium and is most informative for much older samples; it dates the rock, not the fossil’s organic matter itself, and is not as direct for dating petrified wood.