Which dating technique would be most appropriate to determine the age of petrified wood?

Which dating technique would be most appropriate to determine the age of petrified wood?

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

Answer: (B)

Petrified wood is fossilized plant material that has been replaced by minerals, so you’re dating rock-like material rather than remaining organic tissue. Carbon-14 dating relies on measuring a once-present organic carbon isotope, but that carbon is typically gone or heavily altered in petrified wood, and radiocarbon dating is effective only up to about 50,000 years. Since petrified wood is often millions of years old, radiocarbon dating isn’t suitable here. Potassium-argon dating, on the other hand, measures the decay of potassium-40 to argon-40 in minerals that contain potassium, such as certain feldspars or micas, and is widely used for older samples—from tens of thousands to billions of years old. In practice, dating petrified wood often involves dating surrounding volcanic material (ash beds or intrusions) or the mineral matrix within the fossil if it contains suitable minerals, providing a numeric age for the fossil’s context. Relative dating methods, like fossil succession or the principle of superposition, can tell you whether the fossil is older or younger than other layers or fossils but do not give an exact numeric age. So, for obtaining an absolute age for petrified wood, potassium-argon dating is the appropriate choice among these options.

Petrified wood is fossilized plant material that has been replaced by minerals, so you’re dating rock-like material rather than remaining organic tissue. Carbon-14 dating relies on measuring a once-present organic carbon isotope, but that carbon is typically gone or heavily altered in petrified wood, and radiocarbon dating is effective only up to about 50,000 years. Since petrified wood is often millions of years old, radiocarbon dating isn’t suitable here.

Potassium-argon dating, on the other hand, measures the decay of potassium-40 to argon-40 in minerals that contain potassium, such as certain feldspars or micas, and is widely used for older samples—from tens of thousands to billions of years old. In practice, dating petrified wood often involves dating surrounding volcanic material (ash beds or intrusions) or the mineral matrix within the fossil if it contains suitable minerals, providing a numeric age for the fossil’s context.

Relative dating methods, like fossil succession or the principle of superposition, can tell you whether the fossil is older or younger than other layers or fossils but do not give an exact numeric age. So, for obtaining an absolute age for petrified wood, potassium-argon dating is the appropriate choice among these options.