Question

Which of the following is a chronostratigraphic unit?

• A. Member
• B. Stage
• C. Acme Zone
• D. Period

Hint:

Remember: "Stage" is chronostratigraphic (rock deposited during an age), while "Period" is geochronologic (time span).

Answer 1

The Correct Option is B

Step 1: Understand stratigraphic classification. - Stratigraphy is divided into two main categories: - Lithostratigraphic units → based on rock characteristics (e.g., Formation, Member). - Chronostratigraphic units → based on geological time and rock layers deposited during a specific interval.

Step 2: Recall chronostratigraphic hierarchy. Chronostratigraphic units include: Eonothem, Erathem, System, Series, and Stage.

Step 3: Match options. - (A) Member → a lithostratigraphic unit, not chronostratigraphic. - (B) Stage → correct, a chronostratigraphic unit. - (C) Acme Zone → a biostratigraphic unit. - (D) Period → a geochronologic unit (time unit), not chronostratigraphic (rock unit).

Final Answer: \[ \boxed{\text{Stage}} \]