Question

In a sedimentary succession shown in the figure, the last occurrence of the fossil species Q (dated 50 Ma) and the first occurrence of the fossil species R (dated 30 Ma) are recorded at Y and X, respectively. The estimated rate of sedimentation is (assume constant rate of sedimentation). 

Hint:

The rate of sedimentation can be calculated by dividing the depth difference by the time difference between fossil occurrences.

Answer 1

Correct Answer: 2

Step 1: Understanding the question.
The question provides the ages of two fossil species (Q and R) at different depths in the sedimentary sequence and asks for the rate of sedimentation.
Step 2: Analyzing the solution.
The rate of sedimentation is calculated using the formula: \[ \text{Rate of Sedimentation} = \frac{\text{Depth difference}}{\text{Time difference}} \] From the figure:
- The depth difference between Y (Q) and X (R) is 20 meters.
- The time difference between the first and last occurrences is 50 - 30 = 20 million years.
Thus, the rate of sedimentation is: \[ \text{Rate of Sedimentation} = \frac{20 \, \text{m}}{20 \, \text{million years}} = 1.0 \, \text{m/million years} \] Step 3: Conclusion.
The correct answer is 1.0 m/million years.