ASBOG Practice Exam

Post-depositional features useful to orient strata include which of the following?

1. Bioturbation, climate changes, organic remains

2. Ripples and ripple markings, sole markings, erosional phenomenon

3. Lithological variation, sediment size, mineral composition

4. Fossil assemblages, tectonic shifts, volcanic activity

The correct answer is: Ripples and ripple markings, sole markings, erosional phenomenon

Post-depositional features are significant for determining the orientation and conditions of stratified rocks after they have been deposited. The correct choice highlights features that directly modify or are evident on the sediment surfaces or within the sedimentary layers, allowing geologists to interpret the depositional environment and changes over time. Ripples and ripple markings are essential indicators of shallow water conditions and can suggest flow direction, which is critical for understanding sediment transport and deposition. Sole markings, or features at the base of sedimentary layers caused by erosion or bioturbation, provide insight into the processes that occurred at the time of deposition. Erosional phenomena, which reflect the forces that acted upon the surface of the sediments after they were laid, can indicate changes in environmental conditions that influenced the layering and current structure of the strata. These features collectively provide valuable clues about the physical environment and processes that affected the sediment after deposition, thereby assisting geologists in accurately interpreting the geological history recorded in the strata.