what is a possible explanation for why strata may be absent from some outcrops
There are several potential explanations for why strata may be absent from some outcrops, including:
1. Erosion: The layers of rock may have been eroded away over time due to weathering, water flow, or other natural processes.
2. Tectonic activity: Folding, faulting, or other geological processes may have disrupted the layers of rock, causing them to be shifted or even inverted, making them difficult to observe.
3. Depositional environment: The area may have experienced periods of non-deposition, where no new sediment was being laid down, resulting in a lack of visible strata.
4. Unconformity: A geologic discontinuity or gap in the rock record may be present, where older layers are missing or have been eroded away, making it difficult to observe the complete sequence of strata.
5. Geological structure: The outcrop may be located in an area where the rock layers are not well-exposed or are obscured by other geological features such as overlying vegetation, soil cover, or human-made structures.