Final answer:
An increase in global sea level, or transgression, could result in sediment shifts that either preserve or destroy fossils in sedimentary rocks, depending on the environmental conditions and sediment type involved.
Step-by-step explanation:
An increase in global sea level, known as transgression, can significantly influence the preservation of fossils in sedimentary rocks. As sea level rises, new layers of sediment are deposited, shifting sediment types toward the coastline. This shift can cover existing fossils with different types of materials, such as sandstone or limestone, and can result in different layers stacking on top of each other, a phenomenon known as onlapping.
This process is explained by Walther's Law, which states that vertical changes in sedimentary rock sequences reflect the lateral changes in the environment. This means that if a fossil was initially deposited in a coastal environment and later covered by different sediment due to rising sea levels, this change would be represented in the vertical sedimentary record. Conversely, a drop in sea level, called regression, would expose sediments to erosion, which could potentially destroy fossil records.
Overall, rising sea levels can create conditions that either enhance the preservation of fossils by rapid burial or lead to their destruction by increased erosion. The context of sea level change is crucial for paleontologists and geologists who interpret the sedimentary record and thus the history of life on Earth.