Fossilization Flashcards
Q: Why are floodplains ideal for fossil preservation?
A: Floodplains are ideal because they are regularly covered with sediments, which can quickly bury and preserve carcasses.
Q: How do lakes contribute to fossil preservation?
A: Lakes accumulate fine sediments like mud, which can cover and preserve carcasses.
Q: Why is fossil preservation less likely in forests?
A: Forests have high decomposition rates due to plant roots and microbial activity, which rapidly break down remains.
Q: What effect does rainfall have on fossil preservation?
A: Rainwater can lead to flooding of rivers and filling of lakes, which increases sediment transport and the likelihood of carcasses being buried and preserved.
Q: How do marine environments contribute to fossil preservation?
A: Marine environments, such as ancient seafloors, can preserve fossils; however, they are rarer compared to terrestrial environments due to dinosaurs primarily living on land.
Q: What is a common feature of marine sedimentary rocks?
A: Marine sedimentary rocks, like limestone, are composed of calcium carbonate from the exoskeletons of marine plankton.
Q: What type of rock is formed from sand deposited by water?
A: Sandstone is formed from sand deposited by water in rivers, beaches, and dunes.
Q: How is mudstone or shale created?
A: Mudstone or shale is created from fine mud or silt deposited in still or slow-moving water bodies like lakes, which then compresses into rock.
Q: What environment is associated with the formation of coal?
A: Coal forms in swampy or marshy areas where plant material accumulates and compresses.
Q: Where is limestone typically found, and what is it composed of?
A: Limestone is commonly found in lagoons and shallow seas and is composed of calcium carbonate from marine plankton.
Q: What factors contribute to incomplete or fragmented fossil records?
A: Factors include rivers carrying away and scattering bones, scavengers breaking apart bones, and decomposition in forests due to microbes and plant roots.
Q: How does predation affect fossil preservation?
A: Large carnivores can dismember and scatter carcasses while feeding, and bones transported by water may become abraded and aligned with the current.
Q: What is permineralization, and how does it occur?
A: Permineralization is when internal spaces of bones or tissues are filled with mineral-rich water, and the minerals precipitate out to preserve the original structure in detail.
Q: What does replacement involve in fossil preservation?
A: Replacement involves the original biological material being replaced by minerals over time, resulting in a cast or impression of the original material.
Q: What is plastic deformation, and give an example?
A: Plastic deformation occurs when the weight and pressure of overlying sediments deform fossilized bones without breaking them, such as an asymmetrical Tyrannosaurus skull showing deformation due to sediment pressure.
