What do paleontologists find in the evidence after a major extinction occurs?

1. Mass graves: These are places where large numbers of animals died at the same time. Mass graves often contain the remains of animals that were killed by sudden environmental changes, such as climate change or volcanic eruptions.

2. Impact craters: These are circular depressions in the ground that are caused by the impact of large objects, such as asteroids or comets. Impact craters can provide evidence of an extinction event if they are found near mass graves or if they contain the remains of impact ejecta, such as shocked quartz.

3. Changes in the fossil record: After a major extinction event, there is often a sudden change in the fossil record. This can include the disappearance of certain species, the appearance of new species, and changes in the relative abundance of different species.

4. Microfossils: These are microscopic fossils that can provide evidence of environmental conditions at the time of an extinction event. For example, the presence of certain types of algae or pollen can indicate changes in climate or sea level.

5. Geochemical evidence: This includes changes in the chemical composition of rocks and sediments that can provide evidence of changes in the environment at the time of an extinction event. For example, a spike in the levels of carbon dioxide in the atmosphere can indicate a volcanic eruption.