Volcanism significantly affects the biostratigraphic record by contributing to special preservation of fossil floras and faunas, and by modifying the paleoenvironments in which they developed and evolved.

The main local or near-source influences of ash and tephra falls, and downslope pyroclastic and debris flows, are rapid burial of biotas that are either in situ or transported only short distances. Large eruptions may cause similar rapid burial farther from source.

Volcanism also affects the development of local substrates and the configuration of lakes and drainages near source, and on a regional scale, causes the construction of volcanic islands. In all cases, new habitats are provided for biotas that may subsequently be represented in the biostratigraphic record.

On the local, regional, and global scale, volcanogenic emanations of CO₂, H₂S, SO₂, and other gaseous and particulate material are a significant cause of climatic perturbation leading to temperature fluctuations, and in some cases, disequilibrium in global biogeochemical cycles. This suggests that volcanism may have contributed more to the Cretaceous-Tertiary extinctions and other turnover/extinction episodes than is usually supposed.