Sediment Core

Time to get our hands dirty! Paleoclimate researchers study sediment cores, which are accumulated layers of mud and dead plant material collected in a long tube, to learn about what the climate and environment of the past was like.

Sediment cores provide glimpses into Earth’s climate and environment through time. They are collected from lake bottoms, wetlands, estuaries, and oceans, where changes in the environment around the waterbody are recorded by the particles that settle on the bottom. Scientists study pollen and plant remains, microfossils, algae, and charcoal, and they analyze elemental composition and stable isotopes, that are preserved in the layers of sediment. These analyses help build a picture of what the world was like when the sediment layer was formed – which plants and animals were alive, how much it rained, recent volcanic eruptions or forest fires, etc.

Since the oldest sedimentary rocks are ~3.9 billion years old, sediment records can provide a way to study past climate throughout most of Earth’s history! The information gained from sediment cores helps provide a baseline record for how Earth’s climate varied before modern human society and is used to test and improve our models of future climate scenarios.

Graphic by: Ben Slyngstad, USGS ORISE