Earth's climate has experienced major shifts over its billions of years of history, including numerous periods where ice proliferated across the planet. Today, ice cores can be a valuable resource for understanding these periods of Earth's history as they capture a snapshot of the climate at that time, both through geochemical constituents and entrained dust and debris preserved through millennia.
Often, higher dust content in the ice cores can be indicative of glacial periods as continental shelf exposure, weaker rainfall, increased aridity and wind can all drive higher dust transport.
The oldest known continuous ice record from Antarctica (European Project for Ice Coring in Antarctica Dome C; Epica Dome C) extends back 800,000 years, but an international partnership of scientists is attempting to increase this to 1.5 million years.
This is because they capture Earth's climate cycles (swapping between glacial and interglacial periods) with a periodicity of ~41,000 years prior to 1.2 million years ago, irregular lengths between 700,000 years and 1.2 million years ago (known as the mid-Pleistocene transition), followed by ~100,000 year cycles since 700,000 years ago.
Such an endeavor is challenging as topography can disturb the ice stratigraphy as glaciers move across land, and basal melting can eradicate records. Therefore, extensive reconnaissance is required to identify suitable sites for drilling cores.
