How are volcanic eruptions recorded in ice?

Answer 1

A violent large scale eruption such as that of Mt St Helens or Mt Pinatubo can be seen the ice record for a number of 2 main reasons.

Firstly the eruption is likely to release a large amount of volcanic ash and debris. Mt Pinatubo estimated emission of around 10 billion metric tonnes was spewed into the atmosphere.

Quantities of this will be deposited locally and regionally however also extensive amount will be flung high in to the atmosphere. The material can be caught in trade winds and deposited as the winds drop over the Arctic/Antarctic the matter can be deposited leaving a record of the type of material deposited.

The second reason is the change in the earths temperature created by volcanic eruptions. At cold periods more water is formed in the upper atmosphere with heavy oxygen. Heavy oxygen is an isotope of oxygen (greater number of neutrons) this is measurable and allows scientist to predict what the climate used to be like (paleoclimatology). A very quick change in climate may be in be caused by a vast eruption and hence can be seen in the isotopic ratios of oxygen within ice cores.

Answer 2

When a volcano erupts, ash and gases are released into the atmosphere. Some of these particles settle on ice sheets and glaciers, creating distinct layers in the ice. By analyzing these layers, scientists can determine when volcanic eruptions occurred and study their impact on the climate over time.