Ice core dating methods
Where characteristic layers of known ages can be detected, these provide valuable chronostratigraphic markers against which other dating methods can be verified.
So-called reference horizons have resulted from major explosive volcanic eruptions.
For example, the upper 1000m of a core may represent 50,000 years, whilst the next 50m may span another 100,000 year time period, due to the severe compaction, deformation and flow of the ice sheet in question.
You may find it useful for the clear definitions, and for excellent links on a variety of topic.These inject large quantities of dust and gases (principally sulphur dioxide) into the atmosphere, where they are globally dispersed.The gases are converted into aerosols (principally of sulphuric acid) before being washed out in precipitation.Many of these links also appear where appropriate below.James Hutton and William Smith advanced the concept of geologic time and strengthened the belief in an ancient world.