Problems with ice core dating

17 Mar

They can check for telltale markers, such as volcanic ash signatures.The Krakatoa eruption of 1883 and the Vesuvius eruption that wiped out Pompeii and Herculaneum in AD 79 left their specific marks in exactly the annual layers anticipated. As it turns out, these cycles-caused by regular variations in the eccentricity or ellipticity of Earth's orbit (period = 100,000 years) and the tilt of Earth's orbit (period = 41,000 years)-correspond perfectly with what's seen in those core layers.1,2 since these layers get even thinner as they are buried under more and more snow and ice, due to compression and lateral flow (see diagram), the thinner layers of the Antarctic ice cap become much harder to count than those of the Greenland ice cap at an equivalent depth.

The ice cores reveal hundreds of thousands of ice layers laid down on top of one another year by year, just as a tree adds one new growth ring per year.

It's a freezing cold day inside the National Ice Core Laboratory (NICL) in Denver, Colo., as it is every day of the year.

That's because the NICL is a facility for storing and studying ice cores recovered from the polar regions of the world.

Problems associated with borehole closure can be solved by the limitation of the drilling depth in dry holes and the limitation of the closure rate in wet holes.

Series of proven and unproven measures were suggested to improve drilling performance in the warm ice but still now the ultimate decision is not found.