Amino acids reveal ice sheet changes

Published 05-12-2013

A new method for dating ancient marine shells reveals that the Greenland ice sheet reached a minimum between 3000 and 5000 years ago.

An international group of researchers including Danish researchers have developed a new analytical method to estimate the size of the ice sheet in the past. The method involves measuring the ratio between L- and D- forms of amino acids in ancient marine shells. The scientists can use to determine when the bivalves were alive.

In this way, scientists can work out when there in given areas of Greenland was water and when there was ice that is how far the ice sheet grew. The result of the research shows that the margin of the ice sheet in north-west Greenland was significantly inland of today and that the timing of this ice cover minimum was between 5000 and 3000 years ago.

The new study suggests that the ice sheet will start to grow again if it gets colder. But according to all climate models the temperatures will rise in the future.

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The article on the study is published in the journal Geology. Abstract is available at:

A pdf file of the article in Geology can be obtained from geologist Ole Bennike (