Graham Hancock,

“In 1988 the German oceanographer Hartmut Heinrich was the first to come up with the firm geological evidence for such a cataclysmic 'iceberg-calving' process during the last Ice Age. By examining deep-sea drill cores sampled at various points across the North Atlantic he demonstrated the existence of widely dispersed layers of 'ice-rafted detritus' -- millions of tonnes of rocks and rocky debris that had once stood on land, that had been clawed up by the ice-sheets and that had ultimately been carried out to sea frozen into huge icebergs:'As they melted they released rock debris that was dropped into the fine-grained sediments of the ocean floor. Much of this ice-rafted debris consists of limestones similar to those exposed over large areas of eastern Canada today. The Heinrich layers as they have become known, extend 3000 kilometers across the North Atlantic, almost reaching Ireland.'The Heinrich layers record at least six separate discharges of 'stupendous flotillas of ice-bergs' into the North Atlantic -- discharges that are now known, obviously enough, as 'Heinrich Events' and that are thought to have unfolded in concentrated bursts of activity that may, in each case, have lasted less than a century. Because of the progressive thickening of the Heinrich layers towards the western side of the Atlantic and the continuation of this trend into the Labrador Sea in the direction of Hudson Bay, it is obvious to geologists that 'much of the floating ice was sourced from the Laurentide ice-sheet'.However, other debris has been found intermingled in some Heinrich layers that 'could only have come from separate ice-sheets covering not only Canada, but Greenland, Iceland, the British Isles and Scandinavia'. Likewise, research into southern hemisphere ice-caps in the Andes and New Zealand shows that these too 'grew and then collapsed synchronously with the ice-rafting pulses recorded in the North Atlantic'. The implication [...] is that some 'global rather than regional forcing of climate change' must have been at work.”