Paleo Slide Set: Heinrich Events: Marine Record of Abrupt Climate Changes in the Late Pleistocene
Color of the sediment at core site HU87033-009.

To Heinrich and other scientists, the most conspicuous component of Heinrich event sediments was the ice rafted 
detritus. Comprised of sand grains, pebbles and even stones that were carried out onto the shelf margin and beyond 
by icebergs, their true significance to climate events was not understood until the unusual composition of these 
lithic fractions was identified. Bond et al (1992) documented the presence of high concentrations of light colored 
detrital carbonate within the ice rafted detritus. High IRD counts and abundances of detrital carbonate within the 
IRD reinforce the theory that Heinrich events are truly ice rafting events and not merely indications of reduced 
numbers of foraminifers.

Just as the light and dark shades of x-radiographs help scientists pinpoint the beginning and end of Heinrich events 
in the core record, the different coloration of detrital carbonate within a split core can also help scientists 
determine Heinrich events. The patterns of Heinrich event detrital carbonate coloration within cores far away from 
the former ice margin is detectable only upon careful examination. In contrast, the patterns of Heinrich event 
coloration at sites close to the margin, especially sites near the Hudson Strait, is much more easy to observe. 


Photo Credits:
Bedford Institute of Oceanography