Paleo Slide Set: The Ice Ages
Marine sediment samples collected with a multicorer.

Once a core is brought aboard, the sediment together with its plastic liner are split 
lengthwise into two halves so that the sediment layers can be analyzed. These cores 
have captured the uppermost layers of sediment, revealing the transition from brown, 
oxidized layers to greenish-gray clay. Once the water is drained from above the sediment, 
the soupy sediment will be carefully sampled and dated to produce a time series of sediment 
accumulation extending back thousands of years. At this site in the tropical eastern Pacific, 
where sedimentation rates are typically around 2 cm per thousand years, the bottom of this 
40 cm section probably corresponds to the last ice age 20,000 years ago.

Photo of marine sediment samples collected with a multicorer. Scientists use a variety of tools 
to recover undisturbed seafloor sediments, ranging from small coring devices like the multicorer, 
to drilling rigs operated from specialized ships. The multicorer shown here excels at collecting 
undisturbed tubes of the uppermost layers of sediment together with the overlying seawater. 
Once the overlying seawater has been drained off, the ends of the tube will be capped, 
and the tubes will be split lengthwise so the sediment layers can be analyzed.


Photo Credits:
David M. Anderson
NOAA Paleoclimatology Program and INSTAAR, University of Colorado, Boulder