Paleo Slide Set: Heinrich Events: Marine Record of Abrupt Climate Changes in the Late Pleistocene X-ray of lithic-rich sediments. Heinrich discovered that the dominant component of these sediments not only differed substantially, but that the transitions between foraminifera-dominated and lithic-dominated sediments were unexpectedly abrupt. Heinrich's analysis of long sediment cores demonstrated that foraminifera were dominant for long stretches of time, but lithic sediments punctuated the sedimentological record in six spikes. These sudden changes in sediments, since termed Heinrich events, were also visible in X-rays of sediment cores represented here as sharp transitions between dark-colored (foraminifera-dominated) and light-colored (lithic-dominated) segments. Since Heinrich's discovery, subsequent research around the world by dozens of scientists has contributed to a better understanding of these events. Photo Credits: Bedford Institute of Oceanography and Dalhousie University for the University of Colorado