Heinrich event
![Chronology of climatic events of importance for the Last Glacial Period (~last 120 000 years) as recorded in polar ice cores, and approximate relative position of Heinrich events, initially recorded in marine sediment cores from the North Atlantic Ocean. Light violet line: δ18O from the NGRIP ice core (Greenland), permil (NGRIP members, 2004). Orange dots: temperature reconstruction for the NGRIP drilling site (Kindler et al., 2014). Dark violet line: δ18O from the EDML ice core (Antarctica), permil (EPICA community members, 2006). Grey areas: major Heinrich events of mostly Laurentide origine (H1, H2, H4, H5). Grey hatch: major Heinrich events of mostly European origine (H3, H6). Light grey hatch and numbers C-14 to C-25: minor IRD layers registered in North Atlantic marine sediment cores (Chapman et al., 1999). HS-1 to HS-10: Heinrich Stadial (HS, Heinrich, 1988; Rasmussen et al., 2003; Rashid et al., 2003). GS-2 to GS-24: Greenland Stadial (GS, Rasmussen et al., 2014). AIM-1 to AIM-24: Antarctic Isotope Maximum (AIM, EPICA community members, 2006). Antarctica and Greenland ice core records are shown on their common timescale AICC2012 (Bazin et al., 2013; Veres et al., 2013).](/Images/godic/202501/17/Approximate_chronology_of_Heinrich_events_vs_Dansgaard-Oeschger_events_and_Antarctic_Isotope_Maxima5712.png")
![As well as indicating oceanic productivity, foramanifera tests also provide valuable isotopic data](/Images/godic/202501/17/Elphidium_excavatum_clavatum5712.jpg")
![The lithic proportion of sediments deposited during H3 and H6 is substantially below that of other Heinrich events](/Images/godic/202501/17/Sand_bei_200_fach_25713.jpg")
![Present day ocean circulation. The Gulf stream, far left, may be redirected during Heinrich events](/Images/godic/202501/17/Thermohaline_circulation5713.png")
A Heinrich event is a natural phenomenon in which large armadas of icebergs break off from glaciers and traverse the North Atlantic. First described by marine geologist Hartmut Heinrich, they occurred during the past glacial periods or "ice ages" and are particularly well documented for the last glacial period. The icebergs contained rock mass, which has been eroded by the glaciers, and as they melted, this matter was dropped onto the sea floor as ice rafted debris (abbreviated to "IRD").