Melt in the Greenland EastGRIP ice core reveals Holocene warm events

Abstract. We present a record of melt events obtained from the East Greenland Ice Core Project (EastGRIP) ice core in central northeastern Greenland, covering largest part Holocene. The data were acquired visually using an optical dark-field line scanner. detect and describe layers lenses, seen as bubble-free throughout above bubble–clathrate transition. This transition is located at 1150 m depth EastGRIP core, corresponding to age 9720 years b2k. define brittle zone that 650 950 depth, where we count on average more than three breaks per meter. analyze layer thicknesses, correct for thinning, account missing due breaks. Our shows large, distinct peak around 1014 b2k (986 CE) broad 7000 b2k, Holocene Climatic Optimum. In total, can identify approximately 831 mm (corrected thinning) over past 10 000 years. find event 986 CE most likely large rain similar 2012 CE, these two are unprecedented also compare recent 2500 tree ring composite overlap between anomalies indicating warm summers. Considering dynamics site resulting flow Northeast Stream (NEGIS), summer temperatures must have been least 3 ± 0.6 ∘C warmer during Early compared today.