Late-Holocene terrestrial glacial history of Miki and I.C. Jacobsen Fjords, East Greenland

Abstract

We present a late-Holocene glacial and environmental history of three valleys within Miki and I.C. Jacobsen Fjords, East Greenland (68°N). The fjords have no direct connection with the main ice sheet and are presently glacierized by a series of local ice caps and glaciers. Little sediment has been deposited within the study area, but bedrock is distinctly glacially striated, which suggests that extensive valley glaciers reached the present coastline in the past. Moraines are the prominent morphological features including distinct end and lateral moraines. Most of the moraines are related to the existing glaciers in the area. Apparent moraines extend as far as 2 to 2.5 km in front of present-day glaciers. Based on morphological and stratigraphical studies of the sediments in these valleys, five glacier advances during the late Holocene are implied. Stabilization of the oldest moraines is lichenometrically dated to c. 1450 to 1650 years ago. Younger moraines in both Miki and I.C. Jacobsen Fjords are lichenometrically dated to c. 1050–1100 years ago, c. 750–950 years ago and c. 600–700 years ago. The youngest moraines containing measurable lichens stabilized c. 300–400 years ago. The timing of this moraine formation correlates to marine records from previous research on the inner part of Miki Fjord, where apparent intensification in sediment stratification is related to a glacier advance into the fjord c. 290 years ago. This glacial advance may correlate to the‘Little Ice Age’ cooling observed in many records from the North Atlantic region. Our glacial record from Miki and I.C. Jacobsen Fjords also shows good correlation with temperature proxies within the GRIP ice core in Greenland and foraminifera records from Nansen Fjord, East Greenland. Less pronounced correlation is observed with the Icelandic Sea Ice Index and records of glacier fluctuation in Iceland during the last .1000 years. These results suggest that widespread climatic cooling was the direct cause of many of the late-Holocene glacier variations documented in this study, although the glacial advance at c. 1050–1100 years ago coincides with the so-called‘Medieval Warm Period’, and could reflect the response of glaciers to increased precipitation within the area.