Late-Holocene terrestrial glacial history of Miki and IC Jacobsen Fjords, East Greenland

被引:25
作者
Geirsdóttir, A
Hardardóttir, J
Andrews, JT
机构
[1] Univ Iceland, Dept Geosci, IS-101 Reykjavik, Iceland
[2] Univ Colorado, INSTAAR, Boulder, CO 80309 USA
[3] Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA
关键词
Holocene; moraine chronology; glacier variations; lichenometry; fjords; 'Little Ice Age'; East Greenland;
D O I
10.1191/095968300666213169
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
We present a late-Holocene glacial and environmental history of three valleys within Miki and LC. Jacobsen Fjords, East Greenland (68 degrees 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 goad 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 Iate-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.
引用
收藏
页码:123 / 134
页数:12
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