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Evaluating ice‐rafted debris as a proxy for glacier calving in Upernavik Isfjord, NW Greenland
Author(s) -
Vermassen Flor,
Wangner David J.,
Dyke Laurence M.,
Schmidt Sabine,
Cordua Amalie E.,
Kjær Kurt H.,
Haubner Konstanze,
Andresen Camilla S.
Publication year - 2019
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.3095
Subject(s) - fjord , glacier , geology , ice core , debris , ice calving , oceanography , iceberg , physical geography , greenland ice sheet , glacier mass balance , chronology , proxy (statistics) , climatology , sea ice , geomorphology , paleontology , geography , pregnancy , lactation , biology , genetics , machine learning , computer science
Records of ice‐rafted debris (IRD) in sediments are commonly used as a proxy for iceberg production and to reconstruct past changes of glacier stability. However, the interpretation of IRD is complex as multiple processes modulate its variability. This study investigates the relationship between IRD variability and glaciological change by measuring IRD records from Upernavik Fjord and comparing these to frontal positions of Upernavik Isstrøm during the past century. Results show that the spatial variability of IRD deposition throughout the fjord is high, indicating that randomness inherent to IRD distorts the calving signal. However, we investigate whether IRD records can be combined to improve the reconstruction, as previously suggested, and show the importance of core site selection and number of cores on this approach. The outer‐fjord core compares relatively well to the observed front positions and this is reflected in the composite record: increased IRD deposition in 1937–1946, 1968–1980, and 1996–1999 occurred during periods of faster retreat. Comparison with climatic records shows that the calving episodes in the late ‘30 s/early ‘40 s and late ‘90 s are related to warm ocean and air temperatures, whereas intensified retreat and calving during the ‘70 s reflects partly an internal glacier response to the fjord geometry.