John D. Milliman
A. E. Jennings
N. Rynes
J. Dwyer
J. T. Andrews
1994
<p><span>We compared measured and estimated sediment budgets in heavily glaciated fjords in East Greenland. Mass balance calculations and regional glacio-climatic conditions suggest that the sediment flux to the seafloor in Kangerdlugssuaq and Nansen fjords should be dominated by iceberg rafting and not by the rain-out of suspended particulates in meltwater, as the glacier calving flux is estimated at 15 and </span><span class="NLM_tex-math"><img src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00001.gif" alt="" data-mce-src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00001.gif"></span><span>, compared to meltwater volumes of 4.4 and </span><span class="NLM_tex-math"><img src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00002.gif" alt="" data-mce-src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00002.gif"></span><span>, respectively. Gravity cores in the three fjords indicate that the uppermost 1-2.5 m of sediment consists of diamictons or fine-grained laminated muds. AMS radiocarbon dates on calcareous foramininfera or shells (16 total) indicate sedimentation rates of 110 to 340 cm/ka within the fjords over the last 1 ka, and 10-20 cm/ka during the Holecene on the inner and middle shelf. Annual sediment discharge is around </span><span class="NLM_tex-math"><img src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00003.gif" alt="" data-mce-src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00003.gif"></span><span> tonnes/yr within the Kangerdlugssuaq Fjord and Trough system, which translates into an average basin-wide rate of denudation of 0.01 mm/yr (0.01 m/ka). Air gun and deep-towed (Huntec) seismic profiling was carried out in Kangerdlugssuaq and Nansen fjords, East Greenland, and showed that sediment fills averaged 500 and 350 m respectively; they consist primarily of acoustically stratified sediments. If the sediment fills are entirely Holocene in age then the required average sediment accumulation rates of 35-50 m/ka are an order of magnitude larger than the </span><span class="NLM_tex-math"><img src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00004.gif" alt="" data-mce-src="https://www.journals.uchicago.edu/na101/home/literatum/publisher/uchicago/journals/content/jg/1994/i30065636/629711/20180625/images/eqs/eq-00004.gif"></span><span>controlled rates of the last 1-2 ka. This raises the possibility that fjord sediments may be by-passed and not always recycled during glacial advances; this will affect sedimentation rates on adjacent shelves and deep-sea areas during successive glaciations.</span></p>
application/pdf
10.1086/629711
en
University of Chicago Press
Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)
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