Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N)
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Abstract
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
, compared to meltwater volumes of 4.4 and
, 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
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
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.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Sediment thicknesses and holocene glacial marine sedimentation rates in three east Greenland fjords (ca. 68°N) |
| Series title | The Journal of Geology |
| DOI | 10.1086/629711 |
| Volume | 102 |
| Issue | 6 |
| Year Published | 1994 |
| Language | English |
| Publisher | University of Chicago Press |
| Contributing office(s) | Earth Resources Observation and Science (EROS) Center |
| Description | 15 p. |
| First page | 669 |
| Last page | 683 |
| Country | Greenland |