Descriptive text to Geological map of Greenland, 1:500 000, Dove Bugt, Sheet 10

Henriksen, N; Higgins, A.K. (Tony)

doi:10.34194/geusb.v4.4581

Cited by 16 publications

(3 citation statements)

References 43 publications

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“…Both our remodelling of the Shelf 92 line and the original model (Argyle et al 1992) show a dipping surface of 2.5°. The sedimentary and metasedimentary rocks in North Greenland have a documented northward tilt of 2–4° (Henriksen 1992). This slope in the model is postulated to be a continuation of the tilt on land.…”

Section: Discussionmentioning

confidence: 99%

Sedimentary and crustal structure from the Ellesmere Island and Greenland continental shelves onto the Lomonosov Ridge, Arctic Ocean

Jackson

Dahl‐Jensen

2010

Geophysical Journal International

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S U M M A R YOn the northern passive margin of Ellesmere Island and Greenland, two long wide-angle seismic reflection/refraction (WAR) profiles and a short vertical incident reflection profile were acquired. The WAR seismic source was explosives and the receivers were vertical geophones placed on the sea ice. A 440 km long North-South profile that crossed the shelf, a bathymetric trough and onto the Lomonosov Ridge was completed. In addition, a 110 km long profile along the trough was completed. P-wave velocity models were created by forward and inverse modelling. On the shelf modelling indicates a 12 km deep sedimentary basin consisting of three layers with velocities of 2.1-2.2, 3.1-3.2 and 4.3-5.2 km s −1 . Between the 3.1-3.2 km s −1 and 4.3-5.2 km s −1 layers there is a velocity discontinuity that dips seaward, consistent with a regional unconformity. The 4.3-5.2 km s −1 layer is interpreted to be Palaeozoic to Mesozoic age strata, based on local and regional geological constraints. Beneath these layers, velocities of 5.4-5.9 km s −1 are correlated with metasedimentary rocks that outcrop along the coast. These four layers continue from the shelf onto the Lomonosov Ridge. On the Ridge, the bathymetric contours define a plateau 220 km across. The plateau is a basement high, confirmed by short reflection profiles and the velocities of 5.9-6.5 km s −1 . Radial magnetic anomalies emanate from the plateau indicating the volcanic nature of this feature. A lower crustal velocity of 6.2-6.7 km s −1 , within the range identified on the Lomonosov Ridge near the Pole and typical of rifted continental crust, is interpreted along the entire line. The Moho, based on the WAR data, has significant relief from 17 to 27 km that is confirmed by gravity modelling and consistent with the regional tectonics. In the trough, Moho shallows eastward from a maximum depth of 19-16 km. No indication of oceanic crust was found in the bathymetric trough.

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Section: Discussionmentioning

confidence: 99%

Sedimentary and crustal structure from the Ellesmere Island and Greenland continental shelves onto the Lomonosov Ridge, Arctic Ocean

Jackson

Dahl‐Jensen

2010

Geophysical Journal International

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“…A row of flat-topped mountains 500 to 900 m high are found along the western side of the island, but on the eastern side there is a plain at 100 to 200 m a.s.l. The bedrock is dominated by Lower Proterozoic basement gneiss that has been reworked into the Caledonian fold belt, and Jurassic and Cretaceous marine sediments are found in some areas on the eastern part of the island (Henriksen 1997;Henriksen & Higgins 2009). A few small ice caps occur in the mountains, and, in addition, perennial snow fields are found, but most parts of the island are snow-free during the summer.…”

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confidence: 99%

Early Pleistocene sediments on Store Koldewey, northeast Greenland

Bennike¹,

Knudsen²,

Abrahamsen³

et al. 2010

Boreas

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Marine Quaternary deposits, here named the Store Koldewey Formation, are found at $120 m above sea level in northeast Greenland (761N). The sequence is referred to the Olduvai normal polarity subchron at 1.95-1.78 Ma BP based on palaeomagnetic studies (palaeomagnetically reversed), amino acid epimerization ratios and evidence from marine and non-marine fossils. The sediments and the fauna show that the sequence was deposited on a mid or inner shelf, and some elements of the marine mollusc and foraminiferal assemblages indicate water temperatures between À1 and 111C and seasonal sea ice cover during deposition. Mean summer air temperatures were around 61C higher than at present, as demonstrated by the occurrence of southern extralimital terrestrial species. Wellpreserved remains of land plants indicate that the adjacent land area was dominated by sub-arctic forest-tundra with the trees Larix and Betula, shrubs, herbs and mosses. Most of the species represented as fossils have recent circumpolar geographical ranges. An extinct brachiopod species and an extinct gastropod species have been found, but the other macrofossils are referred to extant species. The brachiopod is erected as a new genus and species, Laugekochiana groenlandica.

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“…The bedrock in the study area is mainly Precambrian gneiss (e.g. Henriksen, 2008; Ozols and Broll, 2003; Scholz and Grottenthaler, 1988); therefore, the aeolian transported material consists of non-calcareous and non-basaltic material. Based on the authors’ field observations, the Ørkendalen glacier (Figure 1b) at the eastern side of the study area forms an active moraine system, which is overrunning current vegetation (Figure 2a).…”

Section: Study Areamentioning

confidence: 99%

Holocene palaeosols and aeolian activities in the Umimmalissuaq valley, West Greenland

2016

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Abstract:Aeolian sand sheets and active dunefields preserve an ancient Holocene land surface represented by palaeosols that occur around the present ice margin in the Kangerlussuaq area, West Greenland. To determine the relation between Holocene aeolian activities and periods of soil formation, both substantially dependent on the deglaciation history, palaeosols, aeolian sand sheets, and dunefields were analysed using field data, grain size analyses, optically stimulated luminescence dating and AMS 14 C data in an area of about 15 km² of the Ummimalissuaq valley. Located under dunefields close to the ice margin (< 2 km), palaeosols are developed in fine-grained aeolian sediment (silt loam) and covered by sandy aeolian layers. Silt contents of palaeosols of partly > 60 wt.% are comparable to aeolian sand sheets currently formed at further distances (4-5 km) from the present ice margin. We propose a transport distance of fine aeolian sediments, in which the palaeosols are formed, of at least 4 kilometres from inboard of the present ice margin. Soil formation of the palaeosols started around 2700 cal yr b2k. Datings from the youngest parts of the palaeosols suggest a stable period of around 2400 years, which allowed for pedogenesis and was characterised by low but constant aeolian activity. Since aeolian activity intensified after around 300 cal yr b2k and developed still active dunefields with coarse and medium sand accumulation, the ice margin must have reached its present position since then. kilometres from inboard of the present ice margin. Soil formation of the palaeosols started around 2700 cal yr b2k. Datings from the youngest parts of the palaeosols suggest a stable period of around 2400 years, which allowed for pedogenesis and was characterised by low but constant aeolian activity. Since aeolian activity intensified after around 300 cal yr b2k and 35 developed still active dunefields with coarse and medium sand accumulation, the ice margin must have reached its present position since then.

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Descriptive text to Geological map of Greenland, 1:500 000, Dove Bugt, Sheet 10

Cited by 16 publications

References 43 publications

Sedimentary and crustal structure from the Ellesmere Island and Greenland continental shelves onto the Lomonosov Ridge, Arctic Ocean

Sedimentary and crustal structure from the Ellesmere Island and Greenland continental shelves onto the Lomonosov Ridge, Arctic Ocean

Early Pleistocene sediments on Store Koldewey, northeast Greenland

Holocene palaeosols and aeolian activities in the Umimmalissuaq valley, West Greenland

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