scholarly journals Glacier velocities from aerial photographs in North and North-East Greenland

1988 ◽  
Vol 140 ◽  
pp. 102-105
Author(s):  
A.K Higgins
Keyword(s):  
Sea Ice ◽  
Aerial Photographs ◽  
Surface Pattern ◽  
East Greenland ◽  
Ice Caps ◽  
North East ◽  
Glacier Terminus ◽  
Stable Conditions ◽  
Glacier Velocity ◽  
North Greenland

General descriptions of the glaciers of North and North-East Greenland have been given by Koch (1928), Davies & Krinsley (1962) and Weidick (1975). These descriptions, however, provide little in the way of quimtitative data on glacier velocities, although Davies & Krinsley cancluded that a large number af glaciers and small ice caps in North Greenland exhibited stable conditions, with a significant number showing evidence of recent retreat. Comparisons of vertical aerial photographs taken in 1959-63, 1971 and 1978 permit measurements ef glacier velocity to be made on floating ice tongues which have preserved a distinctive surface pattern of meandering streams and crevasses. These show the largest glaciers draining the Inland Ice in North and North-East Greenland to have average velocities ranging from 300 to 900 m/year. This study of vertical aerial photographs has also demonstrated that for floating glacier tongues the position of the glacier terminus is not areliable indicator of advance or retreat. In the fjords of North Greenland semi-permanent sea ice often maintains the integrity of advancing floating glacier fronts for periods of ten to twenty years (Koch, 1928; Weidick, 1975); the break-up of the floating tongue in rare summers when the sea ice melts completely may give the impression of a sudden retreat, but this 'retreat' is unrelated to changes in the mass balance.

Observations on the Quaternary geology around Nioghalvfjerdsfjorden, eastern North Greenland

1999 ◽  
pp. 56-60
Author(s):  
Ole Bennike ◽  
Anker Weidick
Keyword(s):  
Late Summer ◽  
Open Water ◽  
Quaternary Geology ◽  
Mean Annual Precipitation ◽  
Outlet Glacier ◽  
Ice Caps ◽  
North East ◽  
Pack Ice ◽  
Lake Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bennike, O., & Weidick, A. (1999). Observations on the Quaternary geology around Nioghalvfjerdsfjorden, eastern North Greenland. Geology of Greenland Survey Bulletin, 183, 56-60. https://doi.org/10.34194/ggub.v183.5205 _______________ In North and North-East Greenland, several of the outlet glaciers from the Inland Ice have long, floating tongues (Higgins 1991). Nioghalvfjerdsfjorden (Fig. 1) is today occupied by a floating outlet glacier that is about 60 km long, and the fjord is surrounded by dissected plateaux with broad valleys (Thomsen et al. 1997). The offshore shelf to the east of Nioghalvfjerdsfjorden is unusually broad, up to 300 km wide (Cherkis & Vogt 1994), and recently small low islands were discovered on the western part of this shelf (G. Budeus and T.I.H. Andersson, personal communications 1998). Quaternary deposits are widespread around Nioghalvfjerdsfjorden and include glacial, glaciofluvial, marine, deltaic and ice lake deposits. Ice margin features such as kame deposits and moraines are also common (Davies 1972). The glaciation limit increases from 200 m a.s.l. over the eastern coastal islands to 1000 m in the inland areas; local ice caps and valley glaciers are common in the region, although the mean annual precipitation is only about 200 mm per year. Most of the sea in the area is covered by permanent sea ice, with pack ice further east, but open water is present in late summer in some fjords north of Nioghalvfjerdsfjorden, and in the Nordøstvandet polynia.

An outer shelf shelly fauna from Cambrian Series 2 (Stage 4) of North Greenland (Laurentia)

2021 ◽  
Vol 95 (S83) ◽  
pp. 1-41
Author(s):  
John S. Peel
Keyword(s):  
New York ◽  
New Species ◽  
North America ◽  
World Wide ◽  
Wide Distribution ◽  
East Greenland ◽  
North East ◽  
Small Shelly Fossils ◽  
Stage 4 ◽  
North Greenland

AbstractAn assemblage of 50 species of small shelly fossils is described from Cambrian Series 2 (Stage 4) strata in North Greenland, the present day northernmost part of the paleocontinent of Laurentia. The fossils are derived from the basal member of the Aftenstjernesø Formation at Navarana Fjord, northern Lauge Koch Land, a condensed unit that accumulated in a sediment-starved outer ramp setting in the transarctic Franklinian Basin, on the Innuitian margin of Laurentia. Most other small shelly fossil assemblages of similar age and composition from North America are described from the Iapetan margin of Laurentia, from North-East Greenland south to Pennsylvania. Trilobites are uncommon, but include Serrodiscus. The Australian bradoriid Spinospitella is represented by a complete shield. Obolella crassa is the only common brachiopod. Hyoliths, including Cassitella, Conotheca, Neogloborilus, and Triplicatella, are abundant and diverse, but most are represented just by opercula. Sclerites interpreted as stem-group aculiferans (sachitids) are conspicuous, including Qaleruaqia, the oldest described paleoloricate, Ocruranus?, Inughuitoconus n. gen., and Hippopharangites. Helcionelloid mollusks are diverse, but not common; they are associated with numerous specimens of the bivalve Pojetaia runnegari. The fauna compares best with that of the upper Bastion Formation of North-East Greenland, the Forteau Formation of western Newfoundland, and the Browns Pond Formation of New York, but several taxa have a world-wide distribution. Many specimens are encrusted with crystals of authigenic albite. New species: Anabarella? navaranae, Stenotheca? higginsi, Figurina? polaris, Hippopharangites groenlandicus, Inughuitoconus borealis, and Ocruranus? kangerluk.UUID: http://zoobank.org/160a17b1-3166-4fcf-9849-a3cabd1e04a3

Application of Satellite Remote Sensing Techniques to Quantify Terminus and Ice Mélange Behavior at Helheim Glacier, East Greenland

2014 ◽  
Vol 48 (5) ◽  
pp. 81-91 ◽  
Author(s):  
Steve Foga ◽  
Leigh A. Stearns ◽  
C.J. van der Veen
Keyword(s):  
Remote Sensing ◽  
Sea Ice ◽  
East Greenland ◽  
Object Based Image Analysis ◽  
Glacier Terminus ◽  
Object Based ◽  
Radar Imagery ◽  
Iceberg Calving ◽  
Calving Rate ◽  
Remote Sensing Techniques

AbstractIceberg calving is an efficient mechanism for ice mass loss, and rapidly calving glaciers are often considered to be inherently unstable. However, the physical controls on calving are not well understood. Recent studies hypothesize that the presence of a rigid ice mélange (composed of icebergs, bergy bits, and sea ice) can reduce iceberg calving by providing “backstress” to the terminus. To test this hypothesis we use remote sensing techniques to construct a time series model of calving rate and size and composition of the adjacent ice mélange. We describe a semi-automated routine for expediting the digitization process and illustrate the methods for Helheim Glacier, East Greenland, using 2008 data. Ice velocities of the glacier terminus and ice mélange are derived with feature-tracking software applied to radar imagery, which is successfully tracked year-round. Object-based image analysis (OBIA) is used to inventory icebergs and sea ice within the ice mélange. We find that the model successfully identifies the calving rate and ice mélange response trends associated with seasonal increases in terminus retreat and advance and shows seasonal trends of ice mélange potentially providing seasonal backstress on the glacier terminus.

scholarly journals Regions of open water and melting sea ice drive new particle formation in North East Greenland

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
M. Dall´Osto ◽  
C. Geels ◽  
D. C. S. Beddows ◽  
D. Boertmann ◽  
R. Lange ◽  
...  
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Particle Formation ◽  
New Particle Formation ◽  
East Greenland ◽  
North East

Chapter 16 Devonian history

1997 ◽  
Vol 17 (1) ◽  
pp. 289-309 ◽  
Author(s):  
W. Brian Harland
Keyword(s):  
Early Devonian ◽  
East Greenland ◽  
Red Sandstone ◽  
North East ◽  
The North ◽  
Fossil Fish ◽  
Red Bay ◽  
The Many ◽  
Orogenic Events ◽  
North Greenland

Svalbard is part of the Old Red Sandstone province with affinities in East Greenland, Norway, Appalachian North America and, of course, the British Isles where the Devonian Period was defined. This allows Devonian history in this region, controlled by Caledonian events, to form a neat and natural chapter, though not necessarily a global one. Old Red Sandstone environments in each area were already becoming established in Late Silurian time. Olaf Holtedahl was the prime author of both Caledonian tectogenesis in Svalbard and the Old Red Sandstone aftermath.Of the many and varied biotas of Svalbard the fossil fish have made remarkable and classic contributions to Spitsbergen geology.The earliest 'Old Red Sandstone' Spitsbergen strata have yet to yield evidence of age and so may be latest Silurian (Siktefjellet Group). But the earliest Devonian strata to be identified biostratigraphically begin with the Red Bay Group. Similarly the (major) Ny Friesland Orogeny and the various late orogenic granite emplacements, while initially Silurian, continued at least to cool in Devonian time. For convenience the orogenic events that may continue as early Devonian are treated in the Silurian chapter and the sedimentary events that may be Silurian are treated here.Devonian successions in Svalbard are known only from terranes which are postulated to have originated from the North East Greenland Province. No record has yet been established for Devonian strata in Svalbard either from the eastern terranes (East Greenland Province) or from the western terranes (North Greenland-Pearya Province). Moreover, the East Greenland succession lacks

III.—A Gravity Survey of a Glacier-dammed Lake in North Greenland

1958 ◽  
Vol 67 (1) ◽  
pp. 42-53
Author(s):  
C. Bull
Keyword(s):  
Lake Level ◽  
Bouguer Anomaly ◽  
Gravity Survey ◽  
Contour Map ◽  
East Greenland ◽  
North East ◽  
Local Topography ◽  
Lake Bottom ◽  
Dammed Lake ◽  
North Greenland

SynopsisA gravity survey has been made of a glacier-dammed lake in Dronning Louise Land, North-East Greenland. Corrections for the effect of the local topography and the regional Bouguer anomaly are made to the values of the acceleration due to gravity measured at about 230 points on the lake and its shores. From the differences between the corrected values at the lake stations and those of the shores, depths of water under the lake stations are calculated, and a contour map of the lake bottom is drawn. A submerged shelf, 75 metres below the present lake level, persists around the western part of the lake. This may be the shore-line of a pre-glacial lake.

scholarly journals Jurassic dinoflagellate cysts from Hochstetter Forland, North-East Greenland

2004 ◽  
Vol 5 ◽  
pp. 89-97 ◽  
Author(s):  
Stefan Piasecki ◽  
Lars Stemmerik
Keyword(s):  
Dinoflagellate Cysts ◽  
East Greenland ◽  
North East ◽  
Upper Callovian ◽  
North Greenland

Three sections in Hochstetter Forland, North-East Greenland, referred to the Jurassic Payer Dal and Bernbjerg Formations, have been analysed for dinoflagellate cysts. The dinoflagellate cysts, new finds of ammonites and previously recorded marine faunas form the basis for improved dating of the succession. The basal strata of the Payer Dal Formation at Kulhus is here dated as Late Callovian, Peltoceras athleta Chronozone, based on the presence of relatively abundant Limbicysta bjaerkei, Mendicodinium groenlandicum, Rhychoniopsis cladophora and Tubotuberella dangeardii in an otherwise poor Upper Callovian dinoflagellate assemblage. Ammonites have not been recorded from these strata. The upper Payer Dal Formation at Agnetesøelven is dated as Late Oxfordian, Amoeboceras glosense – Amoeboceras serratum Chronozones, based on the presence of Sciniodinium crystallinum, together with Cribroperidinium granuligera and Stephanelytron sp. The age is in accordance with ammonites present in the uppermost part of the formation at Søndre Muslingebjerg. New ammonites in the Bernbjerg Formation at Agnetesøelven together with dinoflagellate cysts indicate an earliest Kimmeridgian age, Rasenia cymodoce and Aulacostephanoides mutabilis Chronozones. The Upper Callovian dinoflagellate cysts from Hochstetter Forland belong to a local brackish to marginal marine assemblage, which only allows a fairly broad correlation to coeval assemblages in central East Greenland. In contrast, the Oxfordian and Kimmeridgian assemblages are fully marine and can be correlated from Milne Land in central East Greenland via Hochstetter Forland to Peary Land in eastern North Greenland.

scholarly journals 14C-dating of samples collected during the 1979 expedition to North Greenland

1982 ◽  
Vol 110 ◽  
pp. 9-14
Author(s):  
S Funder
Keyword(s):  
Geological Survey ◽  
14C Dating ◽  
East Greenland ◽  
Radiocarbon Age ◽  
Carbon 14 ◽  
North East ◽  
Two Samples ◽  
North Greenland ◽  
Land Region ◽  
Age Determinations

Thirty-two radiocarbon age determinations of bivalve shelIs (30), gyttja (1) and peat (1) are summarised below. All but two of the samples were collected during the GGU geological expedition to the Peary Land region. Two samples comprise contemporary shelIs from north and north-east Greenland, and were collected earlier. The samples have been dated at the Carbon-14 Dating Laboratory of the Geological Survey of Denmark and the National Museum, Copenhagen (samples marked K, by courtesy of the Geological Survey of Denmark), the C-14 Laboratory at the Department of Quatemary Geology, University of Lund, Sweden (samples marked Lu, by courtesy of the laboratory and the Department of Quatemary Geology, University of Lund), and the Harwell Carbon 14/Tritium Laboratory, AERE, England (samples marked HAR).

Tectono-stratigraphic history of northern Amdrup Land, eastern North Greenland: implications for the northernmost East Greenland shelf

2000 ◽  
pp. 167-191
Author(s):  
Lars Stemmerik ◽  
Birgitte D. Larsen ◽  
Finn Dalhoff
Keyword(s):  
Plate Boundary ◽  
Southern Limit ◽  
East Greenland ◽  
North East ◽  
The North ◽  
Upper Proterozoic ◽  
Structural Style ◽  
History Of ◽  
Land Changes ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Larsen, B. D., & Dalhoff, F. (2000). Tectono-stratigraphic history of northern Amdrup Land, eastern North Greenland: implications for the northernmost East Greenland shelf. Geology of Greenland Survey Bulletin, 187, 167-191. https://doi.org/10.34194/ggub.v187.5192 _______________ The NW–SE-oriented Sommerterrasserne fault in Amdrup Land marks the southern limit of Mesozoic compression related to the transform plate boundary between North Greenland and Svalbard. Structural style in Amdrup Land changes across the fault; Carboniferous, Permian and Jurassic sediments in northern Amdrup Land north-east of the fault are gently folded, with NE– SW-trending fold axes, whereas they are gently dipping south of the fault. The Sommerterrasserne fault is regarded as the south-eastern extension of the Trolle Land fault zone of eastern Peary Land. Upper Moscovian carbonates of the Foldedal Formation rest unconformably on isoclinally folded Upper Proterozoic sediments of the Independence Fjord Group in northern Amdrup Land and are conformably overlain by chert-rich limestones of the Permian Kim Fjelde and Midnatfjeld Formations. Locally, up to 70 m of Jurassic sandstone and siltstone are preserved in the axes of the synclines, resting conformably on Permian limestones; the folding thus post-dates their deposition. The folding of the sediments to the north-east of the Sommerterrasserne fault most likely took place during the latest Cretaceous; it is post-dated by a post- Paleocene extensional event.

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