Geological Survey of Denmark and Greenland Bulletin 33, 2015, 41-44


41

The Continental Shelf Project of the Kingdom of
Denmark – status and issues

Christian Marcussen, Finn Mørk, Thomas Funck, Willy Lehmann Weng and Mikael Pedersen

Th is paper summarises the status of the Continental Shelf 

Project of the Kingdom of Denmark aft er the recent submis-

sion for an extended continental shelf in the area to the north 

of Greenland. We discuss some of the similarities between 

the submission areas north of the Faroe Islands and north 

of Greenland including the morphological continuation of 

ridges extending seaward of the geomorphical continental 

shelf. Documentation of the sediment thickness in the ad-

joining basins and sediment continuity with the continental 

slope plays a vital role in the delineation of the outer limits of 

the extended continental shelf. Here, we compare how these 

issues were addressed around the well-studied Faroe Islands 

and in the sparsely surveyed Arctic Ocean.   

Th e Kingdom of Denmark ratifi ed the 1982 United Na-

tions Convention on the Law of the Sea (UNCLOS) in 

2004. According to Annex II of UNCLOS, the particulars 

of the outer limits of the extended continental shelf beyond 

200 nautical miles shall be submitted to the Commission on 

the Limits of the Continental Shelf (CLCS) within a period 

of ten years aft er ratifi cation. To acquire the necessary data 

for delineating the extended continental shelf, the Continen-

tal Shelf Project of the Kingdom of Denmark was launched 

by the Ministry of Higher Education and Science in coopera-

tion with the Government of the Faroe Islands and the Gov-

ernment of Greenland (Marcussen et al. 2004; Marcussen & 

Heinesen 2009).

Five partial submissions have been submitted by the King-

dom of Denmark regarding areas north of the Faroe Islands 

in 2009, south of the Faroe Islands in 2010, south of Green-

land in 2012, north-east of Greenland in 2013 and north of 

Greenland in 2014 (Fig. 1).

The area north of the Faroe Islands
North of the Faroe Islands, the extinct Ægir sea-fl oor spread-

ing ridge is a prominent feature of the continental margin 

(Figs 1, 2). Th e initial opening of the North Atlantic oc-

curred along the Ægir Ridge with active sea-fl oor spreading 

in the Eocene and Oligocene. Subsequent thermal subsid-

ence of the oceanic crust resulted in the formation of the 

Northern Deep with a sediment accumulation of up to 3 km. 

Th e CLCS examined the partial submission regarding 

the area north of the Faroe Islands between 2012 and 2014 

and gave special attention to: (1) the morphological continu-

ation of the Ægir Ridge and (2) the continuity of sediments 

throughout the Northern Deep. In a strict morphological 

sense, the land mass of the Faroe Islands is connected to the 

Faroe–Iceland Ridge (Fig. 2). Furthermore, the Faroe–Ice-

land Ridge coalesces with and is morphologically linked to 

the Ægir Ridge. Th is means that the Ægir Ridge is morpho-

logically continuous with the rest of the continental margin 

© 2015 GEUS. Geological Survey of Denmark and Greenland Bulletin 33, 41–44. Open access:  www.geus.dk/publications/bull

NFM

150°E

1 000 km
30°W

50°N

30°E

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°N

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0
°N

NEGM

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R u s s i a n  F e d e r a t i o

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s

Fig. 1. The five partial submissions of the Kingdom of Denmark. Red line: 

The 200 nautical mile limit of the five Arctic coastal states in the Arc-

tic Ocean. NEGM: North-east Greenland Margin. NFM: North Faroes 
Margin, NGM: North Greenland Margin. SFM: South Faroes Margin. 
SGM: South Greenland Margin. Colour scale: see Fig. 3.



4242

and lies within a common envelope of the foot of the con-

tinental slope.  Th us, in the sense of UNCLOS, the Ægir 

Ridge is an integral part of the continental margin of the 

Faroe Islands, notwithstanding the tectonic and crustal dif-

ferences between the two terrains (Recommendations of the 

Commission 2014).

Th e sediment thickness in the Northern Deep was docu-

mented primarily using modern seismic refl ection data. Se-

lected seismic lines were re-processed in order to improve the 

defi nition of the base of the sediments as well as the determi-

nation of the seismic velocities used for the depth conversion. 

Th e CLCS agreed with the procedure used to establish the 

sediment thickness, i.e. the methodology of depth conver-

sion and the seismic interpretations. However, the CLCS in-

itially disagreed with the method by which the Kingdom of 

Denmark demonstrated sedimentary continuity throughout 

the Northern Deep. To satisfy the CLCS, additional seismic 

lines, a sediment thickness map and gravity maps were pro-

vided and subsequently deemed suffi  cient for this purpose.

In March 2014, the CLCS adopted the recommendations 

regarding the partial submission north of the Faroe Islands. 

Th e Commission agreed with the determination of the fi xed 

points establishing the outer limits of the continental shelf 

north of the Faroe Islands as originally listed in the submis-

sion.

The area north of Greenland
Th e Lomonosov Ridge is a sliver of continental crust that 

extends for a distance of almost 1800 km across the Arc-

tic Ocean (Fig. 3). Th e ridge is 45 to 200 km wide, mostly 

fl at-topped to slightly rounded at its crest and rises from wa-

ter depths of more than 4300 m in the adjacent basins to 

typically 1000 to 1300 m. Th e shallowest part of the ridge 

is found towards Greenland. Th e Lomonosov Ridge was 

separated from the Barents and Kara shelves during the 

Paleocene (55 to 60 Ma), when sea-fl oor spreading started to 

open the Eurasia Basin. Th is process continues today along 

the ultraslow-spreading Gakkel Ridge. Th e geological devel-

opment of the Amerasia Basin is not well understood, but 

most authors agree that the Alpha and Mendeleev Ridges in 

that basin comprise a large igneous province of Cretaceous 

age (e.g. Jackson et al. 1986) and that sea-fl oor spreading has 

occurred in the Canada Basin (e.g. Grantz et al. 1998).  

Th e Lomonosov Ridge is morphologically continuous with 

the Lincoln Shelf north of Greenland and furthermore shares 

geological characteristics with the land mass of Greenland. 

Th ese geological characteristics are based on evidence for con-

tinuous continental crust (Jackson et al. 2010), similar lith-

ologies and ages of rocks sampled from the fl anks of the ridge 

compared to rocks of the adjacent land masses, and a common 

tectonic history. In the sense of UNCLOS, this means that 

the Lomonosov Ridge is a submarine elevation that is a natu-

ral component of the continental margin of Greenland and 

therefore the extended continental shelf north of Greenland 

extends across the Arctic Ocean to the 200 nautical mile line 

from Russia (Executive Summary 2014).

Facing the Amerasia Basin, the Lomonosov Ridge is mor-

phologically amalgamated with the Alpha and Mendeleev 

Ridges and the Chukchi Borderland, which together are re-

garded as one complex but coherent morphological sea-fl oor 

high relative to the adjacent deep ocean fl oor within the Eur-

asia and Amerasia Basins. Th at is, all of this complex sea-fl oor 

high lies within a common envelope of the foot of the conti-

nental slope. However, the existing geological data for some 

of the individual sea-fl oor highs are insuffi  cient to prove that 

they share geological characteristics with the Greenland land 

mass. For this reason, and in accordance with UNCLOS, the 

extended continental shelf, based on the Alpha and Mend-

eleev Ridges and the Chukchi Borderland, is constrained to 

a distance of 350 nautical miles from the territorial sea base-

line of Greenland (Executive Summary 2014).

4°W
68°N

64°N

62°N

8°W8°W 0°8°W 100 kmF
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P l a t e a u

Fig. 2. The Northern Continental Shelf of the Faroe Islands showing the 

submission area. The continental shelf beyond 200 nautical miles in the 

area north of the Faroe Islands, as delineated in the submission, amounts 

to 87 792 km2 in area and is highlighted. Green: agreed maritime bounda-

ries within 200 nautical miles. Red: Faroese 200 nautical mile limit. Yel-

low: Iceland’s and Norway’s 200 nautical mile limits. Orange: outer limit 

of the continental shelf north of the Faroe Islands. Colour scale: see Fig. 3.



43

By analogy with the Ægir Ridge north of the Faroe Islands, 

bathymetric and morphological data show that the Gakkel 

Ridge coalesces with the continental slope north of Green-

land. Th e oceanic, sea-fl oor-spreading characteristics of the 

Gakkel Ridge diff er geologically from the continental crust of 

Greenland; hence the extended continental shelf based on the 

Gakkel Ridge cannot exceed 350 nautical miles from the ter-

ritorial sea baseline of Greenland (Executive Summary 2014).

Published seismic data from the Amundsen Basin north 

of Greenland (Weigelt & Jokat 2001) indicate the presence 

of sediments of suffi  cient thickness (i.e. at least 1200 m) for 

use in extending the continental shelf. For this reason, a pur-

pose-built seismic acquisition system was developed (Hopper 

et al. 2012) that could operate in the Arctic sea ice and at 

sub-zero temperatures. To locate the most promising regions 

for seismic data acquisition, a sediment thickness map was 

derived from gravity inversion (Døssing et al. 2014). Th is 

study was based on the LOMGR AV airborne gravity data 

(Døssing et al. 2013).

Th ree GEUS LOMROG expeditions were carried out in 

2007, 2009 and 2012 to acquire seismic data in the Arctic 

Ocean. However, ice conditions only allowed for a maxi-

mum streamer length of 300 m, which is too short to extract 

velocities from the seismic refl ection data. For this reason, 

sonobuoys were deployed along the profi les to record the seis-

mic energy at larger off sets of up to 34 km. Ray-tracing mod-

elling was then used to obtain velocity models of sediments 

in the Amundsen Basin. Th e velocities show little scatter 

(Fig. 4). Assuming normal compaction, the data points can 

be approximated by an exponential function of instantane-

ous slowness versus burial depth (Al-Chalabi 1997) using re-

duced major axis regression techniques. Th e velocity–depth 

relationship obtained from this approach is shown in Fig. 4 

and can be used to convert the sediment thickness from time 

to depth.

Th e seismic refl ection lines surveyed were generally less 

than 50 km long and focused on regions that were more 

than 60 nautical miles away from the Lomonosov Ridge. As 

the CLCS requires the documentation of sediment continu-

ity, supplementary data had to be used. In ice-covered areas 

gravity data can supplement a sparse seismic database. For 

this reason, the results of the gravity inversion (Døssing et 

x

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Bathymetry

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75°N70°N

Fig. 3. Bathymetric map showing the main features of the Arctic Ocean.



4444

al. 2014) were used to document continuity of the sediments 

supported by additional subbottom profi ler and seismic re-

fl ection data. 

Concluding remarks
Th e Continental Shelf Project of the Kingdom of Denmark 

mapped fi ve areas relevant to extended continental shelf be-

yond 200 nautical miles. Th e project gathered bathymetric, 

geodetic, geological and geophysical data to compile the sub-

mission documents required by the CLCS. Despite diffi  cult 

logistics, challenging climatic conditions and permanent ice 

cover in some of the fi ve areas, the project was completed 

within the initially allocated budget of 330 million DKK 

(44 million €) and the given time frame. 

Large data sets have been acquired in the fi ve submis-

sion areas and key results have been or will be published in 

scientifi c journals. Particularly valuable are the datasets in 

the Arctic Ocean as this remains a poorly studied frontier 

region. Furthermore, the project was able to support other 

science projects by sharing logistics, in particular by provid-

ing access to icebreakers. Th e results could not have been 

achieved without extensive international cooperation. Due 

to the modus operandi of the CLCS, recommendations for 

the latest submission north of Greenland cannot be expected 

before the middle of the next decade. It represents a signifi -

cant challenge to keep both data and knowledge within the 

project updated and state of the art.

References
Al-Chalabi, M. 1997: Instantaneous slowness versus depth functions. 

Geophysics 62, 270–273.
Døssing, A., Hopper, J.R., Olesen, A.V., Rasmussen, T.M. & Halpenny, 

J. 2013: New aero-gravity results from the Arctic: Linking the latest 

Cretaceous–early Cenozoic plate kinematics of the North Atlantic and 

Arctic Ocean. Geochemistry, Geophysics, Geosystems 14, 4044–4065. 
Døssing, A., Hansen, T.M., Olesen, A.V., Hopper, J.R. & Funck, T. 2014: 

Gravity inversion predicts the nature of the Amundsen Basin and its 

continental borderlands near Greenland. Earth and Planetary Science 

Letters 408, 132–145.
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Kingdom of Denmark together with the Government of Greenland to 

the Commission on the Limits of the Continental Shelf – Th e North-

ern Continental Shelf of Greenland. http://www.un.org/depts/los/clcs_

new/submissions_ fi les/dnk76_14/dnk2014_es.pdf

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saki, T. 2012: Th e Norwegian Basin revisited: from continental break-

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tinental shelf claims off  Greenland and the Faroe Islands – geological 

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Recommendations of the Commission on the Limits of the Continental 

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Denmark together with the Government of the Faroes in respect of the 

Continental Shelf North of the Faroe Islands on 29 April 2009. Adopted 

by the Commission, with amendments, on 12 March 2014. http://www.

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SCDNK_ R EC_COM_ 20140521.pdf 

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International 145, 505–516.

0.0

0.5

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2.0

D
e
p
th

 b
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lo

w
 s

e
af

lo
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r 

(k
m

)

1.5 2.0 2.5 3.0 3.5 4.0

Velocity (km/s)

Fig. 4. Sediment velocities in the Amundsen Basin obtained from ray-trac-

ing of the sonobuoy recordings from the three GEUS LOMROG expedi-

tions. Green circles show individual data points; the red line indicates an 

approximation obtained from reduced major axis regression techniques.

Authors' address
Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: cma@geus.dk