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Nr. 4, Review of Survey activities 2003, pp. 61-64


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Following the expected ratification in 2004 of the United
Nations Convention on the Law of the Sea (UNCLOS from
1982), Denmark, Greenland and the Faroe Islands have a
period of maximum 10 years to make claims beyond 200
nautical miles (NM) in five potential areas off Greenland and
the Faroe Islands (Fig. 1). In order to provide the necessary
database, the Danish Continental Shelf Project has been
launched by the Ministry for Science, Technology and
Innovation in cooperation with the Faroese and Greenland
Home Rule governments. Several institutions are participat-
ing in this project, with the Geological Survey of Denmark
and Greenland (GEUS) as the coordinator of the technical
work for the Greenland part of the project, and sharing the
responsibility for coordination of the Faroese part with the
Faroese Geological Survey (JFS).
Background
Article 76 of UNCLOS is the key to future jurisdiction over
resources on and below the seabed beyond 200 NM. The
right to explore and exploit these resources, which include
both non-living resources (hydrocarbons and minerals) and
bottom-dwelling living resources, may have significant eco-
nomic implications. Furthermore, jurisdiction of the
extended continental shelf gives the right to regulate trans-
port, environment and research. The technical data needed
for a submission to the Commission on the Limits of the
Continental Shelf (CLCS) include geodetic, bathymetric,
geophysical and geological data. The most critical issue is to
be able to demonstrate a natural prolongation of the sub-
merged land territory based on geological and geomorpho-
logical factors, and later to document claims in detail by
using the various formulas and constraint lines of Article 76
(Commission on the Limits of the Continental Shelf (CLCS)
1999; Cook & Carleton 2000). For construction of these
lines it is necessary to know distances from territorial sea base
lines (+ 200 and 350 NM), to define the location of the foot
of the continental slope and the 2500 m isobath, and to
know the sediment thickness beyond the foot of the slope.
The foot of the continental slope (FOS) is defined as the
point of maximum change of gradient at the base of the con-
tinental slope.
Areas of interest around Greenland
There are three potential claim areas off Greenland. One
south of Greenland is outlined by the 200 NM limit, a yet to
be established boundary with Canada, and the new outer
limit. The second area north-east of Greenland is outlined by
the 200 NM line from Greenland, Jan Mayen (Norway) and
Svalbard (Norway) and the new outer limit. The third is
north of Greenland, outlined by the 200 NM limit and yet
to be established boundaries with Canada and possibly also
Russia and/or Norway, and a new outer limit. All three areas
are situated along margins of mixed rifted and strike-slip
nature, and contain significant successions of volcanic and
sedimentary rocks.
Geological Survey of Denmark and Greenland Bulletin 4, 61­64 (2004) © GEUS, 2004
Exploring for extended continental shelf claims off
Greenland and the Faroe Islands -­ geological perspectives
Christian Marcussen, Flemming G. Christiansen, Trine Dahl-Jensen, Martin Heinesen,
Steen Lomholt, Jens Jørgen Møller and Kai Sørensen
Fig. 1. Map of the North Atlantic region. Arrows indicate the five poten-
tial claim areas of interest. 1: Lomonosov Ridge, 2: Amundsen Basin, 3:
Morris Jesup Rise, 4: Gakkel Ridge, 5: Knipovitch Ridge, 6: East Green-
land Ridge, 7: Mohns Ridge, 8: Eiriks Ridge, 9: Labrador Sea, 10: Hatton
Bank, 11: Rockall Bank, 12: Rockall Trough. JM, Jan Mayen.
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South of Greenland
The Eiriks Ridge is assumed to be a natural prolongation of
southern Greenland with the foot of slope on the deep-water
side of the ridge (Fig. 2). The existence of very thick sedi-
mentary successions between Greenland and Canada, espe-
cially within the extinct spreading zone, may form the basis
for a claim far out into the Labrador Sea. There is a general
consensus on a tectonic model with sea-floor spreading in the
Labrador Sea in Paleocene­Eocene time, possibly continuing
into the Miocene. Models have changed considerably with
time, since the early work by Srivastava and co-workers sug-
gested large areas were underlain by oceanic crust of Late
Cretaceous to Miocene age, anomaly 33­20 time (e.g.
Srivastava 1978; Roest & Srivastava 1989). These models
were revised by Chalmers & Pulvertaft (2001), who suggest
spreading from anomaly 27­20 time.
The 2003 geophysical programme focused on data acqui-
sition along the Eiriks Ridge, and within and across the
extinct spreading zone, to document and correlate thick sed-
imentary successions. A total of 1500 km reflection seismic
data were acquired. The new seismic data confirm the sedi-
mentary nature of the Eiriks Ridge (Fig. 2) and furthermore
show that sediment thicknesses are a potential factor for a
future claim beyond 200 NM.
North-east of Greenland
The East Greenland Ridge is assumed to be a natural prolon-
gation of north-eastern Greenland, and the foot of the slope
extends around the ridge (Fig. 3). The thick sedimentary suc-
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Fig. 3. A: Map of the East Greenland Ridge region. The seismic lines
acquired in 2002 are shown in orange and white, the 200 NM limits of
Greenland, Svalbard and Jan Mayen in red, and the 350 NM limit of
Greenland in blue. The stippled black line is the unofficial median line
between Greenland and Svalbard; the full black line is the official bor-
der between Greenland and Norway (Jan Mayen), and Greenland and
Iceland. B: Seismic section across the East Greenland Ridge. Position in-
dicated in Fig. 3A (white line).
Fig. 2. A: Map of the South Greenland region showing seismic lines
acquired in 2003 (orange and white) and older seismic lines (black).
Stippled line is the unofficial median line with Canada; 200 NM line in
red. B: Seismic line along the Eiriks Ridge. Position indicated in Fig. 2A
(white line).
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cessions that exist both north and south of the ridge are likely
to contribute to the claim area. Although there is general con-
sensus on the opening history of the North Atlantic, prob-
lems with details of the structural elements are apparent,
especially north of the East Greenland Ridge where major
strike-slip movements occur in the region between the shelf
break and the Knipovitch Ridge. A simpler spreading pattern
is observed south of the ridge since anomaly 24 B time, with
active spreading along the Mohns Ridge (Mosar et al. 2002;
Tsikalas et al. 2002).
In the summer of 2002 GEUS and the University of
Bergen carried out a joint refraction and reflection seismic
survey over the East Greenland Ridge. There is a marked dif-
ference in water depth and subsurface structure north and
south of the ridge (Fig. 3). The preliminary wide-angle veloc-
ity model shows standard oceanic crust to the south, while
the northern side of the ridge and the crust further north may
be stretched continental crust.
North of Greenland
The Lomonosov Ridge and the Morris Jesup Rise are
assumed natural prolongations of northern Greenland. If rel-
atively thick sedimentary successions can be demonstrated in
the Amundsen Basin it may be possible to enlarge the poten-
tial claim area (Fig. 1). The existing data coverage from the
Arctic Ocean north of Greenland is very sparse, due to the
adverse physical conditions with metre-thick sea ice and
many pressure ridges. There is, however, general consensus
on a tectonic model with active spreading since Paleocene
time along the Gakkel Ridge, and with the Lomonosov Ridge
most likely consisting of continental crust separated from the
Barents­Kara shelf (Jokat et al. 1995; Lawver et al. 2002).
Preliminary studies in 2004 will focus on testing data acqui-
sition methods on the sea ice, and on a passive earthquake
seismological experiment for the crustal structure of North
Greenland. Subsequent studies will include acquisition of
refraction seismic data on the sea ice along the innermost
parts of the Lomonosov Ridge, followed by data acquisition
from ice breakers across the Lomonosov Ridge and in the
Amundsen Basin.
Areas of interest around the Faroe Islands
The Faroe Islands consist of basaltic rocks with a cumulative
stratigraphic thickness of more than 6.5 km resting on top of
presumed Precambrian basement (Ellis et al. 2002). During
the initial phases of continental break-up between Europe
and Greenland, the Faroe Islands and the Hatton­Rockall
area (the Faroe­Rockall Plateau) were partly isolated from the
main European continent. Subsequent shift of the break-up
axis to the west of the plateau resulted in extensive (basaltic)
volcanism, seafloor spreading and the creation of the north-
east Atlantic Ocean between Europe and Greenland. The two
potential claim areas off the Faroe Islands are an area north-
east of the islands, and the Hatton­Rockall area to the south-
west (Fig. 4).
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Fig. 4. A: Map of the Faroe Islands region. The designated area is out-
lined with blue lines. The red lines indicate the 200 NM limits of the
surrounding coastal states. Continental shelf median lines are drawn in
black. The position of the three seismic lines acquired in 2003 are shown
in orange and white. B: Seismic line LOS_FO_03-1. Position indicated
in Fig. 4A (white line).
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The north-eastern area
The basaltic rocks that form the Faroe Islands reach far off-
shore on the continental shelf and continue onto the conti-
nental margins to the north of the islands (Boldreel &
Andersen 1994). In the central part of this region the slope
beyond the shelf break is steep and the transition from shelf
to deep ocean sea floor is narrow. Elsewhere, the slope is more
gentle (Fig. 4).
Thick sediment accumulations in the deep-water areas
favour claims extending beyond the 200 NM limit. Three
seismic lines were acquired in 2003 (Fig. 4) to study the con-
tinent­ocean transition (COT) and to assess the sediment
thickness along the continental shelf margin.
The south-western area
Based on UNCLOS, Article 76, and on the assumption that
the Faroe­Rockall Plateau constitutes a micro-continent, the
Danish authorities designated a large continental shelf area to
the south-west of the Faroe Islands in 1985 (Fig. 4). This area
includes the parts of the Hatton and Rockall Banks situated
outside the 200 NM limits of the neighbouring states (Great
Britain, Ireland and Iceland), who in their turn have made
individual designations for the same area.
The basaltic rocks that form the Faroe Islands continue
and thin south-westwards, and disappear at several locations
at the Hatton and Rockall Banks where the underlying rocks
are exposed at seabed. The plateau margin to the west is rela-
tively simple with a well-defined slope area (Fig. 4). Different
volcanic and tectonic features to the south of the plateau
complicate the marginal area in this region. Towards the east
the plateau borders the Rockall Trough, which reaches water
depths of 3­4 km in its southernmost part. Work planned for
2004 includes a deep reflection and refraction seismic pro-
gramme and a geochemical study.
Conclusion
The Danish Continental Shelf Project has so far acquired
new data in three out of five potential claim areas off
Greenland and the Faroe Islands, and much more data acqui-
sition and interpretation will follow in the next few years.
The results of the project, together with similar projects by
neighbouring countries, will create new focus on the geology
and tectonics of the North Atlantic and Arctic regions.
References
Boldreel, L.O. & Andersen, M.S. 1994: Tertiary development of the Fa-
roe­Rockall Plateau based on reflection seismic data. Bulletin of the
Geological Society of Denmark 41(2), 162­180.
Chalmers, J.A. & Pulvertaft, T.C.R. 2001: Development of the continental
margins of the Labrador Sea ­ a review. In: Wilson, R.C.L. et al. (eds):
Non-volcanic rifting of continental margins: a comparison of evidence
from land and sea. Geological Society Special Publication (London)
187, 77­105.
Commission on the Limits of the Continental Shelf (CLCS) 1999: Scientific
and technical guidelines of the Commission on the Limits of the
Continental Shelf. CLCS/11, 91 pp. + annexes.
Cook, P.J. & Carleton, C.M. (eds) 2000: Continental shelf limits: the sci-
entific and legal interface, 363 pp. New York: Oxford University Press.
Ellis, D., Bell, B.R., Jolley, D.W. & O'Callaghan, M. 2002: The stratigra-
phy, environment of eruption and age of the Faroes Lava Group, NE
Atlantic Ocean. In: Jolley, D.W. & Bell, B.R. (eds): The North Atlantic
igneous province: stratigraphy, tectonic, volcanic and magmatic
processes. Geological Society Special Publication (London) 197,
253­269.
Jokat, W., Weigelt, E., Kristoffersen, Y., Rasmussen, T. & Schöne, T. 1995:
New insights into the evolution of the Lomonosov Ridge and the
Eurasian Basin. Geophysical Journal International 122(2), 378­392.
Lawver, L.A., Grantz, A. & Gahagan, L.M. 2002: Plate kinematic evolution
of the present Arctic region since the Ordovician. In: Miller, E.L.,
Grantz, A. & Klemperer, S.L. (eds): Tectonic evolution of the Bering
Shelf­Chukchi Sea­Arctic Margin and adjacent landmasses. Geological
Society of America, Special Paper 360, 333­358.
Mosar, J., Lewis, G. & Torsvik, T.H. 2002: North Atlantic sea-floor spread-
ing rates; implications for the Tertiary development of inversion struc-
tures of the Norwegian­Greenland Sea. Journal of the Geological
Society (London) 159(5), 503­515.
Roest, W.R. & Srivastava, S.P. 1989: Sea-floor spreading in the Labrador
Sea: a new construction. Geology 17, 1000­1003.
Srivastava, S.P. 1978: Evolution of the Labrador Sea and its bearing on the
early evolution of the North Atlantic. Geophysical Journal of the Royal
Astronomical Society 52, 313­357.
Tsikalas, F., Eldholm, O. & Faleide, J.I. 2002: Early Eocene sea floor
spreading and continent­ocean boundary between Jan Mayen and
Senja fracture zones in the Norwegian­Greenland Sea. Marine
Geophysical Researches 23(3), 247­270.
Authors' addresses
C.M., F.G.C., T.D.-J., S.L., J.J.M. & K.S., Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K,
Denmark. E-mail: cma@geus.dk
M.H., Jar
frø
isavni
(JFS) ­ Faroese Geological Survey, Postboks 3169, FO-110 Tórshavn, The Faroe Islands.
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