1. Mapping of volcanic facies variations onshore West Greenland
Asger Ken Pedersen
Geological Museum
University of Copenhagen

2. The Nuussuaq Basin in central West Greenland
Sediments: Mid Cretaceous
to Palaeogene
Volcanic Formations:
Main stage in Paleocene
Late stage in Eocene

3. Plateau basalt lava stage. Lavas progress far
beyond basin margin into graiss hinterland
Lava-infilling of lakes, subaqueatic lava flows
and invasive lavas (sills)
Lava plateau expands. Formation of large
Lake complexes, infilling by hyaloclastites,
Abundant eruption sites on land and in the
Lakes.
Lava plateau expands, narrowing of marine
basin, large scale infilling by hyaloclastites
Volcanism starts in marine basin. Volcanic
island stage: Lavas, hyaloclastites,
mass flows

4. S U N D

5. Five sections through the Nuussuaq Basin
Nuussuaq north coast 2006
Five sections through the Nuussuaq Basin
constructed
1993 and 2001 to 2006
Central Nuussuaq 2002
Nuussuaq south coast 1993
Central Disko 2005
Disko south coast 2003

6. Photos taken from helicopter,
boat and fixed-wing plane.
Construct multi-stereo panels
Combine with aerial
photographs
Product: Geological maps
Large sections
Detailed sections
Structural measurements
The sections compile
Information from
Field work
Petrology
Geochemistry
Palaeomagnetism
Palaeontology
Sedimentology
Multi-model photogrammetry: Photos takes with stereo-overlap
using calibrated small-frame cameras.

7. W E
Section 1: South coast of Nuussuaq, , 80 km profile length.

8. W E
Section 2: Aaffarsuaq valley in central Nuussuaq, 1:20 000, 110 km profile length

9. W E
Section 3: The south and south-west coast of Disko, 1:20 000, 130 km profile length

10. W E
Section 4: Across central Disko, 1:20 000, ca. 110 km profile length

11. Topics to be presented Subaerial lava flows Infilling of marine basins
Basin subsidence and early volcanic aggradation
Large plateau lavas and their interaction with sediments
The early volcanic island stage, mass flows and conglomerates
Significance of the volcanic feeder systems

12. Picrite lavas on gneiss in central Nuussuaq

13. The transition between the Vaigat Formation (picritic pahoehoe flows) and the Maligât Formation (thick plateau basalts) on Nuussuaq

14. Vaigat Formation: Lavas and hyaloclastites
cover Cretaceous and Palaeogene sediments

15. W E

16. Pahoehoe lava flows enter the sea at the south coast of Hawaii
Hawaii,USGS

17. Facies transition at Nuuk Killeq, Nuussuaq
Lava
Hyaloclastite
Facies transition at Nuuk Killeq, Nuussuaq

18. Nuussap Qaqqarsua

19. Magnetic transition zone ca 5000 y
Chron 26R
Magnetic transition zone ca 5000 y
Nuussap Qaqqarsua

20. Large plateau basalts from the Maligât Formation at Giesecke Monument, Nuussuaq

21. Skarvefjeld east of Qeqertarsuaq, Godhavn. 3 3 2 1 1 1 1
Skarvefjeld east of Qeqertarsuaq, Godhavn.
1.Subaqueous lavas 2: hyaloclastites 3: Subaerial lavas

22. 3 2 1

23. Subaqueous lava flow who has started to burrow into Paleocene mudstone, Maligât Formation, Disko

24. On top subaerial lava flows, below lava flows who have continued eastwards as ”sills” (invasive lavas), eastern part of the sediment basin

25. Drill cores and profiles in Anaanaa Member
Heavy colours: lava series, light colours: hyaloclastites
Max duration of A Mb ca y, chron 27n

26. Lipman et al. 2006

27. Early picritic eruption site on the sea floor. It is a pillow cone
Anaanaa Member in the Vaigat Formation on Nuussuaq

28. Clast supported conglomerate formed by erosion of lava flows at the coast of small lava island. The conglomerate is now oil-saturated. Early Vaigat Formation at Sikillingi on Nuussuaq

29. Large mass flow at Nuusaq, Early Vaigat Formation
Large fragment with several subaerial lava flows
Mass flow
A more than 20 m sized fragment with several lava flows, who has slided to a palaeodepth of more than 200 m from the old shore zone.
Large mass flow at Nuusaq, Early Vaigat Formation

30. Eruption sites Subaerial on the lava plain On the sea or lake floor
Eruptions channeled into older fault structures
Phreatic craters

31. Eruption site in central Nuussuaq
Picrite crater
Feeder dyke
Eruption site in central Nuussuaq

32. Two picrite crater sites within the upper part of the Vaigat Formation on Nuussuaq

33. Thin subaerial picritic lava flows
Hyaloclastite with numerous thin picritic feeder dykes
Subaqueous eruption site within a large lake

34. Subaqueous eruption site
Thin picritic lava flows
Thin feeder dykes
Subaqueous eruption site

35. Picritic lava flows Hy
Subaqueous
Eruption
site
Several hundred metres deep lake being filled by hyaloclastites derived from lava flows and by subqueous eruption sites

36. Large fault at basin margin in central Nuussuaq
Gneiss

37. Central Nuussuaq just west of a large marginal fault zone.
Foreset-bedded picritic hyaloclastites from the Vaigat Formation covered by lava flows
Central Nuussuaq just west of a large marginal fault zone.

38. Southern part of the Ilugissoq graphite andesite volcano
Erosion on top of cone
Southern cone
Subaerial graphite andesite tuff
Pi Lava
Pi Hy
Submarine graphite andesite tuff
Pi Hy
Southern part of the Ilugissoq graphite andesite volcano

39. What can you learn by studying the Nuussuaq Basin in West Greenland
A wide range of subaerial basalt lava features
Volcanic infilling patterns in passive and dynamically active marine and lacustrine basins.
The morphology and distribution of basaltic eruption sites.
Well exposed examples of interaction between basalts and unconsolidated sediments. Invasive lavas.
Large and coherent exposures of a sedimentary and volcanic basin and its margin.