The dissetation has been a joint project between GEUS (The National Geological Survey of Denmark and
Greenland) and The Department of Sedimentology at The University of Aarhus.
Associated Professor Henrik Friis has been counsellor/guiding teacher on the dissetation.

Methods and structure

19 samples of sandstone (collected in periferal areas of the Kap Stewart Formation) has been analized with
powder X-ray diffraction methods (both bulk samples and the clay fraction). The thin sections has been
examined with polarization microscope, electronic microprobe and scanning electron microscope (SEM).

The dissetation consists of 2 volumes - the first is descriptive (88 pp., presentation of the area and the sample
material, general lines of the geological evolution in Central-East Greenland, methods of analysis, presentation
of results, discussion and interpretation of the results and conclusion) and the second is a collection of the photos
taken during the analysis (32 color-micrographs taken through the polarisation microscope and 23 black and
white photos taken during SEM-analysis).

Abstract

During Rhaetian to Sinemurian time a large hydrological closed lake, were situated in the Jameson Land area in
Central Eastern Greenland. The lacustrine sediments consists of alternating layers of indurated non-fossiliferous
black mud with a high content of organic material and sheet-sandstone. The sandstones were deposited during
delta progradation in a wave- and storm dominated basin in waterdepth less than 15 m.
Sequence stratigraphic interpretations suggest that the black mud was deposited during periods with increasing
and high lake level, while the sheet sandstones were deposited by delta progradation during "forced regression"
caused by significant lowering of the lake level.

Bodies of deltaic sandstone deposited in shallow water isolated in lacustrine mud with a high content of organic
matter, are situated in a extensive area of south- and central Jameson Land.

The samples analized can be classified (according to Folk) as Subarcoses and Sublitharenits for samples from
the localities in the north and north-east and as Lithic arcoses to feldspatic litharenits for the samples from the two
eastern localities.

The provenance areas for the sediments were the imediate hinterland to the shores of the lake for the samples taken
along the shores and for the more central parts of the lake the sediments had a prevailing northern source.
The difference in provenance areas has influated the course of diagenesis of the sediments. In the northern and
north-western areas we find carbonate cements rich in iron and manganese and to the east we find only calcit.
The carbonate cementation has totally destructed all primary and secondary porosity before the hydrocarbons started
to migrate in the beginning of the Tertiary period. The present porosity (maximum 9 %) is exclusively secondary
and was created in response to uplift (telo(dia)genesis) initiated in the Oligocene period.
In the analized samples there has not been found any traces of hydrocarbons (except in a sample strongly influated
by a sill).
The bowl-shaped basin and the sheet-like distribution of the sandstones indicates a low conservation potential
for the hydrocarbons in the samples analized in this survey (lack of an efficient seal). Future surveys of the Kap
Stewart sandstone should concentrate on the central areas of the ancient lake, where the ratio shale:sandstone
is higher and therefore renders a higher conservation potential (i.e.were are more likely to find sandstone
bodies totally isolated in the shale).

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