Abstracts - Vol. 1 Geol. Surv. of Denmark and Greenland Bulletin

The Lower Jurassic of Europe: its subdivision and correlation
Kevin N. Page
The Lower Jurassic Sub-system comprises four stages, in chronological order, the Hettangian, Sinemurian, Pliensbachian and Toarcian. Each stage is subdivided into a sequence of `standard zones' (= chronozones) and subzones - each correlated primarily on the basis of its ammonite fauna. A further increase in stratigraphical resolution is available by the use of intra-subzonal units known collectively as `horizons'. The close link between ammonites and chronostratigraphy means that faunal provincialism may determine which zonal framework, and therefore which subdivision of the Lower Jurassic, applies in different regions of Europe. Such provincialism is of minor importance in the early Jurassic (Hettangian - Lower Pliensbachian) but increases significantly in the Upper Pliensbachian and into the Toarcian where at least three ammonoid faunal provinces are distinguishable. The standard zonal schemes for each relevant faunal area are discussed here, with greatest emphasis being placed on the Northwest European Province, which is characteristic of much of northern Europe throughout most of the Early Jurassic. Intra-subzonal units have only been described in certain regions for parts of the Lower Jurassic but where recognisable these are introduced.
Keywords : Europe, Lower Jurassic, ammonite zonal biostratigraphy
Department of Geological Sciences, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK. E-mail: KevinP@bello-page.fsnet.co.uk
Geological Survey of Denmark and Greenland Bulletin 1, 23-59 (2003) © GEUS, 2003

The Middle Jurassic of western and northern Europe: its subdivisions, geochronology and correlations
John H. Callomon
The palaeogeographic settings of Denmark and East Greenland during the Middle Jurassic are outlined. They lay in the widespread epicontinental seas that covered much of Europe in the post-Triassic transgression. It was a period of continuing eustatic sea-level rise, with only distant connections to world oceans: to the Pacific, via the narrow Viking Straits between Greenland and Norway and hence the arctic Boreal Sea to the north; and to the subtropical Tethys, via some 1200 km of shelf-seas to the south.
The sedimentary history of the region was strongly influenced by two factors: tectonism and
climate. Two modes of tectonic movement governed basinal evolution: crustal extension leading to subsidence through rifting, such as in the Viking and Central Grabens of the North Sea; and subcrustal thermal upwelling, leading to domal uplift and the partition of marine basins through emergent physical barriers, as exemplified by the Central North Sea Dome with its associated volcanics. The climatic gradient across the 30º of temperate latitude spanned by the European seas governed biotic diversity and biogeography, finding expression in rock-forming biogenic carbonates that dominate sediments in the south and give way to largely siliciclastic sediments in the north.
Geochronology of unrivalled finesse is provided by standard chronostratigraphy based on the
biostratigraphy of ammonites. The Middle Jurassic saw the onset of considerable bioprovincial endemisms in these guide-fossils, making it necessary to construct parallel standard zonations for Boreal, Subboreal or NW European and Submediterranean Provinces, of which the NW European zonation provides the primary international standard. The current versions of these zonations are presented and reviewed.
Keywords : Northwest Europe, North Sea, East Greenland, Middle Jurassic, palaeogeography, geochronology, ammonite biostratigraphy, standard chronostratigraphy
University College London, 20 Gordon Street, London WC1H 0AJ, UK. E-mail: johncallomon@lineone.net
Geological Survey of Denmark and Greenland Bulletin 1, 61-73 (2003) © GEUS, 2003

The Upper Jurassic of Europe: its subdivision and correlation
Arnold Zeiss
In the last 40 years, the stratigraphy of the Upper Jurassic of Europe has received much attention and considerable revision; much of the impetus behind this endeavour has stemmed from the work of the International Subcommission on Jurassic Stratigraphy.
The Upper Jurassic Series consists of three stages, the Oxfordian, Kimmeridgian and Tithonian
which are further subdivided into substages, zones and subzones, primarily on the basis of ammonites. Regional variations between the Mediterranean, Submediterranean and Subboreal provinces are discussed and correlation possibilities indicated. The durations of the Oxfordian, Kimmeridgian and Tithonian Stages are reported to have been 5.3, 3.4 and 6.5 Ma, respectively.
This review of the present status of Upper Jurassic stratigraphy aids identification of a number of problems of subdivision and definition of Upper Jurassic stages; in particular these include correlation of the base of the Kimmeridgian and the top of the Tithonian between Submediterranean and Subboreal Europe. Although still primarily based on ammonite stratigraphy, subdivision of the Upper Jurassic is increasingly being refined by the incorporation of other fossil groups; these include both megafossils, such as aptychi, belemnites, bivalves, gastropods, brachiopods, echinoderms, corals, sponges and vertebrates, and microfossils such as foraminifera, radiolaria, ciliata, ostracodes, dinoflagellates, calcareous nannofossils, charophyaceae, dasycladaceae, spores and pollen. Important future developments will depend on the detailed integration of these disparate biostratigraphic data and their precise combination with the abundant new data from sequence stratigraphy, utilising the high degree of stratigraphic resolution offered by certain groups of fossils. This article also contains some notes on the recent results of magnetostratigraphy and sequence chronostratigraphy.
Keywords : Europe, Upper Jurassic, Oxfordian, Kimmeridgian, Tithonian, Volgian, ammonite zonal and subzonal biostratigraphy and correlations, subdivision by non-ammonite fossil groups, chronometric data, magnetostratigraphy, sequence stratigraphy
Institut für Paläontologie der Universität Erlangen-Nürnberg, Loewenichstr. 28, D-91054 Erlangen, Germany. Present address: Albert Schweitzer Strasse 19, D-91080 Uttenreuth, Germany. E-mail: arnold.zeiss@t-online.de
Geological Survey of Denmark and Greenland Bulletin 1, 75-114 (2003) © GEUS, 2003

The Jurassic dinoflagellate cyst zonation of Subboreal Northwest Europe
Niels E. Poulsen and James B. Riding
With an appendix by Bjørn Buchardt: Oxygen isotope palaeotemperatures from the Jurassic in Northwest Europe
The Jurassic dinoflagellate cyst zonation for the British-Danish area is revised and discussed in relation to palaeoenvironmental factors, in particular, eustatic changes and fluctuations in palaeotemperature. The stepwise evolution of dinoflagellate cyst assemblages as defined by inceptions and apparent extinctions was largely controlled by sea-level change, particularly during intervals with significant short-term eustatic fluctuations. During times characterised by less pronounced, or longer term, sea-level change, fluctuations in oceanic palaeotemperatures appear to have influenced dinoflagellate evolution. Differences in the ranges of certain taxa between Denmark and the United Kingdom may be partly related to differences in palaeotemperature.
Keywords : Subboreal Northwest Europe, Jurassic, dinoflagellate cyst zonation, palaeotemperatures and biotic provincialism, dinoflagellate palaeoecology
N.E.P., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: nep@geus.dk
J.B.R., British Geological Survey, Keyworth, Nottingham NG12 5GG, UK.
B.B., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 115-144 (2003) © GEUS, 2003

Jurassic lithostratigraphy and stratigraphic development onshore and offshore Denmark
Olaf Michelsen, Lars H. Nielsen, Peter N. Johannessen, Jan Andsbjerg and Finn Surlyk
A complete updated and revised lithostratigraphic scheme for the Jurassic succession of the onshore and offshore Danish areas is presented together with an overview of the geological evolution. The lithostratigraphies of Bornholm, the Danish Basin and the Danish Central Graben are described in ascending order, and a number of new units are defined. On Bornholm, the Lower-Middle Jurassic coal-bearing clays and sands that overlie the Lower Pliensbachian Hasle Formation are referred to the new Sorthat Formation (Lower Jurassic) and the revised Bagå Formation (Middle Jurassic). In the southern Danish Central Graben, the Middle Jurassic succession formerly referred to the Lower Graben Sand Formation is now included in the revised Bryne Formation. The Lulu Formation is erected to include the uppermost part of the Middle Jurassic succession, previously referred to the Bryne Formation in the northern Danish Central Graben. The Upper Jurassic Heno Formation is subdivided into two new members, the Gert Member (lower) and the Ravn Member (upper). The organic-rich part of the upper Farsund Formation, the former informal `hot unit', is established formally as the Bo Member.
Dominantly shallow marine and paralic deposition in the Late Triassic was succeeded by widespread deposition of offshore marine clays in the Early Jurassic. On Bornholm, coastal and paralic sedimentation prevailed. During maximum transgression in the Early Toarcian, sedimentation of organic-rich offshore clays took place in the Danish area. This depositional phase was terminated by a regional erosional event in early Middle Jurassic time, caused by uplift of the central North Sea area, including the Ringkøbing-Fyn High. In the Sorgenfrei-Tornquist Zone to the east, where slow subsidence continued, marine sandy sediments were deposited in response to the uplift. Uplift of the central North Sea area was followed by fault-controlled subsidence accompanied by fluvial and floodplain deposition during Middle Jurassic time. On Bornholm, deposition of lacustrine muds, fluvial sands and peats dominated. The late Middle Jurassic saw a gradual shift to shallow marine deposition in the Danish Central Graben, the Danish Basin and Skåne, southern Sweden. During the Late Jurassic, open marine shelf conditions prevailed with deposition of clay-dominated sediments while shallow marine sands were deposited on platform areas. The Central Graben received sand by means of sediment gravity flows. The clay sediments in the Central Graben became increasingly rich in organic matter at the Jurassic-Cretaceous transition, whilst shallow marine coarse-grained deposits prograded basinwards in the Sorgenfrei- Tornquist Zone.
Keywords : Denmark, Danish Central Graben, Danish Basin, Sorgenfrei-Tornquist Zone, Bornholm, Jurassic, lithostratigraphy, basin development
O.M., Geological Institute, University of Aarhus, C.F. Møllers Allé, DK-8000 Århus C, Denmark.
L.H.N., P.N.J. & J.A., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: lhn@geus.dk
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 147-216 (2003) © GEUS, 2003

The Jurassic of the Netherlands
G.F. Waldemar Herngreen, Wim F.P. Kouwe and Theo E.Wong
A recent revision of the lithostratigraphy of the Netherlands has triggered an extensive re-evaluation of existing ideas on the Jurassic structural and depositional history. Significant advances can be attributed to the incorporation of sequence stratigraphic concepts. In the course of the Triassic and Jurassic, structural complexity increased progressively. The Jurassic sedimentary succession can be subdivided into three depositional megasequences. Megasequence I (Rhaetian- Aalenian) reflects the period between the so-called early and mid-Cimmerian tectonic phases. Megasequence II (Aalenian - Middle Callovian) covers the period of activity of the mid-Cimmerian phase. Megasequence III (Middle Callovian - Ryazanian) corresponds with the period between the mid-Cimmerian and late Cimmerian phases (particularly after pulse II). In this latter megasequence, six stages (IIIa-f) are recognised. Sediments deposited during the Rhaetian and Ryazanian bear a stronger affinity with the Jurassic succession than with Triassic and Cretaceous sediments respectively. These stages are thus treated here as an integral part of the Jurassic succession. During the Rhaetian-Bajocian the area subsided relatively uniformly. A sheet of predominantly fine-grained marine sediments of great lateral uniformity was deposited. During the Toarcian, in particular, basin circulation was largely restricted.
The cooling that followed the thermal Central North Sea dome uplift triggered an important
extensional phase during the Aalenian-Callovian. The rift phase resulted in the formation of several smaller basins, each with its own characteristic depositional succession. The basins fall into three structural provinces: the eastern province (Lower Saxony Basin, E-W-striking); the northern province (Central Graben, N-S-striking); and the southern-central system (Roer Valley Graben - Broad Fourteens, with a strong NW-SE strike). The mid-Cimmerian event started to affect the Dutch basins during the Bajocian. Sedimentation ceased in the Dutch Central Graben while it persisted in a predominantly coarse-grained, shallow marine facies in the southern basins (Roer Valley Graben, West Netherlands Basin). Extensional tectonics in the Central Graben were initiated during the Middle Callovian, with the deposition of continental sediments. During the Oxfordian-Kimmeridgian, marine incursions gradually became more frequent. Marine deposition in the other basins in the south persisted into the Oxfordian, at which time deposition became predominantly continental. Marine conditions gradually returned in the south during the Ryazanian-Barremian, with a series of advancing partial transgressions from the north. The present-day distribution of Jurassic strata in the Netherlands was determined largely by erosion associated with Late Cretaceous - Paleocene uplift.
Keywords : The Netherlands onshore and offshore, Jurassic, lithostratigraphy, sequence stratigraphy, tectonics, regional geology
G.F.W.H.* & T.E.W., Netherlands Institute of Applied Geoscience TNO - National Geological Survey, P.O. Box 80015, NL-3508 TA Utrecht, The Netherlands. *Retired. E-mail: G.F.W.Herngreen@bio.uu.nl
W.F.P.K., Wintershall Noordzee B.V., Eisenhowerlaan 146, NL-2517 JL The Hague, The Netherlands.
Geological Survey of Denmark and Greenland Bulletin 1, 217-229 (2003) © GEUS, 2003

Upper Jurassic - Lower Cretaceous of the Danish Central Graben: structural framework and nomenclature
Peter Japsen, Peter Britze and Claus Andersen
The Danish Central Graben is part of the mainly Late Jurassic complex of grabens in the central and southern North Sea which form the Central Graben. The tectonic elements of the Danish Central Graben in the Late Jurassic are outlined and compared to those in the Early Cretaceous based on reduced versions of published maps (1:200 000), compiled on the basis of all 1994 public domain seismic and well data. The Tail End Graben, a half-graben which stretches for about 90 km along the East North Sea High, is the dominant Late Jurassic structural feature. The Rosa Basin (new name) is a narrow, north-south-trending basin extending from the south-western part of the Tail End Graben. The Tail End Graben ceased to exist as a coherent structural element during the Early Cretaceous and developed into three separate depocentres: the Iris and Gulnare Basins to the north and the Roar Basin to the south (new names). The Early Cretaceous saw a shift from subsidence focused along the East North Sea High during the Late Jurassic to a more even distribution of minor basins within the Danish Central Graben.
The depth to the top of the Upper Jurassic - lowermost Cretaceous Farsund Formation reaches
a maximum of 4800 m in the northern part of the study area, while the depth to the base of the Upper Jurassic reaches 7500 m in the Tail End Graben, where the Upper Jurassic attains a maximum thickness of 3600 m. The Lower Cretaceous Cromer Knoll Group attains a maximum thickness of 1100 m in the Outer Rough Basin.
Keywords : North Sea, Danish Central Graben, Upper Jurassic, Lower Cretaceous, isochore maps, structure contour maps, structural nomenclature
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: pj@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 233-246 (2003) © GEUS, 2003

Middle Jurassic - Early Cretaceous rifting of the Danish Central Graben
Jens J. Møller and Erik S. Rasmussen
During the Jurassic - Early Cretaceous, the Danish Central Graben developed as a N-S- to NNW- SSE-trending graben bounded by the Ringkøbing-Fyn High towards the east and the Mid North Sea High towards the west. The graben consists of a system of half-grabens and evolved by faultcontrolled subsidence; three main rift pulses have been recognised. The first pulse ranged from the Callovian to the Early Oxfordian, the second pulse was initiated in the latest Late Kimmeridgian and lasted for most of the Early Volgian, and the third and final pulse occurred within the Ryazanian in the Early Cretaceous.
The first pulse was characterised by subsidence along N-S-trending faults. The most pronounced fault-controlled subsidence occurred in the east, especially along N-S-striking segments of the boundary fault to the Ringkøbing-Fyn High. During this period, minor salt movements occurred with the development of salt pillows. The activity along the N-S-trending faults ceased during the Oxfordian. During the second pulse, in Early Volgian times, subsidence was concentrated along new NNW-SSE-trending faults and the main depocentre shifted westward, being most marked within the Tail End Graben, the Arne-Elin Graben, and the Feda Graben. This tectonic event was accompanied by the accumulation of a relatively thick sediment load resulting in the development of salt diapirs, especially within the Salt Dome Province. The third tectonic pulse was essentially a reactivation of the NNW-SSE-trending structures and there is clear evidence of subsidence controlled by faulting and salt movements. Despite the overall extensional tectonic regime, local compressional tectonics resulted in thrusting. For instance, the Gert Ridge is interpreted to have formed by readjustment at the boundary fault between two subsiding blocks.
The structural framework during graben evolution controlled, to some degree, the distribution of
reservoir sandstones. Reservoir sandstones associated with periods of rotational tilt include Middle Jurassic deposits referred to the Bryne and Lulu Formations, and Upper Jurassic sandstones referred informally to the `Fife Sandstone Formation'. Sands deposited during tectonic relaxation are represented by the Heno Formation and Upper Jurassic turbidites interbedded in the Farsund Formation. Sea-level changes were probably most important during periods of tectonic relaxation, particularly with respect to the deposition of lowstand sandstones in basinal areas.
Keywords : North Sea, Danish Central Graben, Middle Jurassic - lowermost Cretaceous, 3D seismic data, structural evolution, reservoir sandstone distribution
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: jjm@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 247-264 (2003) © GEUS, 2003

Sequence stratigraphy of the Jurassic of the Danish Central Graben
Jan Andsbjerg and Karen Dybkjær
A sequence stratigraphic framework is established for the Jurassic of the Danish Central Graben based primarily on petrophysical log data, core sedimentology and biostratigraphic data from about 50 wells. Regional seismic lines are used to assist in the correlation of some wells and in the construction of isochore maps. In the Lower Jurassic (Hettangian-Pliensbachian) succession, five sequences have been identified. The Middle Jurassic is subdivided into four sequences that together span the uppermost Aalenian/lowermost Bajocian to the Callovian. In the Upper Jurassic, better well coverage permits greater stratigraphic resolution, and 11 sequences are identified and mapped.
On the basis of the sequence stratigraphic correlation and the construction of isochore maps
for individual sequences, the Jurassic basin history of the Danish Central Graben can be subdivided into seven discrete phases: (1) Shallow marine and offshore sediments deposited in a prerift basin extending from the North Sea to the Fennoscandian Border Zone (Hettangian-Pliensbachian). (2) Uplift and erosion in association with a Toarcian-Aalenian North Sea doming event. A major hiatus represents this phase in the study area. (3) Terrestrial and marginal marine sedimentation during initial rifting (latest Aalenian/earliest Bajocian - Late Callovian). (4) Early Oxfordian - Early Kimmeridgian transgression during and after a rift pulse. The sedimentary environment changed from coastal plain and marginal marine to fully marine. (5) Regression associated with a cessation or slowing of subsidence during a structural rearrangement that took place in the Late Kimmeridgian during a break in the main rift climax. Shallow to marginal marine sandstones were deposited above an erosion surface of regional extent. (6) Deep-water mudstones deposited in a composite graben with high subsidence rates related to rift pulses (latest Late Kimmeridgian - middle Middle Volgian). (7) Deposition of organic-rich mudstones and turbidite sandstones during the late Middle Volgian - Early Ryazanian. The main basin shallowed, became more symmetrical and experienced a decreasing rate of subsidence, recording the onset of the post-rift stage.
A relative sea-level curve is constructed for the Middle-Late Jurassic. It shows close similarity
to published eustatic (global) and relative (North Atlantic area) sea-level curves in the latest Bathonian - late Early Kimmeridgian, but differs in the Late Kimmeridgian - Middle Volgian interval, probably due to the high rate of subsidence in the study area.
Keywords : Danish Central Graben, Jurassic, sequence stratigraphy, palaeogeography, basin evolution, sea-level changes
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: ja@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 265-300 (2003) © GEUS, 2003

Sedimentology and sequence stratigraphy of the Bryne and Lulu Formations, Middle Jurassic, northern Danish Central Graben
Jan Andsbjerg
The Middle Jurassic Bryne and Lulu Formations of the Søgne Basin (northern part of the Danish Central Graben) consist of fluvially-dominated coastal plain deposits, overlain by interfingering shoreface and back-barrier deposits. Laterally continuous, mainly fining-upwards fluvial channel sandstones that locally show evidence for tidal influence dominate the alluvial/coastal plain deposits of the lower Bryne Formation. The sandstones are separated by units of fine-grained floodplain sediments that show a fining-upwards - coarsening-upwards pattern and locally grade into lacustrine mudstones. A regional unconformity that separates the lower Bryne Formation from the mainly estuarine upper Bryne Formation is defined by the strongly erosional base of a succession of stacked channel sandstones, interpreted as the fill of a system of incised valleys. Most of the stacked channel sandstones show abundant mud laminae and flasers, and rare herringbone structures, suggesting that they were deposited in a tidal environment, probably an estuary. Several tens of metres of the lower Bryne Formation may have been removed by erosion at this unconformity. The estuarine channel sandstone succession is capped by coal beds that attain a thickness of several metres in the western part of the Søgne Basin, but are thin and poorly developed in the central part of the basin. Above the coal beds, the Lulu Formation is dominated by various types of tidally influenced paralic deposits in the western part of the basin and by coarsening-upwards shoreface and beach deposits in central parts. Westwards-thickening wedges of paralic deposits interfinger with eastwards-thickening wedges of shallow marine deposits.
The Middle Jurassic succession is subdivided into nine sequences. In the lower Bryne Formation,
sequence boundaries are situated at the base of laterally continuous fluvial channel sandstones whereas maximum flooding surfaces are placed in laterally extensive floodplain or lacustrine mudstones. The unconformity that separates the alluvial plain deposits of the lower Bryne Formation from the estuary deposits of the upper Bryne Formation is interpreted as a sequence boundary that bounds a system of incised valleys in the western and southern parts of the basin. Sequence boundaries in the Lulu Formation are situated at the top of progradational shoreface units or at the base of estuarine channels. Maximum flooding surfaces are located within marine or lagoonal mudstone units. Marine highstand deposits are partitioned seawards, in the eastern part of the basin, whereas paralic transgressive deposits are partitioned landwards, in the west. This marked sediment partitioning in the uppermost part of the succession resulted from the alternation of episodes of fault-induced half-graben subsidence with periods of slow uniform subsidence.
Keywords : Danish Central Graben, Middle Jurassic, Bryne Formation, Lulu Formation, sedimentology, sequence stratigraphy, alluvial/coastal plain - shallow marine, sediment partitioning
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: ja@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 301-347 (2003) © GEUS, 2003

The use of spectral natural gamma-ray analysis in reservoir evaluation of siliciclastic sediments: a case study from the Middle Jurassic of the Harald Field, Danish Central Graben
Ida L. Fabricius, Louise Dahlerup Fazladic, Armgard Steinholm and Uffe Korsbech
A cored sandstone interval from the Middle Jurassic Harald Field of the Danish North Sea was chosen for an investigation of the mineralogical sources for the gamma-ray activity, and with the purpose of determining how the Spectral Natural Gamma (SNG) log could be used as an indicator of reservoir quality. Core intervals of quartz arenites and quartz wackes were selected.
Although no linear relationship was found between clay content and potassium (K), thorium (Th), or uranium (U), the K content characterises three discrete lithofacies. Lithofacies I has a grain-supported texture, with a predominance of quartz grains; only minor fine-grained matrix is present. Sandstones of lithofacies I have a low K content and most of the K is hosted in feldspar. Porosity varies between 23% and 28% and permeability is in the range 200-2000 mD. Lithofacies II sandstones have a grain-supported texture, with a predominance of quartz grains; fine-grained matrix fills the intergranular volume. Sandstones of lithofacies II have an intermediate K content, with K-feldspar, mica, and illite as the main sources. Porosity varies between 11% and 17% and permeability is in the range 0.4-25 mD. Lithofacies III has a matrix-supported texture with quartz grains floating in a clay-rich matrix. Samples from lithofacies III have the highest K signal. Illite and illitised kaolinite are roughly equal in importance as sources of K. Porosity is up to 11% and permeability up to 0.5 mD. The Th and U content of all lithofacies is governed primarily by the presence of heavy minerals; no apparent general relationship between U and Total Organic Carbon (TOC) was found.
Comparisons between the core measurements of K, Th, and U, and the SNG log disclosed a
discrepancy between the calibrations of laboratory and borehole measurements. For U the discrepancy contains an erratic element, whereas the difference for K and Th can be eliminated by correction factors. Thus, the conclusions based on laboratory measurements appear to be applicable to the log data, and, using corrected K values, the facies subdivision can be extended throughout the reservoir section based on the SNG log.
Keywords : Danish Central Graben, North Sea, Middle Jurassic, sandstone reservoir, gamma-ray spectometry, mineralogy, geochemistry
I.L.F., L.D.F.*, A.S. & U.K., Technical University of Denmark (DTU), DK-2800 Lyngby, Denmark. *Present address: Internationalt Patent-Bureau, DK-2630 Tåstrup, Denmark. Present address: Jarðfrøðisavnið, Brekkutún 1, FO-110 Tórshavn, Faroe Islands. E-mail: ilf@er.dtu.dk
Geological Survey of Denmark and Greenland Bulletin 1, 349-366 (2003) © GEUS, 2003

Sedimentology and sequence stratigraphy of paralic and shallow marine Upper Jurassic sandstones in the northern Danish Central Graben
Peter N. Johannessen
Paralic and shallow marine sandstones were deposited in the Danish Central Graben during Late Jurassic rifting when half-grabens were developed and the overall eustatic sea level rose. During the Kimmeridgian, an extensive plateau area consisting of the Heno Plateau and the Gertrud Plateau was situated between two highs, the Mandal High to the north, and the combined Inge and Mads Highs to the west. These highs were land areas situated on either side of the plateaus and supplied sand to the Gertrud and Heno Plateaus. Two graben areas, the Feda and Tail End Grabens, flanked the plateau area to the west and east, respectively. The regressive-transgressive succession consists of intensely bioturbated shoreface sandstones, 25-75 m thick. Two widespread unconformities (SB₁, SB₂ ) are recognised on the plateaus, forming the base of sequence 1 and sequence 2, respectively. These unconformities were created by a fall in relative sea level during which rivers may have eroded older shoreface sands and transported sediment across the Heno and Gertrud Plateaus, resulting in the accumulation of shoreface sandstones farther out in the Feda and Tail End Grabens, on the south-east Heno Plateau and in the Salt Dome Province. During subsequent transgression, fluvial sediments were reworked by high-energy shoreface processes on the Heno and Gertrud Plateaus, leaving only a lag of granules and pebbles on the marine transgressive surfaces of erosion (MTSE₁, MTSE₂
The sequence boundary SB₂ can be traced to the south-east Heno Plateau and the Salt Dome Province, where it is marked by sharp-based shoreface sandstones. During low sea level, erosion occurred in the southern part of the Feda Graben, which formed part of the Gertrud and Heno Plateaus, and sedimentation occurred in the Norwegian part of the Feda Graben farther to the north. During subsequent transgression, the southern part of the Feda Graben began to subside, and a succession of backstepping back-barrier and shoreface sediments, 90 m thick, was deposited. In the deep Tail End and Feda Grabens and the Salt Dome Province, sequence boundary SB₂ is developed as a conformity, indicating that there was not a significant fall in relative sea level in these grabens, probably as a result of high subsidence rates. Backstepping lower shoreface sandstones overlie SB₂ and show a gradual fining-upwards to offshore claystones that are referred to the Farsund Formation. On the plateaus, backstepping shoreface sandstones of sequence 2 are abruptly overlain by offshore claystones, indicating a sudden deepening and associated cessation of sand supply, probably caused by drowning of the sediment source areas on the Mandal, Inge and Mads Highs. During the Volgian, the Gertrud Plateau began to subside and became a graben. During the Late Kimmeridgian - Ryazanian, a long-term relative sea-level rise resulted in deposition of a thick succession of offshore claystones forming highstand and transgressive systems tracts on the Heno Plateau, and in the Gertrud, Feda and Tail End Grabens.
Keywords : North Sea, Danish Central Graben, Kimmeridgian, sedimentology, sequence stratigraphy, ichnology, back-barrier - shoreface sediments, palaeogeography, sand distribution
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: pjo@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 367-402 (2003) © GEUS, 2003

Volgian-Ryazanian 'hot shales' of the Bo Member (Farsund Formation) in the Danish Central Graben, North Sea: stratigraphy, facies and geochemistry
Jon R. Ineson, Jørgen A. Bojesen-Koefoed, Karen Dybkjær and Lars H. Nielsen
Upper Jurassic - lowermost Cretaceous marine mudstones represent the most significant source of hydrocarbons in the Central and Northern North Sea. Of particular importance in the Danish sector of the Central Graben is a succession of radioactive `hot shales' referred to the Bo Member, in the upper levels of the Farsund Formation (Kimmeridge Clay Formation equivalent). This mudstone-dominated succession is typically 15-30 m thick and has a total organic carbon (TOC) content of 3-8%, though locally exceeding 15%. Although truncated on some structural highs, the Bo Member is a persistent feature of the Danish Central Graben. Lateral variation in both thickness and organic richness is attributed to intrabasinal structural topography and to the location of sediment input centres.
Detailed study of the dinoflagellate cyst biostratigraphy of 10 wells indicates that the onset of enhanced organic carbon burial began in the middle-late Middle Volgian in this portion of the Central Graben. The Bo Member, representing the peak of organic carbon enrichment, is largely of Early Ryazanian age. Core data (Jeppe-1, E-1 wells) indicate that the organic-rich shales of the Bo Member are not wholly of hemipelagic origin, as commonly assumed, but may locally be dominated by fine-grained turbidites. Absence of bioturbation, well-preserved lamination and high TOC values suggest that bottom waters were predominantly anoxic although the presence of in-situ benthic bivalves at discrete horizons in the E-1 well suggests that suboxic conditions prevailed on occasion. The Bo Member is a good to very good source rock, showing very high pyrolysis yields (10-100 kg HC/ton rock) and Hydrogen Index (HI) values in the range 200-600. In particular, the Bo Member is characterised by an abundance of 28,30 bisnorhopane (H28), a compound that is indicative of anoxic environments.
These new data from the Danish sector of the Central Graben are compatible with the model of Tyson et al. (1979) in which the accumulation of organic-rich mudstones was controlled primarily by bottom-water anoxia beneath a stratified watermass. A number of factors probably contributed to the development of watermass stratification, both intrinsic such as the tectonic morphology of the graben system and extrinsic including climate and sea-level stand.
Keywords : Danish Central Graben, North Sea, Volgian-Ryazanian, organic-rich mudstones, marine source rock, depositional processes, geochemistry, anoxia
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: ji@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 403-436 (2003) © GEUS, 2003

Triassic and Jurassic transtension along part of the Sorgenfrei-Tornquist Zone in the Danish Kattegat
Tommy Egebjerg Mogensen and John A. Korstgård
In the Kattegat area, Denmark, the Sorgenfrei-Tornquist Zone, an old crustal weakness zone, was repeatedly reactivated during Triassic, Jurassic and Early Cretaceous times with dextral transtensional movements along the major boundary faults. These tectonic events were minor compared to the tectonic events of the Late Carboniferous - Early Permian and the Late Cretaceous - Early Tertiary, although a dynamic structural and stratigraphic analysis indicates that the Sorgenfrei-Tornquist Zone was active compared to the surrounding areas.
At the end of the Palaeozoic, the area was a peneplain. Regional Triassic subsidence caused onlap towards the north-east, where the youngest Triassic sediments overlie Precambrian crystalline basement. During the Early Triassic, several of the major Early Permian faults were reactivated, probably with dextral strike-slip along the Børglum Fault. Jurassic - Early Cretaceous subsidence was restricted primarily to the area between the two main faults in the Sorgenfrei-Tornquist Zone, the Grenå-Helsingborg Fault and the Børglum Fault. This restriction of basin development indicates a change in the regional stress field at the Triassic-Jurassic transition. Middle Jurassic and Late Jurassic - Early Cretaceous subsidence followed the Early Jurassic pattern with local subsidence in the Sorgenfrei-Tornquist Zone, but now even more restricted to within the zone. The subsidence showed a decrease in the Middle Jurassic, and increased again during Late Jurassic - Early Cretaceous times. Small faults were generated internally in the Sorgenfrei-Tornquist Zone during the Mesozoic with a pattern that indicates a broad transfer of strike-slip/oblique-slip motion from the Grenå-Helsingborg Fault to the Børglum Fault.
Keywords : Kattegat, Denmark, Sorgenfrei-Tornquist Zone, Triassic-Jurassic, Børglum Fault, Grenå-Helsingborg Fault, transtension, structural evolution
T.E.M., Norsk Hydro a.s., N-0246 Oslo, Norway. E-mail: tommy.mogensen.egebjerg@hydro.com
J.A.K., Geological Institute, University of Aarhus, C.F. Møllers Allé 120, DK-8000 Århus C, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 439-458 (2003) © GEUS, 2003

Late Triassic - Jurassic development of the Danish Basin and the Fennoscandian Border Zone, southern Scandinavia
Lars H. Nielsen
The continental to marine Upper Triassic - Jurassic succession of the Danish Basin and the Fennoscandian Border Zone is interpreted within a sequence stratigraphic framework, and the evolution of the depositional basin is discussed. The intracratonic Permian-Cenozoic Danish Basin was formed by Late Carboniferous - Early Permian crustal extension followed by subsidence governed primarily by thermal cooling and local faulting. The basin is separated from the stable Precambrian Baltic Shield by the Fennoscandian Border Zone, and is bounded by basement blocks of the Ringkøbing-Fyn High towards the south. In Late Triassic - Jurassic times, the basin was part of the epeiric shallow sea that covered most of northern Europe. The Upper Triassic - Jurassic basin-fill is subdivided into two tectono-stratigraphic units by a basinwide intra-Aalenian unconformity. The Norian - Lower Aalenian succession was formed under relative tectonic tranquillity and shows an overall layer-cake geometry, except for areas with local faults and salt movements. Deposition was initiated by a Norian transgression that led to shallow marine deposition and was accompanied by a gradual climatic change to more humid conditions. Extensive sheets of shoreface sand and associated paralic sediments were deposited during short-lived forced regressions in Rhaetian time. A stepwise deepening and development of fully marine conditions followed in the Hettangian - Early Sinemurian. Thick uniform basinwide mud blankets were deposited on an open storm-influenced shelf, while sand was trapped at the basin margins. This depositional pattern continued until Late Toarcian - Early Aalenian times when the basin became restricted due to renewed uplift of the Ringkøbing-Fyn High. In Middle Aalenian - Bathonian times, the former basin area was subjected to deep erosion, and deposition became restricted to the fault-bounded Sorgenfrei-Tornquist Zone. Eventually the fault margins were overstepped, and paralic-marine deposition gradually resumed in most of the basin in Late Jurassic time. Thus, the facies architecture of the Norian - Lower Aalenian succession reflects eustatic or large-scale regional sea-level changes, whereas the Middle Aalenian - Volgian succession reflects a strong tectonic control that gradually gave way to more widespread and sea-level controlled sedimentation. The uplift of the Ringkøbing-Fyn High and most of the Danish Basin occurred concurrently with the uplift of the North Sea and a wide irregular uplifted area was formed, which differs significantly from the postulated domal pattern.
Keywords : Danish Basin, Fennoscandian Border Zone, Upper Triassic - Jurassic, sedimentology, sequence stratigraphy, basin development, intra-Aalenian unconformity, sea-level control
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: lhn@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 459-526 (2003) © GEUS, 2003

The Jurassic of Skåne, southern Sweden
Anders Ahlberg, Ulf Sivhed and Mikael Erlström
In Sweden, Jurassic strata are restricted to Skåne and adjacent offshore areas. Jurassic sedimentary rocks predominantly comprise sandy to muddy siliciclastics, with subordinate coal beds and few carbonate-rich beds. During Mesozoic times, block-faulting took place in the Sorgenfrei- Tornquist Zone, a tectonic zone which transects Skåne in a NW-SE direction. The Jurassic depositional environments in Skåne were thus strongly influenced by uplift and downfaulting, and to some extent by volcanism. Consequently, the sedimentary record reveals evidence of numerous transgressions, regressions and breaks in sedimentation. Relative sea-level changes played a significant role in controlling the facies distribution, as deposition mainly took place in coastal plain to shallow shelf environments.
The alluvial deposits in Skåne include floodplain palaeosols, autochthonous coals, overbank sandstones, and stream channel pebbly sandstones. Restricted marine strata comprise intertidal heteroliths with mixed freshwater and marine trace fossil assemblages, and intertidal delta distributary channel sandstones. Shallow marine sediments encompass subtidal and shoreface sandstones with herringbone structures, and bioturbated mudstones with tempestite sandstones. Offshore deposits typically comprise extensively bioturbated muddy sandstones.
Floral remains, palaeopedology, clay mineralogy and arenite maturity indicate a warm and humid climate in Skåne throughout the Jurassic, possibly with slightly increasing aridity towards the end of the period. Most Jurassic strata in Skåne have been subjected to mild burial diagenesis, and the petroleum generative window has rarely been reached.
Keywords : Skåne, southern Sweden, Fennoscandian Border Zone, Danish Basin, Jurassic, lithostratigraphy, depositional environments, diagenesis
A.A., Department of Geology, Lund University, Sölvegatan 13, S-223 62 Lund, Sweden. E-mail: anders.ahlberg@geol.lu.se
U.S. & M.E., Geological Survey of Sweden, Kiliansgatan 10, S-223 50 Lund, Sweden.
Geological Survey of Denmark and Greenland Bulletin 1, 527-541 (2003) © GEUS, 2003

An offshore transgressive-regressive mudstone-dominated succession from the Sinemurian of Skåne, Sweden
Nils Frandsen and Finn Surlyk
A Sinemurian mudstone-dominated succession was exposed until recently in the Gantofta quarry in Skåne, southern Sweden. The deposits are placed in the Döshult and Pankarp Members of the Sinemurian-Aalenian Rya Formation. Similar facies of the same age are widespread in the Danish Basin where they constitute the F-Ib unit (F-I member) of the Fjerritslev Formation. The Gantofta succession thus represents the easternmost extension of the environment characteristic of the Fjerritslev Formation and is essentially the only locality where it has been possible to study the facies of this formation in outcrop. Sedimentation seems to have taken place under relatively quiet tectonic conditions except for the possible fault-control of the basin margin. The lower part of the Gantofta section is of Early and early Late Sinemurian age. It represents the upper part of the Döshult Member and consists of muddy, lower shoreface sandstones, abruptly overlain by dark, bioturbated, fossiliferous mudstones with thin storm siltstones and sandstones. They are overlain by the Upper Sinemurian Pankarp Member which comprises red-brown, restricted marine calcareous mudstones with an upwards increasing number of storm siltstones and sandstones reflecting general shallowing and shoreline progradation.
The succession spans the greater part of two simple sequences with a distal sequence boundary located at the boundary between the Döshult Member and the Pankarp Member. The exposed part of the lower sequence includes a thick transgressive systems tract and a very thin highstand systems tract. The upper sequence is represented by an undifferentiated transgressive and highstand systems tract. An Early Sinemurian sea-level rise, a late Early Sinemurian highstand, an early Late Sinemurian fall and a Late Sinemurian minor rise and a major fall are recognised. Nearby boreholes show evidence for an end-Sinemurian - Early Pliensbachian major rise. This evolution corresponds well with trends recorded in the subsurface Fjerritslev Formation of the Danish Basin.
Comparison with published European and British Jurassic sea-level curves show similar overall trends, but exhibit differences in the precise ages of sequence boundaries and maximum flooding surfaces. This may reflect poor biostratigraphical resolution of the Gantofta section, differences in sequence stratigraphic interpretation, real differences in the age of sequence stratigraphic key surfaces, or the basin marginal position of Gantofta in the Fennoscandian Border Zone.
Keywords : Skåne, southern Sweden, Lower Jurassic, Sinemurian, facies analysis, sequence stratigraphy, sedimentary environments, sea-level change
N.F., DONG, Agern Allé 24-26, DK-2970 Hørsholm, Denmark. E-mail: nfr@dong.dk
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 543-554 (2003) © GEUS, 2003

Lower Jurassic (Pliensbachian) ammonites from Bornholm, Baltic Sea, Denmark
Desmond T. Donovan and Finn Surlyk
The Jurassic succession of the island of Bornholm in the Baltic Sea includes the Hettangian - lowermost Pliensbachian Rønne Formation, the Lower Pliensbachian Hasle Formation, the Upper Pliensbachian - (?)Lower Aalenian Sorthat Formation and the (?)Upper Aalenian - Bathonian Bagå Formation. Ammonites are only known from the Hasle Formation, and all available ammonite specimens from this formation are described and figured. Material reported by previous authors has been re-examined, together with previously undescribed specimens. Nine genera and eleven species are recognised. The ammonites show that the rocks from which they were collected fall into the Lower Pliensbachian (Carixian) Substage. The lowermost subzone proved in the Hasle Formation is the basal Taylori Subzone of the Jamesoni Zone of the Northwest European Subboreal standard zonation, which marks a marine transgression over underlying marginal marine beds without ammonites belonging to the Rønne Formation. All subzones of the Jamesoni Zone are proved together with the Valdani Subzone of the Ibex Zone. The Upper Pliensbachian (Domerian) Substage, previously reported, is now thought to be unproved by ammonite evidence. The underlying and overlying Rønne and Sorthat Formations are dated by dinoflagellate cysts and terrestrial palynomorphs, and the ammonite occurrences provide important control points for palynostratigraphic dating of the succession.
Keywords : Bornholm, Baltic Sea, Lower Jurassic, ammonite fauna
D.T.D., Research School of Geological & Geophysical Sciences, Birkbeck College and University College London, Gower Street, London WC1E 6BT, UK. E-mail: ucfb03d@ucl.ac.uk
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 555-583 (2003) © GEUS, 2003

The Lower-Middle Jurassic of the Anholt borehole: implications for the geological evolution of the eastern margin of the Danish Basin
Ole B. Nielsen, Marit-Solveig Seidenkrantz, Niels Abrahamsen, Birthe J. Schmidt, Eva B. Koppelhus, Helle Ravn-Sørensen, Uffe Korsbech and K. Gynther Nielsen
This study of Upper Pliensbachian - Bajocian/Bathonian deposits in a borehole drilled on the island of Anholt, Denmark incorporates sedimentology, biostratigraphy (palynomorphs and foraminifera), palaeomagnetism and coal petrology. The studied succession records a gradual change from marine inner shelf storm-influenced clays to mainly terrestrial sands, clays, and lignite containing a flora of mainly freshwater algae and pollen. The regression was initiated at the Pliensbachian-Toarcian boundary and marine influence ceased during Bajocian-Bathonian times; the regression thus took place earlier at Anholt than in the centre of the Danish Basin. The sediments in the Anholt borehole are referred to the Fjerritslev and Haldager Sand Formations. Although the Lower-Middle Jurassic boundary is commonly placed at the boundary between the two formations, our data indicate that at Anholt the upper Fjerritslev Formation (member F-IV) is of Aalenian age. The Lower-Middle Jurassic boundary occurs close to the boundary between members F-III and F-IV of the Fjerritslev Formation.
In contrast to other Lower-Middle Jurassic successions in the North Sea region, smectites of inferred volcanic origin are preserved in the Anholt section, suggesting limited burial and hence less intense diagenetic illitisation or chloritisation of smectites. A down-hole increase in diagenetic influence is reflected by the increase down-section both in the thermal stability of kaolinite and in the vitrinite reflectance. Kaolinite of inferred authigenic origin forms a white powder in the quartz-dominated sands of the Haldager Sand Formation; this kaolinite is thermally very unstable and is interpreted to be of late diagenetic, post-uplift origin. The vitrinite reflectance data indicate that the Jurassic formations have been exposed to thermal maturation corresponding to burial to a depth of 1000-1200 m below their present depth. Post-maturation uplift of the order of 1 km probably occurred partly during Late Cretaceous - Paleocene inversion in the Kattegat area and partly during Oligocene-Recent regional uplift, the latter being the most important of the two uplift phases. Palaeomagnetic data indicate that the main carrier of magnetic remanence is fine-grained magnetite. The stable remanence shows a pronounced inclination shallowing, which is attributed to post-depositional compaction.
Keywords : Danish Basin, Fennoscandian Border Zone, Lower-Middle Jurassic, Anholt borehole, biostratigraphy, palaeomagnetics, sedimentology, clay mineralogy, organic petrology, geochemistry
O.B.N. & M.-S.S., Department of Earth Sciences, University of Aarhus, C.F. Møllers Allé, DK-8000 Århus C, Denmark. E-mail: geololen@aau.dk
N.A., Department of Earth Sciences, University of Aarhus, Finlandsgade 6-8, DK-8200 Århus N, Denmark.
B.J.S., Statoil, Exploration Division, Forushagen, N-4035 Stavanger, Norway.
E.B.K., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Present address: Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller T0J 0Y0, Alberta, Canada.
H.R.-S., Samfundsteknik A/S, Vesterballevej 4-6, Fredericia Miljøcenter, DK-7000 Fredericia, Denmark. Present address: Bascon A/S, Åboulevarden 21, P.O. Box 510, DK-8100 Århus C, Denmark.
U.K. & K.G.N.*, Ørsted-DTU, Building 327, Technical University of Denmark, DK-2800 Lyngby, Denmark. *Retired.
Geological Survey of Denmark and Greenland Bulletin 1, 585-609 (2003) © GEUS, 2003

Burial depth and post-Early Cretaceous uplift of Lower-Middle Jurassic strata in the Fennoscandian Border Zone based on organic maturity
Henrik I. Petersen, Lars H. Nielsen,Torben Bidstrup and Erik Thomsen
The burial depth and the magnitude of Late Cretaceous - Early Cenozoic and Neogene-Pleistocene uplift of Lower-Middle Jurassic strata in the Fennoscandian Border Zone are estimated from measurements of huminite reflectance and comparison with a regional coalification gradient. The regional coalification curve is constructed by plotting uplift-corrected sample depths against more than 300 huminite/vitrinite reflectance values from Upper Triassic - Lower Cretaceous deposits in the Danish Basin and the Fennoscandian Border Zone. The present sample depths are corrected for Late Cretaceous inversion in the Sorgenfrei-Tornquist Zone and for Neogene-Pleistocene regional uplift. A coalification curve is erected; it cuts the abscissa at 0.2 %R_o corresponding to the reflectance of peat. This curve is considered to approximate to a reliable coalification profile over much of the study area.
The Jurassic coals from the Fennoscandian Border Zone are of low rank and, based on the regional coalification curve, they have been buried to c . 625-2450 m. In the eastern part of the Rønne Graben, in the Kolobrzeg Graben and in the Arnager-Sose Fault Block, the Jurassic strata were subsequently uplifted c . 290-1400 m, corresponding to the amount of Late Cretaceous - Early Cenozoic inversion observed on seismic sections. Thus, it appears that Neogene-Pleistocene uplift did not influence the Bornholm area significantly. The data from the Höganäs Basin and Fyledal indicate a total uplift of c . 1450-2450 m, corresponding to estimates from the inversion zone in the Kattegat. The data from Anholt, on the eastern margin of the inversion zone, indicate c . 975 m of uplift.
Keywords : Danish Basin, Fennoscandian Border Zone, Lower-Middle Jurassic, organic maturity, coalification curve, burial depth, Late Cretaceous - Early Tertiary inversion, Neogene-Pleistocene uplift
Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: hip@geus.dk
Geological Survey of Denmark and Greenland Bulletin 1, 611-630 (2003) © GEUS, 2003

Early and Middle Jurassic mires of Bornholm and the Fennoscandian Border Zone: a comparison of depositional environments and vegetation
Henrik I. Petersen, Lars H. Nielsen, Eva B. Koppelhus and Henning S. Sørensen
Suitable climatic conditions for peat formation existed during Early-Middle Jurassic times in the Fennoscandian Border Zone. Autochthonous peat and allochthonous organic matter were deposited from north Jylland, south-east through the Kattegat and Øresund area, to Skåne and Bornholm. The increase in coal seam abundance and thickness from north Jylland to Bornholm indicates that the most favourable peat-forming conditions were present towards the south-east. Peat formation and deposition of organic-rich muds in the Early Jurassic coastal mires were mainly controlled by a continuous rise of relative sea level governed by subsidence and an overall eustatic rise. Watertable rise repeatedly outpaced the rate of accumulation of organic matter and terminated peat formation by lacustrine or lagoonal flooding. Organic matter accumulated in open-water mires and in continuously waterlogged, anoxic and periodically marine-influenced mires. The latter conditions resulted in huminite-rich coals containing framboidal pyrite. The investigated Lower Jurassic seams correspond to peat and peaty mud deposits that ranged from 0.5-5.7 m in thickness, but were generally less than 3 m thick. It is estimated that on Bornholm, the mires existed on average for c . 1200 years in the Hettangian-Sinemurian and for c . 2300 years in the Late Pliensbachian; the Early Jurassic (Hettangian-Sinemurian) mires in the Øresund area existed for c . 1850 years. Aalenian uplift of the Ringkøbing-Fyn High and major parts of the Danish Basin caused a significant change in the basin configuration and much reduced subsidence in the Fennoscandian Border Zone during the Middle Jurassic. This resulted in a more inland position for the Middle Jurassic mires which on occasion enabled peat accumulation to keep pace with, or temporarily outpace, watertable rise. Thus, peat formation was sometimes sustained for relatively long periods, and the mires may have existed for up to 7000 years in the Øresund area, and up to 19 000 years on Bornholm. The combination of the inland position of the mires, a seasonal climate, and on occasion a peat surface above groundwater level caused temporary oxidation of the peat surfaces and formation of inertinite-rich coals. The spore and pollen assemblages from coal seams and interbedded siliciclastic deposits indicate that the dominant plant groups in both the Early and Middle Jurassic mires were ferns and gymnosperms. However, significant floral differences are evident. In the Lower Jurassic coals, the palynology testifies to a vegetation rich in cycadophytes and coniferophytes (Taxodiaceae family) whereas club mosses were of lesser importance. Conversely, in the Middle Jurassic coals, the palynology indicates an absence of cycadophytes, a minor proportion of coniferophytes (Taxodiaceae) and a significant proportion of club mosses. These variations are probably related to adaptation by different plants to varying environmental conditions, in particular of hydrological character.
Keywords : Danish Basin, Fennoscandian Border Zone, Bornholm, Lower-Middle Jurassic, coal distribution, coal petrography, sedimentology, palynology, mire environments, mire vegetation, peat accumulation rates, sea-level change
H.I.P., L.H.N., E.B.K.* & H.S.S.**, Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: hip@geus.dk
Present addresses: *Royal Tyrrell Museum of Paleontology, Box 7500, Drumheller T07 0Y0, Canada. **Danfoss A/S, L7-S38, DK-6430 Nordborg, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 631-656 (2003) © GEUS, 2003

The Jurassic of East Greenland: a sedimentary record of thermal subsidence, onset and culmination of rifting
Finn Surlyk
The Late Palaeozoic - Mesozoic extensional basin complex of East Greenland contains a record of deposition during a period of Rhaetian - Early Bajocian thermal subsidence, the onset of rifting in the Late Bajocian, its growth during the Bathonian-Kimmeridgian, culmination of rifting in the Volgian - Early Ryazanian, and waning in the Late Ryazanian - Hauterivian. The area was centred over a palaeolatitude of about 45°N in the Rhaetian and drifted northwards to about 50°N in the Hauterivian. A major climate change from arid to humid subtropical conditions took place at the Norian-Rhaetian transition. Deposition was in addition governed by a long-term sea-level rise with highstands in the Toarcian-Aalenian, latest Callovian and Kimmeridgian, and lowstands in the latest Bajocian - earliest Bathonian, Middle Oxfordian and Volgian.
The Rhaetian - Lower Bajocian succession is considered the upper part of a megasequence, termed J1, with its base in the upper Lower Triassic, whereas the Upper Bajocian - Hauterivian succession forms a complete, syn-rift megasequence, termed J2. The southern part of the basin complex in Jameson Land contains a relatively complete Rhaetian-Ryazanian succession and underwent only minor tilting during Middle Jurassic - earliest Cretaceous rifting. Rhaetian - Lower Jurassic deposits are absent north of Jameson Land and this region was fragmented into strongly tilted fault blocks during the protracted rift event. The syn-rift successions of the two areas accordingly show different long-term trends in sedimentary facies. In the southern area, the J2 syn-rift megasequence forms a symmetrical regressive-transgressive-regressive cycle, whereas the J2 megasequence in the northern area shows an asymmetrical, stepwise deepening trend.
A total of eight tectonostratigraphic sequences are recognised in the Rhaetian-Hauterivian interval. They reflect major changes in basin configuration, drainage systems, sediment transport and distribution patterns, and in facies and depositional environments. The sequences are bounded by regional unconformities or flooding surfaces and have average durations in the order of 10 Ma. They are subdivided into conventional unconformity-bounded depositional sequences with durations ranging from tens of thousands of years, in the Milankovitch frequency band, up to several million years. Deposition was alluvial and lacustrine in the Rhaetian-Sinemurian, but almost exclusively marine during the Pliensbachian-Hauterivian time interval when a marine strait, up to 500 km wide and more than 2000 km long, developed between Greenland and Norway, connecting the Arctic Sea and the North Sea. Coal-bearing fluvial and paralic deposits occur, however, at the base of the onlapping Middle Jurassic succession in the central and northern part of the basin complex. The sedimentary development is similar to that in the Northern North Sea and on the Norwegian shelf, and East Greenland offers important onshore analogues for virtually all of the types of deeply buried Jurassic depositional systems of these areas and especially their hydrocarbon reservoirs.
Keywords : East Greenland, Jurassic, sequence stratigraphy, pre-rift megasequence, syn-rift megasequence, basin evolution, regional correlation/comparison, onshore Moray Firth
Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: finns@geo.geol.ku.dk
Geological Survey of Denmark and Greenland Bulletin 1, 659-722 (2003) © GEUS, 2003

Palynostratigraphy and palaeoenvironments of the Rævekløft, Gule Horn and Ostreaelv Formations (Lower-Middle Jurassic), Neill Klinter Group, Jameson Land, East Greenland
Eva B. Koppelhus and Gregers Dam
The Neill Klinter Group of Jameson Land, East Greenland contains rich and diverse palynomorph assemblages. Spores, pollen and freshwater algae dominate most of the samples, but dinoflagellate cysts and acritarchs also form important components. The ages suggested by the palynomorphs from the Rævekløft, Gule Horn and Ostreaelv Formations span the period from the Early Pliensbachian to the early Aalenian. The number of palynomorphs identified totals 136, including 83 miospore and 53 microplankton species; they are grouped into seven palynological assemblage zones.
In general, there is good agreement between the palynological and sedimentological data, and the palynological data has refined the understanding of the depositional palaeoenvironments of the Neill Klinter Group. In some cases, the boundaries of the palynological assemblage zones are congruent with major sequence stratigraphic surfaces and the palynological data thus support the sequence stratigraphic interpretation. In other cases, however, regional correlation indicates that the zone boundaries cross important sequence stratigraphic surfaces, such as sequence boundaries; such behaviour is thought to reflect the facies-dependent nature of certain of the palynological assemblage zones. The pattern of palynological events in East Greenland has also been recognised on the mid-Norwegian shelf.
Keywords : East Greenland, Jameson Land Basin, Lower-Middle Jurassic, Early Pliensbachian - early Aalenian, palynostratigraphy, sedimentology, sequence stratigraphic implications, regional correlation
E.B.K.* & G.D.**, Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Present addresses: *Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller T0J 0Y0, Alberta, Canada. Email: evakoppelhus@hotmail.com
**DONG A/S, Agern Allé 24-26, DK-2970 Hørsholm, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 723-775 (2003) © GEUS, 2003

Palynostratigraphy and palaeoenvironment of the Middle Jurassic Sortehat Formation (Neill Klinter Group), Jameson Land, East Greenland
Eva B. Koppelhus and Carina F. Hansen
The grey-black mudstones of the Sortehat Formation form part of the Middle Jurassic fill of the Jameson Land Basin in East Greenland. The formation is exposed in the southernmost part of the north-south-trending, Mesozoic rift system in East Greenland that was part of the epeiric seaway between East Greenland and Norway. Sedimentological observations of the Sortehat Formation indicate deposition in an offshore marine setting that was typically low energy and periodically oxygen-deficient but was influenced by storm currents on occasion. Detailed palynological studies of the Sortehat Formation have resulted in the definition of three palynological assemblage zones recognised at four localities, namely Enhjørningen Dal and Pelion (north Jameson Land), the type section at Sortehat (central Jameson Land) and Albuen at Neill Klinter along Hurry Inlet (south-east Jameson Land). In stratigraphic order, these zones are termed the Botryococcus Assemblage Zone, the Nannoceratopsis gracilis - Nannoceratopsis senex Assemblage Zone, and the Sentusidinium pelionense Assemblage Zone. They are recognised on the basis of the identification of approximately 110 species of palynomorphs, including 45 species of spores, 30 of pollen, 22 of dinoflagellate cysts, 10 acritarch species, two species of algae, and some fungal spores. An Aalenian - ?Early Bajocian age is suggested for the Sortehat Formation on the basis of the palynoflora.
Interpretation of the palynomorph assemblages suggests that the formation accumulated in a shallow, brackish marine environment. A significant terrestrial input, including the freshwater green alga Botryococcus , is recorded in the lower part of the formation and interpreted as an allochthonous accumulation in an offshore marine environment related to transgression of a low-lying coastal plain. A marked shift in the palynomorph assemblage seen by diversification of marine microplankton above the base of the formation, indicates an increase in the marine signal probably related to the onset of highstand conditions following the marine transgression.
Keywords : East Greenland, Jameson Land Basin, Middle Jurassic, Aalenian - ?Early Bajocian, palynostratigraphy, sedimentology, palaeoenvironment, transgressive-highstand mudstones, allochthonous Botryococcus assemblage
E.B.K., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Present address: Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller T0J 0Y0, Alberta, Canada. E-mail: evakoppelhus@hotmail.com
C.F.H., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. Present address: Skovhegnet 4, DK-3460 Birkerød, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 777-811 (2003) © GEUS, 2003

Shallow marine syn-rift sedimentation: Middle Jurassic Pelion Formation, Jameson Land, East Greenland
Michael Engkilde and Finn Surlyk
The Middle Jurassic Pelion Formation - Fossilbjerget Formation couplet of Jameson Land, East Greenland, is a well-exposed example of the Middle Jurassic inshore-offshore successions characteristic of the rifted seaways in the Northwest European - North Atlantic region. Early Jurassic deposition took place under relatively quiet tectonic conditions following Late Permian - earliest Triassic and Early Triassic rift phases and the Lower Jurassic stratal package shows an overall layer-cake geometry. A long-term extensional phase was initiated in Middle Jurassic (Late Bajocian) time, culminated in the Late Jurassic (Kimmeridgian-Volgian), and petered out in the earliest Cretaceous (Valanginian). The Upper Bajocian - Middle Callovian early-rift succession comprises shallow marine sandstones of the Pelion Formation and correlative offshore siltstones of the Fossilbjerget Formation. Deposition was initiated by southwards progradation of shallow marine sands of the Pelion Formation in the Late Bajocian followed by major backstepping in Bathonian-Callovian times and drowning of the sandy depositional system in the Middle-Late Callovian. Six facies associations are recognised in the Pelion-Fossilbjerget couplet, representing estuarine, shoreface, offshore transition zone and offshore environments. The north-southtrending axis of the Jameson Land Basin had a low inclination, and deposition was sensitive to even small changes in relative sea level which caused the shorelines to advance or retreat over tens to several hundreds of kilometres. Eight composite sequences, termed P1-P8, are recognised and are subdivided into a total of 28 depositional sequences. The duration of the two orders of sequences was about 1-2 Ma and 360,000 years, respectively. The Upper Bajocian P1-2 sequences include the most basinally positioned shallow marine sandstones, deposited during major sealevel lowstands. The lowstands were terminated by significant marine flooding events, during which sandstone deposition was restricted to northern, more proximal parts of the basin. The Upper Bajocian - Middle Bathonian P3-4 sequences show an overall progradational stacking pattern. The sequence boundary at the top of P4 marks a significant shift in stacking pattern, and the Upper Bathonian - Middle Callovian P5-8 sequences show large-scale backstepping, terminating in a widespread condensed succession at the distal, southern end of the basin. The largescale backstepping was governed by combined tectonically-induced subsidence, reflecting increased rates of extension, and eustatic sea-level rise. The depositional trends of the Pelion Formation - Fossilbjerget Formation couplet provide a well-exposed analogue to contemporaneous subsurface deposits which form major hydrocarbon reservoirs on the west Norway shelf, and in the Northern North Sea.
Keywords : East Greenland, Jameson Land, Upper Bajocian - Middle Callovian, Pelion Formation, Fossilbjerget Formation, sedimentology, sequence stratigraphy, shallow marine - offshore environments, regressive-transgressive clastic wedge
M.E.* & F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: finns@geo.geol.ku.dk
*Present address: Denerco Oil A/S, Kongevejen 100C, Postbox 110, DK-2840 Holte, Denmark. E-mail: mke@denerco.dk
Geological Survey of Denmark and Greenland Bulletin 1, 813-863 (2003) © GEUS, 2003

The Jurassic of Kuhn Ø, North-East Greenland
Per C. Alsgaard, Vince L. Felt, Henrik Vosgerau and Finn Surlyk
The Middle-Upper Jurassic succession of Kuhn Ø, North-East Greenland accumulated in a major half-graben and is an excellent analogue for the subsurface of the mid-Norwegian shelf. On Kuhn Ø, peneplaned crystalline basement was incised by a drainage system during a major base-level lowstand, probably in late Early or early Middle Jurassic times. It was filled with fluvial conglomerates of the newly defined Middle Jurassic Bastians Dal Formation during subsequent base-level rise. As sea level continued to rise, precursor-peat of the coals of the Muslingebjerg Formation formed in swamps which covered the conglomerates and filled the remaining space of the incised valley system. The valley and interfluve areas were flooded in Late Bathonian - Callovian times and tidally-dominated, shallow marine sandstones of the Pelion Formation were deposited on top of the valley fill and over the adjacent basement peneplain. These sandstones are overlain by the newly defined shallow marine Oxfordian Payer Dal Formation which is subdivided into a lower unit and an upper unit, separated by a major drowning surface. The Payer Dal Formation sands were flooded in the Late Jurassic and organic-rich, offshore mudstones of the Bernbjerg Formation were deposited. The Jurassic succession of Kuhn Ø can thus be subdivided into large-scale sedimentary units separated by major drowning surfaces. They are of regional extent, and in combination with biostratigraphic and 87Sr/86Sr isotope data they allow the correlation of the sedimentary units on Kuhn Ø with more offshore deposits to the south in Wollaston Forland and more landwards successions to the north in Hochstetter Forland.
Petrographically, the trough cross-bedded sandstones of the Pelion Formation and the lower unit of the Payer Dal Formation include both calcite-cemented and poorly cemented quartz sandstones. The calcite cement was derived from dissolution of abundant calcareous fossils and forms concretionary horizons. The upper unit of the Payer Dal Formation mainly consists of weaklycemented quartz sandstones with porosities around 30%. The sandstones of the Pelion and Payer Dal Formations on Kuhn Ø are petrographically very similar to Jurassic sandstones from the midNorwegian shelf and the Barents Sea with regard to original mineralogical composition, sorting and grain size. The Bernbjerg Formation mudstones are comparable to the Upper Jurassic source rock of the mid-Norwegian shelf and the Barents Sea, but have lower hydrogen index (HI) values due to terrigenous input in a relatively proximal setting. Coals of the Muslingebjerg Formation have significant source rock potential with measured HI values up to 700, kerogen types II-III and total organic carbon (TOC) values above 50%.
Keywords : Kuhn Ø, North-East Greenland, Middle-Upper Jurassic, lithostratigraphy, sedimentology, petrography, source rocks
P.C.A.* & V.L.F.**, Amoco Norway Oil Company. Present addresses: *Norsk Hydro, N-0246 Oslo, Norway. **BP Amoco - Egypt, 14, Road 252, Digla, Maadi Cairo, Egypt; P.O. Box 2409. E-mail: per.chr.alsgaard@hydro.com
H.V., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 865-892 (2003) © GEUS, 2003

Stratigraphy and sedimentology of a basement-onlapping shallow marine sandstone succession, the Charcot Bugt Formation, Middle-Upper Jurassic, East Greenland
Michael Larsen, Stefan Piasecki and Finn Surlyk
A rocky shore developed in early Middle Jurassic times by transgression of the crystalline basement in Milne Land at the western margin of the East Greenland rift basin. The basement is onlapped by shallow marine sandstones of the Charcot Bugt Formation, locally with a thin fluvial unit at the base. The topography of the onlap surface suggests that a relative sea-level rise of at least 300 m took place in Early Bathonian - Middle Oxfordian times. The sea-level rise was punctuated by relative stillstands and falls during which progradation of the shoreline took place.
Palynological data tied to the Boreal ammonite stratigraphy have greatly improved time resolution within the Charcot Bugt Formation, and the Jurassic succession in Milne Land can now be understood in terms of genetically-related depositional systems with a proximal to distal decrease in grain size. The sequence stratigraphic interpretation suggests that translation of the depositional systems governed by relative sea-level changes resulted in stacking of sandstone-dominated falling stage deposits in the eastern, basinwards parts of Milne Land, whereas thick, remarkably coarsegrained transgressive systems tract deposits formed along the western basin margin. The bulk of the Charcot Bugt Formation consists of stacked sandstone-dominated shoreface units that prograded during highstands.
The overall aggradational to backstepping stacking pattern recognised in the Charcot Bugt Formation is comparable to that in the contemporaneous Pelion Formation of the Jameson Land Basin and in correlative units of the mid-Norway shelf and the Northern North Sea. We suggest that the long-term evolution of the depositional systems may have been controlled by long-term eustatic rise acting in concert with relative sea-level changes reflecting regionally contemporaneous phases of rift initiation, climax and gradual cessation of rifting.
Keywords : East Greenland, Milne Land, Bathonian-Oxfordian, Charcot Bugt Formation, Kap Leslie Formation, sedimentology, biostratigraphy, dinoflagellates, sequence stratigraphy, shallow marine, basement onlap, clinoform unit
M.L. & S.P., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: mil@geus.dk
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 893-930 (2003) © GEUS, 2003

Shelf-edge delta and slope deposition in the Upper Callovian - Middle Oxfordian Olympen Formation, East Greenland
Michael Larsen and Finn Surlyk
The Upper Bajocian - Upper Volgian succession of the Jameson Land Basin in East Greenland forms an overall transgressive-regressive cycle. The Upper Callovian - Middle Oxfordian Olympen Formation represents the first regressive deposits after maximum flooding in the Middle to early Late Callovian. The formation was deposited during two southwards progradational phases separated by a major drowning event in the Early Oxfordian. The first phase was marked by incoming of massive slope and base-of-slope sand (Athene Member), but the delta front and top did not reach the area of present-day exposure. The second phase was initiated by deposition of a thick mud succession (Hades Member) indicating that the delta had shifted far to the north during the drowning event. Southwards progradation of the delta was heralded by gully erosion and the deposition of lenticular bodies of massive slope sand; on this occasion, medium- and largescale cross-bedded sand of the delta front and top (Zeus Member) reached the area.
The boundary between Middle-Upper Callovian mudstones in the upper part of the underlying Fossilbjerget Formation and the Upper Callovian Athene Member sandstones formed at the turn-around point between sea-level rise and fall. The Athene Member sandstones are interpreted as an undifferentiated falling stage - lowstand systems tract and span a sequence boundary. The top of the Athene Member is the basinal correlative of the transgressive surface. The basal few metres of the overlying Hades Member mudstones represent the transgressive systems tract and a level with organic-rich mudstones is interpreted to represent the maximum flooding zone. The remainder of the Hades Member and the slope sandstones are assigned to the highstand systems tract. The succeeding cross-bedded delta front sandstones of the Zeus Member are placed in the falling stage systems tract and their sharp base is interpreted as a marine regressive surface of erosion. Comparison of this history with published sea-level curves suggests that the short term changes may be eustatic in origin including the Middle Callovian maximum flooding ( K. jason - lower P. athleta Chronozones), Late Callovian regression ( P. athleta Q. lamberti Chronozones), latest Callovian - Early Oxfordian flooding ( Q. mariae C. cordatum Chronozones) and late Early - Middle Oxfordian regression ( C. densiplicatum Chronozone).
Keywords : East Greenland, Jameson Land Basin, Middle-Upper Jurassic, sedimentology, lithostratigraphy, sequence stratigraphy, shelf-edge delta, slope gullies, massive sandstones, sediment gravity flow, sea-level curve
M.L., Geological Survey of Denmark and Greenland, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: mil@geus.dk
F.S., Geological Institute, University of Copenhagen, Geocenter Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
Geological Survey of Denmark and Greenland Bulletin 1, 931-948 (2003) © GEUS, 2003

[Til top] Sidst ændret: 2. december 2003 © De Nationale Geologiske Undersøgelser for Danmark og Grønland - GEUS
Øster Voldgade 10, 1350 København K - Tlf.: 38142000 - Fax: 38142050 - E-post: geus@geus.dk
Siden vedligeholdes af: webredaktøren

www.geus.dk > Publikationer > Geological Survey of Denmark and Greenland Bulletin > Nr. 1 > Siden her
Udskriftsvenlig

Geological Survey of Denmark and Greenland Bulletin

Abstracts fra nr. 1, The Jurassic of Denmark and Greenland