Lithostratigraphy of the Upper Oligocene - Miocene succession of Denmark

This paper presents a revised lithostratigraphic scheme for the uppermost Upper Oligocene – Miocene succession of Denmark. The marine Oligocene Brejning Clay Member is upgraded to formation status and includes the Sydklint Member and the Øksenrade Member (new). The shallow marine and deltaic deposits of mainly Early Miocene age are included in the Ribe Group (new) while the fully marine Middle and Upper Miocene clay-rich deposits are referred to the Måde Group (new). The Ribe Group is subdivided into 6 formations: the Vejle Fjord Formation is revised and includes the Skansebakke Member,the Billund Formation (new) includes the Addit and Hvidbjerg Members (new), the Klintinghoved Formation is redefined formally and includes the Koldingfjord Member (new), the Bastrup Formation(new) includes the Resen Member (new), the Vandel Member is a new member in the Arnum Formation (revised), the Odderup Formation is redefined and includes the Stauning Member (new) and the coalbearing Fasterholt Member. The Måde Group is subdivided into the Hodde, Ørnhøj (new), Gram and Marbæk (new) Formations. Subdivision of the Upper Oligocene – Miocene succession into two groups, the Ribe and Måde Groups, is compatible with the North Sea lithostratigraphic framework where they correlate with the upper part of the Hordaland Group and the Nordland Group, respectively. The revised lithostratigraphic framework correlated in three dimensions provides rigorous constraints on the palaeogeographic interpretation of the Late Oligocene – Miocene period. Three major deltaic units (Billund, Bastrup and Odderup Formations) prograded from the north and north-east into the North Sea Basin during the Early – early Middle Miocene. Delta progradation was punctuated by deposition of marine clay and silt associated with minor transgressive events (Vejle Fjord, Klintinghoved and Arnum Formations). During the Middle–Late Miocene, marine depositional conditions dominated (Hodde, Ørnhøj and Gram Formations). A fourth and final progadational event (Marbæk Formation) commenced in the latest Tortonian heralding the emergence of present-day Denmark (including the North Sea sector)

A digital, spatial, geological model of the Miocene in Jylland, Denmark

A major hydrogeological programme has been carried out to map the Miocene succession in central and southern Jylland (Fig. 1). The Miocene deposits comprise several aquifers with potential drinking water resources and have been investigated by drilling and acquisition of seismic data integrated with sedimentology and biostratigraphy. Scharling et al. (2009) described a 3D hydrogeological model that covers part of the onshore Danish Miocene deposits. The model was based on a sequence-stratigraphic approach and led to a better understanding of the geological architecture of the aquifers than traditional lithofacies models. Hence it was decided to establish a digital, spatial, geological model covering the entire onshore Miocene succession (Kristensen et al. 2010)

De norske fjelde - rodløse realiteter

I GeologiskNyt 5/2007 opsummerede vi et væld af oplysninger, der viser, at de norske fjelde har været udsat for vertikale bevægelser i kilometer-skala i Kænozoikum, og at fjeldene først har nået deres nuværende højder i Neogen. Søren B. Nielsen (SBN) kommenterer i GeologiskNyt 1/2008 vores indlæg, men kommer desværre ikke med yderligere argumenter for sin hypotese om, at de norske fjelde er resterne af den bjergkæde, der blev dannet under den kaledonske kollision mellem Baltica og Grønland for mere end 400 millioner år siden. Derimod skaber SBN usikkerhed om simple kendsgerninger, der er af afgørende betydning for vurderingen af de norske fjeldes alder og struktur

Discrepancy between Sr isotope and biostratigraphic datings of the upper middle and upper Miocene successions (Eastern North Sea Basin, Denmark)

AbstractOne hundred and fifty-six 87Sr/86Sr analyses have been performed on 129 samples from 18 outcrops and boreholes in Oligocene–Miocene deposits from Jylland, Denmark. These analyses were mainly conducted on mollusc shells but foraminiferal tests, Bolboforma and one shark tooth were also analysed.The main purpose of the study is to compare the ages of the Danish succession suggested by the biostratigraphic zonation on dinoflagellate cysts (Dybkjær and Piasecki, 2010) with the ages based on analyses of the 87Sr/86Sr composition of marine calcareous fossils in the same succession.Analyses of samples from the Danish Brejning, Vejle Fjord, Klintinghoved, Arnum, Odderup, Hodde, Ørnhøj and Gram formations gave ages between 25.7My (late Oligocene) and 10.3My (late Miocene). The Sr isotope ages from the lower part of the succession, i.e. Brejning to Odderup formations, agree with the age estimates based on biostratigraphy. However, the 87Sr/86Sr ratios of fossil carbonates from the middle–upper Miocene, Hodde to Gram succession consistently indicate ages older than those recorded by biostratigraphy. Post-depositional processes as an explanation for this offset are inconsistent with good preservation of shell material and little reworking. A palaeoenvironmental cause for the observed mismatch is therefore indicated.Search for geological events that could explain the older ages obtained by Sr isotope compositions have not led to any conclusions and we had recognised the same problem in earlier reports and communications. We conclude that this is a general and possibly global, middle–late Miocene problem that has to be reconsidered and explained geologically

Norges fjelde - og de geologiske kendsgerninger

Hvorfor der er bjerge i Norge? For at kunne besvare dette tilsyneladende simple spørgsmål, må man først fi nde ud af, hvornår bjergene blev til bjerge. Er de gamle og skabt af kolliderende kontinenter, eller er de unge og dannet af aktive (men måske dårligt forståede) kræfter i Jordens indre

Establishment of a Basic Interactive Interpretation and Data Correlation System (IIDCS) at the Croatian Geological Survey

Modelling of Geological Basins is typically based on integration of deep seismic and borehole data. In order to have systematically arranged data needed for the interpretation and modelling, it requires establishment of a basic Interactive Interpretation and Data Correlation Sys-tem (IIDCS). The establishment of a basic Interactive Interpretation and Data Correlation System (IIDCS) at the Croatian Geological Survey is one of the main goals of the GeoTwinn project. GeoTwinn is a Horizon 2020 project intended and designed to twin the Croatian Geological Survey (HGI-CGS) with two world-leading geoscience research insti-tutes; the Geological Survey of Denmark and Greenland (GEUS) and the British Geological Survey of the United Kingdom Research and Innovation (BGS-UKRI), leading to significantly strengthen HGI-CGS’s research collabo-ration (http://projects.hgi-cgs.hr/geotwinn/). GeoTwinn project consists four Work Packages (WPs); (1) 3D geo-logical surveying and modelling, (2) advanced groundwater flow and contaminant transport modelling, (3) geological hazards, and (4) geothermal energy.The IIDCS is built primarily for the GeoTwinn project, and will be used for the interpretation of geophysical and geological data, the advanced reservoir modelling, and fi-nally, for building an Initial 3D reservoir-properties model for the greater Zagreb area. It is also the intention of Geo-Twinn to use the IIDCS for introducing the digital storage, organization and management of all kinds of geophysical, geological and petrophysical data available at the Croatian Geological Survey.Geological modelling of the greater Zagreb area and its deep geothermal aquifer is the main objective of WP1. The model is to be used for modelling of geochemical processes, and fluid and heat flow modelling in the WP4. Zagreb geothermal aquifer is situated inside Triassic do-lostones and dolomitic limestones, and Badenian bioclas-tic limestones of the Vrapče formation. Well data shows that geothermal aquifer lays in depths between (approx.) 800 to 900 meters, and seismic data shows very com-plex structural and stratigraphic relations. The bottom and the base of aquifer were mapped using Halliburton Landmark DecisionSpace Geoscience software, and the data was stored into the Interpretation and Data Cor-relation System (IIDCS) using Halliburton Landmark OpenWorks database

The lower Miocene flint conglomerate, Jylland, Denmark: a result of the Savian tectonic phase

The early Miocene was an important period for the development of the eastern North Sea. Tectonism in North-West Europe resulted in uplift of the Scandinavian mountains, reactivation of salt structures, inversion of old graben structures and deposition of the most coarse-grained deposits in the Danish pre-Quaternary succession. Some of these deposits were later cemented into conglomerates. The deposits are common in the fluvial parts of the Billund Formation (Aquitanian) and the basal transgressive lag of the late Aquitanian – Burdigalian Klintinghoved Formation capping the Billund Formation. Questions remained as to the age of these deposits and what they infer about tectonic events in the region. This study reviews the geology of the flint-dominated conglomerates and presents the first dates for a sample of these unique deposits. We observe grain sizes up to 5 cm diameter. Palynological analyses place the sample as early Miocene. Some samples from the area have suggested a local source near active salt structures, associated with the uplift of the pre-Neogene sedimentary successions. We suggest that the common occurrences of flint clasts in the lower Miocene succession reveal significant erosion of Upper Cretaceous and Danian chalk, likely associated with the uplift of the Scandinavian lowlands during the Savian tectonic phase, early Miocene