Lithostratigraphy of the Upper Oligocene – Miocene succession of Denmark

Abstract

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 review of the lower and middle Miocene of northern Belgium

“…The relative shallow depositional environment of the Genk Member despite the deposition during a eustatic sealevel rise related to the middle Miocene Climatic Optimum (MMCO, 17-14.5 Ma) (Zachos et al, 2001;Miller et al, 2005;), can be explained by an increase in sediment supply . A similar explanation was given for the synchronous (Langhian) shallowing in the eastern North Sea Basin (Rasmussen et al, 2010).…”

“…The latter authors' dinocysts species analyses indicated a middle to early late Serravallian age for the maximum flooding surface. Also, in other parts of the North Sea Basin, such as the southern Roer Valley Graben or eastern North Sea Basin, indications for Serravallian transgression were found despite eustatic sea-level lowering (Rasmussen et al, 2010;Thöle et al, 2014;Prinz et al, 2017). Rasmussen (2004a) explained the relative sea-level rise during eustatic sea-level lowering by Serravallian tectonic subsidence of the North Sea Basin.…”

“…The North Sea was a semi-enclosed basin during the Neogene. The marine connection between the southern North Sea Basin and the Channel was prevented by the Weald-Artois ridge, while in the north an open marine connection with the Norwegian-Greenland Sea existed (Ziegler, 1990;Rasmussen et al, 2008;Rasmussen et al, 2010).…”

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

“…Consequently, most of the present-day Denmark became land during the early Miocene (Fig. 1; Rasmussen et al 2010). Major reorganisation of the tectonic regime during the mid-Miocene resulted in flooding of the early Miocene deltas in the North Sea, and marine conditions were re-established.…”

“…Detailed studies of outcrops, drilling and analysis of more than 50 boreholes, acquisition of high-resolution seismic data and the development of a solid biostratigraphic framework for the succession now exist (e.g. Dybkjaer & Rasmussen 2000, 2007Rasmussen et al 2010).…”