Ubachsberg Member DCGEU


Premise Unit, defined by Van Adrichem Boogaert and Kouwe (1995).
Derivatio nominis Named after the village of Ubachsberg in the Dutch province of Limburg. The name stems from an old stratigraphic unit, representing the Namurian C (Jongmans (1940) ).
Type section Location map See figure (pdf)
  Well S02-02 (pdf)
  Location N 51°51’21.7
E 03°36’32.3
  Depth 1609 to 1717 m
  Length 108 m along hole
Additional section Location map See figure (pdf)
  Well Nagele-1 (pdf)
  Location N 52°37’10.0
E 05°44’23.3
  Depth 2622 to 2656 m
  Length 34 m along hole
Definition Single massive sandstone bed, or set of beds, separated by light to dark-grey mudstone intervals, at or near the top of the Epen Formation. The sands are grey, very fine- to medium-grained, fairly well-sorted, well-cemented, thinly-bedded (smaller than 2 m), stacked into bed sets of 10 to 25 m thick. Disperse carbonaceous matter is common, but coal seams are absent. A number of intercalated clay layers with marine fossils is observed locally. In some cases, these can be correlated with specific marine bands.
Upper Boundary The upper boundary has been placed at the top of the (uppermost) thick sandstone interval or below the lowermost coal seam of the Baarlo Formation.
Lower Boundary The basal contact with the main Epen Formation has been placed at the base of the lowermost sandstone interval which is more than 10 m thick.
Correlation The Millstone Grit Formation is the thicker, usually coarser-grained equivalent in the UK and northwestern Dutch offshore Cameron (1993) .
Distribution Encountered at various localities in the Netherlands on- shore and southern offshore. Recognition of this member depends on the presence of intercalated sandstones in the Epen Formation. The regional distribution of these sandstones is not yet fully understood.
Age As a consequence of their lithofacies-related definition, both top and bottom are diachronous. The bulk of the unit is of Namurian-B or -C age, but locally it may include some Early Westphalian A.
Depositional Setting The sandstones have been interpreted as turbiditic delta-front deposits, mouth bars, distributary-channel fills and associated overbank deposits. Intercalated fines reflect a combination of turbiditic and pelagic deposition. The commonly intercalated marine bands reflect marine incursions into the predominantly lacustrine basin. Sediments in the Ubachsberg Member show an important southerly sediment source component.
References See References Upper Carboniferous

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
Retrieved [Datum] from [url].