Maurits Formation DCCU

 

Premise Unit, defined by Van Adrichem Boogaert and Kouwe (1995). This unit corresponds to the former coal-mining groups Maurits (Upper Westphalian B) and Jabeek (Lower Westphalian C). It comprises the upper part of the Productive Measures of NAM and RGD (1980) . The youngest occurrences of the Westoe Formation and the basal Schooner Formation in the UK offshore are lateral equivalents. In order to avoid confusion with the Coal Measures code DCCM used by NAM and RGD (1980) , the new code DCCU has been chosen for this unit.
Derivatio nominis Named after the former colliery Maurits in the south of the province of Limburg. In the coal-mining nomenclature this name referred to the Upper Westphalian B.
Type section Location map See figure (pdf)
  Well E13-01 (pdf)
  Location N 54°17’26.1
E 03°08’22.2
  Depth 3773 to 3950 m
  Length 177 m along hole
Additional section Location map See figure (pdf)
  Well Hengevelde-1 (pdf)
  Location 52°11’45.0
E 06°39’12.5
  Depth 994 to 1373 m
  Length 379 m along hole
  Well Kemperkoul-1 (pdf)
  Location N 50°59’36.9
E 05°53’07.0
  Depth 498 to 1598 m
  Length 1100 m along hole
  Well Woubrugge-1 (pdf)
  Location N 52°09’49.6
E 04°33’34.2
  Depth 3023 to 3117 m
  Length 94 m along hole
  Well G18-1 (pdf)
  Location (N 54°00’47.9
E 05°57’39.4
  Depth 3887 to 4127 m
  Length 240 m along hole
Definition Succession of mainly light-grey mudstones with relatively frequent intercalations of coal seams and subordinate intercalations of grey and buff, (sub-)angular, poorly- to moderately-sorted, very fine- to coarse-grained, argillaceous sandstones. Combined fining- and coarsening-upward trends of 20 to 90 m thick are frequently observed. Some dark-grey mudstone intervals contain brackish-water fossil assemblages. On wire-line logs the formation stands out by its relatively smooth GR-log pattern, combined with highly serrate patterns in other logs. Spikes of low acoustic velocity and low density with a high resistivity correspond with the coal seams.
Upper Boundary Practically all formations of the Limburg Group can be overlain unconformably by the Lower Rotliegend Group (volcanics, volcaniclastics, red beds), Upper Rotliegend Group (red-bed clastics, evaporites), Zechstein Group (claystones, carbonates, evaporites), Rijnland Group (glauconitic sands, clays, marls), or Chalk Group (glauconitic sands, marl and chalk). In the specific unit definitions these truncated situations will not be mentioned separately. Over large areas, late-diagenetic reddening has penetrated several tens of metres into the top of the Limburg Group. If a reddened interval of the Limburg Group is covered unconformably by a younger red-bed unit, the exact boundary can be difficult to pick.
Lower Boundary The formation rests conformably on the Klaverbank or the Ruurlo Formation. The contact is characterised by an abrupt upward increase in clay and coal-seam content. This level marks the top of the overall coarsening-upward trend in the lower part of the Limburg Group. In the onshore, this boundary can be somewhat difficult to discern because of the argillaceous, locally coal-rich nature of the underlying Ruurlo Formation.
Correlation In the UK offshore adjoining the Dutch quadrants P and K, the Westoe Coal Formation is the equivalent of the Baarlo, Ruurlo and Maurits Fms. Adjoining Quadrants J and D the Caister Coal Formation corresponds with the Klaverbank Formation. The Westoe Coal Formation is equivalent to the Maurits Formation there Cameron (1993) . The basal interval of the Schooner Formation can be correlated with the youngest interval of the Maurits Formation.
Distribution Originally present over most of the Netherlands on- and offshore. Contrary to the older formations of the Caumer Subgroup, the formation occurs both in the northwestern and the southern province. Currently, the distribution of the formation is determined by the degree of truncation of the Limburg Group beneath the Saalian (or younger) unconformities (Figure C.4 (see pdf) ).
Age Late Westphalian B to Early/Late Westphalian C. The basal contact of the unit with the Klaverbank or Ruurlo Formations practically coincides with the Upper-Lower Westphalian B-boundary (‘Domina’ marine band) over most of the Netherlands. It is one of the most prominent near-time lines of the Limburg Group. The age of the upper boundary varies from Early Westphalian C in more proximal areas (e.g. central Gelderland) to Late Westphalian C in distal settings. Over large areas (e.g. Twente, West Netherlands Basin, northwestern offshore) it practically coincides with the Upper/Lower Westphalian C-boundary. In three areas, the Upper Westphalian C interval falls in the Maurits Formation: central Drenthe, the northeastern offshore, and the southeastern part of the Campine Basin. In the latter, this interval has received a formal member status.
Depositional Setting Deposited in a predominantly lacustrine setting with intermittent swamp and fluvial-plain conditions. Isolated sandstone beds were formed by meandering and anastomosing fluvial systems, which on emergence into the lakes formed lacustrine deltas and crevasses David (1990) . Marine incursions were rare, generally only leading to brackish conditions.
Subdivision One member has been recognised in the Maurits Formation. It reflects the continuation of predominantly fine-grained deposition in the eastern Campine Basin into the Late Westphalian C.
  DCCUK Kemperkoul Member
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].