|Premise||Unit, defined by Van Adrichem Boogaert and Kouwe (1994).|
|Derivatio nominis||Name derived from the British stratigraphic nomenclature where it is used for the massive Lower Carboniferous carbonate deposits of northwestern Europe.|
|Type section||Location map||See figure (pdf)|
|Depth||1883 to 2836 m|
|Length||953 m along hole|
|Definition||Formation of mainly light-grey to brownish and black limestones, and medium-grey to dark-brown dolomites. Intercalations of thin to medium-thickness fissile claystone and chert beds are common. The claystones occur mainly in the upper- and lowermost parts of the group. Towards the east, the number of these claystones increases gradually. The thickness of the formation in the southern Netherlands varies from 900 to 1400 m. In areas where the Zeeland Formation was truncated by later erosion, the upper part of the formation may be strongly leached and subsequently silicified. An enrichment in organic carbon is frequently observed under these circumstances.|
|Upper Boundary||The top of the formation has been placed where the calcareous deposits change into the fine clastics of the basal Epen Formation of the Limburg Group. This boundary may be gradual (borehole Geverik-1). However, in many places a sharp, disconformable contact is observed when the transitional layers are absent. Where severe post-Carboniferous erosion took place, the Zeeland Formation can be overlain unconformably by younger formations.|
|Lower Boundary||The base of the formation is formed by the contact with the clastic sediments of the earliest Carboniferous (Tn 1b) Bosscheveld formation or the Late Devonian Bollen claystone. The former can be a gradual transition (well Kastanjelaan-2; Bless (1977) ), the latter a disconformable boundary (e.g. S02-02.) More towards the east, on the northern flank of the London-Brabant Massif, the base of the formation may be the unconformable contact with Middle Devonian or even older rocks.|
|Correlation||Bless (1977) show the transition to the Kulm deposits in western Germany.|
|Distribution||The formation is found along the northern flank of the London-Brabant Massif in the Netherlands, United Kingdom, Belgium and the adjacent part of Germany. The northern limit of deposition is not known.|
|Age||A late Visean (V3a-V3c; late Holkerian to Brigantian) age is generally found for the member, based on biomarkers including amongst others the conodont Gnathodus bi-lineatus and the foraminifers Archaediscus (Archaediscus), Nodosarchaediscus (Asperodiscus), Nodosarchaediscus (Asteroarchaediscus), Endothyra omphalata, Endothyranopsis, Howchinia, Millerella, Palaeotextularia (bilaminar) and Vissariotaxis compressa.|
|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].