Neomiodon Claystone Member SLDBN


Premise Member defined by van Adrichem Boogaert & Kouwe (1993). The former Upper Delfland Formation NAM and RGD (1980) has now been split up into the Bloemendaal, and Neomiodon Claystone Members. Originally used inform-ally by Conoco as the ’Neomiodon Shale Member’.
Derivatio nominis Named after the fossil fresh-brackish water bivalve Neomiodon (syn. Cyrena), found abundantly throughout the sequence.
Type section Location map See figure (pdf)
  Well K18-Kotter-07A (pdf)
  Location N 53°04’56.1
E 03°57’56.8
  Depth 1881 to 1987 m
  Length 106 m along hole
  Reference 105 m TVD
Definition Sequence of claystones, medium- to dark-grey and grey-brown, carbonaceous with common to abundant shell debris, dominated by the bivalve Neomiodon spp. Thin sandstones are developed locally. The sequence is internally truncated by a minor unconformity, which is visible on seismic and in wire-line logs by a basal limestone bed. The sequence above this level appears to be especially fossiliferous.
Upper Boundary The member is bounded by two Late Kimmerian II unconformities above and below (resp. IIa and IIb). The top is formed by the Late Kimmerian IIb unconformity, which is covered by the Vlieland Sandstone Formation. The oldest occurrences of this member may be a lateral equivalent of part of the youngest Bloemendaal Member
Lower Boundary The base is mildly unconformably underlain by the more sandy Bloemendaal Member, or in rare locations the Neomiodon Claystone Member can unconformably rest on older members of the Breeveertien Formation Another minor, but well traceable unconformity is seen within the Neomiodon Claystone Member
Distribution Restricted to those parts of the Broad Fourteens Basin where Late Kimmerian uplift is least prominent (P03-Q01-K18, part of K15).
Age Ryazanian. From the bottom to the top, the member shows a gradual increase in dinoflagellate abundance, reflecting and increase in marine influence. The basal interval is dominated by Botryococcus spp., Celyphus rallus (both fresh water algae), sporomorphs and small dinoflagellates. Dinoflagellates such as Cantulodinium speciosum, Microdinium opacum, Muderongia simplex microperforata, or Egmontodinium torynum, Tehama-dinium evittii, Kleithriasphaeridium porosispinum are found in the upper parts. Micropalaeontological markers include several species of agglutinated forams and Darwinula leguminella.
Depositional Setting The lower part of the Neomiodon Claystone Member is thought to have been deposited in a lacustrine to lagoonal environment with restricted-marine influence, judging from the association of common Botrycoccus, sporomorphs and small dinoflagellates. The upper part of the member is interpreted as a marginal-marine (lagoonal) deposit.
Sequence Stratigraphy The stratigraphic age and lithofacies of the deposits suggest formation during the Transgressive to Highstand systems tract of Haq (1988) ’s sequence LZB 1.6. The internal unconformity is interpreted as the base of subsequence LZB 1.6b.
References See References Upper Jurassic/ Lower Cretaceous

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