Voort Member NMVFV


Premise Original definition by NAM and RGD (1980) as Voort Sand Member. Amended to include the clay layer that directly overlies the coarsening-upwards sequence of the Steensel Member of the Rupel Formation. Because the Voort member does not consist of sands only, the lithological affix has been deleted. The Belgian Voort Formation, as defined by Marechal and Laga (1988) , covers probably only part of the Voort member, as far as age is concerned.
Derivatio nominis Named after the hamlet of Voort, near Zolder in the Belgian province of Limburg, Belgium.
Type section Location map See figure (pdf)
  Well Veldhoven-1 (pdf)
  Location N 51°26'20.8
E 05°21'37.2
  Depth 1047 to 1103 m
  Length 56 m along hole
  Reference (amended after NAM and RGD (1980) ).
Additional section Location map See figure (pdf)
  Well Asten-1 (pdf)
  Location N 51°23'47.7
E 05°47'27.3
  Depth 1088 to 1300 m
  Length 212 m along hole
  Well Broekhuizenvorst 52E/114 (pdf)
  Location N 51°30'41.3
E 06°09'12.8
  Depth 246 to 410.5 m
  Length 164.5 m along hole
Definition . The member represents the predominantly sandy lower part of the Veldhoven Formation as it occurs in the southern Netherlands. The member is best described as a stacking of coarsening upwards sequences at the scale of decametres. The proportion of clays is highest in the lower upper part of the member. The uppermost part stands out on logs as a relatively homogeneous and clean sand. The member is well-developed in the Roer Valley Graben. On the Peel and Venlo blocks the proportion of argillaceous sediments is very low.
Upper Boundary It is overlain by the clays that constitute the middle part of the Veldhoven Formation. In the axial zone of the Roer Valley Graben the boundaries are conformable, elsewhere an unconformity, generally of minor proportions, is inferred both at the base and the top.
Lower Boundary The member conformably or mildly unconformably overlies the Steensel Member or the Rupel Clay Member of the Rupel Formation. In the southern distribution area of this member, the boundary is placed at the base of a distinct clay layer.
Distribution Restricted to the southeastern part of the Netherlands, to an area centred around the Roer Valley Graben. The member rapidly thins in a northerly direction.
Age Chattian (NP 24 - 25). The foraminiferal fauna is characteristic of the FE3 and FE2-Subzones.
Depositional Setting Middle neritic to littoral environment. The topmost sands seem intensively reworked.
Sequence Stratigraphy The Voort Member represents the time interval covered by the transgressive part of sequence TB 1.1 up to sequence TB 1.3. The sequences are considered to be relatively complete in the Roer Valley Graben. Hiatuses are presumed to be present at the boundaries on the Venlo Block, but it is not clear to what extent the Lowstand tracts are actually represented. Significant hiatuses are present on the Peel Block. The architecture of the member suggests that a coarse-grained clastic wedge was building out into the Roer Valley Graben system.
References See References Tertiary

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