Alblasserdam Member SLDNA

 

Premise Member defined by van Adrichem Boogaert & Kouwe (1993).
Derivatio nominis Named after the village of Alblasserdam near Rotterdam.
Type section Location map See figure (pdf)
  Well Nieuwerkerk-1 (pdf)
  Location N 51°57’00.2
E 04°37’32.4
  Depth 1052 to 1942 m
  Length 890 m along hole
Additional section Location map See figure (pdf)
  Well Alblasserdam-1 (pdf)
  Location N 51°52’18.9
E 04°40’33.5
  Depth 900 to 1650 m
  Length 750 m along hole
  Well Botlek-1 (pdf)
  Location N 51°52’09.2
E 04°19’39.0
  Depth 2224 to 2374 m
  Length 150 m along hole
  Well Eemhaven-1 (pdf)
  Location N 51°53’26.1
E 04°24’21.5
  Depth 1888 to 2475 m
  Length 587 m along hole
  Well Woubrugge-1 (pdf)
  Location N 52°09’49.6
E 04°33’34.2
  Depth 741 to 1096 m
  Length 355 m along hole
Definition A succession of typically dark to light grey, red and variegated clay- and siltstones, fine to medium grained sandstones with bed thicknesses up to a few metres, and massive, thick-bedded, coarse grained sandstones. Coal and lignite beds are associated with the grey claystones. Dispersed lignitic matter, siderite spherulites and concretions are common. Cored sections show extensive mott-ling of the variegated claystones. Sands occur as sheets, isolated or stacked channels.
Upper Boundary The Alblasserdam Member is normally overlain by the massive sandstone of the coastal-plain Delft Sandstone Member, or the shallow-marine Vlieland Sandstone Formation (various members). Locally the Delft Sandstone Member is not developed, and the Alblasserdam Member is overlain by the Rodenrijs Claystone Member In areas of Subhercynian/ Laramide inversion the Alblasserdam Member is overlain by the Chalk Group, Lower North Sea Group or Middle North Sea Group.
Lower Boundary The base is formed by the unconformable contact with the Altena Group. The age of the subcrop varies between Lower Jurassic (Aalburg Formation) to Middle-Upper Jurassic (Brabant Formation)
Distribution Confined to the West Netherlands Basin and Roer Valley Graben. Over large areas the Alblasserdam Member is truncated by Subhercynian/Laramide inversion. The total thickness is extremely variable, ranging from less than 100 m to more than 1300 m. This variation is controlled by synsedimentary graben formation, with the main faults trending northwest-southeast, and by a rapid pinch-out in a southwesterly direction towards the London-Brabant Massif. Parts of the Alblasserdam Member in the Rotterdam-Alblasserdam area are laterally equivalent to the Delft Sandstone Member and Rodenrijs Claystone Member, and to the West Netherlands Basin-members of the Vlieland Sandstone Formation and Vlieland Claystone Formation
Age Ryazanian and Valanginian ages are found (e.g. Van Amerom, Herngreen and Romein, 1976; Klukisporites variegatus, Trilobosporites hannonicus, Cicatricosisporites purbeckensis), but in the Rotterdam area the age can range up to Hauterivian (Pseudoceratium pelliferum, Subtilisphaera terrula, Muderongia simplex) or Barremian (e.g. Odontochitina operculata, Impardeci- spora apiverrucatua(?)). The basal part can be of Port-landian (locally even Kimmeridgian/Oxfordian) age. Biostratigraphical results may be inaccurate because of low sporomorph content, especially in the lower, oxi-dised part of the member. It appears that in the south-east the Portlandian - Ryazanian is relatively thick, while the Valanginian is thin or absent. Towards the northwest, the Ryazanian tends to become thinner, whereas the Valanginian thickens. Along the southern margin of the West Netherlands Basin the member has yielded taxa indicating Middle Barremian deposition.
Depositional Setting Interpreted as fluvial-plain deposits, with sand concentrated in mostly channels and crevasse-splays. On the floodplains outside the channels, development of swamps and soils took place. The main sediment transport direction has been reconstructed as southeast-northwest.
Sequence Stratigraphy Three major depositional sequences have been recognised within the Alblasserdam Member These can be interpret-ed as related to Haq (1988) ’s sequence LZB 1.5-2.1. Older sequences, down to sequence LZA 4.4, are restricted to scattered erosional remnants. Along the southern margin of the West Netherlands Basin the member can range up into sequence LZB 3.5 (Transgressive systems tract). Local synsedimentary tectonics can overprint the sequence patterns.
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].