Twello Member

Code
NUKRTW
Status
Formal (Busschers & Weerts 2003).
Lithological description

Grey to brown fine to medium, sand, locally clayey and calcareous, and commonly firm dark grey to brown clay, silty and calcareous, clearly laminated. Local slump structures, load casts and fine-grained turbidite-like sequences.

Depositional setting

Fluvio-deltaic (Rhine filling a tongue-basin; Busschers et al. 2008).

Definition of lower boundary

Sharp contact with coarser fluvioglacial sand (Schaarsbergen Member, Drente Formation) and till (Gieten Member, Drente Formation).

Definition of upper boundary

Gradual transition into finer fluvial sand and clay (Zutphen Member, Kreftenheye Formation).

Thickness indication
Up to 75 m in the IJssel Valley glacial basin.
Geographical distribution
Near the IJssel river in the central-eastern Netherlands.
Regional correlation
North Sea: not present UK: not present; GER: not present; BEL: not present.
Age
late Middle Pleistocene (late Saalian) - early Late Pleistocene (early Eemian).
Hypostratotype
Well:
B33E0250 (Twello)
Depth (thickness) AH:
40.00 - 116.00 m (76 m) below land surface
Origin of name
Named after the village of Twello in the central-eastern Netherlands.
Previous name(s)
None.
Reviewed by (date)
Wim Dubelaar (2018), Sytze van Heteren (2019).
References
Busschers, F.S., Weerts, H.J.T. 2003. Beschrijving lithostratigrafische eenheid. Nederlands Instituut voor Toegepaste Geowetenschappen TNO. Utrecht.
Busschers, F.S., Van Balen, R.T., Cohen, K.M., Kasse, C., Weerts, H.J.T., Wallinga, J., Bunnik, F.P.M. 2008. Response of the Rhine–Meuse fluvial system to Saalian ice‐sheet dynamics. Boreas, 37 (3), 377-398.
Cite as
TNO-GDN ([YEAR]). Twello Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/twello-member.