De Wijk Member

NLDOWY

Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1997). Renamed (2019).

Tuffaceous clay and silt, blue to violet-grey in colour, alternating with dark-grey and red-brown clay. Contains volcanic ashes originated from a source located N(W) of the North Sea (Morton & Knox, 1990).

Marine.

Can be distinguished from the under- and overlying rock units by its characteristic wire-line log expression, consisting of a somewhat lower gamma-ray reading than the average clay, and by its high-velocity peaks on the acoustic log (Jacqué & Thouvenin 1975).

Can be distinguished from the under- and overlying rock units by its characteristic wire-line log expression, consisting of a somewhat lower gamma-ray reading than the average clay, and by its high-velocity peaks on the acoustic log (Jacqué & Thouvenin 1975).

Tens of meters.

UK: Balder Formation; GER: ?; BEL: not present.

early Eocene (Ypresian).

Named after the village of Wijk in the northeast of the Netherlands.

Basal Dongen Tuffite Member (Van Adrichem Boogaert & Kouwe 1997). The name "Dongen" is already in use as formation name.

Geert-Jan Vis (2019).

Jacqué, M. and Thouvenin, J., 1975: Lower Tertiary tuffs and volcanic activity in the North Sea. In: Woodland, A.W. (ed.): Petroleum and the continental shelf of North West Europe, I Geology, p. 455-465 - Applied Science Publ., Barking.

Morton, A.C. and Knox, R.W.O'B, 1990: Geochemistry of late Paleocene and early Eocene tephras from the North Sea Basin - Journ. Geol. Soc. London, 147, p. 425-437.

NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1997. Stratigraphic nomenclature of The Netherlands, revision and update by RGD and NOGEPA, Section I, Tertiary. Mededelingen Rijks Geologische Dienst, 50, 1-39.