The information on this page is a summary description.
The full formal description is available here: Berchem Formation
Abbreviation
Bc
Parent unit
Child units
Edegem Member, Kiel Member, Antwerpen Member, Zonderschot Member
Lithological description
The Berchem Formation was redescribed in detail by Louwye et al. (2020). The Berchem Formation is a green to blackish, fine to medium-grained unit, often very glauconitic and with a minor clay content (Louwye et al., 2020). Smectite is the dominant clay mineral (Adriaens, 2015). The mode of the grain size within the formation varies between c. 130 μm and c. 330 μm (Verhaegen, 2020). The Berchem Formation holds a significant amount of epidote, amphiboles and garnet, making up on average more than 50% of the transparant heavy minerals (Verhaegen, 2020). Shells are abundantly present, dispersed or concentrated in massive layers. Parts of the formation, such as the Kiel Member, are locally decalcified. The Berchem Formation is on wireline log data typified by high gamma ray and moderate resistivity values (Deckers et al., 2019). A distinct gravel bed of dark, rounded flint pebbles is present at the base. The Berchem Formation holds four members: the Edegem Member, Kiel Member, Antwerpen Member and Zonderschot Member.
Age
Dinoflagellate cyst analysis positions the Berchem Formation in the type area between the mid-Burdigalian and late Serravallian (Louwye et al., 2020). Deposits of the Berchem Formation of Aquitanian age, based on dinoflagellate analysis, have been recorded at the base of the Weelde and Mol boreholes (Munsterman & Deckers, 2020).
Thickness
The Berchem Formation has a thickness of about 30 m in the Antwerp area to over 100 m in the east in the Campine area (Louwye et al., 2020).
Area of occurrence
The Berchem Formation occurs in northern Belgium between Antwerp in the west and Lommel in the east (see Figure 0-1 and Figure 0-2 in annex).
Type locality
The type locality is Berchem, as defined by De Meuter & Laga, 1976. No single type section for the entire formation is available. The temporary outcrops for the construction of the highway around the city of Antwerp can be considered as a composite type section. The Edegem Member, Kiel Member and Antwerpen Member occur in the type locality in following temporary outcrops of the composite type section:
Antwerpen – Zuidstation III AR , I AR, IV AR, V AR, AR (De Meuter et al., 1976)
Antwerpen – Montignystraat AM (De Meuter et al., 1976)
Antwerpen – Van Rijswijcklaan AV (De Meuter et al., 1976)
Antwerpen – Nachtegalenpark AN (De Meuter et al., 1976)
Antwerpen – Berchem Station AM (De Meuter et al., 1976)
Antwerpen – Borbeeksepoort II BP (De Meuter et al., 1976)
Antwerpen – Kievitstraat II, V, VI AK (De Meuter et al., 1976), revised by Everaert et al. (2020)
Berchem – Grote Steenweg AG (De Meuter et al., 1976)
Borgerhout – Stenen Brug I SB (De Meuter et al., 1976), revised by Deckers and Everaert (2022)
Borgerhout – Rivierenhof XI BR (De Meuter et al., 1976) correlated to CPT GEO-07/154-S11 by Deckers and Everaert (2022)
Posthofbrug (Louwye et al., 2010) correlated to CPT GEO-68/101-SVII by Deckers and Everaert (2022)
Posthofbrug 2-3 (Hoedemakers & Dufraing, 2018)
Tweelingenstraat (Everaert et al., 2020)
Argenta (Everaert et al., 2020)
Post X (Everaert et al., 2020)
Wilrijk – Ter Weyde (Hooyberghs, 1996 & Hoedemakers & Dufraing, 2021)
Wilrijk – Revalidatiecentrum (Hoedemakers & Dufraing, 2021)
The type section of the Zonderschot Member is located about 30 km southeast of Antwerp and was described by Huyghebaert & Nolf (1979).
Alternative names
Authors
Louwye, S. & Deckers, J.
Date
01/09/2023
Cite as
Louwye, S. & Deckers, J., 2023. The Berchem Formation, 01/09/2023. National Commission for Stratigraphy Belgium. http://ncs.naturalsciences.be/lithostratigraphy/Berchem-Formation
