Rees Facies

The information on this page is a summary description.
The full formal description is available here: Rees Facies

Abbreviation Re
Parent unit
Child units
Lithological description The Rees Facies consists of pale grey to white structureless quartz sand. No carbonate is present. Neither macro nor micro fossils such as including dinoflagellate cysts, are present. The basal half of the Rees Facies consists almost entirely of grains 250-500 µm in size and even some gravel whilst in its upper part the sand is finer grained and well sorted and traces of bioturbation and lamination are reported in the Rees borehole (017E0399/kb8d17e-B495). The Rees Facies could be considered as a westward evolution of the Mol Formation’s Donk Member to the Merksplas Formation; compared to the Donk Member the Rees Facies contains some more glauconite grains and muscovite flakes but it is less heterogeneous compared to the Merkpslas Formation (see LIS Merksplas Formation).
Age In a dinoflagellate study of the Rees borehole, Al-Silwadi (2017) found mid- to late Pliocene age dinoflagellate cysts above and below the Rees Facies but all samples in the Rees Facies itself are barren.
Thickness The thickness is about 8 m.
Area of occurrence The Rees Facies is occurring at the south-eastern end of the Merksplas Formation. It is bordered to the east by the finer-grained Donk Member of the Mol Formation. Geometrically the Mol Formation seems to occur laterally of the relatively coarse Merksplas Formation (Laga, 1976 – profiles 76/106/2 and 75/104/1) (see also Lithostratigraphic Identification sheet Merksplas Formation). The Rees Facies was mapped on the 8/2 Turnhout Meerle geological map (Buffel et al., 2002) as part of the Mol Formation (see above). To the west of the Rees Facies occur the Schorvoort, Hemeldonk and Malle facies discussed in Buffel et al. (2001) and mapped as Brasschaat Formation on the 8/2 Turnhout Meerle geological map (Buffel et al., 2002). To the north in the subsurface of the Antwerp province, the identification of the Brasschaat Formation in general is not obvious (Laga, 1976 –profile PGL76/106/3) . In the Geologica Belgica Neogene Volume 2020 (Louwye et al. (2020) and Vandenberghe and Louwye (2020)), the Pliocene quartz sand in the west have been named the Merksplas Formation and not Brasschaat Member as this last name is reserved in the NCS for Pleistocene fine-sized sand.
Type locality The reference for the Rees Facies is the Rees unit in the Rees borehole (017E0399/kb8d17e-B495) between 8.6 and 17.3 m, presented in Buffel et al. (2001) with grain-size data and the stratigraphic context.
Alternative names
Authors Vandenberghe, N. & Deckers, J.
Date 01/09/2023
Cite as Vandenberghe, N. & Deckers, J., 2023. The Rees Facies, 01/09/2023. National Commission for Stratigraphy Belgium.
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