Putte Member

The information on this page is a summary description.
The full formal description is available here: Putte Member

Abbreviation BmPu
Parent unit Boom Formation
Child units
Lithological description The Putte Member overlies the Terhagen Member and underlies the Boeretang Member. The Putte Member consists of an alternation of silt-enriched and clay-enriched layers, several dm thick up to over a meter near its top (Vandenberghe & Mertens, 2013). Also the Terhagen Member is layered but in contrast to it, the Putte Member additionally has black stained layers of a few dm at the basis of the clay-enriched layers (Figures 13 and 16). Therefore the Putte Member can be described as a dark grey clay in contrast to the paler grey Terhagen Member (Vandenberghe et al. 2014 fig.10; Vandenberghe, 1978, photo 6, p. 33). Characteristic beds in the Putte Clay are the 2 DB silty beds (Figures 17, 18), the platy septaria bed S50 and the sideritic septaria horizon S60 (Figure 12). From its base to about level S50, the Putte Clay has the thinnest layers of the Boom Clay Formation (Vandenberghe & Mertens, 2013). These features can be particularly well observed in the outcrop area (Figures 13, 16, 17, 18). However in the outcrop area the upper part of the Putte Member is significantly eroded compared to its more complete development in the subsurface. The Putte Clay Member in the subsurface keeps a fairly constant average gamma-ray and resistivity signal across the small wiggles which reflect the alternating silt-enriched and clay-enriched layers. This constant geophysical signal is in contrast with the overlying Boeretang Member of which the resistivity starts to markedly increase upwards, across the wiggles pointing to a much larger silt content than the underlying Putte Member (Figure 2).
Age According to the review in (Figure 5) the nannoplankton biozones NP23 is present in the Putte Member. The presence of the NP24 biozone as reported in literature (see Vandenberghe et al., 2014; Vandenberghe, 2017) is uncertain as the NP24 range figured in De Man et al. (2010), Vandenberghe et al. (2012) and Coccioni et al. (2018) is different from the range in the review in Speijer et al. (2020) and used in the biostratigraphy zonation in Figure 5. The discrepancy is probably linked to the absence in the North Sea Basin of the typical NP24 markers (see discussion in De Man et al. (2010).
Thickness The maximal thickness is slightly over 50 m in the northern Campine (Weelde SCK 98 borehole) but in the reference outcrop area it is reduced by erosion (15 m in Kruibeke-Burcht clay section and 8 m along the Rupel cuesta).
Area of occurrence The Putte Member occurs in the same area as the Boom Clay Formation; it outcrops in the northeast of the Waasland area as in the clay pits Steendorp-Kruibeke, north of the Rupel river, between the Grote Nete and the Dijle-Demer rivers, and in southern Limburg (Figure 1a). North of this outcrop area, the Putte Member occurs in the subsurface except for some locations in the Hageland where the erosion surface underlying the late Miocene Diest Formation has locally removed parts and even locally the total Boom Clay Formation.
Type locality The type section of the Putte Member is exposed in the upper part of the active clay exploitation front along the cuesta between Rumst and Boom (topographic map sheet 23/3-4 Boom-Mechelen) around the coordinates x =154 000, y = 197 500, z = + 30 m. As along the cuesta since some time the exploitation is limited to the Wienerberger clay pit at Rumst and the exploitation has changed from bucket bagger extraction to dragline excavating, also the Argex clay extraction pit at Kruibeke-Burcht can serve as reference section. Remark that the Putte Clay Member in the outcrop area is always eroded and incomplete. Therefore boreholes with cores and geophysical logs have also to be considered for reference to the complete Putte Member such as the Mol-Dessel area borehole sections and geophysical logs (Figure 2).
Alternative names The Putte Member was included pro parte in the unit labelled R2c on the Geological maps 1: 40 0000 (Anonymous 1892,1896, 1900, 1909) and pro parte in the unit labelled R2b in the Stratigraphical register (anonymous 1929,1932). The coding on the recent 1: 50 000 geological maps is BmPu. On the section in Vandenberghe (1980) it was named ‘Argile noire’.
Authors Vandenberghe, N. & Wouters, L.
Date 05/04/2024
Cite as Vandenberghe, N. & Wouters, L., 2024. The Putte Member, 05/04/2024. National Commission for Stratigraphy Belgium. http://ncs.naturalsciences.be/lithostratigraphy/Putte-Member


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