Stratigraphy of the type Maastrichtian – a synthesis

A synthesis of the stratigraphy of the Maastrichtian Stage in its extended type area, that is, southern Limburg (the Netherlands), and adjacent Belgian and German territories, is presented with a brief historical overview. Quarrying activities at the large quarry complex of ENCI-HeidelbergCement Group will officially come to an end on July 1, 2018. However, the stratotype section below the Lichtenberg farmstead and directly behind the main office building at the Lage Kanaaldijk (Maastricht), will be preserved, as will various faces within the quarry complex. Strata of Maastrichtian age include the Vijlen, Lixhe 1-3 and Lanaye members of the Gulpen Formation, as well as the Valkenburg, Gronsveld, Schiepersberg, Emael, Nekum and Meerssen members of the Maastricht Formation. The lower Maastrichtian portion is comparatively poorly preserved, being characterised by frequent reworking; only elements of the Belemnella obtusa, Belemnella sumensis and/or Belemnella cimbrica zones (the two last-named representing the traditional Belemnella occidentalis Zone) have been recorded. Belemnitella junior and Belemnitella lwowensis define the upper Maastrichtian, both first appearing in interval 4 of the Vijlen Member. At the ENCI-HeidelbergCement Group quarry, the lower/upper Maastrichtian boundary is placed at c. 5 m above the Zonneberg Horizon on benthic foraminifer evidence; strontium isotope data are in agreement. The highest portion of the Meerssen Member (uppermost IVf-6 and IVf-7) is missing from the type section; this part of the sequence is exposed at the former Curfs quarry (Geulhem), the Berg en Terblijt Horizon being equated with the Cretaceous/Paleogene (K/Pg boundary).