Dinoflagellate cyst stratigraphy and palaeoecology of the Pliocene in northern Belgium, southern North Sea Basin

Abstract

Dinoflagellate cysts and other palynomorphs from the Pliocene Kattendijk and Lillo formations, exposed in two temporary outcrops in northern Belgium, provide new information on the biostratigraphic position and sequence stratigraphic interpretation of these units. Dinoflagellate cysts from the Kattendijk Formation indicate an age between about 5.0 Ma and 4.7–4.4 Ma (early Early Pliocene) in our sections, confirming a correlation with standard sequence 3.4 and implying a slightly greater age than the Ramsholt Member of the Coralline Crag Formation of eastern England. The unconformity at the base of the Kattendijk Formation was not seen, but presumably correlates with sequence boundary Me2 at 5.73 Ma. The overlying Lillo Formation is late Early Pliocene or early Late Pliocene (c. 4.2–2.6 Ma) in age, and the unconformity at its base may be correlated with sequence boundary Za2 at 4.04 Ma or Pia1 at 3.21 Ma. The Oorderen Sands and superjacent Kruisschans Sands members (Lillo Formation) are both part of the same depositional cycle. They were probably deposited before 2.74 Ma, and certainly before the onset of Northern Hemisphere cooling at c. 2.6 Ma. Evidence from dinoflagellate cysts indicates that both a shelly unit at the base of the Lillo Formation and the lower part of the overlying Oorderen Sands were deposited during a conspicuously cool climatic phase, with warmer temperatures returning during later deposition of the Oorderen Sands and Kruisschans Sands members. Many dinoflagellate cyst and acritarch species are reported here for the first time from the southern North Sea Basin. Selenopemphix conspicua (de Verteuil & Norris, 1992) stat. nov. is proposed.

Neogene stratigraphy of the Langenboom locality (Noord-Brabant, the Netherlands)

“…The first occurrence of this taxon is in the aforementioned 'Basal Shelly Unit'. Louwye et al (2004) show that the last occurrence of M. choanophorum is associated with the Kruisschans Member in Belgium. Kuhlmann et al (2006) show that the L0D of Barssidinium spp.…”

“…According to Head (1998) the LODs of A. andalousiensis suttonensis and M. choanophorum are in the early Piacenzian (~3.4 -3.6 Ma). Louwye et al (2004) recorded A. andalousiensis suttonensis in the Oorderen Sands Member. The first occurrence of this taxon is in the aforementioned 'Basal Shelly Unit'.…”

“…Moreover, the F0D of A. andalousiensis suttonensis is evidenced from the 'Basal Shelly Unit' in Belgium , matching our record from Langenboom. Also, the LOD of 0. tegillatum, discussed in Louwye et al (2004), has an age of ~3.5 Ma (near the Zanclean-Piacenzian boundary). This while occurrences younger than ~3.9 Ma possibly represent reworking according to unpublished studies of M.J. Head (pers.…”

A new fossil rorqual (Mammalia, Cetacea, Balaenopteridae) from the Early Pliocene of the North Sea, with a review of the rorqual species described by Owen and Van Beneden

“…obs.). Seasurface temperatures were cool to temperate (less than 7.2°C for April sea-surface temperatures) (Gaemers 1988;Louwye et al 2004;Lambert 2007).…”

Septidelphis morii, n. gen. et sp., from the Pliocene of Italy: new evidence of the explosive radiation of true dolphins (Odontoceti, Delphinidae)

“…Type horizon: The skull was found in the Kattendijk Formation, 2 m below the Oorderen Sands Member, Lillo Formation, in a layer of grey glauconitic sand without mollusc shells. The Kattendijk Formation is dated from the early Pliocene (Zanclean) based on dinoflagellates, foraminifers, and molluscs (Vandenberghe et al 1998;Louwye et al 2004), more precisely between 5 and 4.4 Ma (De Schepper et al 2009 widely-open antorbital notch, not laterally limited by an extension of the antorbital process; and from extant phocoenids in a more pronounced asymmetry of the vertex, with medial sutures more distinctly shifted to the left side. It further differs from the other North Sea fossil phocoenid Septemtriocetus in that it possesses: an anteriorly longer pterygoid sinus fossa, reaching the level of the antorbital notch; a higher premaxillary eminence, overhanging the posterolateral sulcus; a significantly transversely narrower frontal boss; a lower, not dorsally pointed temporal fossa; a deeper and longer squamosal fossa; and a postglenoid process of the squamosal being thickened in lateral view.…”