Biomarker 2: Bolivinoides miliaris/Gavelinella spp FDO
Found in the Tor Formation in the Central and Northern North Sea and Rowe Formation of the Southern North Sea Basin (King, 1989, places the biomarker in the early Maastrichtian, lanceolata Zone, but in Norfolk it occurs higher, lower occidentalis according to Swiecicki, 1980MS) (Hart et al., 1981, 1989; King, 1989; unpublished BGS data). The FDO Bolivinoides miliaris and the increase in diversity of Gavelinella (e.g. G. bembix, G. pertusa and G. voltziana) are characteristic of this horizon. Other benthonic species include Cibicidoides velascoensis, Lingulogavelinella vombensis, Gyroidinoides nitidus, Pullenia quaternaria, Osangularia cordieriana and Stensioeina pommerana. Of the planktonic species, Rugoglobigerina rugosa is abundant and Globotruncana havanensis rarely occur.
In view of its distribution at Trimingham, Norfolk, the position of the biomarker is placed slightly higher than that shown by King (1989), which was followed by Wilkinson et al. (1994).
Correlation: This biomarker can be placed in the BGS foraminiferal Biozone 25 (Wilkinson, 2000).