Holtjernet Member
(Holtjernleddet)
(Opalinski & Harland 1981)
Main Lithologies. Limestones with local siltstone.
Basal Stratotype. Mjøsa (Toten): Holtjern (Opalinski & Harland 1981, Fig. 10) (NN 907 262).
Definition. The Holtjernet Member is developed above the Eina Member in Toten, the Gålås Member in northern Nes-Hamar and the Bergevika Member on Helgøya, southern Nes-Hamar (Fig. 18). Its base comprises coarse, conglomeratic, bioclastic limestones in Toten and fissile siltstones in Nes-Hamar. The remainder of the member is composed of reticulate weathering bioturbated limestone. The Holtjernet Member is 25.9m thick at Holtjernet and maintains this thickness except at Kyset (Toten) where it is much thinner. The top of the member is the karst top of the formation.
Fauna and Flora. Opalinski & Harland (1981 pp.7476) recognised four lithofacies within the Holtjernet Member and listed diverse shelly faunas and algal floras from two of them: the limestone conglomerates and the fissile siltstones which constitute the basal parts of the member.
(From Owen et al., 1990: The Ordovician Successions of the Oslo Region, Norway. NGU Special Publication 4. Figs. refer to the printed version.