The origin of the famous late Precambrian striated pavement at Oaibaččannjar'ga (Bigganjargga), northern Norway, remains controversial. Most investigators have accepted a glacial formation, but some prefer a soft-sediment mechanism. However, a newly discovered c. 2.5 mm thick zone of brecciation under rare polished striations indicates a hard substrate during formation and thus a glacial origin for the striations. Other points indicating that the striations formed in a hard substrate are: (1) the striated platform (in the Veidnesbotn Formation) is c. 150 Ma older than the overlying diamictite (Smalfjord Formation); having been buried to c. 2.5 km depth, cementation should have started before Smalfjord times; (2) the marked irregularity of the sub-Smalfjord Formation palaeotopography on Skjåholmen; (3) the presence of rounded Veidnesbotn Formation boulders in the diamictite above the striations. Imprints of clasts appearing to lie across the striations are re-interpreted as relicts of mud-flakes within the Veidnesbotn Formation which were cut across and quarried-out during pavement formation. The origin of the overlying diamictite (tillite vs. debris-flow) is not constrained by the presence of glacial striations and most probably was deposited some time after striation formation.

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BackgroundWe revisit the palaeopalynological record of Loranthaceae, using pollen ornamentation to discriminate lineages and to test molecular dating estimates for the diversification of major lineages.MethodsFossil Loranthaceae pollen from the Eocene and Oligocene are analysed and documented using scanning-electron microscopy. These fossils were associated with molecular-defined clades and used as minimum age constraints for Bayesian node dating using different topological scenarios.ResultsThe fossil Loranthaceae pollen document the presence of at least one extant root-parasitic lineage (Nuytsieae) and two currently aerial parasitic lineages (Psittacanthinae and Loranthinae) by the end of the Eocene in the Northern Hemisphere. Phases of increased lineage diversification (late Eocene, middle Miocene) coincide with global warm phases.DiscussionWith the generation of molecular data becoming easier and less expensive every day, neontological research should re-focus on conserved morphologies that can be traced through the fossil record. The pollen, representing the male gametophytic generation of plants and often a taxonomic indicator, can be such a tracer. Analogously, palaeontological research should put more effort into diagnosing Cenozoic fossils with the aim of including them into modern systematic frameworks.