Preliminary palynological study of the Upper Ordovician Pin Formation in northern Indian Himalaya

The Pin Formation of the northern Indian Himalaya may contain a record of the late Katian (LateOrdovician) warming event (the Boda Event). Palynological samples collected from two members ofthis formation are investigated in order to evaluate the biostratigraphical potential of the differentmicrofossil groups. Acritarchs and chitinozoans are the most abundant microfossils, but fragments ofscolecodonts and melanosclerites are also present. Several of the acritarchs from the Pin Formationare long-ranging through the lower Palaeozoic, but other taxa can be compared to Upper Ordovician(Katian) assemblages described from other parts of the world. The chitinozoan assemblages, consistingof 13 species (including those in open nomenclature) belonging to seven genera, are mainly recordedfrom two layers. The chitinozoan assemblage collected from the sample at 87.3 m in the uppermostpart of the Farka Muth Member, and that collected at 184.89 m from the Takche Member, indicate alate Katian age. This age interpretation is in accordance with conodont data from the Takche Member,a positive carbon isotopic peak from the top of a shale unit in the Takche Member, and the initialpart of the rapid negative shift of the Paroveja isotopic excursion related to the Boda Event of lateKatian age. Further detailed studies with a higher number of samples are needed, that describe betterpreserved and more diversified palynomorph assemblages, which would help to more precisely refinethe Upper Ordovician biostratigraphy in this area.