Three new species of dinoflagellate cyst from Cretaceous–Paleogene (K-Pg) boundary sections at mid-Waipara River and Fairfield Quarry, South Island, New Zealand

Abstract

A palynological investigation of marine uppermost Maastrichtian to lower Paleocene strata in two New Zealand sections, mid-Waipara River and Fairfield Quarry, revealed well-preserved dinoflagellate cyst assemblages including three new dinoflagellate cyst species. A formal description of the new dinoflagellate cyst species are presented here. Furthermore a variation of Carpatella cornuta, named C. aff. cornuta is discussed. In the mid-Waipara River section the ranges of the new species Adnatosphaeridium regulatum sp. nov., Alterbidinium mcmillanii sp. nov. and Canningia fairfieldensis sp. nov. are calibrated directly with other microfossil groups including foraminifera, radiolarian and terrestrially derived spores and pollen. The last occurrence of Adnatosphaeridium regulatum sp. nov. is within the lowermost Danian foraminiferal zone Pα and this event is recorded in sections located in several New Zealand sedimentary basins. Alterbidinium mcmillanii sp. nov. has a very restricted range within the latest Maastrichtian to basal Danian with its last occurrence within foraminferal zone P0. Canningia fairfieldensis sp. nov. has so far only been recorded in lower Danian strata and occurs within the foraminiferal zones Pα to P1c and radiolarian zones RP1?–RP2. A morphological variation of Carpatella cornuta named Carpatella aff. cornuta is only observed in a very narrow interval across the Cretaceous–Paleogene (K-Pg) boundary in the mid-Waipara River section. Based on comparison with other New Zealand K-Pg boundary sections, A. mcmillanii sp. nov. and C. fairfieldensis sp. nov. seem to have a palaeoenvironmental affinity for shallow marine to inner neritic depositional environments.

Keywords:

• dinoflagellate cysts
• taxonomy
• Cretaceous–Paleogene boundary transition
• stratigraphy
• biostratigraphy
• South Island
• New Zealand

Acknowledgements

This palynological study was part of a multidisciplinary research programme supported by the New Zealand Marsden Fund and lead by Chris Hollis, Geological and Nuclear Sciences, New Zealand (GNS). The author acknowledges a personal grant from the Danish Carlsberg Foundation (Grant No. 2008_01_0404) and financial support from Lund University Center for Studies of Carbon Cycle and Climate Interactions (LUCCI). Graeme J. Wilson and Ian Raine (GNS) are acknowledged for sharing their extensive knowledge of Mesozoic–Cainozoic palynology. Simon McMillan is thanked for his assistance when the K-Pg boundary transition in Fairfield Quarry was sampled. Chris Hollis, Jerry Dickens, Brad Field, Percy Strong and Poul Schiøler are thanked for assisting in the sampling of the mid-Waipara section. Margaret Collinson is thanked for collecting the high-resolution sample suite across the K-Pg boundary transition in the mid-Waipara River section.