ARTICLE Received 17 Aug 2015 | Accepted 26 Apr 2016 | Published 26 May 2016 DOI: 10.1038/ncomms11738 OPEN Macrofossil evidence for a rapid and severe Cretaceous–Paleogene mass extinction in Antarctica James D. Witts1, Rowan J. Whittle2, Paul B. Wignall1, J. Alistair Crame2, Jane E. Francis2, Robert J. Newton1 & Vanessa C. Bowman2 Debate continues about the nature of the Cretaceous–Paleogene (K–Pg) mass extinction event. An abrupt crisis triggered by a bolide impact contrasts with ideas of a more gradual extinction involving flood volcanism or climatic changes. Evidence from high latitudes has also been used to suggest that the severity of the extinction decreased from low latitudes towards the poles. Here we present a record of the K–Pg extinction based on extensive assemblages of marine macrofossils (primarily new data from benthic molluscs) from a highly expanded Cretaceous–Paleogene succession: the Lo´pez de Bertodano Formation of Seymour Island, Antarctica. We show that the extinction was rapid and severe in Antarctica, with no significant biotic decline during the latest Cretaceous, contrary to previous studies. These data are consistent with a catastrophic driver for the extinction, such as bolide impact, rather than a significant contribution from Deccan Traps volcanism during the late Maastrichtian. 1 School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK. 2 British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET, UK. Correspondence and requests for materials should be addressed to J.D.W. (email: [email protected]). NATURE COMMUNICATIONS | 7:11738 | DOI: 10.1038/ncomms11738 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms11738 he Cretaceous–Paleogene (K–Pg) mass extinction at occasional, thin glauconite-rich sandstone horizons becoming 66 Ma is the most intensively studied of the more prevalent in the uppermost 300 m, along with indurated T‘Big Five’ crises to have affected life during the layers formed of early diagenetic concretions and thin bioturbated Phanerozoic1–8. The extinction led to a fundamental sands26–28. Despite the lithological homogeneity of the restructuring of global ecosystems and the rise of modern succession, several environmental changes have been proposed taxonomic groups7,9–11. Despite this interest, debate continues as that have a bearing on marine biodiversity. The depositional to the duration of the crisis as well as the relative contributions of environment of the Lo´pez de Bertodano Formation is the bolide impact at Chicxulub1,4, voluminous eruptions from broadly transgressive; the lower portion has been interpreted as the Deccan Traps large igneous province12,13, and dynamic relatively shallow water, outer estuarine facies28,29, with a climate instability during the preceding Maastrichtian stage low-energy, marine shelf facies forming the remainder of the (72.1–66 Ma)6,14. Parts of this discourse have particularly succession27,30. focused on the Antarctic fossil record. Previous studies on high Here we address these debates on the timing and intensity of southern latitude biotas have claimed the extinction to be either a Antarctic marine extinctions with a detailed analysis of marine gradual diversity decline15,16, a series of extinction pulses linked diversity trends during the Maastrichtian to earliest Paleocene to episodes of Deccan volcanism17 or, for ammonites at least, B70–65.6 Ma (ref. 23) from the Lo´pez de Bertodano Formation. a single rapid event18. In addition, it has been suggested that the We evaluate the nature of the K–Pg extinction, its abruptness and intensity of the extinction and environmental stress varied with intensity in this region. In addition, we test the relationship latitude and was related to the proximity of the impact site or the between palaeoenvironmental changes and diversity, using pyrite volcanism (both at mid to low latitudes)19,20. As a result, the high petrography as an indicator of palaeoenvironmental conditions. southern latitudes are thought to have weathered the crisis better Besides comparisons of existing low-resolution faunal range than lower latitude regions15,21,22. charts with oxygen isotope data as a proxy for marine The Lo´pez de Bertodano Formation of southern Seymour palaeotemperature trends17, there have been few previous Island, Antarctica (Fig. 1) represents one of the most attempts to relate faunal diversity trends in this succession to highly expanded onshore Maastrichtian–Danian sedimentary other local environmental conditions, for example benthic redox successions in the world with B1,000 m of sedimentation in changes. We suggest that the K–Pg extinction in Antarctica was B4 Myr (refs 17,23,24). At a palaeolatitude of B65° S during the as rapid and severe as that seen at lower latitudes, with no latest Cretaceous25, this succession represents a true high latitude evidence for significant precursor extinction events during the record of events during this critical time period. The succession latest Maastrichtian, which can be related to the onset of Deccan exposed on Seymour Island is dominated by silty-clays with volcanism or climatic instability. Cross valley & La Meseta Fms ab60°W (Paleocene - Eocene) South America Sobral Fm (Paleocene) JRB López de Bertodano Fm c (Cretaceous - Paleocene) Snow Hill lsland Fm (Cretaceous) 65°S 65° ° BAS section S 60 W lines c 64°15'S 90°W b C A Weddell Seymour Sea lsland K-Pg B 56°45'W Antarctica Indian Ocean 180° 90°E Figure 1 | Location map of Seymour Island. (a) Modern Southern Hemisphere geography showing location of Antarctica, Antarctic Peninsula highlighted. (b) Map of northern Antarctic Peninsula, location of James Ross Basin (JRB) circled and highlighted. (c) Geological map of Seymour Island showing locations of principal lithological units, their ages, as well as the locations of British Antarctic Survey section lines mentioned in the text. Location of K–Pg boundary indicated by dotted line on c. Circled letters in c correspond to individual British Antarctic Survey section lines, A, 1999 field season, B, 2006 field season, C, 2010 field season. Scale bar, 5 km. See Supplementary Figs 1–4 for more details. 2 NATURE COMMUNICATIONS | 7:11738 | DOI: 10.1038/ncomms11738 | www.nature.com/naturecommunications magnetostratigraphy derived from ref. 23 (seefossils Supplementary (MR), Fig. lamniform 1 shark for vertebrae detailed (S), explanation). echinoid Time spines scale (E) is and based serpulid on worm Sr tubes isotope ( chemostratigraphy (italicized A–C) S, Sobral Formation. See Supplementary Note 1 for details of species identifications. found throughout theand Maastrichtian diverse portion molluscan of fauna, the other Lo common faunal elements decapod crustaceans, marinecidaroid reptiles, shark echinoid vertebrae and spines, fossil scaphopods, rare solitary corals, et al. boundary interval on Seymour Island undertaken by Zinsmeister same sections from nektonic and nekto-benthicthese cephalopod collections were molluscs combined from and(Fig. the compared 1; directly Supplementary with data Figssedimentary sections 1–4). through Species the rangestations Lo charts accurately based located on (bivalves within a and series of detailed gastropods) measured from 377 individual sampling marker for the K–Pgsection boundary of the globally(Fig. recognized 2; iridium (Ir) Supplementary anomaly Figs used 1–5) as and a the presence in a parallel for thisFossil study evidence for comprises Results diversity and extinction NATURE COMMUNICATIONS | DOI: 10.1038/ncomms11738 NATURE COMMUNICATIONS Figure 2 | Composite stratigraphic range data for molluscan taxa from the Lo based on biostratigraphichorizon data 1,007.5 m fromSeymour above marine Island the palynology base occurs of in our a composite section, 2.5–3-m-thick glauconite-rich (Supplementary Table 1), in additionappearance to in collections the from composite overlying section.Supplementary Paleocene Range Fig. strata extensions 5). calculated Separated based intolithostratigraphy and on bivalves (B) age a model. (1–32), literature Includes gastropods review of (G) new molluscan data (33–51), occurrences from and from this cephalopods underlying study (A formations (see and Methods N) and (52–66), Supplementary with Figs taxa 1–4), ordered and by from first refs 16,18 (see also Bertodano Formation include serpulid worm tubes ( A Danian model Age Maastrichtian B late 67.0 66.0 C early 69.0 68.0 16 (Supplementary Fig. 6). The K–Pg boundary on C31R C31N C30N C29R1,000 1,100 100 200 300 400 500 600 700 800 900 0 m Lithostratigraphy 18 Pg K S SHI López de Bertodano Formation (Fig. 2) and from previous studies of the K–Pg c 17 si , updated with ages from the Geological Time Scale 2012 (ref. 69) and using the K–Pg boundary datum. G, glauconite-rich intervals. fs G G G ms G G G | 7:11738 | DOI: 10.1038/ncomms11738 | www.nature.com/naturecommunications 1 Oistotrigonia pygoscelium (B) 2 Leionucula suboblonga (B) 3 Nordenskjoldia nordenskjoldi (B) 4 Marwickial Cyclorismina sp. (B) 4 5 Panopea clausa (B) 30,32 6 Pycnodonte (Phygraea) vesicularis (B) 6,000 benthic molluscan fossils 7 Eselaevitrigonia regina (B) 8 Cucullaea antarctica (B) ´ (Fig. 3). Besides an abundant 9 Thracia askinae (B) pez de Bertodano Formation 10 “Lucina” scotti (B) 11 “Thyasira” townsendi (B) 12 Solemya rossiana (B) 13 Austrocucullaea oliveroi (B) 14 Modiolus cf. pontotocencis (B) 15 Seymourtula antarctica (B) 16 Neilo casei (B) . The primary data 17 Limopsis (Limopsis) antarctica (B) 18 Pinna freneixae (B)