The Cretaceous/Tertiary boundary mass extinction in planktic foraminifera at Agost, (Spain)

Abstract

ABSTRACT. --The planktic foraminiferal mass extinction across the Cretaceous/Tertiary boundary at Agost (Spain) occurred over an extended period, with 7 species disappearing in the late Maastrichtian, 47 species extinct at the K/T boundary and 16 ranging into the earliest Danian. The species that became extinct at the K/T boundary are large, complex tropical and subtropical forms dwelling in deep and intermediate water depths, which constitute only about 20 % of the individuals in the population larger than 63 microns. Nevertheless, their disappearance constitutes the major and sudden extinction event in the history of planktic foraminifera. However, the small cosmopolitan surface dwellers with simple morphologies appear to survive and the last of them gradually disappear in the lower part of the P. pseudobulloides Biozone. This planktic foraminiferal extinction model can be interpreted as a catastrophic mass extinction that centred at the K/T boundary, and was superimposed on a gradual mass extinction which began in the late Maastrichtian and continued into the early Danian. The catastrophic pattern of extinction at the K/T boundary is very compatible with the effect of a large meteorite impact, whereas the gradual and extended pattern of extinction across the Maastrichtian-Danian transition is compatible with temperature and sea level changes that may be related to massive volcanism.R~SUM~. -L'extinction en masse des foraminif~res planctoniques h travers la limite Cr6tac6/Tertiaire h Agost (Espagne) s'est produite au cours d'une certaine p6riode; 7 espbces disparaissant au Maastrichtien sup6rieur, 47 ~ la limite K/T et 16 au Danien inf6rieur. Les esp~ces ayant disparu h la limite K/T sont grandes et complexes, des formes vivant en milieux oc6aniques profonds tropicaux et subtropicaux, qui ne constituent qu'environ 20 % des individus de la population de taille sup6rieure h 63 microns. Cependant, leur disparition repr6sente l'6vbnement d'extinction le plus important et soudain de l'histoire des foraufinif~res planctoniques. Toutefois, les petites formes cosmopolites ayant une morphologie simple et vivant dans les eaux superficielles semblent avoir surv6cu et la phipart ont disparu progressivement darts la partie inf6rieure de la Biozone ~ P. pseudobuUoides. Ce module d'extinction des foraminif~res planctoniques peut ~tre consid6r6 comme une extinction en masse catastrophique eoncentr6e h la limite K/T et superpos6e h une extinction en masse graduelle qui avait commenc6 au Maastrichtien sup6rieur et continua jusqu'au Danien inf6rieur. Le module d'extinction catastrophique h la limite K/T est bien compatible avec les effets de l'in~pact d'un grand m6t6orite, tandis que le patron d'extinction graduelle au cours de la transition Maastrichtien-Danien l'est avec les changements de temp6rature et du nivean de lamer qui pourraient ~tre en rapport avec un volcanisme massif.

Biostratigraphy of the Cretaceous/Tertiary boundary in the Sirwan Valley (Sulaimani Region, Kurdistan, NE Iraq)

“…The present P. palpebra Zone is equivalent to the upper part of Abathomphalus mayaroensis Zone recorded from different parts of the world -Premoli Silva & Sliter (1995; from Spain: Canudo et al (1991), Molina et al (1996); from eastern Mediterranean: Premoli Silva et al (1998); from USA California: Maestas et al (2003); from Egypt: Luning et al (1998), Elnady & Shahin (2001), Samir (2002), and Obaidalla (2005). The present P. palpebra Zone is equivalent to the upper part of the Abathomphalus mayaroensis Zone recorded from different localities in Iraq (Kassab 1972(Kassab , 1974(Kassab , 1975a(Kassab ,b, 1976a(Kassab ,b, 1979Abawi et al 1982;Abdel-Kireem 1986a;Kassab et al 1986;Al-Mutwali 1996;Hammoudi 2000;Al-Mutwali & Al Juboury 2005).…”

Planktonic Foraminiferal Biostratigraphy and Correlation Across the Cretaceous-Paleogene Transition at the Tethyan and the Atlantic Realms

“…The Agost section was first described by Leclerc [63], who documented the planktonic foraminiferal faunas and argued that the sedimentation was essentially continuous from Santonian to Eocene. Since then, the Agost section has been studied by numerous authors (e.g., [10,15,[64][65][66][67]) who analysed the biostratigraphy of planktonic foraminifera. Most of these authors are of the opinion that planktonic foraminifera underwent a catastrophic mass extinction at the K/Pg boundary [10,66,68], but some interpret the extinction as more gradual [9,67].…”

“…These extinctions affecting many other biological groups of vertebrates and invertebrates induced a major crisis considered as the most severe and catastrophic biological event in the history of our planet. This crisis documented in many research on the foraminifers groups ( [4][5][6], among others) became more accurate until the specialists began to use the high resolution biostratigraphical analyses ( [7][8][9][10][11][12][13][14][15][16], among others).…”

“…Consistent debates on the upper Maastrichtian-lower Danian interval based on planktic foraminiferal zonations and biochronology for the middle and lower latitudes are documented ( [7,8,10,[12][13][14][15][16][24][25][26], among others).…”

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“…Los términos próximos al límite Cretácico-Terciario en algunos de estos cortes han sido estudiados, mediante foraminíferos planctónicos, por otros autores (p. ej., Canudo et al, 1991;Canudo, 1994;Molina et al, 1996Molina et al, y 1998.…”