Stratigraphy with biotic responses to the Paleocene-Eocene Thermal Maximum(PETM) in the Central Basin of Spitsbergen

Abstract In this thesis the Paleocene and Eocene transition is the main focus of the analyses of Svalbard cores BH 10/06, BH 07/08 and BH 09/06, from the Central Basin. Special emphasis is laid on biotic responses through the Paleocene-Eocene Thermal Maximum (PETM) and its background environments. The thesis is based on quantitative foraminiferal analysis and data from sediment logs and samples. The foraminiferal assemblages are agglutinated (benthic) and show low to intermediate diversities. Three assemblages are distinguished and named after the dominant species: FA 1, the Recticulophragmium arcticum assemblage; FA 2, the Trochammina aff. inornata assemblage; FA 3, the Thurammina aff. papillata assemblage. The pre-PETM is characterized by the relatively high diversity FA 1 assemblage dominated by shallow digging and deep digging foraminifera suggesting relatively good oxygenation in the upper part of the bottom sediments. The PETM shows major faunal changes including benthic foraminiferal extinctions, and reduced species diversities in FA 2 because the water contains very low amount of oxygen. FA 3 shows a faunal change after the PETM because of delta progradation. The PETM is used as the time horizon in the correlation of the three cores. The Hollendardalen and Marstranderbreen members are present in core BH 09/06 and BH 07/08, and absence in the core BH 10/06. This may show that the Hollendardalen Member was deposited from the west or north-west. Parts of two depositional sequences and a whole sequence are present in the studied cores: S1 represent the uppermost part of the Grumantbyen Formation. S2 is complete and includes the topmost part of the Grumantbyen Formation and the Marstranderbreen and Hollendardalen members. S3 comprises the lower part of the Gilsonryggen Member. Keywords: Svalbard, PETM, biofacies, Paleogene, benthic foraminifera.