1 Intercalibration of Boreal and Tethyan timescales: the magneto-biostratigraphy of the Middle Triassic and the latest Early Triassic from Spitsbergen (arctic Norway)

• Main Authors: Mark W. Hounslow, Mengyu Hu, Atle Mørk, Wolfgang Weitschat, Os Vigran, Vassil Karloukovski, Michael J. Orchard
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Norway; Vikinghøgda; Botneheia; Tschermakfjellet; Vendomdalen; Milne Edwardsfjellet; Spitsbergen
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.686.5277; http://eprints.lancs.ac.uk/26871/1/08Hounslow-etal-ME-draft.pdf

An integrated bio-magnetostratigraphic study of the latest Early Triassic to the upper parts of the Middle Triassic, at Milne Edwardsfjellet (central Spitsbergen), allows a detailed correlation of Boreal and Tethyan biostratigraphies. The biostratigraphy consists of ammonoid and palynomorph zonations, supported by conodonts, through some 234 m of succession in two adjacent sections. The magnetostratigraphy consists of ten substantive normal-reverse polarity chrons defined by sampling at 150 stratigraphic levels. The magnetisation is carried by magnetite and an unidentified magnetic sulphide, and is difficult to fully separate, from a strong present-day like magnetisation. The bio-magnetostratigraphy from the late Olenekian (Vendomdalen Member) is supplemented by data from nearby Vikinghøgda. The early and mid Anisian has a high sedimentation rate, comprising over half the ca. 140 m thickness of the Botneheia Formation, whereas the late Anisian and lower Ladinian is condensed into about 20 m. The two latest Boreal Ladinian ammonoid zones are absent due to erosional truncation below the Tschermakfjellet Formation. Correlation to Tethyan bio-magnetostratigraphies shows the traditional base of the Boreal Anisian (base of