Magnetobiostratigraphy of the Spathian to Anisian (Lower to Middle Triassic) Kçira section, Albania

Abstract

Magnetobiostratigraphic data are presented from three Early/Middle Triassic HanBulog Limestone successions from Kçira, northern Albania. A total of 206 standard palaeomagnetic samples were obtained for thermal demagnetization and statistical analysis from the 42, 10 and 5 m thick sections. The reversal-bearing characteristic component, carried by haematite and magnetite, defines a composite sequence of six main polarity intervals (Kçln to Kç3r) in which are embedded four short polarity intervals, one at the base of Kçln and three towards the top of Kçlr. The early acquisition of the characteristic remanence is supported by the lateral correlation of magnetozones between sections. The Early/Middle Triassic boundary, approximated by the first occurrence of the conodont Chiosella timorensis, falls close to the Kçlr/Kç2n polarity transition. This is in good agreement with recently published magnetobiostratigraphic data from the coeval Chios (Greece) sections. The palaeomagnetic pole calculated from the Kçira characteristic directions lies close to the Triassic portion of the apparent polar wander path for Laurussia (in European coordinates). However, a 40-45° clockwise rotation of the external zone of the Albano-Hellenic Belt to the south of the Scutari-Pec Line is thought to have occurred since the Early-Middle Miocene. The Kçira pole acquires a West Gondwana affinity when restored for the Neogene clockwise rotation. If the clockwise rotation was entirely related to Neogene tectonics, the Kçira area was evidently associated with West Gondwana and located at 12-16°N of the western Tethys margin.