New paleomagnetic results from Upper Cretaceous arc-type rocks from the northern and southern branches of the Neotethys ocean in Anatolia

Abstract

A paleomagnetic study of Cretaceous arc type rocks in the Central-Eastern Pontides and in the Southeastern Taurides investigates the tectonic and paleolatitudinal evolution of three volcanic belts in Anatolia, namely the Northern and Southern Volcanic Belts in the Pontides and the SE Taurides volcanic belt. The paleomagnetic data indicate that magnetizations were acquired prior to folding at most sampling localities/sites, except for those in the Erzincan area in the Eastern Pontides. The Southern Volcanic Belt was magnetized at a paleolatitude between 23.8(-3.8)(+4.20)N and 20.2(-1.2)(+1.30)N. Hisarli (J Geodyn 52:114-128, 2011) reported a more northerly paleolatitude (26.6(-4.6)(+5.10)N) for the Northern Volcanic Belt. The comparison of the new paleomagnetic results with previous ones in Anatolia allows to conclude that the Southern Volcanic Belt in the Central-Eastern Pontides was emplaced after the Northern Volcanic Belt as a result of slab-roll back of the Northern Neotethys ocean in the Late Cretaceous. In the Southeast Taurides, Upper Cretaceous arc-related sandstones were at a paleolatitude of 16.8(-3.8)(+4.2). The Late Cretaceous paleomagnetic rotations in the Central Pontides exhibit a counterclockwise rotation of R +/- Delta R = -37.1 degrees +/- 5.8 degrees (Group 1; Cankiri, Formation) while Maastrichtian arc type rocks in the Yozgat area (Group 2) show clockwise rotations R + Delta R = 33.7 degrees +/- 8.4 degrees and R + Delta R = 29.3 degrees +/- 6.0 degrees. In the SE Taurides counterclockwise and clockwise rotations of R +/- Delta R = -48.6 degrees +/- 5.2 degrees and R +/- Delta R = +34.1 degrees +/- 15.1 degrees are obtained (Group 4; Elazig Magmatic Complex). The Late Cretaceous paleomagnetic rotations in the Pontides follow a general trend in concordance with the shape of the suture zone after the collision between the Pontides and the Kirsehir block. The affect of the westwards excursion of the Anatolian plate and the associated fault bounded block rotations in Miocene are observed in the east of the study area and the SE Taurides.