New paleomagnetic results from Ordovician sedimentary rocks from NW Anatolia: Tectonic implications for the paleolatitudinal position of the Istanbul Terrane

- We have conducted a paleomagnetic study to determine the paleolatitude of the Istanbul terrane during the Ordovician.
- Characteristic higher temperature components passed fold test and direction-correction test (DC test).
- Our result shows a lower paleolatitudinal position closer to the equatorial zone than previously inferred.

The Istanbul terrane, classically known as the “Paleozoic of Istanbul”, is geologically one of the important continental components of NW Turkey. The terrane comprises an Early Ordovician to Early Carboniferous transgressive sedimentary sequence and appears as an exotic unit with respect to its present surroundings.The paleogeographical position of the Ordovician rocks is unknown. We have therefore conducted a paleomagnetic study from a total of 56 sites in red fluvial clastics of the Kurtkoy formation and shallow marine quartzites of the Aydos formation to determine the paleolatitude of the Istanbul terrane during the Ordovician. The Lower Ordovician group mean direction calculated from 17 reliable sites provides a mean inclination of I = 19.4°, (α95 = 2.3°, k = 146.0) accepting only inclination data. A paleolatitude of 16.4° is obtained after considering an inclination correction factor of f = 0.6 due to the E/I results. The Early Ordovician paleolatitude of the Istanbul terrane shows a lower paleolatitudinal position closer to the equatorial zone than previously inferred.