Miocene remagnetisation of carbonate platform and Antalya Complex units within the Isparta angle, SW Turkey

Abstract

A palaeomagnetic study has been carried out within the Mesozoic and Tertiary units of the relatively autochthonous carbonate platforms and the allochthonous deep-sea volcanics and sediments of the Antalya Complex, exposed around the Isparta angle, SW Turkey. The Antalya Complex is interpreted as a mosaic of carbonate platforms, basinal sediments, volcanic and ophiolitic rocks which formed within a southerly strand of the Neotethyan ocean, adjacent to Gondwana. The results indicate a widespread remagnetisation event. Negative fold tests show that the remanence at most sites is of secondary origin (e.g., within the çirali lavas). The magnetisation is carried by magnetite of presumed authigenic origin. The remagnetisation event is believed to have occurred in the Early-Middle Miocene (Burdigalian-Langhian). It was possibly triggered by the migration of orogenic fluids ahead of the advancing Lycian nappes during their emplacement onto the carbonate platforms. Subsequent to remagnetisation, a large segment of the Isparta angle underwent an anticlockwise rotation of 30°. This rotation is attributed to the overall convergence and bending of the Hellenic arc and the final stages of emplacement of the Lycian Nappes during the Late Miocene, in agreement with previous studies. Previously, southerly palaeolatitudes were inferred from Late Triassic extrusives of the Gödene Zone (Čalbali Dag unit). The post-folding magnetisation identified here within the Çirali lavas of the Gödene Zone to the south implies that these low palaeolatitudes result from the inappropriate application of structural tilt corrections. The available data cannot be used to substantiate an origin for the Antalya units south of the equator in the early Mesozoic. Instead, a position close to the northern margin of Gondwana is indicated.