Chert blocks in the ophiolitic mélange of Zlatibor Mt. (SW Serbia): Age and geodynamic implications

Natasa Gerzina,Nevenka Djeric

doi:10.2298/gabp1677013g

Abstract

Cherts are quite frequently occurring rocks in the Internal Dinarides, an extremely complex area composed of several tectonostratigraphic units in which oceanic sediments, ophiolites and partly metamorphosed parts of the distal continental margin of Adria are preserved. Therefore, these cherts differ in age and the original depositional environment in which they were formed. Results of investigations carried out in the chert blocks found in the melange in the vicinity of Jasenovo village on SE slopes of Zlatibor Mt. are presented here. Radiolarian cherts from the studied localities represent blocks in melange of the East-Bosnian-Durmitor Unit, exposed in a large tectonic window below the Triassic carbonates of Drina-Ivanjica Unit. Biostratigraphic data revealed Callovian-early Kimmeridgian ages of the studied chert blocks, thus implying a Kimmeridgian or younger age of obduction of the West Vardar ophiolites.

Highlights

Precise dating of wide variety of oceanic sediments is necessary for reconstructions of palaeogeography and geodynamic evolution of oceanic basins and their continental margins
Jurassic ages have not been proven in the Internal Dinarides in Serbia, while Upper Jurassic ages have been questioned recently
Both Triassic and Jurassic radiolarians occur in chert blocks embedded in mélange of Late Jurassic age in the Internal Dinarides (e.g. OBRADOVIĆ et al 1987/88; GORIČAN et al 1999; VISHNEVSKAYA et al 2009; OZSVÁRT & KOVÁCS 2012; GAWLICK et al 2009; DJERIĆ et al 2010)

Summary

Introduction

Precise dating of wide variety of oceanic sediments is necessary for reconstructions of palaeogeography and geodynamic evolution of oceanic basins and their continental margins. Radiolarian biostratigraphy is extensively used today in dating pelagic marine sediments. Jurassic ages have not been proven in the Internal Dinarides in Serbia, while Upper Jurassic ages have been questioned recently. Both Triassic and Jurassic radiolarians occur in chert blocks embedded in mélange of Late Jurassic age in the Internal Dinarides (e.g. OBRADOVIĆ et al 1987/88; GORIČAN et al 1999; VISHNEVSKAYA et al 2009; OZSVÁRT & KOVÁCS 2012; GAWLICK et al 2009; DJERIĆ et al 2010).

Objectives

Conclusion