Formation of a Late Jurassic carbonate platform on top of the obducted Dinaridic ophiolites deduced from the analysis of carbonate pebbles and ophiolitic detritus in southwestern Serbia

Abstract

In the Inner Dinarides of southwestern Serbia, Tithonian polymictic carbonate turbidites, deposited in a deep-water foreland basin below overthrust ophiolites, contain Kimmeridgian–Tithonian shallow-water clasts, Triassic open-marine limestone and radiolarite clasts, and chrome spinels of a harzburgitic source (suprasubduction and MOR ophiolites). The results from the component analysis of these Tithonian polymictic carbonate turbidites constrain a Middle to Late Jurassic orogeny in the Western Tethys realm with following geodynamic evolution: (1) The closure of the western part of the Neo-Tethys Ocean caused west- to northwestward-directed ophiolite obduction onto the wider Adriatic shelf from Middle Jurassic times onwards. The former Triassic–Middle Jurassic outer passive continental margin of the Neo-Tethys imbricated and a nappe stack in lower plate (wider Adriatic) position was formed in front of the propagating obducting ophiolites. (2) During a period of relative tectonic quiescence, formation of a Late Jurassic carbonate platform started around the Oxfordian/Kimmeridgian boundary on top of the obducted ophiolites. This detection of a Late Jurassic carbonate platform formed above the obducted Dinaridic ophiolites close an important gap in knowledge about the geodynamic evolution of the Inner Dinarides. (3) From the Kimmeridgian/Tithonian boundary onwards uplift of the imbricated rocks below the obducted ophiolites triggered unroofing. During Tithonian times the obducted ophiolites were transported west-directed along low-angle fault plains near to its present position in the Dinarides. Mountain uplift and unroofing caused the partly erosion of the Late Jurassic carbonate platform, the underlying ophiolites and the Triassic–Jurassic nappe stack consisting of outer shelf sedimentary rocks.