Published: 2026-02-12
Late Cretaceous volcano-sedimentary complex along the Adria–Tisza boundary: New insights from the westernmost Sava Suture Zone
Authors: Iva Olić Peco, Bojan Matoš, Dejan Prelević, Zorica Petrinec, Kristijan Sokol, Anja Kocjančič, Alan Moro, Borna Lužar-Oberiter
Abstract:
The Late Cretaceous collision of Adria-European plates marks an important tectonic stage in the Alpine-Mediterranean-Himalayan orogenic system formation in the southeastern Europe evidenced by Sava Suture Zone (SSZ). To better understand stratigraphic relations and ascertain their regional implications within the westernmost SSZ, we present new biostratigraphic, petrographic and geochemical data from a volcano-sedimentary complex in the Zrinska Gora Mt. area. The sedimentary part of the studied complex is consisted of deep-marine pelagic Scaglia-type limestones intercalated with sandstones and shales in its upper part. The foraminiferal assemblage of the analysed carbonate rocks corresponds to the Dicarinella asymetrica planktonic foraminiferal zone, indicating a middle Santonian age to possibly earliest base of Campanian age. The volcanic part of the studied complex comprises hydrothermally altered basalts with skeletal, dendritic and intersertal textures. These basalts are classified as tholeiitic with enriched mid-ocean ridge basalt (E-MORB) characteristics. They exhibit light rare earth element enrichment relative to heavy rare earth elements, with LaN/YbN ratios ranging from 2.35 to 3.37. These basalts are similar to other basaltic occurrences in the western part of the SSZ (e.g., North Kozara, Požeška Gora), but differ from basalts exposed in the central part of the SSZ (Ripanj, Klepa). The geochemical signature of Zrinska Gora basalts suggest that the basic magmatism in the western SSZ probably originated from the enriched mantle sources, within the oceanic lithosphere of considerable shortened oceanic realm, or alternatively young continental crust, which may experience onset of transtensional tectonics due to Adria-Europe oblique collision. Such activity is advanced and pronounced towards southeast, the central SSZ.
The Late Cretaceous collision of Adria-European plates marks an important tectonic stage in the Alpine-Mediterranean-Himalayan orogenic system formation in the southeastern Europe evidenced by Sava Suture Zone (SSZ). To better understand stratigraphic relations and ascertain their regional implications within the westernmost SSZ, we present new biostratigraphic, petrographic and geochemical data from a volcano-sedimentary complex in the Zrinska Gora Mt. area. The sedimentary part of the studied complex is consisted of deep-marine pelagic Scaglia-type limestones intercalated with sandstones and shales in its upper part. The foraminiferal assemblage of the analysed carbonate rocks corresponds to the Dicarinella asymetrica planktonic foraminiferal zone, indicating a middle Santonian age to possibly earliest base of Campanian age. The volcanic part of the studied complex comprises hydrothermally altered basalts with skeletal, dendritic and intersertal textures. These basalts are classified as tholeiitic with enriched mid-ocean ridge basalt (E-MORB) characteristics. They exhibit light rare earth element enrichment relative to heavy rare earth elements, with LaN/YbN ratios ranging from 2.35 to 3.37. These basalts are similar to other basaltic occurrences in the western part of the SSZ (e.g., North Kozara, Požeška Gora), but differ from basalts exposed in the central part of the SSZ (Ripanj, Klepa). The geochemical signature of Zrinska Gora basalts suggest that the basic magmatism in the western SSZ probably originated from the enriched mantle sources, within the oceanic lithosphere of considerable shortened oceanic realm, or alternatively young continental crust, which may experience onset of transtensional tectonics due to Adria-Europe oblique collision. Such activity is advanced and pronounced towards southeast, the central SSZ.
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