Petrographic and geochemical characteristics of Paleogene turbidite deposits in the southern Aegean (Karpathos Island, SE Greece): Implications for provenance and tectonic setting

摘要

The provenance and depositional setting of Paleogene turbidite sediments from the southern Aegean are investigated using petrography and whole-rock geochemistry. Petrography indicates that Karpathos Island turbidites are consisting of compositionally immature sandstones (graywackes-litharenites) derived from igneous (plutonic-volcanic), sedimentary, low-grade metamorphic and ophiolitic sources. The studied sediments probably reflect a mixing from an eroded magmatic arc and from quartzose, recycled sources. Major and trace element data are compatible with an acidic to mixed felsic/basic source along with input of ultramafic detritus and recycling of older sedimentary components. Geochemical data also reveal that the sediments have undergone a minor degree of weathering and no significant sediment recycling. Chondrite-normalized REE plots show a light REE enrichment (LaN/YbN ca. 7) and absence of significant negative Eu anomalies, indicating provenance from young undifferentiated arc material with contribution from an old upper continental crust source. Turbidite sedimentation probably took place in a continental island arc depositional setting as a result of subduction of a branch of Neotethys beneath a continental fragment of the Anatolide domain in Early Tertiary times. The relation of Karpathos turbidites with the Pindos foreland basin (Gavrovo and Ionian Zones of western Greece) remains problematic.