Sedimentary and thermal evolution of the Eocene-Oligocene mudrocks from the southwestern Thrace Basin (NE Greece)

摘要: Paleothermal indicators based on clay mineral and organic matter analyses, were integrated with mudrock geochemistry stratigraphic data to define the sedimentary evolution of southwestern Thrace Basin during Eocene Oligocene. This multi-method approach allowed us reconstruct the burial basin in Oligocene times study mudrock composition relate this their provenance source area weathering. The studied mudrocks show similar chemical variations. distribution some major trace elements for studied samples reflect heterogeneous areas containing both felsic mafic rocks. In particular, the Light Rare Earth Elements/Transition (LREEs/TEs) ratios are very high Avdira and Organi samples (on average between 1.5 2.2 (La Ce)/Cr 3.5–8 Ce)/ Ni), suggesting a source(s), low Samothraki, Limnos, Paterma Iasmos samples 0.4 0.6 0.6–1 Ce)/Ni), suggesting a mainly basic source(s). mineralogical composition coupled with A-CN-K AN- K plots suggest complex evolution. (illite percentage I/S stacking order R K€ubler Index) vitrinite reflectance analysis indicate intermediate diagenetic grade Middle Upper (from Iasmos, Gratini, Organi, Paterma, Esimi Samotraki sections) diagenetic Oligocene samples Limnos Avdira sections). These helped interpreting geodynamic evolution basins where magmatic activity plays an important role. particular, Middle sediments show intermediate since they are located portion dominated by intrusion of granitoids, whereas, not involved magmatic activity intrusion granitoids and, thus, grade. Furthermore, Middle to experienced deeper processes caused lithostatic load, rather than uppermost sediments, relation position along the stratigraphic succession. depth at least 3–4 km tectonic exhumation mainly related extensional phases Miocene age.