TIMING OF LATE PLIOCENE TO MIDDLE PLEISTOCENE TECTONIC EVENTS IN RHODES (GREECE) INFERRED FROM MAGNETO-BIOSTRATIGRAPHY AND 40AR/39AR DATING OF A VOLCANICLASTIC LAYER

Abstract

We discovered a volcaniclastic layer in the Plio-Pleistocene coastal sequences on the island of Rhodes (Aegean fore-arc, Greece). Here, we present an integrated isotopic, magnetostratigraphic, and biostratigraphic (planktonic foraminifers) study for the Haraki section, where this layer is found intercalated in several meters of sedimentary rocks corresponding to the Lindos Bay clay Member of the Rhodes Formation. 40Ar/39Ar dating of the volcaniclastic layer provides an age of 1.89 ± 0.09 Ma, which is consistent with our planktonic foraminiferal data. Magnetostratigraphic results show that the entire Haraki section is of normal polarity and according to the isotopic results this corresponds to the Olduvai subchron (1.95-1.77 Ma). The new age determination provides severe constraints for deciphering the sedimentary and tectonic evolution of Rhodes since the Late Pliocene, which can be summarized in the following: (1) 500 to 600 m drowning during the latest Pliocene that could be related to the westward motion of the Anatolian Plate; (2) at least 520 m of uplift at around 1.4-1.3 Ma related to activity of the sinistral strike-slip of the Pliny Trench, the deep Rhodes basin being separated from the island of Rhodes; (3) a counterclockwise rotation of Rhodes, younger than 1.2-1.1 Ma, and possibly synchronous with the young clockwise rotation of the western Aegean arc. © 2006 Elsevier B.V. All rights reserved.