Orbital signatures in a late Miocene dinoflagellate record from Crete (Greece)

• Published in: Marine micropaleontology Vol. 33; no. 3; pp. 273,297 - 295,297
• Main Authors: Santarelli, A., Brinkhuis, H., Hilgen, F.J., Lourens, L.J., Versteegh, G.J.M., Visscher, H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.1998
• Subjects: dinoflagellate cysts; Late Miocene; Mediterranean; Milankovitch theory; sapropels; MED, Greece; Mediterranean; Milankovitch theory; sapropels; Late Miocene; dinoflagellate cysts
• ISSN: 0377-8398; 1872-6186
• DOI: 10.1016/S0377-8398(97)00042-X

A high-resolution palynological study of the cyclically bedded Faneromeni section (upper Tortonian-lower Messinian) on Crete (Greece) is presented. This study aims to recognize orbitally-driven variations in the palynological record and to validate the age model based on the astronomical calibration of the sedimentary cycles. Four palynology-based environmental proxies were utilised using interpretations of fossil dinoflagellate associations based on modern ecological characteristics. Cross-spectral analysis between the proxy records and astronomical target curve, the 65°N summer insolation, yielded in most cases significant spectral power and coherence in the precession and/or obliquity frequency bands. Precession-controlled variations in the proxy records are related to lithology and indicate that maxima in continental input and minima in sea surface salinity coincide with sapropel formation. The influence of obliquity is most clearly reflected in the index of continental versus marine palynomorphs (S-D). The absence of a distinct time lag relative to obliquity indicates that the 41-kyr component in continental input is controlled by oscillations in regional Mediterranean climate rather than by glacial cyclicity. Phase relations in the different astronomical frequency bands of the spectrum, as compared with the Mediterranean Pliocene, essentially confirm the validity of the Miocene astronomical time scale. Finally, a major non-cyclic change in the palynological assemblage at 6.68 Ma indicates enhanced salinity and decreased river discharge. This shift coincides with a significant drop in sedimentation rate informally termed the “Early Messinian Sediment starvation Event”.