Upper Messinian Lago-Mare deposits in the stratigraphy of the Messara Basin (central Crete, Greece).

In the Crete Island, late Messinian Lago-Mare facies are not well known. At present, the occurrence in Crete of the uppermost Messinian post evaporitic deposits is matter of debate. According to several Authors the well-known late Messinian Lago-Mare facies did not occur in Crete. There, Lower Pliocene open-marine clays of the Finikia Group directly overlie the upper Messinian evaporites of the Hellenikon Group (Dermitzakis et alii, 1979; Frydas, 1998; Fassoulas, 2001).Meulenkamp et alii (1977 and 1979) described continental coarse-grained deposits and lagoonal sediments with Cyprideis pannonica agrigentina Decima (= C. agrigentina) from eastern Crete (Ag. Nicolaos). Moreover, fine-grained deposits with Cyprideis sp. have been, also, detected in a few places of central Crete (Meulenkamp et alii, 1977). The stratigraphic positions of all these Cyprideis-bearing deposits, which occur above upper Messinian gypsum, allow us to consider them as deposited during the late Messinian Lago-Mare event. The aim of this paper is to show the preliminary results obtained from the analyses of some stratigraphical sections sampled in the Messarà Plain. Nearby Faneromeni village, the Miocene/Pliocene boundary is well exposed. The uppermost lower Messinian deposits (pre-evaporitic stage) are characterized by brownish laminated tripolaceous marls with intercalations of marl horizons rich in benthic forams, ostracods and molluscs. Moreover, two organic-rich horizons have been found in the uppermost part of the tripolaceous marls. Upsection, these marls pass to clays with gypsum, beds of laminated microcrystalline gypsum and gypsiferous breccias. Above these evaporitic deposits, fine-laminated polychrome clays with intercalations of sandstones and conglomerates (bedding attitude N 183°, 17°) have been found resting unconformable below Pliocene grey clays and conglomerates (bedding attitude N 164°, 24°).In this preliminary phase, 12 samples have been collected across the Messinian/Pliocene boundary in the Faneromeni section. In the Kasteli-Ano Akria area, above gypsiferous breccias and laminated microcrystalline gypsum deposits, silty-clays with intercalations of sandstone and conglomerate horizons have been found. In this area, 2 samples from the post evaporitic fine-grained deposits have been collected. More recently, a 20 cm-spaced sampling has been performed in both the sections, for about 100 samples collected.Micropaleontological analyses have been performed on the preliminary sampling of the post evaporitic deposits from both Faneromeni and Kasteli-Ano Akria sections.The results of these analyses point to the presence of an ostracod assemblage containing: Cyprideis sp., Amnicythere spp., Amnicythere cf. A. palimpsesta (Livental), Amnicythere cf. A. propinqua (Livental), Camptocypria sp., and Pseudocythere sp. Reworked planktonic foraminifera and well-preserved charophyte gyrogonites have been also found.The ostracod assemblage found in the Messarà Plain belongs to the Loxoconcha djafarovi Zone (sensu Carbonnel, 1978), which characterizes the uppermost Messinian deposits of the whole Mediterranean Basin. At that time, the well-known Lago-Mare biofacies was widespread on the Crete Island also. The presence of Paratethyan ostracods in the post-evaporitic Messinian deposits of both Faneromeni and Kasteli-Ano Akria sections suggests that in the latest Messinian Crete Island was affected by sedimentation processes in brackish water palaeoenvironm