73 research outputs found
The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean)
During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna
Alien foraminifers from Greek coastal areas (Aegean Sea, Eastern Mediterranean)
The present study provides additional data on the distributional range of six alien foraminiferal species in living assemblages from Greek coastal areas (Aegean Sea, Eastern Mediterranean). Amphistegina lobiferaLARSEN 1976, Sorites orbiculus (FORSK L 1775) and Coscinospira hemprichii EHRENBERG 1839 are well established in Greek coastal areas, whereas Triloculina fichteliana D'ORBIGNY 1839, Planogypsina acervalis (BRADY 1884) and Cymbaloporetta plana (CUSHMAN 1924), are recorded for the first time in this paper. The occurrence of these species in a number of sites in the Aegean Sea establishes their presence in the Eastern Mediterranean
Comment on: 'A late Pleistocene clockwise rotation phase of Zakynthos (Greece) and implications for the evolution of the western Aegean Arc'
In a recent paper, Duermeijer et al. [1] report
new palaeomagnetic results from the island of Zakynthos
(Greece). In many cases, these authors
have re-sampled the original sites of Laj et al.
[2] and the results are virtually identical to those
of the earlier study except for much more precise
biostratigraphic age control. Three middle Pleistocene
sites (Bochali, Zakynthos town and Porto
Roma) which were not sampled by Laj et al.
document signi¢cant clockwise rotations. From
the results obtained from these three new sites,
the authors conclude that the 25° clockwise rotation
of Zakynthos described by Laj et al. as affecting
the entire western Hellenic margin more or
less progressively over the last 5 Myr is much
more recent (early Pleistocene)
A Late Pleistocene clockwise rotation phase of Zakynthos (Greece) and implications for the evolution of the western Aegean arc
Palaeomagnetic measurements have been carried out on Eocene to Pleistocene sediments on the Ionian island
of Zakynthos, NW Greece. Magnetostratigraphic constraints, biostratigraphic analyses of planktonic foraminifera and
calcareous nannofossils provide a reliable time frame for these deposits. The results show that no significant rotation
occurred between 8.11 and 0.77 Ma, but that Zakynthos underwent a 21.6º 7.4º clockwise rotation between 0.77 Ma
and Recent. Thus, our data indicate a rapid rotational event, in contrast to continuous rotation since 5 Ma as previously
postulated [Laj et al., Tectonophysics 86 (1982) 45 67]. We speculate this late Pleistocene tectonic rotation phase to be
linked to rapid uplift in the Greek region which results from rebound processes caused by (African) slab detachment
underneath the Ionian islands. Ó 1999 Elsevier Science B.V. All rights reserved
Calcareous nannofossil dating of Ionian and Gavrovo flysch deposits in the External Hellenides Carbonate Platform (Greece): Overview and implications
The available biostratigraphic data based on calcareous nannofossil analysis determine the mean ages for the onset of flysch sedimentation (base of transitional beds) of the Ionian unit at ~. 34-35. Ma (external/internal Ionian), and at ~. 41. Ma (middle Ionian). The top of the Ionian flysch at ~. 25. Ma constrains the emplacement of Gavrovo nappe, providing an average duration of at least 11-16. Myr for the flysch sedimentation. Gavrovo flysch deposition started at a mean age of ~. 34. Ma and lasted till ~. 29. Ma (emplacement of Pindos nappe), suggesting an average duration of approximately 5. Myr. Phenomena of synsedimentary tectonism have been reported at the external Ionian unit, indicating that pre-flysch extension of the basin lasted at least 4. Myr. The ~. 6-7. Myr difference of the onset of flysch sedimentation between the external/internal and middle parts of Ionian unit implies evidence for an axial symmetry of the basin before the underthrusting of Mani unit under Pindos nappe. © 2012 Elsevier B.V
Biostratigraphical observations in Pliocene deposits of Heraklion Province, Crete. Skythia section
Calcareous nannofossils, planktonic foraminifera and mollusc associations have been studied in order to define the biostratigraphical and chronostratigraphical position of a sequence of marly and diatomaceous Neogene sediments (Skythia section, Heraklion province, central Crete). The integrated analysis indicates a Pliocene (Lower Piacenzian) age.
Additional paleoecological observations certify the presence of a rather shallow warm-temperate depositional environment.Observations stratigraphiques sur les dépôts du Pliocène de la Province de Heraklion, Crête. La coupe de Skythia.
Nannofossiles calcaires, foraminifères planctoniques et associations de mollusques ont été étudiés pour définir la position stratigraphique et chronostratigraphique des sédiments néogènes de la section Skythia (Heraklion province, Crète centrale). L'intégration des résultats de l'analyse a indiqué que l'âge des sédiments est pliocène (Piacenzian inférieur). Les observations paléoécologiques additionelles certifient la présence d'environnements peu profonds et chaud-tempérés.Dermitzakis M.D., Triantaphyllou M.V. Biostratigraphical observations in Pliocene deposits of Heraklion Province, Crete. Skythia section. In: Géologie Méditerranéenne. Tome 24, numéro 1-2, 1997. pp. 15-26
Biostratigraphical observations in Pliocene deposits of Heraklion Province, Crete. Skythia section
Calcareous nannofossils, planktonic foraminifera and mollusc associations have been studied in order to define the biostratigraphical and chronostratigraphical position of a sequence of marly and diatomaceous Neogene sediments (Skythia section, Heraklion province, central Crete). The integrated analysis indicates a Pliocene (Lower Piacenzian) age. Additional paleoecological observations certify the presence of a rather shallow warm-temperate depositional environment
The Plio-Pleistocene boundary in the Gerakas section, Zakynthos (Ionian Islands) Biostratigraphical and paleoecological observations
The Gerakas section which is located on the SE side of the island of Zakynthos, consists of three depositional sequences which arc indicative of a coastal-shallow marine environment and are bounded by unconformities. Based on calcareous nannofossil biostratigraphic events, it is possible to recognize the Plio-Pleistocene boundary in Depositional Sequence I. The quantitative micropaleontological analysis of calcareous nannofossils indicates a coastal-shallow marine environment characterised by an increase in surface water temperature
Biostratigraphical and paleoenvironmental determination of a marine Plio/Pleistocene outcrop in Cefallinia Island (Greece)
Lofos section is located in the southern part of Paliki peninsula in southwest Cefallinia island. It consists of 15-20 m of homogenous bluish marls with macrofossils and coarse grained alternations, followed by almost 10 m of sandy marls. The data from the quantitative biostratigraphic analysis based on calcareous nannofossils of the studied material allow the correlation of the lower part of Lofos section with MNN19a biozone which chronostratigraphically points to an uppermost Pliocene. At about 16 m from the base of the section, it is possible to recognize the MNN19a/MNN19b biozones boundary which points to the Pliocene/Pleistocene boundary. The rest of the section can be assigned to Pleistocene. Finally, a paleoenvironmental reconstruction and determination of the paleoenvironmental parameters is attempted based on the quantitative, paleoecological analysis of the benthic foraminifera. The paleoecological data indicate that the lower part of the studied sequence have been deposited in waters with lowered oxygen levels. Stagnant conditions became less severe in the course of deposition
- …