Pre-Apulian Zone Research Articles

Reassessing Depositional Conditions of the Pre-Apulian Zone Based on Synsedimentary Deformation Structures during Upper Paleocene to Lower Miocene Carbonate Sedimentation, from Paxoi and Anti-Paxoi Islands, Northwestern End of Greece

The studied area is situated in northwestern Greece and corresponds to the northern end of the Pre-Apulian Zone, in contact with the Apulian platform to the west and the Ionian Basin to the east. The proposed model is based on fieldwork, measured deformation structures, and age determination of the studied deposits. Until now, the known Pre-Apulian platform or Pre-Apulian zone represents the margins of the Apulian platform to the Ionian Basin and was formed due to the normal faults’ activity during the Mesozoic to Cenozoic Eras. Soft sediment deformation (SSD) structures are widespread within the upper Paleocene to lower Miocene limestones/marly limestones that are exposed in both Paxoi and Anti-Paxoi Islands, mostly along their eastern coasts, across sections of 2–3 km long and up to 60 m high. SSD structures, with a vertical thickness up to 10 m, have been observed in limestones and were formed during or immediately after deposition, during the first stage of sediment consolidation. SSD structures are cross-cut by normal faults, indicating their development during the rift stage. There are at least five different SSD horizons, and most of them present either an eastward or a westward progradation. These SSD structures are classified into four (4) different types of deformations: (1) thick synclines and anticlines, formed due to strong synsedimentary deformation; (2) strong and thick SSD structures that produced erosional contacts both with the underlying and the overlying undeformed horizons; (3) thin slumps, having sharp contacts with the underlying undeformed horizons and erosional contacts with the overlying undeformed horizons; and (4) thin slump horizons passing laterally to undeformed deposits in the same horizon. The studied SSD structures and their age of development introduce active margins between the Apulian platform and the Ionian Basin that have been influenced by normal fault activity. These normal faults have been active since the Ionian Basin changed gradually to a foreland basin, and after the tectonic regime changed from extension to compression, during the early to middle Eocene. It seems that compression in the studied Apulian platform margins arrived later and after the lower Miocene, and after the development of the SSD structures. The confinement of the lower Miocene deposits, both northwards and southwards (in Anti-Paxoi Island), indicates the presence of active transfer faults, with flower structure geometry, that were formed during sedimentation, producing highs and troughs. The present open anticline geometry of Paxoi Island indicates that the Island represents the forebulge area of the middle Miocene Ionian Foreland due to Ionian Thrust activity.

Comparison between Siliceous Concretions from the Ionian Basin and the Apulian Platform Margins (Pre-Apulian Zone), Western Greece: Implication of Differential Diagenesis on Nodules Evolution

Siliceous concretions (nodules), from two different geological settings—the Apulian platform margins in Kefalonia island, and the Ionian Basin in Ithaca, Atokos, and Kastos islands—have been studied both in the field and in the laboratory. Nodule cuttings are mainly characterized by the development of a core, around which a ring (rim) has been formed. Mineralogical study, using X-ray powder diffraction (XRPD) analysis, showed that the rim is usually richer in moganite than the core. Homogeneous concretions, without discernible inner core and outer ring, were observed generally in both settings. Mineralogical analysis of the selected siliceous concretions from Kefalonia island showed the presence mostly of quartz and moganite, while calcite either was absent or participated in a few samples in minor/trace abundances. Moganite was generally abundant in all the samples from Kefalonia island. Concretions from the Ionian Basin showed a variation in the quartz, moganite, and calcite contents. Mineralogical differences were recognized both between the different studied geodynamic settings and internally in the same setting, but with different stages of development. The above-mentioned differential diagenesis on nodules evolution could be related to the presence and/or abundance of stylolites, later fluid flows, restrictions from one area to another due to synchronous fault activity, and the composition of substances dissolved in fluids. Moreover, the development of concretions produced secondary fractures in the surrounding area of the nodule-bearing rocks.

PALEOBATHYMETRIC EVOLUTION OF THE EARLY LATE MIOCENE DEPOSITS OF THE PRE-APULIAN ZONE, LEVKAS ISLAND, IONIAN SEA

The Manassi section in Levkas Island belongs to the Pre-Apulian (Paxos) zone, the most external domain of the Hellenic realm. Its Early Tortonian sediments contain a rich foraminiferal fauna dominated, in numbers of individuals, by planktic species. Its benthic foraminiferal assemblage is characterized by a high number of taxa, with low numbers of individuals. Their study provides a basis for interpreting the paleobathymetry of the basin.The Manassi section represents deposition in upper to lower bathyal depths, during a period of intense tectonic activity. Downslope transport of fauna by turbidity currents partly overprints the signal of paleobathymetrically-diagnostic foraminifera distribution. The recognition of allochthonous taxa is used, together with %P, to identify turbidite beds intercalated with in-situ marly sediments. The micropaleontological and paleobathymetrical analyses of the studied sediments indicate that these correspond to distal atypical flysch deposited in the foredeep depozone of the most external domain (Pre-Apulian zone) of the Hellenide foreland basin.

A CARBONATE RAMP EVOLUTION IN THE TRANSITION FROM THE APULIA PLATFORM TO THE IONIAN BASIN DURING EARLY TO LATE CRETACEOUS (NW GREECE)

Facies analysis of Cretaceous carbonate sequences from the external and central Ionian zone revealed a homoclinal ramp model of evolution. During Berriasian to Valanginian, the carbonate ramp was differentiated to an inner-mid and outer ramp environment, which corresponded to the external and central Ionian zone, respectively, while the main inner ramp environment is assumed that was located in the Pre-Apulian zone. The external Ionian zone (inner-mid ramp) is characterized by muds tones-wackes tones with fragmented echinoderms, bivalves, radiolarians and rare aptychus considered to be deposited below the fairweather wave base (FWWB). Locally, thin graded storm deposits intervene, indicating deposition above the storm weather wave base (SWB). Minor occurrences of packs tonesgrainstones, with fragmented echinoderms, calcareous algae, tubiphytes, lagenid foraminifera and rare ooids occur, as well, considered to be deposited at the lowermost part of the inner ramp, near the constantly agitated fairweather wave base (FWWB). The central Ionian zone (outer ramp) is mainly characterized by mudstones-wackestones with abundant radiolarians and rare calpionellids and calcispheres, considered to be deposited below the storm wave base (SWB). No talus or breccias deposits were observed, during the mentioned time interval, in any part of the studied area. From Hauterivian to Turonian, continual sea-level rise, led to establishment of outer ramp environment in the external Ionian zone, over the previous inner-mid ramp, and outer ramp-basin environment, over the previous outer ramp, in the central Ionian zone. The transition from shallower to deeper conditions is characterized by an overall deposition of mudstones-wackestones with abundant radiolarians rooted in pure micrite.

PRELIMINARY STUDY ON THE SLUMP STRUCTURES OF THE EARLY OLIGOCENE SEDIMENTS OF THE PRE-APULIAN ZONE (ANTIPAXOS ISLAND, NORTH-WESTERN GREECE)

A spectacular slump is observed in the Alpine sediments of the Antipaxos Island (Pre-Apulian zone, Western Greece). It can be followed in a zone of about 2000 m, in the eastern coast of the island. The slumped unit exposure length extends for more than 200 m, and is directly overlain and underlain by undeformed strata. The slump has an average thickness of 15 m and is composed, as the surrounding undeformed units, of calcareous mudstones and fine-grained calcareous sandstones. Synsedimentary folds that very often are transformed to contorted beds affect slump sediments. Fold and contorted bed axes present a NNW-SSE direction, coinciding with the general direction of the Pre-Apulian zone. Slump and overlain/underlain undeformed sediments originate from the flux of clastic mainly pelagic/neritic biogenic particles, emanating from turbidity currents. More than 50 samples have been collected and analyzed for calcareous nannofossil content. All samples were featured by the contemporaneous presence of abundant nannofossil flora implying the biostratigraphic correlation with the NP23 nannofossil biozone. The biostratigraphic assignment places the slump and the surrounding sediments to the Early Oligocene. As the Pre-Apulian zone corresponds to the slope between the Apulian Platform and the Ionian Basin, the presence of the slump is directly related to the same age sloping and tectonic mobility of this domain. The Antipaxos turbidites sediments are well integrated to the flysch deposition of the external Hellenide foreland basin system.

Climatic vs tectonic control on the Early Late Miocene tectono-stratigraphic deposits of the Pre-Apulian Zone, Western Greece.

Here, we elucidate the relationship between tectonics and climate and their influence on sedimentation. A number of marine sediment samples were collected from a section located in the northern margin of the Agios Petros Basin (Early Tortonian, Levkas Island, W. Greece) for micropalaeontological analysis, in order to establish and interpret of the palaeoenvironmental and palaeobathymetric changes. The distribution patterns of the dominant and associated benthic foraminiferal species (Siphonina reticulata and Cibicidoides kullenbergi), together with the decreased Benthic Foraminiferal Number (BFN) values, elevated diversities and higher planktonic- to-benthic ratios, suggest deposition at bathyal water depths with moderate organic matter fluxes and elevated oxygen contents of the bottom water, typical for this water depth interval. The early Late Miocene infilling of the Agios Petros basin is related to the westward advances of the Ionian zone which induced flexural loading and subsequent relative sea-level rise.

Remarks on the Messinian evaporites of Zakynthos Island (Io- nian Sea, Eastern Mediterranean).

Detailed mapping of the Neogene deposits on Zakynthos Island shows that the Messinian primary evaporite basins, formed over Ionian basement, are delimited by the westernmost outcrop of the Triassic evaporitic diapirs, located west of the Kalamaki-Argasi Messinian gypsum unit. The post-Miocene external Ionian thrust is emplaced west of the Triassic diapirs. Planktonic foraminifera biostratigraphy indicates that primary evaporite accumulation took place probably during the first stage of the Messinian salinity crisis (5.96-5.60 Ma), in shallower parts of a foreland basin, formed over the Pre-Apulian and the Ionian zone basement. Establishment of these depositional environments, before the Ionian thrust emplacement, was probably due to the particularities of the foreland basin, which extended from the external Ionian to the internal Pre-Apulian zone. Field observations, borehole data and an onshore seismic profile show that the Neogene sediments over the Pre-Apulian basement correspond to the foredeep through forebulge domain of the foreland basin, as it is documented from their spatial thickness distribution. In contrast, the Neogene sediments over the Ionian basement correspond to the wedge top of the foreland basin, which was less subsiding, as it is deduced by their reduced thickness. This lower subsidence rate was the result of the concurrent diapiric movements of the Ionian Triassic evaporites. In Agios Sostis area, located over Pre-Apulian basement, the Neogene sequence is intercalated by decametre-thick resedimented blocks consisting of shallow water selenite. To the southeast, this mass-wasting Messinian gypsum passes to mainly gypsum turbidite. In Kalamaki-Argasi area, located over Ionian basement, the shallow water environment led to the deposition of the observed primary gypsum. Erosion of the primary gypsum of both forebulge and wedge top supplied the foreland basin’s depocenter with gypsum turbidites.

Microfacies analysis of deep-water breccia clasts: a tool for interpreting shallow- vs. deep-ramp Paleogene sedimentation in Cephalonia and Zakynthos (Ionian Islands, Greece)

The tectono-sedimentary evolution of the western Pre-Apulian zone of the Hellenides is investigated through comparison of the microfacies of clasts from breccia beds within gravity-flow successions of Zakynthos with those of the carbonate ramp of the westernmost part of Cephalonia. After the demise of a Late Cretaceous rimmed platform, the Paleogene successions of the Ionian Islands represent different facies patterns of a carbonate ramp. In western Cephalonia (Lixouri peninsula), different successions suggest the existence of five juxtaposed tectono-sedimentary sectors, remnants of a larger carbonate ramp. In Zakynthos, six distinct sectors with different toe of slope-proximal basin stratigraphic successions were recognized, all affected by a Paleocene-Lower Eocene hiatus, which can be grouped into two tectono-sedimentary units. Through the analysis of successions of the Lixouri peninsula and breccia clasts from Zakynthos, 24 age-constrained and spatially related Upper Cretaceous–Oligocene microfacies types were recognized, illustrating a variety of sedimentary environments. These microfacies were allocated to five different stages in the evolution of a tectono-sedimentary model from down-faulting, through backstepping, uplift and dismantling, to fault-controlled subsidence and finally complete drowning. Various microfacies of the clasts can be correlated to the stratigraphic record of the Lixouri peninsula, whereas others are absent there. Thus an inferred adjacent source terrain, now tectonically obliterated, was likely located west of the present-day Ionian Islands.

Western Greece and Ionian Sea petroleum systems

In western Greece, the Ionian and pre-Apulian zones represent, respectively, the basin and the transitional zone (slope) to the Apulian platform. The Apulian platform constitutes the weakly deformed foreland of the external Hellenides. The pre-Apulian zone appears in the Ionian Islands and the eastern Ionian Sea, whereas the Apulian platform is exclusively found in the Ionian Sea. The Ionian zone consists of Triassic evaporites, Jurassic– upper Eocene (mostly pelagic carbonates, minor cherts, and shales), overlainbytheOligoceneflysch.Organic-richsourcerocks occur within Triassic evaporites and Jurassic–Cretaceous pelagic argillaceous-siliceous rocks. The pre-Apulian zone consists of Triassic to Miocene deposits, mainly mixed neritic-pelagic carbonates. Hydrocarbon source rocks include pelagic and hemipelagic deposits rich in marine organic material, although terrigenous organic matter is also found in siliciclastic layers. Apulian platformsourcerocksaremainlytheorganic-richshaleswithinthe Triassic Burano evaporites. Western Greece contains major petroleum systems, which extend into the Ionian Sea. Ionian, pre-Apulian, and Apulian petroleum systems contribute to the probable hydrocarbon accumulations within the big offshore (Ionian Sea) anticlines. Western Greece contains important oil and gas shale reservoirs with a potential of unconventional exploration. Promising areas for hydrocarbons need systematic and detailed threedimensional seismic data. Exploration for conventional petroleum reservoirs, through the interpretation of seismic profiles and the abundant surface geologic data, will provide the subsurface geometric characteristics of the unconventional reservoirs. Their exploitation should follow that of conventional hydrocarbons to benefit from the anticipated technological advances, eliminating environmental repercussions.

Palaeoceanography of the Miocene (Tortonian) deposits of the Pre-Apulian zone, western Greece, as recorded by foraminifer and stable isotope records

An integrated faunal and geochemical dataset has been generated by the study of a late Miocene (early Tortonian) sedimentary section outcropping at Manassi, Levkas Island (eastern Mediterranean). Quantitative analysis of benthic foraminifers from the 25-m-thick section indicates changes of bottom palaeoecological conditions in this part of the eastern Mediterranean, during the analyzed time interval. Benthic foraminifer assemblages are typical of a bathyal environment and testify to relatively oxygenated conditions with low to moderate food supply alternating with periods with an increase in organic matter content. The long-term palaeoceanographic analyses indicate an anti-estuarine circulation model based on the benthic foraminifer and stable isotope results, which evolved in a strong estuarine circulation. The positive relationship existing between the plankton δ18O and δ13C, in most of the record, agrees well with the hypothesis of a variable contribution of runoff. In three stratigraphic levels, samples record heavy bottom water δ18O and δ13C values and light surface δ18O values, representing a wet, warm, estuarine climate with a stratified water column. In two stratigraphic levels, samples have depleted δ13C and δ18O values for both surface and bottom waters. These two samples represent wet, warm climates with some ocean mixing and stratification. The stable isotope signal of foraminifer tests from the Manassi section was influenced by the global temperature changes, but the local factors also played an important role. The palaeoenvironments derived from stable isotope analysis in this study are interpreted as responses to the local tectonic instability together with monsoon intensities that enhanced continental runoff, characteristic for the time interval studied in the study area. Due to the limited data available from this study, no correlations with the precessional, obliquity, or eccentricity cycles can be made.

Origin and migration mechanism of the main hydrocarbon seeps in western Greece

In this presentation a description of the main hydrocarbon indications of Western Greece is given, in relation to their origin and migration mechanism. Five groups of oil have been defined (Palacas et al.1986, Ν. Rigakis 1999) and their appearance on surface or in wells is explained. Doger shales are the source rocks of the first group of oil seeps in the central Ionian zone in Epirus (Botsara). Migration takes place through inverse or thrust faults. The second group is located at Trifos of Etoloakarnania, and Kyllini and West Katakolon well of NW Peloponissos. It is originated from Lower Cretaceous source rocks and migration happens through active diapiric movements of the Triassic evaporites. Triassic evaporites play important role in the maturation and migration and possible entrapment of this group of oil. The third group has genetic and migration relation with Triassic evaporites and their movements and is found at Delvinaki of Epirus and in the Well South Katakolon, offshore West Peloponissos. The fourth group that appears at Keri and Alikes of Zakynthos Island, it is possible to be originated from Middle- Upper Miocene post-tectonic sediments. The unconformity between Alpine and Post-Alpine sediments and some normal faults, is the possible pathway of migration mechanism. In the same team another oil show at Marathopolis, near Filiatra, is included with some doubts about its real origin. The fifth group is found at Paxos Island in the Preapulian zone. The oil is generated mainly from Middle-Upper Jurassic sediments, while older sediments of Lower Jurassic and Triassic are not excluded as possible source of the oil seeps. It is important to note that the contribution of the ground water movements is important in migration mechanism in some of the described cases. Finally, we strongly believe that the geological sections that are included in the text explain better our results and thoughts.

ABSTRACT: Sedimentology and Petroleum Potential of Cretaceous Limestones in the Preapulian Zone, Ionian Islands, Western Greece

ABSTRACT: Sedimentology and Petroleum Potential of Cretaceous Limestones in the Preapulian Zone, Ionian Islands, Western Greece

Late Cenozoic deformation of the Hellenide foreland, western Greece

Research Article| May 01, 1989 Late Cenozoic deformation of the Hellenide foreland, western Greece JOHN R. UNDERHILL JOHN R. UNDERHILL 1Department of Geology and Geophysics, Grant Institute, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JY, Scotland, United Kingdom Search for other works by this author on: GSW Google Scholar GSA Bulletin (1989) 101 (5): 613–634. https://doi.org/10.1130/0016-7606(1989)101<0613:LCDOTH>2.3.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation JOHN R. UNDERHILL; Late Cenozoic deformation of the Hellenide foreland, western Greece. GSA Bulletin 1989;; 101 (5): 613–634. doi: https://doi.org/10.1130/0016-7606(1989)101<0613:LCDOTH>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The late Cenozoic structural evolution of western Greece involved the shortening of Mesozoic passive continental-margin and Cenozoic foreland basin sequences in a foreland-propagating, fold-and-thrust system and superimposed neotectonic deformation related to the development of an active island arc. Although the Pre-Apulian zone has been regarded as the undeformed, western foreland to the thrust belt, three-dimensional exposures in the Ionian islands of Kephalonia and Zakinthos afford evidence of significant late Neogene and Quaternary shortening, including thrusting on reactivated normal faults. Time relations and fault kinematics show that these structures are compatible with the westward migration of the locus of Hellenide thrusting beyond its previously recognized limit and outer-arc compression related to active subduction. The presence of the Pre-Apulian zone in the west contrasts with other Aegean foreland areas, where no such intermediate block lay between the thrust pile and old (?Mesozoic) oceanic crust. Consequently, the Pre-Apulian block took up continued Hellenide shortening in the late Miocene while oceanic crust was being overridden (subducted) in southern parts of the arc to the east. The Pre-Apulian zone subsequently overrode the ocean-floored Ionian Sea during the late Neogene. The confusion in determining driving mechanisms for late Cenozoic deformation in western Greece and the apparent conflict between evidence for the age of initial subduction in different parts of the arc are explained by this model, which is consistent with regional considerations, including structuration in adjacent areas and important paleomagnetic rotations in the arc. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Structural controls on basin evolution: Neogene to Quaternary of the Ionian zone, Western Greece

Turbidite deposition of Oligocene to Early Miocene age occurred in the foreland basin to the Pindus mountains which formed the NNW-trending Hellenide thrust front. Deposition was interrupted by the migration of the deformation front westwards through the foreland basin itself. The Kalamitsi Thrust, exposed in West Levkas, became active in late Early Miocene times. A Miocene to Pliocene piggy-back basin developed, fed both from the thrust front to the west and the mountain belt to the east. During the mid–Late Miocene, deformation remained confined to the Ionian and Gavrovo zones, possibly related to the presence of lubricating evaporites which terminate in the Pre-Apulian zone to the west. During the Late Plio-Quaternary, inner arc extension (trenchward of the Hellenic arc) caused a system of ENE and WNW basins to open under the N-S tensional regime. These were linked by NNW and NE transtensional faults and the system is still active in the Lake Trikhonis and Gulf of Corinth areas today. In the west of the study area, however, post-Pliocene NW-SE compressional faults dissected the piggy-back basin. This compressional phase must have been either contemporaneous with or interrupted the extension active in the east from Late Pliocene times.

Etude geologique et stratigraphique des ilots de Dodecanese, Ro et Stronghili. Correlation a l'ile de Castellorizo

The geological—stratigraphic study of the two islets Ro and Stronghili indicates that they belong to the same stratigraphic unit as the adjacent island of Castellorizo and form part of the upward evolution of carbonaceous sediments. The limestone unit on these islands ranges stratigraphically from Maastrichtian up to Middle Miocene. Concerning the geotectonic position of the sediments of the Castellorizo complex in relation to Hellenides and Taurides, they are relative to the autochthonous series of Bey Daglari in Asia Minor, appearing also as features of the limestones of the Preapulian (Paxi) zone, developed in western Greece.

Tectonics and sedimentation in the Gulf of Corinth and the Zakynthos and Kefallinia channels, Western Greece

Single-channel seismic reflection profiling data are presented from the Gulf of Corinth and from the continental margin outside the Gulf of Patras. Different tectonic styles are exhibited in the two regions. The Gulf of Corinth is occupied by a complex asymmetrical graben structure with major faults trending nearly perpendicular to the local tectonic zones of the Internal Hellenides. The Gulf is interpreted to have formed during the Quaternary in response to approximately north-south extensional stress. The deep floor of the Gulf is underlain by a sequence of turbidites up to 1 km thick affected by normal growth faulting that extends up to the sea floor. The sea areas inside the Ionian Islands of Zakynthos and Kefallinia (Zakynthos and Kefallinia Channels) occupy a broad structural depression that trends parallel to the local tectonic zones of the External Hellenides and is situated on the continental side of the Strophades continental margin rise. The Channels contain local NW-SE trending structural basins (Zakynthos and Kefallinia basins) whose geometry is controlled by reverse faults or thrusts with associated diapirism in Triassic evaporites. Hydra Bank is interpreted as a tilted fault block with a diapiric core and its faulted western margin can be traced into the zone of thrusting and diapirism in southeast Kefallinia at the boundary between the Ionian and pre-Apulian (Paxos) zones of the External Hellinides. The Zakynthos and Kefallinia structural basins are filled with a variety of sediments including prodeltaic deposits (in front of the modern delta complex of the Acheloos river), slumped masses and debris flow deposits and, in the Zakynthos basin, occasional turbidites. The boundary separating zones of extensional and compressional focal mechanisms for shallow earthquakes crosses the Gulf of Patras, the inner part of which exhibits WNW-ESE trending graben tectonics apparently related to the Gulf of Corinth tectonic province. Onshore neotectonic studies around the Gulf of Patras are required in order to understand the nature and cause of the westward tectonic transition from WNW-ESE graben structures in the Gulfs of Corinth and Patras to NW-SE oriented zones of subsidence with associated compressional tectonics and diapirism in the Zakynthos and Kefallinia Channels.

Ionian sea (Western Greece): Its structural outline deduced from drilling and geophysical data

This paper outlines the preliminary structural results obtained by the compilation of geological, drilling and geophysical data in western Greece. Most external geotectonic zones of the Hellenides are included in the geological setting of the marine and insular domain of western Greece: Ionian, pre-Apulian and Apulian zones. The Gavrovo and Pindus zones make a restricted contribution to the marine geological framework (continental shelf of southwest Peloponesus). Besides the geographical setting of the geotectonic units, their general tectonic characteristics allow the following remarks to be made: The main tectonic events younger than Eocene are well-marked in both Ionian and pre-Apulian zones. The detrital sequence shows a fast pinch-out towards the Apulian platform where the Plio-Quaternary clastic layers overlap what are probably late Mesozoïc or early Tertiary limestones. Taking into consideration general tectonic features, we can distinguish a northern area and a southern one, separated by a fault trending 30°N, located on the western margin of Kephallinia, Lefkas Islands: 1. (a) in the northern area we observe a strong tangential tectonism decreasing towards the Apulian platform with transitional characteristics on the pre-Apulian zone (Paxos) where asymmetrical folding occurs; 2. (b) in the southern area (from Lefkas-Kephallinia islands to the S.W. Cape of Peloponesus) the tangential tectomism is well-masked by strong vertical faulting attributed to young Plio-Quaternary deformations. The fast subsidence induces huge diapiric structures in the Ionian zone (salt walls originating from Triassic layers intersect a thick Pleistocene sequence).

Zone preapulienne, zone ionienne et zone du Gavrovo en Peloponnese occidental

Abstract The stratigraphy of faulted calcareous massifs in the western Peloponnesus, east of the front of the Pinde nappe, is examined. The Klokova, Skolis, Lapithos, and Pylos massifs, directly bordering the front of the nappe belong to the Gavrovo zone. Surrounded by discordant Pliocene, they are post-paroxysmal, late Miocene and Pliocene. The Cape Pappas massif displays an upper Cretaceous to Eocene series with facies corresponding to the Ionian zone, further north. The island of Zante belongs to the Preapulian zone. The Ionian trough is observed to be narrower in Peloponnesus than in northern Greece, suggesting an axial termination to the south.

Un profil tectonique d'ensemble de la Grece septentrionale moyenne

Abstract All the Hellenic zones are represented in an east-west structure section across north central Greece (Epirus and Thessaly provinces), except the Vardar and Rhodope zones. The westernmost zones are autochthonous (pre-Apulian, Ionian, and Gavrovo zones). The para-autochthonous complex consists of two nappes, which were thrust westward but which maintained original relationships relative to the autochthonous complex and to each other.