KOSMAS-GYTHIO UNIT: A METAMORPHIC CARBONATE SEQUENCE OVERLYING THE PHYLLITES-QUARTZITES UNIT IN SOUTHERN PELOPONNESUS, GREECE.

New data from southern Peloponnesus show the presence of a metamorphic carbonate sequence sandwiched between the Phyllites Quartzites and the Tyros beds, the permothassic base of the Tripolitza unit. The lithostratigraphic members of this sequence, named Kosmas Gythio unit, are comparable to that of the Plattenkalk unit in Taygetos and Parnon mountains. It is suggested that palaeogeographically the unit belongs to the Ionian basin and its position was between the Plattenkalk unit and the Tripolitza carbonate platform. As for the Phyllites-Quartzites unit it is suggested that this unit is not a metamorphic equivalent to the Tyros Beds or the basement of the Tripolitza platform, but the base or the basement of the Kosmas-Gythio unit, and therefore of the Ionian basin

IMPLICATIONS FOR THE CORRELATION OF THE HELLENIC NAPPES IN SW AEGEAN: THE GEOLOGICAL STRUCTURE OF THE ARCHANGELOS REGION, RHODES ISLAND

Στην περιοχή του Αρχαγγέλου στην κεντροανατολική Ρόδο, η καλυμματική στήλη περιλαμβάνει από κάτω προς τα πάνω τις παρακάτω γεωτεκτονικές ενότητες: i) Την ενότητα Ααέρμα, ένας ολιγοκαινικός άγριος φλύσχης, ii) την ενότητα Αρχαγγέλου, μία ασταθή νηρητική ακολουθία ηλικίας Ανωτέρου Τριαδικού - Μέσου Ηωκαίνου που μεταβαίνει μέσω ερυθρών πηλιτών σε μία κλαστική σειρά τύπου φλύσχη, η οποία συγκρίνεται με την ενότητα Εθιάς στη Κρήτη ή την ενότητα Καληλίμνη στην Κάρπαθο, ni) την ενότητα Προφήτη Ηλία, μία πελαγική σειρά από πλακώδεις ασβεστόλιθους και ραδιολαρίτες ηλικίας Ανωτέρου Τριαδικού - Ανωτέρου Κρητιδικού, συγκρίσιμη με αυτή της ενότητας Πίνδου στην Ηπειρωτική Ελλάδα και iv) τους οφιόλιθους. Η τοποθέτηση των καλυμμάτων στην σχετικά αυτόχθονη ενότητα Ααέρμα έλαβε χώρα σε επιφανειακές συνθήκες στο Μέσο - Ανώτερο Ολιγόκαινο και οφείλεται σε βαρυτικές ολισθήσειςIn the region of Archangelos in central-eastern Rhodes, a nappe sequence from bottom to top consists of i) Laerma unit, an Oligocene age wildflysch, ii) Archangelos unit, a neritic limestone of Upper Triassic - Mid Eocene age grading through red pelites to a flysch sequence, probably combarable to Ethia unit of Crete, iv) the Profus Ilias unit, a pelagic sequence ofplaty limestones and radiolarites of Upper Triassic - Upper Cretaceous age, similar to Pindos Unit and v) the ophiolites. The emplacement of the nappes on the relative autochthonous Laerma unit was carried out in surface conditions and is due to gravitational sliding estimated during Lower Oligocene to Middle - Upper Oligocene

SEDIMENTOLOGY AND BIOSTRATIGRAPHY OF AN UPPER TRIASSIC CARBONATE SUCCESSION OF TRIPOLITZA PLATFORM IN MARI AREA, PARNON MOUNTAIN, SE PELOPONNESUS, GREECE

Η Ανω-Τριαδική ανθρακική ακολουθία στη βάση της πλατφόρμας της Τρίπολης, στην περιοχή Μαρί στο όρος Πάρνωνα, Πελοπόννησος, αποτελείται κυρίως από δολομίτες και σε μικρό ποσοστό ασβεστιτικούς δολομίτες. Λεπτομερής ανάλυση φάσεων και βιοστρωματογραφική μελέτη ανέδειξαν ότι κατά τη διάρκεια του Νόριου-Ραίτιου αποτίθεντο μεσο-υπερπαλιρροιακές και υποπαλιρροιακές (ρηχές λιμνοθαλάσσιες) φάσεις με κυκλική ανάπτυξη στο εσωτερικό της πλατφόρμας, παρόμοιες με αυτές που σχηματίζονταν σε πολλές Αλπικές πλατφόρμες του νότιου περιθωρίου της Τηθύος κατά το ίδιο διάστημα. Διαγενετικές παρατηρήσεις υποδεικνύουν περαιτέρω ότι η ρηχή θαλάσσια ανθρακική ιζηματογένεση διακοπτόταν από διαστήματα υποαέριας έκθεσης και επακόλουθης πρώιμης λιθοποίησης των πρόσφατα αποτεθέντων ιζημάτων. Η εκτεταμένη και πρώιμη κυρίως δολομιτίωση και ανακρυστάλλωση, η παρουσία μετεωρικών συγκολλητικών υλικών κατεισδύοντος ύδατος αλλά ιδιαίτερα η επαναλαμβανόμενη εμφάνιση δολοκρητών οριζόντων στα ανώτερα τμήματα πολλών περιπαλιρροιακών κύκλων υποδεικνύουν σαφώς περιοδική υποαέρια έκθεση των ιζημάτων καθώς και την επικράτηση ημίξηρων κλιματικών συνθηκών στην περιοχή.The Upper Triassic succession in the base of Tripolitza carbonate platform, in the Mari area of the Parnon Mt. in SE Peloponnesus, mostly consists of dolomites and to a lesser extent ofcalcitic dolomites. A detailed fades analysis and biostratigraphical study revealed that during Norian — Rhaetian times inter-supratidal and subtidal (shallow lagoonal) fades presenting cyclic development were deposited in the inner platform, similar to those that were formed in most of the Alpine platforms of the southern margin of the Tethys during the same time period. Diagenetic considerations further indicate that this shallow marine carbonate sedimentation was interrupted by subaerial exposure intervals and subsequent early lithification of the recently deposited sediments. The extensive and, mainly, early dolomitization and recrystallization, the presence of meteoric-vadose cements and specifically the repeated appearance of dolocrete horizons in the upper parts of many peritidal cycles, clearly show periodic subaerial exposure of the sediments, as well as the prevalence of semi-arid conditions in the area

TECTONO-SEDIMENTARY EVOLUTION AND RATES OF TECTONIC UPLIFT OF THE SFAKIA COASTAL ZONE, SOUTHWESTERN CRETE

Η περιοχή των Σφακιών είναι μία στενή παράκτια ζώνη στο νοτιοδυτικό τμήμα των Λευκών Ορέων, στο οποίο διασώζεται τμήμα του Νότιου Κρητικού περιθωρίου. Πρόκειται για μία μακρόχρονη νεοτεκτονική δομή που άρχισε τη δράση της στο Ανώτερο Μειόκαινο και συνεχίζεται μέχρι σήμερα. Χαρακτηρίζεται από μία απότομη μορφολογική ασυνέχεια διεύθυνσης Α-Δ, που σχηματίστηκε από ρήγματα διεύθυνσης Α-Δ και ΑΝΑ-ΔΒΔ προκαλώντας εφελκυσμό Β-Ν. Από το Ανώτερο Μειόκαινο μέχρι το Κατώτερο Π?.ειστόκαινο αποτέθηκαν θαλάσσια, ενώ ακολούθως η ιζηματογένεση συνεχίστηκε με την απόθεση μεγά).ου πάχους αλλουβιακών ριπιδιών, διαδικασία που συνεχίζεται μέχρι σήμερα. Η καλύτερη στοιχειοθέτηση της ηλικίας των θαλάσσιων ιζημάτων σε συνδυασμό με πρόσφατα δημοσιεύματα σχετικά με το βάθος απόθεσης τους και με τη χαρτογράφηση των ρηγμάτων της περιοχής, έδωσε τη δυνατότητα να προβούμε σε σημαντικές διαπιστώσεις σχετικά με τους μακροχρόνιους ρυθμούς ανύψωσης των ρηξιτεμαχών της περιοχής, όπως και για το χρονικό διάστημα που τα ρήγματα που ορί- ζουν αυτά τα ρηξιτεμάχη ήταν ενεργά. Από το Μέσο Πλειόκαινο όλη η περιοχή υπόκειται σε ανύψωση με τις εσωτερικές περιοχές να έχουν ρυθμούς έως και διπλάσιους από εκείνους της παράκτιας ζώνης. Η γενική ανύψωση φαίνεται να ελέγχεται από ρήγματα υποθαλάσσια νότια της περιοχής μελέτης.Sfakia lies within a narrow coastal zone at the southwestern foothills of the Lefka Ori Mt. Here a segment of the South Cretan margin is preserved onshore, a structure that represents a neotectonic structure with continuous activity since the Upper Miocene. This segment is characterized by a steep, E-W striking and south facing morphological escarpment that constitutes numerous E-W and ESE-WNW striking normal faults. Since the Late Miocene, marine sequences of Tortonian, Early Pliocene and Lower Pleistocene age were deposited along the coastal zone. Since the Middle Pleistocene multiple, coalescent alluvial fans covered both the alpine basement and the marine sediments. Fault-kinematic- and stratigraphie data combined with recently published palaeobathymetry reconstructions allow us to make relable estimates of both the uplift rates of fault blocks in the study area and the period that the faults that demarcate them were active. The results show that the study area is experiencing uplift already since the Middle Pliocene and that the uplift rates of the mountainous parts are higher than those of the coastal zone. The general uplift of the coastal zone seems to be controlled by offshore normal faults, south of Sfaki

Building up or out? Disparate sequence architectures along an active rift margin—Corinth rift, Greece

Early Pleistocene synrift deltas developed along the southern Corinth rift margin were deposited in a single, dominantly lacustrine depocenter and were subject to the same climate-related base-level and sediment supply cyclicity. Two synrift deltas, just 50 km apart, show markedly different sequence geometry and evolution related to their location along the evolving border fault. In the west, strongly aggradational fan deltas (>600 m thick; 2–4 km radius) deposited in the immediate hanging wall of the active border fault comprise stacked 30–100-m-thick stratal units bounded by flooding surfaces. Each unit evolves from aggradational to progradational with no evidence for abrupt subaerial exposure or fluvial incision. In contrast, in the central rift, the border fault propagated upward into an already deep lacustrine environment, locating rift-margin deltas 15 km into the footwall. The deltas here have a radius of >9 km and comprise northward downstepping and offlapping units, 50–200 m thick, that unconformably overlie older synrift sediments and are themselves incised. The key factors driving the marked variation in sequence stratigraphic architecture are: (1) differential uplift and subsidence related to position with respect to the border fault system, and (2) inherited topography that influenced shoreline position and offshore bathymetry. Our work illustrates that stratal units and their bounding surfaces may have only local (<10 km) extent, highlighting the uncertainty involved in assigning chronostratigraphic significance to systems tracts and in calculating base-level changes from stratigraphy where marked spatial variations in uplift and subsidence occur

Rapid spatiotemporal variations in rift structure during development of the Corinth Rift, central Greece

The Corinth Rift, central Greece, enables analysis of early rift development as it is young (<5Ma) and highly active and its full history is recorded at high resolution by sedimentary systems. A complete compilation of marine geophysical data, complemented by onshore data, is used to develop a high-resolution chronostratigraphy and detailed fault history for the offshore Corinth Rift, integrating interpretations and reconciling previous discrepancies. Rift migration and localization of deformation have been significant within the rift since inception. Over the last circa 2Myr the rift transitioned from a spatially complex rift to a uniform asymmetric rift, but this transition did not occur synchronously along strike. Isochore maps at circa 100kyr intervals illustrate a change in fault polarity within the short interval circa 620-340ka, characterized by progressive transfer of activity from major south dipping faults to north dipping faults and southward migration of discrete depocenters at ~30m/kyr. Since circa 340ka there has been localization and linkage of the dominant north dipping border fault system along the southern rift margin, demonstrated by lateral growth of discrete depocenters at ~40m/kyr. A single central depocenter formed by circa 130ka, indicating full fault linkage. These results indicate that rift localization is progressive (not instantaneous) and can be synchronous once a rift border fault system is established. This study illustrates that development processes within young rifts occur at 100kyr timescales, including rapid changes in rift symmetry and growth and linkage of major rift faults

Structure and evolution of the western Corinth rift, through new field data from the northern Peloponnesus

Extensional structures with geometrical and kinematic features analogous to the known Gulf of Corinth faults, are found further to the south of what is considered to be the southern margin of the of Proto-Corinth Gulf, reaching south to the northern flanks of Mt Mainalon. This mountain front is marked by the North Mainalon Fault Zone, which comprises a series of normal fault segments with NNE dips. Assuming a listric or ramp-flat geometry for the North Mainalon Fault Zone, it could flatten at a depth of 6-8 km, underneath Mt Khelmos. Its southern, shallow part has been truncated by NNE- and NNW-trending faults, which may be linked to northward propagation of the east-west extension in the Southern Peloponnesus, causing further uplift in the central and northern Peloponnesus, while its deeper part is still active and may reach further north and sole onto the hypothesized detachment zone beneath the Gulf of Corinth. © 2009 Geological Society of London