scholarly journals The ophiolite-related Mersin Melange, southern Turkey: its role in the tectonic–sedimentary setting of Tethys in the Eastern Mediterranean region

2004 ◽  
Vol 141 (3) ◽  
pp. 257-286 ◽  
Author(s):  
OSMAN PARLAK ◽  
ALASTAIR ROBERTSON
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Carbonate Platform ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Leading Edge ◽  
Vertical Axis ◽  
Upper Jurassic ◽  
Passive Margin ◽  
Southern Turkey

The Mersin Melange underlies the intact Mersin Ophiolite and its metamorphic sole to the south of the Mesozoic Tauride Carbonate Platform in southern Turkey. The Melange varies from chaotic melange to broken formation, in which some stratigraphic continuity can be recognized. Based on study of the broken formation, four lithological associations are recognized: (1) shallow-water platform association, dominated by Upper Palaeozoic–Lower Cretaceous neritic carbonates; (2) rift-related volcanogenic–terrigenous–pelagic association, mainly Upper Triassic andesitic–acidic volcanogenic rocks, siliciclastic gravity flows, basinal carbonates and radiolarites; (3) within-plate-type basalt–radiolarite–pelagic limestone association, interpreted as Upper Jurassic–Lower Cretaceous seamounts with associated radiolarian sediments and Upper Cretaceous pelagic carbonates; (4) ophiolite-derived association, including fragments of the Upper Cretaceous Mersin Ophiolite and its metamorphic sole. Locally, the ophiolitic melange includes granite that yielded a K/Ar radiometric age of 375.7±10.5 Ma (Late Devonian). This granite appears to be subduction influenced based on ‘immobile’ element composition.The Mersin Melange documents the following history: (1) Triassic rifting of the Tauride continent; (2) Jurassic–Cretaceous passive margin subsidence; (3) oceanic seamount genesis; (4) Cretaceous supra-subduction zone ophiolite genesis; (5) Late Cretaceous intra-oceanic convergence-metamorphic sole formation, and (6) latest Cretaceous emplacement onto the Tauride microcontinent and related backthrusting.Regional comparisons show that the restored Mersin Melange is similar to the Beyşehir–Hoyran Nappes further northwest and a northerly origin best fits the regional geological picture. These remnants of a North-Neotethys (Inner Tauride Ocean) were formed and emplaced to the north of the Tauride Carbonate Platform. They are dissimilar to melanges and related units in northern Syria, western Cyprus and southwestern Turkey, which are interpreted as remnants of a South-Neotethys. Early high-temperature ductile transport lineations within amphibolites of the metamorphic sole of the Mersin ophiolite are generally orientated E–W, possibly resulting from vertical-axis rotation of the ophiolite while still in an oceanic setting. By contrast, the commonly northward-facing later stage brittle structures are explained by backthrusting of the ophiolite and melange related to exhumation of the partially subducted northern leading edge of the Tauride continent.

scholarly journals THE LATE EARLY CRETACEOUS TRANSGRESSION ON THE LATERITES IN VOURINOS AND VERMION MASSIFS (WESTERN MACEDONIA, GREECE)

2018 ◽  
Vol 40 (1) ◽  
pp. 182 ◽  
Author(s):  
A. Photiades ◽  
N. Carras ◽  
V. Bortolotti ◽  
M. Fazzuoli ◽  
G. Principi
Keyword(s):  
Early Cretaceous ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Carbonate Platform ◽  
Upper Jurassic ◽  
Ophiolite Complex ◽  
Marine Transgression ◽  
The Third ◽  
Normal Salinity

Three stratigraphical sections from eastern Vourinos (Rhodiani area) to eastern Vermion massifs revealed the same age of the latérite events affecting the serpentinized ophiolite complex after its emplacement on the Pelagonian domain. All of them consist from their base upwards of serpentinized harzburgite slivers with lateritic unconformities on the top, followed by transgressive upper Lower Cretaceous neritic limestones. At Kteni locality (Rhodiani area), a laterite horizon, lying on top of serpentinites, is covered by transgressive neritic limestones with Salpingoporella urladanasi, assigning a Barremian - Albian age, followed by Orbitolinidae limestones. At Tsimodia locality (NNW to the previous), the latente horizon, lying on karstified Upper Jurassic reef limestones (which are the top member of a carbonate platform body tectonically lying on the ophiolites), is trans gres s ively overlain by iron-rich pisolith levels and Aptian limestones of the wackes tone-muds tone type, also containing Salpingoporella urladanasi, followed by Cenomanian Orbitolina limestones. Finally, the third examined locality, further north-eastward to the previous, is situated at the eastern slopes of Vermion massif and more precisely at the NWpart of Koumaria village. There, it can again be observed that the lateritized serpentinite slivers are overlain transgress ively by neritic limestones with Salpingoporella urladanasi, passing upwards into Upper Cretaceous recrystallized limestones with Orbitolinidae and rudist fragments and, finally, toflysch deposition. These features allow to recognize that the emersion and the consecutive lateritization of the thrust-emplaced ophiolites in Vourinos and Vermion massifs in the northern Pelagonian domain, starting from the Latest Jurassic, was followed by a marine transgression beginning from the Barremian - Albian, firstly under restricted and brackish carbonate platform conditions, marked by the presence of the dasycladalean alga Salpingoporella urladanasi, followed by normal salinity carbonate platform conditions. The neritic sedimentation was stable until the Early Cenomanian. Subsequently, a deepening, earlier at Vourinos and later at Vermion, resulted in deposition of pelagic and turbiditic carbonates and then offlysch.

scholarly journals Rethinking post-Hercynian basin development: Eastern Mediterranean Region

GeoArabia ◽  
2015 ◽  
Vol 20 (3) ◽  
pp. 175-224
Author(s):  
Barry G.M. Wood
Keyword(s):  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
Passive Margin ◽  
Western Desert ◽  
Alternative Mechanism ◽  
Southern Margin ◽  
Late Palaeozoic ◽  
Tethys Ocean ◽  
Sedimentary Fill ◽  
Ne Africa

ABSTRACT The geological community has broadly accepted that the region of NE Africa and NW Arabia deformed under tension during the post-Hercynian disintegration of northern Gondwana. Further, it has also generally accepted that sedimentation occurred within extensional half-grabens that formed along the length of what was then the southern margin of the Neo-Tethys Ocean. Consensus is that Alpine age compression then forced inversion of these half-grabens to form the well-known Syrian Arc structures that stretch from the Western Desert of Egypt to NE Syria. As new data has become available (Enclosures I and II), there are indications that an alternative mechanism, founded in continuous compression rather than extension then compression, better explains the tectonics and sedimentary history of the region since the late Palaeozoic. Data from Syria, Jordan, the Levant and Egypt demonstrate that distinct post-Hercynian Orogeny, Tethyan and Alpine sequences (basins) lie on a final, deeply eroded and folded Hercynian Unconformity, and that this surface refolded post-Hercynian time to form the confining walls of a single trough extending from NE Syria to the Western Desert of Egypt. Prior to the deposition of the first Tethyan basin in the late Carboniferous, the Hercynian Unconformity surface deformed to establish a plate-scale arch, the Levant Arch, that extended from NE Syria and southern Turkey, over 1,500 km southwest to the three corners region of Egypt, Sudan and Libya. This arch refolded in the late Palaeozoic to form the early Levant Trough composed of the Palmyride Trough, its extension under the Eastern Mediterranean and the Levant, through the Sinai and into western Egypt. Contrary to the now established idea that the southern margin of the Carboniferous–Permian Tethyan Ocean was a “passive margin”, the trough and internally constrained basins, slowly narrowed and deepened under continuous compression from the southeast from at least the late Palaeozoic to the Present. Each internal, distinct basin sequence is well defined by long periods of slow, low-energy, laterally persistent, sedimentation, separated from underlying and overlying basin sequences by almost equally long periods of erosion or non-deposition, coincident with increased regional structuring and volcanism. Each new basin, following a cessation of this regional structural activity, found itself nested within its predecessor, with the older basin lying slightly counter-clockwise to the younger. It is proposed that counter-clockwise, regional (and basin) rotation was facilitated by newly documented NW-oriented cross-shears, with inter-basin periods of erosion or non-deposition due to whole-basin (regional) uplift, forced by trough narrowing. Tectonic-scale geologic features, such as cross-basin and regional shears, trough margin uplift and northwest migration, laterally extensive, sheet-like sedimentation, sediment feathering onto unfaulted margins, regional erosion related to whole-basin uplift and massive flank gravity sliding with resultant down-slope buckle folding, taken together, attest to compression as the driving agent. Whole-basin and regional, counter-clockwise rotation through time, suggests a constant direction of compression. Understanding the correlation of sedimentary fill to local and regional structural events brings new insight to the deformation of the northern regions of Gondwana during the closure of Tethyan oceans. This model may also apply on a larger scale of whole-plate deformation.

The role of the Kyrenia Range Lineament, Cyprus, in the geological evolution of the eastern Mediterranean area

1986 ◽  
Vol 317 (1539) ◽  
pp. 141-177 ◽  
Keyword(s):  
Large Scale ◽  
Carbonate Platform ◽  
Eastern Mediterranean ◽  
Tectonic Setting ◽  
Ocean Basin ◽  
Strike Slip ◽  
Passive Margin ◽  
Late Triassic ◽  
Metamorphic Rocks ◽  
Mountain Areas

Rewarding insights into major crustal lineaments come from the integrated study of well exposed examples. One is the Kyrenia Range, a narrow arcuate lineament of several hundred kilometres in length comprising northern Cyprus and its offshore extension. The Kyrenia Range consists mostly of Mesozoic and Tertiary sedimentary and subordinate volcanic and metamorphic rocks, disposed in four rock groups separated by unconformities recording deformation events. The lineament is dominated by a steeply dipping composite thrust pile located partly along, and partly straddling, the abrupt northward termination of crust similar to the Troodos Igneous Complex at depth. The 200 Ma history of the lineament involved episodic rift, passive-margin, active-margin, strike-slip and uplift phases. The area was rifted off Gondwana in the late Triassic to form a southerly Turkish microcontinent capped by a gently subsiding carbonate platform. After formation of a small ocean basin to the south during the Cretaceous (Troodos ocean), northward subduction began (?Santonian). The first major deformation (D1) is attributed to pervasive (?dextral) strike-slip, which removed the Mesozoic passive margin and brecciated and metamorphosed the remaining platform. In the Maastrichtian and early Tertiary the area subsided and scree breccias were shed from scarps into pelagic carbonate-depositing seas, while bimodal within-plate-type lavas were erupted in an extensional setting influenced by strike-slip. By mid Eocene time, shortening, first evidence by flysch and olistostrome deposition, culminated in strong southward thrusting (D2) and localized metamorphism. Northward subduction south of Cyprus ensued and the range lay in an extensional fore-arc setting in late Eocene and Miocene time. The area then subsided dramatically and accumulated thick turbidite sequences derived from eroding Tauride Mountain areas to the northeast. Faulting and general uplift in the late Miocene was followed by renewed compressional deformation climaxing in mid Pliocene time (D3) with large-scale thrusting and tilting. Pulsed vertical uplift continued through the Quaternary. Similar volcanic and metamorphic rocks formed along the Kyrenia Lineament at intervals. Sedimentary rocks emerge as the most sensitive tectonic setting indicators. Long-lived lineaments like the Kyrenia Range are inherently very complicated, and perceived simple solutions in other cases should be viewed with some scepticism.

scholarly journals Meteoric diagenesis of Upper Cretaceous and Paleocene-Eocene shallow-water carbonates in the Kruja Platform (Albania): geochemical evidence

2009 ◽  
Vol 60 (2) ◽  
pp. 165-179 ◽  
Author(s):  
Grigor Heba ◽  
Gilbert Prichonnet ◽  
Abderrazak El Albani
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Upper Cretaceous ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Depositional Environments ◽  
Passive Margin ◽  
Buffer System ◽  
Geochemical Evidence ◽  
Meteoric Diagenesis

Meteoric diagenesis of Upper Cretaceous and Paleocene-Eocene shallow-water carbonates in the Kruja Platform (Albania): geochemical evidenceIn the central part of the Kruja Platform (Albania) located in the Apulian passive margin, geochemical analyses (calcimetry, Sr, REE and isotopic, δ13C and δ18O) coupled with sedimentological and sequence stratigraphic study were carried out on Upper Cretaceous (CsB4, CsB5, CsB6 Biozones) and Paleocene to Middle Eocene shallow-water carbonates that crop out in the Kruje-Dajt massif (L'Escalier section) and Makareshi massif (La Route section). The lower values in Sr contents, the homogeneous δ18O values in both sections and the covariance between δ13C and δ18O values (La Route section) are attributed to diagenesis influence by a meteoric water-buffer system, supported by petrographic observations. Moreover, a new exposure surface during the Late Cretaceous time (between CsB5 and CsB6 Biozones) may be proposed according to the low or negative excursions of Sr values, the negative excursions of isotopic values in both sections and a positive peak of normalized REE values (La Route section). These variations correlate with the geochemical signal reported by the decreasing strontium isotope values of rudist shells in the Island of Brač carbonate platform (Apulia domain) during the late Middle Campanian (77.3 Ma). Also, this continental exposure is consistent with the global sea-level fall reported from the Boreal Realm, North Atlantic, and the southern Tethyan margin. This geochemical evidence is a complementary tool for the sedimentological analysis and suggests a maximum regression (a sea-level fall) at the transition between the CsB5 and CsB6 Biozones. The high values of Sr content in Middle Eocene carbonates (L'Escalier section) reflect changes in depositional environment from restricted to open marine conditions. REE values increase through transgressive systems tract, characterized by small increase of detrital input. However, anomalies of certain values in both sections suggest disturbances linked either to the changes in clay input and to diagenetic modifications. Peaks in dolomite content are linked with regressive episodes or tendencies, and dolomitic facies, as indicated by intertidal-supratidal depositional environments.

scholarly journals Generation, migration, accumulation, and dissipation of oil in Northern Iraq

GeoArabia ◽  
2005 ◽  
Vol 10 (2) ◽  
pp. 39-84 ◽  
Author(s):  
H.V. Dunnington
Keyword(s):  
Lower Cretaceous ◽  
Large Scale ◽  
Upper Cretaceous ◽  
Upper Jurassic ◽  
Oil Field ◽  
Lateral Migration ◽  
Upward Migration ◽  
Factors Affecting ◽  
Northern Iraq ◽  
Late Tertiary

ABSTRACT Most of the known oil accumulations of Northern Iraq probably originated by upward migration from earlier, deeper accumulations which were initially housed in stratigraphic or long-established structural traps, and which are now largely depleted. The earlier concentrations had their source in basinal sediments, into which the porous, primary-reservoir limestones pass at modest distances east of the present fields. Development of the region favored lateral migration from different basinal areas of Upper Jurassic and Lower-Middle Cretaceous time into different areas of primary accumulation. Important factors affecting primary accumulation included: (1) early emergence and porosity improvement of the reservoir limestones, followed by burial under seal-capable sediments; (2) the timely imposition of heavy and increasing depositional loads on the source sediments, and the progressive marginward advance of such loads; (3) progressive steepening of gradients trending upward from source to accumulation area; (4) limitation of the reservoir formations on the up-dip margin by truncation or by porosity trap conditions. In late Tertiary time, large-scale folding caused adjustments within the primary reservoirs, and associated fracturing permitted eventual escape to higher limestone reservoirs, or to dissipation at surface. The sulfurous, non-commercial crudes of Miocene and Upper Cretaceous reservoirs in the Qaiyarah area are thought to stem from basinal radiolarian Upper Jurassic sediments, which lie down dip, a few tens of miles east of these fields. Upper Cretaceous oils of Ain Zalah and Butmah drained upward from primary accumulations in Middle Cretaceous limestones, which were filled from basinal sediments of Lower Cretaceous age situated in a localized trough a few miles northeast of these structures. The huge Kirkuk accumulation, now housed in Eocene-Oligocene limestones, ascended from a precedent accumulation in porous Middle-Lower Cretaceous limestones, which drew its oil from globigerinal-radiolarian shales and limestones of the contemporaneous basin, a short distance east of the present field limits. Eocene-Oligocene globigerinal sediments, considered by some the obvious source material for Kirkuk oil, seemingly provided little or no part of the present accumulation. The reservoir formation may have been filled from these sources, to lose its oil by surface dissipation during the erosional episode preceding Lower Fars deposition. Upper Cretaceous basinal sediments probably contributed nothing to known oil field accumulations, though they may have subscribed to the spectacular impregnations of some exposed, Upper Cretaceous reef-type limestones. Neither Miocene nor pre-Upper Jurassic sediments have played any discernible role in providing oil to any producing field. Indigenous oils are thought to be negligible in the limestone-reservoir formations considered.

scholarly journals LANDSLIDE AT TSAKONA AREA IN ARKADIA PREFECTURE. GEOLOGICAL CONDITIONS AND ACTIVATION MECHANISM

2004 ◽  
Vol 36 (4) ◽  
pp. 1862
Author(s):  
Λ. Σωτηρόπουλος ◽  
E. Λυμπέρης ◽  
Α. Σιγάλας ◽  
Α. Ντουρούπη ◽  
Κ. Προβιά ◽  
...  
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Road Construction ◽  
Upper Jurassic ◽  
Activation Mechanism ◽  
Tectonic Deformation ◽  
The Road ◽  
Geological Conditions ◽  
Geological Factors ◽  
Geological Formations

The geological conditions of the landslide's area, at Tsakona, in Arkadia Prefecture, are examined, as well as the factors that influenced the landslide's evolution. The landslide occurred at a distance of 15 km south of Megalopoli, on the New Highway, connecting Tripoli to Kalamata and constitutes one of the larger road landslides that have ever taken place. It occupies an area of a length of 1200m and a width of 300m. Geotectonically the landslide's region is placed in a block of the Pindos zone, thrusted on the Gabrovo-Tripoli zone. The geological formations that comprise the closer geological frame, consist of the formation of "First Flysch", Upper Jurassic - Lower Cretaceous and of the Upper Cretaceous limestones. The geological factors that drastically influenced the landslide's activation are lithological, tectonic, hydrogeological and morphological. The mainly siltstone lithology of the flysch, the intense tectonic deformation that occurred during the alpidic horogenetic phase, the morphological depression that is formed by the landslide's region and the large quantities of groundwater supplied by the uphill limestone, are the main geological reasons that activated the landslide. It should be emphasised that the activation and evolution of the landslide were greatly influenced by human activity during the road construction.

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