The Thrace Basin and the Black Sea: the Eocene–Oligocene marine connection

AbstractThe Late Cretaceous – Recent West Black Sea Basin and the Eocene–Oligocene Thrace Basin are separated by the Strandja arch comprising metamorphic and magmatic rocks. Since Late Cretaceous time the Strandja arch formed a palaeo-high separating the two basins which accumulated clastic sediment of >9 km thickness. During late Eocene – early Oligocene time the marine connection between these basins existed through the Çatalca gap west of Istanbul. The Çatalca gap lies on the damage zone of a major Cretaceous strike-slip fault; it formed a 15 km wide marine gateway, where carbonate-rich sediments of thicknessc.350 m were deposited. The sequence consists of upper Eocene shallow marine limestones (SBZ18-20) overlain by upper Eocene – lower Oligocene (P16-P19 zones) pelagic marl with a rich fauna of planktonic foraminifera; the marls are intercalated with 31–32 Ma acidic tuff and calc-arenite beds. The Çatalca gap is bounded in the west by a major normal fault, which marks the eastern boundary of the Thrace Basin. Seismic reflection profiles, well data and zircon U–Pb ages indicate that the Thrace Basin sequence west of the fault is late Eocene – middle Oligocene (37–27 Ma) in age and that the fault has accommodated 2 km of subsidence. Although there was a marine connection between the West Black Sea and Thrace basins during late Eocene – early Oligocene time, no significant exchange of clastic sediment took place. Sedimentation in the Çatalca gap ended abruptly during early Oligocene time by uplift, and this eventually led to the paralic conditions in the Thrace Basin.

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Seroprevalence of Q fever in a district located in the west Black Sea region of Turkey

European Journal of Clinical Microbiology & Infectious Diseases ◽

10.1007/s10096-010-0885-3 ◽

2010 ◽

Vol 29 (4) ◽

pp. 465-469 ◽

Cited By ~ 16

Author(s):

A. Gozalan ◽

J. M. Rolain ◽

M. Ertek ◽

E. Angelakis ◽

N. Coplu ◽

...

Keyword(s):

Black Sea ◽

Q Fever ◽

The West ◽

Black Sea Region ◽

West Black Sea ◽

West Black Sea Region

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Pre-Priabonian Palaeogene formations in southwestern Bulgaria and northern Greece: stratigraphy and tectonic implications

Geological Magazine ◽

10.1017/s0016756897008285 ◽

1998 ◽

Vol 135 (1) ◽

pp. 101-119 ◽

Cited By ~ 24

Author(s):

IVAN S. ZAGORCHEV

Keyword(s):

Late Cretaceous ◽

Middle Eocene ◽

Regional Metamorphism ◽

Late Eocene ◽

Thin Layers ◽

The South ◽

Northern Greece ◽

The North ◽

Early Oligocene ◽

Metamorphic Core

The Paril Formation (South Pirin and Slavyanka Mountains, southwestern Bulgaria) and the Prodromos Formation (Orvilos and Menikion Mountains, northern Greece) consist of breccia and olistostrome built up predominantly of marble fragments from the Precambrian Dobrostan Marble Formation (Bulgaria) and its equivalent Bos-Dag Marble Formation (Greece). The breccia and olistostrome are interbedded with thin layers of calcarenites (with occasional marble pebbles), siltstones, sandstones and limestones. The Paril and Prodromos formations unconformably cover the Precambrian marbles, and are themselves covered unconformably by Miocene and Pliocene sediments (Nevrokop Formation). The rocks of the Paril Formation are intruded by the Palaeogene (Late Eocene–Early Oligocene) Teshovo granitoid pluton, and are deformed and preserved in the two limbs of a Palaeogene anticline cored by the Teshovo pluton (Teshovo anticline). The Palaeocene–Middle Eocene age of the formations is based on these contact relations, and on occasional finds of Tertiary pollen, as well as on correlations with similar formations of the Laki (Kroumovgrad) Group throughout the Rhodope region.The presence of Palaeogene sediments within the pre-Palaeogene Pirin–Pangaion structural zone invalidates the concept of a ‘Rhodope metamorphic core complex’ that supposedly has undergone Palaeogene amphibolite-facies regional metamorphism, and afterwards has been exhumed by rapid crustal extension in Late Oligocene–Miocene times along a regional detachment surface. Other Palaeogene formations of pre-Priabonian (Middle Eocene and/or Bartonian) or earliest Priabonian age occur at the base of the Palaeogene sections in the Mesta graben complex (Dobrinishka Formation) and the Padesh basin (Souhostrel and Komatinitsa formations). The deposition of coarse continental sediments grading into marine formations (Laki or Kroumovgrad Group) in the Rhodope region at the beginning of the Palaeogene Period marks the first intense fragmentation of the mid- to late Cretaceous orogen, in particular, of the thickened body of the Morava-Rhodope structural zone situated to the south of the Srednogorie zone. The Srednogorie zone itself was folded and uplifted in Late Cretaceous time, thus dividing Palaeocene–Middle Eocene flysch of the Louda Kamchiya trough to the north, from the newly formed East Rhodope–West Thrace depression to the south.

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Insectivores (Mammalia) from the earliest Oligocene (MP 21) of Belgium

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600023489 ◽

2004 ◽

Vol 83 (3) ◽

pp. 187-192

Author(s):

R. Smith

Keyword(s):

Late Eocene ◽

Upper Eocene ◽

Faunal Turnover ◽

Early Oligocene ◽

New Immigrants ◽

Lower Oligocene ◽

Primitive Species ◽

Grande Coupure ◽

Important Progress

AbstractInsectivore remains are not common in the Lower Oligocene of Europe. For this reason, the study of the earliest Oligocene insectivore fauna (MP 21) from Boutersem and Hoogbutsel, all together yielding nine species, representing five families, constitutes an important progress in the knowledge of the Late Eocene and Early Oligocene insectivore evolution. Some of the genera discovered in Belgium are known from upper Eocene sites (Saturninia, Amphidozotherium, Euronyctia, Eotalpa), whereas others are not known before the Oligocene (Butselia, Tetracus, Heterosoricinae ind.). The co-occurrence of primitive species of Nyctitheriidae with modern forms belonging to the Plesiosoricidae, Talpidae and Erinaceidae at the Eocene-Oligocene boundary suggests a transition fauna. Between the Priabonian (Late Eocene) and the Rupelian (Early Oligocene), the endemic European insectivores were in competition with the new immigrants. This faunal turnover is generally accepted as the ‘Grande Coupure’ event (the MP 21 event).

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Paleogene extension in the Northern Aegean: Colluvial/debris flow deposits of the Early-Middle Eocene in NW Thrace Basin, Turkey

Geologica Carpathica ◽

10.31577/geolcarp.72.3.3 ◽

2021 ◽

Vol 72 (3) ◽

Author(s):

Serdar Akgündüz ◽

Hayrettin Koral

Keyword(s):

Debris Flow ◽

Fault Zone ◽

Middle Eocene ◽

Late Eocene ◽

Coarse Grained ◽

Fine Grained ◽

Metasedimentary Rocks ◽

Early Oligocene ◽

Thrace Basin ◽

Nw Turkey

The Thrace Basin consists of Paleogene–Neogene deposits that lie in the lowland south of the Strandja highlands in NW Turkey, where metagranitic and metasedimentary rocks occur. The Akalan Formation consisting of colluvial fan/debris flow deposits represents the base of the sequence in the northern Thrace basin where it is bounded by a right lateral strike-slip oblique fault called “The Western Strandja Fault Zone”. This formation exhibits a coarse-grained, angular and grain-supported character close to the fault zone which has releasing-bends. Fine-grained, rounded, and matrix-supported sediments occur away from the contact. During this study, the Akalan Formation is described for the first time as having larger benthic foraminifera (LBF) of Coskinolina sp of Ypresian–Lutetian, Nummulites obesus of early Lutetian, Dictyoconus egyptiensis of Lutetian, Orbitolites sp. of Ypresian–Bartonian, Miliola sp of early–middle Eocene, Idalina grelaudae of early Lutetian–Priabonian, Ammobaculites agglutinans, Amphimorphina crassa, Dentalina sp., Nodosaria sp., Operculina sp., Lenticulina sp., Quinqueloculina sp. and Amphistegina sp. of Eocene. This unit passes upward with a conformity into reefal limestones of the middle/late Eocene–early Oligocene Soğucak Formation. At times, the limestone overlies the conformity, there is an indication of a prograding sedimentary sequence. The new stratigraphic, paleontological, sedimentological and structural findings related to the NW Thrace Basin suggest a strong transtensional/extensional tectonic control for the initial Paleogene sedimentary deposition during the Ypresian–Lutetian period as shown by fossil content of the Akalan Formation. Right lateral-slip extensional tectonics appears to have had activity during the middle–late Eocene transgressive deposition of the Soğucak Formation when the basin became deepened and enlarged.

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Landslide susceptibility assessment of SE Bartin (West Black Sea region, Turkey) by artificial neural networks

Natural Hazards and Earth System Science ◽

10.5194/nhess-5-979-2005 ◽

2005 ◽

Vol 5 (6) ◽

pp. 979-992 ◽

Cited By ~ 87

Author(s):

M. Ercanoglu

Keyword(s):

Black Sea ◽

Landslide Susceptibility ◽

Landslide Inventory ◽

The West ◽

Data Set ◽

Black Sea Region ◽

Landslide Inventory Map ◽

Inventory Map ◽

West Black Sea ◽

West Black Sea Region

Abstract. Landslides are significant natural hazards in Turkey, second only to earthquakes with respect to economic losses and casualties. The West Black Sea region of Turkey is known as one of the most landslide-prone regions in the country. The work presented in this paper is aimed at evaluating landslide susceptibility in a selected area in the West Black Sea region using Artificial Neural Network (ANN) method. A total of 317 landslides were identified and mapped in the area by extensive field work and by use of air photo interpretations to build a landslide inventory map. A landslide database was then derived automatically from the landslide inventory map. To evaluate landslide susceptibility, six input parameters (slope angle, slope aspect, topographical elevation, topographical shape, wetness index, and vegetation index) were used. To obtain maps of these parameters, Digital Elevation Model (DEM) and ASTER satellite imagery of the study area were used. At the first stage, all data were normalized in [0, 1] interval, and parameter effects on landslide occurrence were expressed using Statistical Index values (Wi). Then, landslide susceptibility analyses were performed using an ANN. Finally, performance of the resulting map and the applied methodology is discussed relative to performance indicators, such as predicted areal extent of landslides and the strength of relation (rij) value. Much of the areal extents of the landslides (87.2%) were classified as susceptible to landsliding, and rij value of 0.85 showed a high degree of similarity. In addition to these, at the final stage, an independent validation strategy was followed by dividing the landslide data set into two parts and 82.5% of the validation data set was found to be correctly classified as landslide susceptible areas. According to these results, it is concluded that the map produced by the ANN is reliable and methodology applied in the study produced high performance, and satisfactory results.

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DEVELOPMENT OF THE TERTIARY OFFSHORE PAPUAN BASIN

The APPEA Journal ◽

10.1071/aj74006 ◽

1975 ◽

Vol 15 (1) ◽

pp. 55 ◽

Cited By ~ 2

Author(s):

N. C. Tallis

Keyword(s):

Late Eocene ◽

Early Miocene ◽

Second Phase ◽

The West ◽

Fine Grained ◽

Early Oligocene ◽

Coral Sea ◽

Clastic Sediments ◽

Marine Seismic ◽

Rigid Segment

Marine seismic studies combined with wildcat drilling in the Gulf of Papua have provided a comprehensive insight into the geology of the offshore Papuan Basin. The Basin adjoins a downwarped but structurally rigid segment of the Australian continental shield in the west, and the Coral Sea Basin in the southeast. It incorporates arcuate geosynclinal development eastward and northward beyond the continental margin. The pre-Tertiary history is relatively obscure. Jurassic-Lower Cretaceous clastic sediments overlie granites and volcanics of the continental shield in the west. Eastward, the record is masked by great thicknesses of Tertiary strata, and the pre-Tertiary may be represented in outcrop by a metamorphic series of indeterminate age.The Tertiary offshore basin developed in three distinct phases, commencing in Late Cretaceous/Early Eocene time, when seas transgressed from east to west across a peneplaned surface. An eastward-thickening wedge of argillaceous limestones and cherts was deposited. Regression and erosion occurred in Late Eocene/Early Oligocene time, possibly in association with upwarp of the oceanic crust, which created an eastern volcanic borderland. Typical orthogeosynclinal sedimentation followed in Early Miocene time, with reef, shoal and pelagic limestones deposited marginal to the stable western (continental) shelf, and with prolific volcanism associated with the eastern (oceanic) flank. This volcanism was the source for a thick pile of mudstone-greywacke sediments which was deposited in an intermediate eugeosyncline.This second phase was modified in Late Miocene time by regional uplift, and by development of the Central Mountain geanticlinal belt. This created an immense southeasterly pro-grading system which rapidly buried the Early Miocene profile. These fine grained clastic Plio-Pleistocene sediments have been highly deformed by gravitational and diapiric influences in the east-central portion of the basin. Huge volumes of sediment are still being transported southeastward into the Coral Sea Basin.

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The Prevalence of Goiter and Hypothyroidism among School Children 6 Years after Introduction of a Mandatory Salt Iodination Program in a Severely Iodine-Deficient Area of the West Black Sea Region of Turkey

Journal of Tropical Pediatrics ◽

10.1093/tropej/fmu004 ◽

2014 ◽

Vol 60 (4) ◽

pp. 318-321 ◽

Cited By ~ 2

Author(s):

H. Uzun ◽

S. Gozkaya ◽

N. Yesildal ◽

M. Okur ◽

I. Arslanoglu ◽

...

Keyword(s):

Black Sea ◽

School Children ◽

The West ◽

Black Sea Region ◽

West Black Sea ◽

Deficient Area ◽

West Black Sea Region

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Eocene–Oligocene stratigraphy and structural history of the Karaburun area, southwestern Black Sea coast, Turkey: transition from extension to compression

Geological Magazine ◽

10.1017/s0016756815000229 ◽

2015 ◽

Vol 152 (6) ◽

pp. 1104-1122 ◽

Cited By ~ 3

Author(s):

BORIS NATAL’IN ◽

ADALET GIZEM SAY

Keyword(s):

Black Sea ◽

Tectonic Activity ◽

Normal Faults ◽

Shallow Marine ◽

Early Oligocene ◽

Marine Shale ◽

Thrace Basin ◽

Black Sea Coast ◽

Nw Turkey ◽

Sea Coast

AbstractThe stratigraphic succession exposed in the Karaburun area (southern Black Sea coast, NW Turkey) records multiple changes in depositional and tectonic settings during Cenozoic times. It starts with the Middle–Upper Eocene Soğucak Formation of reef limestone that across a normal fault, omitting the lower part of the Lower Oligocene Ceylan Formation (deep-marine shale unit), abuts the upper part of the Ceylan Formation that is made up of two facies: (1) shallow-marine sandstone and (2) shallow-marine limestone units containing horizons of submarine slumps. Both facies are unconformably overlain by the fluvial Upper Miocene Çukurçeşme Formation. The tectonic record includes: (1) latest Eocene – Early Oligocene NE–SW extension, (2) Early Oligocene NE–SW shortening and (3) Late Miocene NW–NE extension. The earliest normal faults cutting the Soğucak and the lower part of the Ceylan formations are associated with clastic dykes injected into the deep-marine shale. These structures suggest a disruption of the Eocene carbonate platform and are also known in the neighbouring Thrace Basin. The following NE–SW shortening created the NE-vergent Karaburun Thrust that is synchronous with the shallowing and inversion of the Ceylan Basin. Rotation of the stress field is recorded by changes in clastic dyke orientation and their deformation. Compression caused multiple westerly directed submarines slides from uplifts in easterly located regions. This event is not recorded in the Thrace Basin. Finally, the Miocene tectonic activity formed NW- and NE-striking normal faults. The outlined tectonic history includes Early Oligocene extensional and compressional episodes recorded in the southern margin of the Black Sea that had hitherto not been known.

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