Rejuvenation of the eastern Mediterranean passive continental margin in northern and central Sinai: new data from the Themed Fault

1994 ◽  
Vol 131 (4) ◽  
pp. 435-448 ◽  
Author(s):  
A. R. Moustafa ◽  
M. H. Khalil
Keyword(s):  
Continental Margin ◽  
Middle Eocene ◽  
Eastern Mediterranean ◽  
Passive Continental Margin ◽  
Early Miocene ◽  
The North ◽  
Crustal Block ◽  
Early Mesozoic ◽  
Eastern Mediterranean Basin ◽  
North Sinai

AbstractThe Themed Fault marks the southernmost border of the Early Mesozoic passive continental margin of north Sinai. This 200-km long fault transects the northern part of the Tih Plateau that supposedly occupies a tectonically stable area. Post-Middle Eocene–pre-Early Miocene rejuvenation of this fault proceeded by right-lateral wrenching and represents a newly recognized phase of deformation in the history of north and central Sinai. The minimum estimate for the strike-slip movement on this fault is about 300–750 m. To the north of the Themed Fault is a narrow fault belt (Sinai hinge belt) that marks the boundary between a tectonically unstable crustal block to the north (the north Sinai fold belt area) and a tectonically stable crustal block to the south, the main part of the Tih plateau area.Four phases of dextral wrenching rejuvenated the faults of the Early Mesozoic passive continental margin in northern Egypt; one of them affected the Themed Fault. The oldest (Dl) deformation is early Late Senonian and is related to the closure of Neotethys and the Eastern Mediterranean basin. The D1 deformation proceeded by pure wrenching in the north Western Desert of Egypt. In contrast, it proceeded by transpression in north Sinai due to the irregular plate boundary and the relationship of this boundary to the slip vectors. D2 deformation (post-Middle Eocene–pre-Early Miocene) is clear in the Themed Fault area although reported herein for the first time; it is related to continued closure of the Eastern Mediterranean basin and proceeded by pure wrenching. D3 deformation (Late Oligocene–Early Miocene) proceeded by divergent wrenching in the north Eastern Desert and is kinematically related to the transfer of slip from the nearby faults of the Suez rift. D4 deformation (post-Early Miocene to Recent) affected the Sinai hinge belt by pure wrenching and is probably related to the left-lateral slip on the Dead Sea Transform and the related drag of the eastern edges of the fault blocks of this hinge belt. Recent seismic activity in the Sinai hinge belt perhaps indicates that the D4 deformation has continued to the present time, although morphological expression of recent tectonic movement is lacking. In contrast, the Themed Fault is seismically quiet at present.

scholarly journals Late oligocene–early miocene shortening in the Thrace Basin, northern Aegean

2021 ◽  
Author(s):  
Ümitcan Erbil ◽  
Aral I. Okay ◽  
Aynur Hakyemez
Keyword(s):  
Large Scale ◽  
Middle Eocene ◽  
Early Miocene ◽  
Fold Axis ◽  
Late Oligocene ◽  
The Balkans ◽  
Sedimentary Sequences ◽  
The North ◽  
Early Oligocene ◽  
Thrace Basin

AbstractLate Cenozoic was a period of large-scale extension in the Aegean. The extension is mainly recorded in the metamorphic core complexes with little data from the sedimentary sequences. The exception is the Thrace Basin in the northern Aegean, which has a continuous record of Middle Eocene to Oligocene marine sedimentation. In the Thrace Basin, the Late Oligocene–Early Miocene was characterized by north-northwest (N25°W) shortening leading to the termination of sedimentation and formation of large-scale folds. We studied the stratigraphy and structure of one of these folds, the Korudağ anticline. The Korudağ anticline has formed in the uppermost Eocene–Lower Oligocene siliciclastic turbidites with Early Oligocene (31.6 Ma zircon U–Pb age) acidic tuff beds. The turbidites are underlain by a thin sequence of Upper Eocene pelagic limestone. The Korudağ anticline is an east-northeast (N65°E) trending fault-propagation fold, 9 km wide and 22 km long and with a subhorizontal fold axis. It is asymmetric with shallowly-dipping northern and steeply-dipping southern limbs. Its geometry indicates about 1 km of shortening in a N25°W direction. The folded strata are unconformably overlain by Middle Miocene continental sandstones, which constrain the age of folding. The Korudağ anticline and other large folds in the Thrace Basin predate the inception of the North Anatolian Fault (NAF) by at least 12 myr. The Late Oligocene–Early Miocene (28–17 Ma) shortening in the Thrace Basin and elsewhere in the Balkans forms an interlude between two extensional periods, and is probably linked to changes in the subduction dynamics along the Hellenic trench.

Development and parameterization of a general forest gap dynamics simulator for the North-eastern Mediterranean Basin (GREek FOrest Species)

2007 ◽  
Vol 204 (3-4) ◽  
pp. 439-456 ◽  
Author(s):  
Nikolaos M. Fyllas ◽  
Oliver L. Phillips ◽  
William E. Kunin ◽  
Yiannis G. Matsinos ◽  
Andreas I. Troumbis
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Gap Dynamics ◽  
Forest Gap ◽  
Forest Species ◽  
The North ◽  
North Eastern ◽  
Eastern Mediterranean Basin

Alpha-Mendeleev Rise is a Eurasian aborted volcanic passive continental margin

2020 ◽  
Author(s):  
Anatoly Nikishin ◽  
Sierd Cloetingh ◽  
Gillian Foulger ◽  
Sergey Freiman ◽  
Nikolay Malyshev ◽  
...  
Keyword(s):  
Continental Margin ◽  
Seismic Data ◽  
Barents Sea ◽  
Passive Continental Margin ◽  
Ca 125 ◽  
Axial Line ◽  
Borehole Data ◽  
Clastic Rocks ◽  
The North ◽  
Show Evidence

<p>We report interpretations of regional seismic lines and new data of analyses of rocks from Alpha-Mendeleev Rise. A new magmatic province is documented at the bottom of the North Chukchi Basin. Seismic data demonstrate synrift basalt sequences (half-grabens with bright reflectors) and a number of intrusions. The seismic stratigraphic age of the magmatism is ca. 125-100 Ma. Seismic data show evidence of magmatism in the area of De Long High. Basalts have isotopic ages on De Long islands of ca. 130-105 Ma. A huge magmatic province exists in the Barents Sea. Seismic data show a basalt province to the SE from Franz Josef Land. The two-way travel time of the basalt unit is 100 ms. The age of the basalts is ca. 125 Ma from correlation with borehole data. The area is enriched by intrusions of the same age. Similar magmatic provinces are known on Svalbard and the Canadian Archipelago. We recognize half-grabens and/or SDR complexes along the Mendeleev Rise. The dip of SDRs is toward the Podvodnikov and Toll basins. The Mendeleev Rise has an axial line which separates differently dipping SDRs. Half-grabens are filled with clastic rocks and basalts with ages ca. 127-110 Ma (Skolotnev et al. in preparation, and our correlations with seismic data). The Podvodnikov and Toll basins have SDR complexes also. The dipping of the SDRs is toward the axial lines of these basins, and the lines are parallel to the Mendeleev Rise axial line. We propose that intraplate, ca. 125 Ma basalt magmatism started between the Eurasian continent (including the Lomonosov and Alpha-Mendeleev terranes) and the Canada Basin (which formed before 125 Ma). This was followed by concentration of rifting and magmatism along Alpha-Mendeleev Rise and the adjacent Podvodnikov, Nautilus and Toll basins. These processes were aborted at ca. 100 Ma as a result of plate kinematic reorganization. Additional intraplate magmatism took place at 90-80 Ma. We propose that Alpha-Mendeleev Rise is a Eurasian aborted double-sided volcanic passive continental margin with stretched and hyper-extended continental crust intruded by basalts. This work was supported by RFBR grants (18-05-70011 and 18-05-00495).</p>

scholarly journals Evidence from the Kyrenia Range, Cyprus, of the northerly active margin of the Southern Neotethys during Late Cretaceous–Early Cenozoic time

2011 ◽  
Vol 149 (2) ◽  
pp. 264-290 ◽  
Author(s):  
ALASTAIR H. F. ROBERTSON ◽  
KEMAL TASLI ◽  
NURDAN İNAN
Keyword(s):  
Continental Margin ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Basaltic Rocks ◽  
Tectonic Model ◽  
The North ◽  
Basic Volcanic ◽  
Upper Maastrichtian

AbstractSedimentary geology and planktonic foraminiferal biostratigraphy have shed light on the geological development of the northern, active continental margin of the Southern Neotethys in the Kyrenia Range. Following regional Triassic rifting, a carbonate platform developed during Jurassic–Cretaceous time, followed by its regional burial, deformation and greenschist-facies metamorphism. The platform was exhumed by Late Maastrichtian time and unconformably overlain by locally derived carbonate breccias, passing upwards into Upper Maastrichtian pelagic carbonates. In places, the pelagic carbonates are interbedded with sandstone turbidites derived from mixed continental, basic volcanic, neritic carbonate and pelagic lithologies. In addition, two contrasting volcanogenic sequences are exposed in the western-central Kyrenia Range, separated by a low-angle tectonic contact. The first is a thickening-upward sequence of Campanian–Lower Maastrichtian(?) pelagic carbonates, silicic tuffs, silicic lava debris flows and thick-bedded to massive rhyolitic lava flows. The second sequence comprises two intervals of basaltic extrusive rocks interbedded with pelagic carbonates. The basaltic rocks unconformably overlie the metamorphosed carbonate platform whereas no base to the silicic volcanic rocks is exposed. Additional basaltic lavas are exposed throughout the Kyrenia Range where they are dated as Late Maastrichtian and Late Paleocene–Middle Eocene in age. In our proposed tectonic model, related to northward subduction of the Southern Neotethys, the Kyrenia platform was thrust beneath a larger Tauride microcontinental unit to the north and then was rapidly exhumed prior to Late Maastrichtian time. Pelagic carbonates and sandstone turbidites of mixed, largely continental provenance then accumulated along a deeply submerged continental borderland during Late Maastrichtian time. The silicic and basaltic volcanogenic rocks erupted in adjacent areas and were later tectonically juxtaposed. The Campanian–Early Maastrichtian(?) silicic volcanism reflects continental margin-type arc magmatism. In contrast, the Upper Maastrichtian and Paleocene–Middle Eocene basaltic volcanic rocks erupted in an extensional (or transtensional) setting likely to relate to the anticlockwise rotation of the Troodos microplate.

The Tunissian “zone des nappes”: a slightly inverted mesocenozoic continental margin (Taberka/Jendouba; northwestern Tunisia)

2006 ◽  
Vol 177 (3) ◽  
pp. 145-154 ◽  
Author(s):  
Mohamed Abdoullah Ould Bagga ◽  
Saâdi Abdeljaouad ◽  
Eric Mercier
Keyword(s):  
Continental Margin ◽  
Middle Miocene ◽  
Late Quaternary ◽  
Original Model ◽  
Early Miocene ◽  
Thrust Faults ◽  
North African ◽  
Sedimentary Records ◽  
The North ◽  
Tunisian Atlas

Abstract Detailed investigations in the western part of the “zone des nappes” in the Tunisian Atlas enable to propose an original model for this area. We show that, according to sedimentary records, these units appear to be formed by various series originally deposited on tilted crustal blocks of the North African margin. This south-easternward tilting occurred from the Triasic to the early Miocene. The first phase of inversion took place during the early to middle Miocene interval; no older compressive event can be highlighted. The shortening is associated with a system of flats and ramps thrust faults that occurs following a piggy-back sequence and that does not disrupt the paleogeographic order. Subsequently, an “out-of-sequence” event places the upper unit (Numidian Unit) onto the sub-numidian Units. The overlap length remains very moderate betwen sub-numidian Units (a few kilometers only). Finally, during the late Quaternary, the area undergoes a late shortening that folds the syn-tectonic basins.

scholarly journals Dynamics and age of formation of the Seram-Ambon ophiolites (Central Indonesia)

2003 ◽  
Vol 174 (6) ◽  
pp. 529-543 ◽  
Author(s):  
Christophe Monnier ◽  
Jacques Girardeau ◽  
Hariady Permana ◽  
Jean-Pierre Rehault ◽  
Hervé Bellon ◽  
...  
Keyword(s):  
Continental Crust ◽  
Continental Margin ◽  
Passive Continental Margin ◽  
Early Miocene ◽  
Geochemical Data ◽  
Active Margin ◽  
Short Span ◽  
Group 2 ◽  
Type 3

Abstract The Seram-Ambon ophiolitic series comprise peridotites, websterites, gabbros and lavas. Petro-geochemical data show that the peridotites are weakly depleted rocks, except for the rare Cpx-free harzburgites. They underwent a sub-solidus metamorphic re-equilibration in the plagioclase field. The associated websterites and gabbros display various chemical features, allowing to define 3 types of websterites and 2 groups of gabbros. They have mostly BAB characteristics (presence of negative anomalies in Nb, Zr, Ti and Y), except the group 2 gabbros which have N-MORB features and the type 3 websterites which bear adakitic affinities. Lavas also display a variety of compositions, including high-Mg IAT and Mg-rich BABB with sub-alkaline affinities. Both IAT and BABB display high Th/Nb ratios which support an origin close to a continental crust environment. Our 20 to 15 Ma 40K/40Ar ages calculated for the BABB and 15-9 Ma for the IAT show that the basin and arc formed in a very short span of time, before their obduction 9–7 Ma ago [Linthout et al., 1997]. Considering the paleogeographic situation in the Miocene [Haile, 1979 ; Haile, 1981] and our data, we propose that the Seram-Ambon ophiolites formed during the early Miocene in a small, short-lived (10 Ma), transtensive basin bordered on its east by an active margin and on its western part by a passive continental margin over which it was later obducted towards the SW direction.

scholarly journals Pelagic-Benthic Coupling and Diagenesis of Nucleic Acids in a Deep-Sea Continental Margin and an Open-Slope System of the Eastern Mediterranean

2005 ◽  
Vol 71 (10) ◽  
pp. 6070-6076 ◽  
Author(s):  
Antonio Dell'Anno ◽  
Cinzia Corinaldesi ◽  
Spyros Stavrakakis ◽  
Vasilis Lykousis ◽  
Roberto Danovaro
Keyword(s):  
Nucleic Acid ◽  
Continental Margin ◽  
Deep Sea ◽  
Eastern Mediterranean ◽  
Large Fraction ◽  
Aegean Sea ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea ◽  
Benthic Coupling

ABSTRACT Downward fluxes of nucleic acids adsorbed onto settling particles play a key role in the supply of organic phosphorus and genetic material to the ocean interior. However, information on pelagic-benthic coupling, diagenesis, and processes controlling nucleic acid preservation in deep-sea sediments is practically nonexistent. In this study, we compared nucleic acid fluxes, sedimentary DNA and RNA concentrations, and the enzymatically hydrolyzable fraction of DNA in a bathyal continental margin (North Aegean Sea) and an open-sea system (South Aegean Sea) of the Eastern Mediterranean. The two systems displayed contrasting patterns of nucleic acid fluxes, which increased significantly with depth in the North Aegean Sea and decreased with depth in the South Aegean Sea. These results suggest that in continental margin and open-ocean systems different processes control the nucleic acid supply to the sea floor. Differences in nucleic acid fluxes were reflected by nucleic acid concentrations in the sediments, which reached extremely high values in the North Aegean Sea. In this system, a large fraction of DNA may be buried, as suggested by the large fraction of DNA resistant to nuclease degradation and by estimates of burial efficiency (ca. eight times higher in the North than in the South Aegean Sea). Overall, the results reported here suggest that the preservation of DNA in deeper sediment layers may be favored in benthic systems characterized by high sedimentation rates.

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