Inversion tectonics of the northern margin of the Basque Cantabrian Basin

Abstract The northern margin of the Basque-Cantabrian Basin was analysed combining stratigraphic and structural data from both surface and subsurface together with reflectance of vitrinite data from oil wells. The use of cross-section balancing techniques in addition to thermal modelling enabled us to reconstruct the tectonic, burial and thermal evolutions of the basin margin as well as those of the Landes High to the N in two different periods. The section restoration at the end of the Cretaceous shows a northern basin margin structure influenced by evaporites related to south-dipping normal faults. The reconstruction in middle Eocene times yielded up to 1 800 m of Paleocene-middle Eocene deposits on top of the basin margin. Subsequent tectonic inversion related to the Pyrenean compression led to the north-directed thrusting of basement units and to the formation of thrust slices or inverted folds in the cover along the northern margin of the basin. Tectonic subsidence analysis together with maturity data provided evidence that oil was generated in the basin during the late syn-rift and post-rift stages in the Late Cretaceous and became overmature during the period of incipient inversion after 55 Ma. In the autochthonous Landes High, the oil was generated after the tectonic inversion period 37 Ma.

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Progressive development of the Büyük Menderes Graben based on new data, western Turkey

Geological Magazine ◽

10.1017/s0016756809006359 ◽

2009 ◽

Vol 146 (5) ◽

pp. 652-673 ◽

Cited By ~ 55

Author(s):

ÖMER FEYZİ GÜRER ◽

NURAN SARICA-FILOREAU ◽

MUZAFFER ÖZBURAN ◽

ERCAN SANGU ◽

BÜLENT DOĞAN

Keyword(s):

Middle Miocene ◽

Normal Fault ◽

Structural Data ◽

Detachment Fault ◽

Normal Faults ◽

Tectonic Event ◽

Alluvial Deposits ◽

Western Turkey ◽

Northern Margin ◽

The North

AbstractOblique and normal fault systems exposed in the Büyük Menderes Graben (BMG) region record two successive and independent complex tectonic events. The first group tectonic event is defined by an E–W extension related to N–S contraction and transpression. This group is responsible for the development of NW- and NE-trending conjugate pairs of oblique faults which controlled Early–Middle Miocene basin formation. Between the Early–Middle Miocene and Plio-Quaternary strata exists an unconformity, indicating a period of folding, uplift and severe erosion associated with N–S shortening. The second group of events was the change in tectonic regime from E–W extension to N–S extension which controlled the formation of the Büyük Menderes Graben by three progressive pulses of deformation. The first pulse of extensional deformation was initially recorded in the region by the exhumation of the deep part of the Menderes Massif (MM) with the development of the E-trending Büyük Menderes Detachment Fault (BMDF). The minimum age of this pulse is constrained by the older Plio-Quaternary fluviatile deposits of the Büyük Menderes Graben that range in age from the Plio-Pleistocene boundary interval to Late Pleistocene. The second pulse, which is marked by the rapid deposition of alluvial deposits, initiated the formation of approximately E–W-trending high-angle normal faults synthetic and antithetic to the Büyük Menderes Detachment Fault, on the northern margin during Holocene times. These faults are interpreted as secondary steeper listric faults that merge with the main Büyük Menderes Detachment Fault at depth. The third pulse was the migration of the Büyük Menderes Graben depocentre to the present day position by diachronous activity of secondary steeper listric faults. These steeper faults are the most seismically active tectonic elements in western Turkey. According to the stratigraphic and structural data, the N–S extension in the Büyük Menderes Graben region produced a progressive deformation phase with different pulses during its Plio-Quaternary evolution, with migration of deformation from the master fault to the hangingwall. The formation of diachronous secondary synthetic and antithetic steeper faults on the upper plate of the Büyük Menderes Detachment Fault, hence the southward migration of the deformation and of the Büyük Menderes Graben depocentre, should be related to the evolution of detachment in the region. The presence of the seismically active splays of secondary faults implies an active detachment system in the region. This young Plio-Quaternary N–S extension in the Büyük Menderes Graben may be attributed to the combined effects of the two continuing processes in Aegean region. The first process is back-arc spreading or probably the roll-back of African slab below the south Aegean Arc, which seems to be responsible for the change in the stress tensor from E–W extension to N–S extension. The second and later event is the southwestward escape of the Anatolian block along its boundary fault, that is, the North Anatolian fault (NAF).

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Structure of the North Indian continental margin in the Ladakh–Zanskar Himalayas: implications for the timing of obduction of the Spontang ophiolite, India–Asia collision and deformation events in the Himalaya

Geological Magazine ◽

10.1017/s0016756897006857 ◽

1997 ◽

Vol 134 (3) ◽

pp. 297-316 ◽

Cited By ~ 166

Author(s):

MIKE SEARLE ◽

RICHARD I. CORFIELD ◽

BEN STEPHENSON ◽

JOE MCCARRON

Keyword(s):

Continental Margin ◽

Suture Zone ◽

Indian Plate ◽

Normal Faults ◽

Initial Contact ◽

Crustal Shortening ◽

Northern Margin ◽

The North ◽

Late Tertiary ◽

The Himalaya

The collision of India and Asia can be defined as a process that started with the closing of the Tethyan ocean that, during Mesozoic and early Tertiary times, separated the two continental plates. Following initial contact of Indian and Asian continental crust, the Indian plate continued its northward drift into Asia, a process which continues to this day. In the Ladakh–Zanskar Himalaya the youngest marine sediments, both in the Indus suture zone and along the northern continental margin of India, are lowermost Eocene Nummulitic limestones dated at ∼54 Ma. Along the north Indian shelf margin, southwest-facing folded Palaeocene–Lower Eocene shallow-marine limestones unconformably overlie highly deformed Mesozoic shelf carbonates and allochthonous Upper Cretaceous shales, indicating an initial deformation event during the latest Cretaceous–early Palaeocene, corresponding with the timing of obduction of the Spontang ophiolite onto the Indian margin. It is suggested here that all the ophiolites from Oman, along western Pakistan (Bela, Muslim Bagh, Zhob and Waziristan) to the Spontang and Amlang-la ophiolites in the Himalaya were obducted during the late Cretaceous and earliest Palaeocene, prior to the closing of Tethys.The major phase of crustal shortening followed the India–Asia collision producing spectacular folds and thrusts across the Zanskar range. A new structural profile across the Indian continental margin along the Zanskar River gorge is presented here. Four main units are separated by major detachments including both normal faults (e.g. Zanskar, Karsha Detachments), southwest-directed thrusts reactivated as northeast-directed normal faults (e.g. Zangla Detachment), breakback thrusts (e.g. Photoksar Thrust) and late Tertiary backthrusts (e.g. Zanskar Backthrust). The normal faults place younger rocks onto older and separate two units, both showing compressional tectonics, but have no net crustal extension across them. Rather, they are related to rapid exhumation of the structurally lower, middle and deep crustal metamorphic rocks of the High Himalaya along the footwall of the Zanskar Detachment. The backthrusting affects the northern margin of the Zanskar shelf and the entire Indus suture zone, including the mid-Eocene–Miocene post-collisional fluvial and lacustrine molasse sediments (Indus Group), and therefore must be Pliocene–Pleistocene in age. Minimum amounts of crustal shortening across the Indian continental margin are 150–170 km although extreme ductile folding makes any balancing exercise questionable.

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The Late Cenozoic evolution of the Aksu basin (Isparta Angle; SW Turkey). New insights

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.182.2.133 ◽

2011 ◽

Vol 182 (2) ◽

pp. 133-148 ◽

Cited By ~ 15

Author(s):

André Poisson ◽

Fabienne Orszag-Sperber ◽

Erdal Kosun ◽

Maria-Angella Bassetti ◽

Carla Müller ◽

...

Keyword(s):

Coral Reefs ◽

Normal Faults ◽

The West ◽

Shallow Marine ◽

Northern Margin ◽

Sea Level Fluctuations ◽

Marine Deposits ◽

The North ◽

Sw Turkey ◽

Isparta Angle

Abstract The Mio-Pliocene basins around the Antalya gulf in SW Turkey developed above the Tauric Mesozoic platforms on which the Antalya nappes had been thrusted (in Late Cretaceous-Paleocene times). The closure of the initial Isparta Angle during these events (E-W compression) initiated the N-S orientation of the main structural lines, which persisted later and explains the orientation of the Aksu basin in contrast with the E-W orientation of the eastern Neo-gene Mediterranean basins. The area, and all southwestern Turkey, became emergent at the end of the Oligocene and were the site of shallow-marine carbonate deposits in the Chattian-Aquitanian, giving way to the wide Lycian basin in Burdigalian-Langhian times. The progressive emplacement of the Lycian nappes from the north over this basin provoked first its subsidence and then its emersion when the nappes attained their final position over the Bey Daglari platform in Langhian times. Coinciding, or in response to the Lycian nappes emplacement, the Aksu basin was initiated as an elongated N-S graben which was filled by thick accumulations of terrestrial and marine deposits(including coral reefs), which derived from the erosion of the Lycian allochton and its basement (Langhian?, Serravallian and Tortonian times). The syn-sedimentary tectonics : reactivation of the normal faults along the west margin of the basin, the continuous uplift of the neighbouring continental areas (beginning of the Aksu thrust), governed the geometry of the basin. As a result and due to the uplift of its northern margin, the Aksu basin migrated towards the south and in Messinian times it was reduced to a narrow gulf along the eastern margin of which the Gebiz limestones were deposited as fringing coral reefs. The age of these limestones has been debated. Our new data allow us to attribute them to the Messinian. The drastic retreat of the sea at the end of this period, provoked the erosion of large parts of the Messinian deposits and the formation of deep canyons on land and under the sea down to the Antalya abyssal plain, in which evaporites were deposited. During the Zanclean transgression, the Eskiköy-Kargi canyon was filled by coarse clastics of a Gilbert delta derived from the northern continental area following a model well known elsewhere in the Mediterranean basins. Southward, shallow-marine sands and marls unconformably cover the remnants of the Messinian deposits and the emergent areas of the southern Antalya gulf. After Zanclean times (end of Pliocene?), the Aksu basin was deformed, due to the west-directed Aksu compressional event (end of the Aksu thrust). Quaternary terraces of the Aksu river at various altitudes, as well as the terraces of the Antalya tufa can be related to sea level fluctuations.

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From arc evolution to arc-continent collision: Late Cretaceous–middle Eocene geology of the Eastern Pontides, northeastern Turkey

Geological Society of America Bulletin ◽

10.1130/b31913.1 ◽

2019 ◽

Vol 131 (11-12) ◽

pp. 1889-1906 ◽

Cited By ~ 7

Author(s):

Özgür Kandemir ◽

Kenan Akbayram ◽

Mehmet Çobankaya ◽

Fatih Kanar ◽

Şükrü Pehlivan ◽

...

Keyword(s):

Late Cretaceous ◽

Middle Eocene ◽

Structural Data ◽

Massive Sulfide ◽

Arc Volcanism ◽

Eastern Pontides ◽

The North ◽

Fold And Thrust Belt ◽

Volcaniclastic Rocks ◽

Back Arc

Abstract The Eastern Pontide Arc, a major fossil submarine arc of the world, was formed by northward subduction of the northern Neo-Tethys lithosphere under the Eurasian margin. The arc’s volcano-sedimentary sequence and its cover contain abundant fossils. Our new systematical paleontological and structural data suggest the Late Cretaceous arc volcanism was initiated at early-middle Turonian and continued uninterruptedly until the end of the early Maastrichtian, in the northern part of the Eastern Pontides. We measured ∼5500-m-thick arc deposits, suggesting a deposition rate of ∼220 m Ma–1 in ∼25 m.y. We have also defined four different chemical volcanic episodes: (1) an early-middle Turonian–Santonian mafic-intermediate episode, (2) a Santonian acidic episode; when the main volcanic centers were formed as huge acidic domes-calderas comprising the volcanogenic massive sulfide ores, (3) a late Santonian–late Campanian mafic-intermediate episode, and (4) a late Campanian–early Maastrichtian acidic episode. The volcaniclastic rocks were deposited in a deepwater extensional basin until the late Campanian. Between late Campanian and early Maastrichtian, intra-arc extension resulted in opening of back-arc in the north, while the southern part of the arc remained active and uplifted. The back-arc basin was most probably connected to the Eastern Black Sea Basin. In the back-arc basin, early Maastrichtian volcano-sedimentary arc sequence was transitionally overlain by pelagic sediments until late Danian suggesting continuous deep-marine conditions. However, the subsidence of the uplifted-arc-region did not occur until late Maastrichtian. We have documented a Selandian–early Thanetian (57–60 Ma) regional hiatus defining the closure age of the İzmir-Ankara-Erzincan Ocean along the Eastern Pontides. Between late Thanetian and late Lutetian synorogenic turbidites and postcollisional volcanics were deposited. The Eastern Pontide fold-and-thrust belt started to form at early Eocene (ca. 55 Ma) and thrusting continued in the post-Lutetian times.

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Basement-involved thrusting, salt migration and intramontane conglomerates: a case from the Southern Pyrenees

BSGF - Earth Sciences Bulletin ◽

10.1051/bsgf/2021013 ◽

2021 ◽

Author(s):

Laura Burrel ◽

Antonio Teixell ◽

David Gómez-Gras ◽

Xavier Coll

Keyword(s):

Cross Sections ◽

Lower Cretaceous ◽

Complex Structure ◽

Structural Data ◽

Alluvial Fan ◽

Northern Margin ◽

The North ◽

Salt Migration ◽

Sedimentary Evolution ◽

Thrust Sheets

The northern margin of the Organyà basin (Southern Pyrenees) has a complex structure in which syn-rift Lower Cretaceous carbonates flank a wide Keuper evaporite province, featuring the leading edges of the basement-involved thrust sheets of the Pyrenean antiformal stack. Recent observations show that Keuper diapirs and salt walls grew during the Cretaceous extensional episode, conditioning the development of differentiated depocenters and minibasins. The role of salt tectonics during the Pyrenean orogeny has not been addressed in previous structural studies, but present-day cross-sections indicate a Keuper evaporite-bearing vertical thickness of up to 3000 m in the Senterada-Gerri de la Sal area. We infer that salt migration was a determinant mechanism in triggering a gentle northward tilting of the Organyà basin during the Eocene-Oligocene, recorded in the La Pobla de Segur and Gurp syn-tectonic conglomerates in a basin-wide progressive unconformity and a large north-directed onlap, opposite to the main sedimentary influx direction. Contemporaneously, salt migration, promoted by conglomerate differential loading, enabled the sinking and rotation of the unrooted Nogueres thrust units (têtes plongeantes). We use new and published structural data for the Lower Cretaceous margin of the Organyà basin, combined with structural and clast provenance data from the Cenozoic alluvial fan conglomerates of La Pobla and Gurp, to understand the Lutetian to late Oligocene evolution of the northern margin of the Central South-Pyrenean Unit. The tectono-sedimentary evolution of this area and the salt evacuation patterns are closely related to the exhumation history of the stacked Paleozoic thrust sheets of the Pyrenean hinterland to the north. In this study we correlate the movements over a mobile substratum and the paleogeographic changes of conglomeratic basins at the toe of an exhuming orogenic interior.

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Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽

10.3390/geosciences11020102 ◽

2021 ◽

Vol 11 (2) ◽

pp. 102

Author(s):

Paraskevi Nomikou ◽

Dimitris Evangelidis ◽

Dimitrios Papanikolaou ◽

Danai Lampridou ◽

Dimitris Litsas ◽

...

Keyword(s):

Fault Zone ◽

Seismic Activity ◽

Volcanic Rocks ◽

Active Tectonics ◽

Normal Fault ◽

Aegean Sea ◽

Northern Margin ◽

The North ◽

Eastern Aegean ◽

Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

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

International Journal of Earth Sciences ◽

10.1007/s00531-021-02047-3 ◽

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.

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