Geological and seismic evidence for the tectonic volution of the NE Oman continental margin and Gulf of Oman

Geosphere ◽

10.1130/ges02376.1 ◽

2021 ◽

Author(s):

Bruce Levell ◽

Michael Searle ◽

Adrian White ◽

Lauren Kedar ◽

Henk Droste ◽

...

Keyword(s):

Continental Margin ◽

Late Cretaceous ◽

Deep Water ◽

Large Scale ◽

Accretionary Prism ◽

Oceanic Lithosphere ◽

Seismic Reflection Data ◽

Gulf Of Oman ◽

Semail Ophiolite

Late Cretaceous obduction of the Semail ophiolite and underlying thrust sheets of Neo-Tethyan oceanic sediments onto the submerged continental margin of Oman involved thin-skinned SW-vergent thrusting above a thick Guadalupian–Cenomanian shelf-carbonate sequence. A flexural foreland basin (Muti and Aruma Basin) developed due to the thrust loading. Newly available seismic reflection data, tied to wells in the Gulf of Oman, suggest indirectly that the trailing edge of the Semail Ophiolite is not rooted in the Gulf of Oman crust but is truncated by an ENE-dipping extensional fault parallel to the coastline. This fault is inferred to separate the Semail ophiolite to the SW from in situ oceanic Gulf of Oman crust to the NE. It forms the basin margin to a “hinterland” basin formed atop the Gulf of Oman crust, in which 5 km of Late Cretaceous deep-water mudstones accumulated together with 4 km of Miocene and younger deep-water mudstones and sandstones. Syndepositional folding included Paleocene–Eocene folds on N-S axes, and Paleocene to Oligocene growth faults with roll-over anticlines, along the basin flank. Pliocene compression formed, or tightened, box folds whose axes parallel the modern coast with local south-vergent thrusts and reversal of the growth faults. This Pliocene compression resulted in large-scale buckling of the Cenozoic section, truncated above by an intra-Pliocene unconformity. A spectacular 60-km-long, Eocene(?) to Recent, low-angle, extensional, gravitational fault, down-throws the upper basin fill to the north. The inferred basement of the hinterland basin is in situ Late Cretaceous oceanic lithosphere that is subducting northwards beneath the Makran accretionary prism.

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Revised stratigraphy of the Mesozoic rocks of southern Cyprus

Geological Magazine ◽

10.1017/s0016756800028892 ◽

1980 ◽

Vol 117 (6) ◽

pp. 547-563 ◽

Cited By ~ 40

Author(s):

R. E. Swarbrick ◽

A. H. F. Robertson

Keyword(s):

Oceanic Crust ◽

Continental Margin ◽

Late Cretaceous ◽

Sedimentary Cover ◽

Igneous Rocks ◽

Late Triassic ◽

Metamorphic Rocks ◽

Southern Cyprus

SummaryRecent resurgence of interest in the Mesozoic rocks of SW and southern Cyprus necessitates redefinition of the Mesozoic sedimentary and igneous rocks in line with modern stratigraphical convention. Two fundamentally different rocks associations are present, the Troodos Complex, not redefined, a portion of late Cretaceous oceanic crust, and the Mamonia Complex, the tectonically dismembered remnants of a Mesozoic continental margin. Based on earlier work, the Mamonia Complex is divided into two groups, each subdivided into a number of subsidiary formations and members. The Ayios Photios Group is wholly sedimentary, and records the evolution of a late Triassic to Cretaceous inactive continental margin. The Dhiarizos Group represents Triassic alkalic volcanism and sedimentation adjacent to a continental margin. Several other formations not included in the two groups comprise sedimentary mélange and metamorphic rocks. The Troodos Complex possesses an in situ late Cretaceous sedimentary cover which includes two formations of ferromanganiferous pelagic sediments, radiolarites and volcaniclastic sandstones. The overlying Cainozoic calcareous units are not redefined here.

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Architecture of the crust and lithosphere beneath the Semail Ophiolite from ambient noise tomography and receiver functions: insights on the tectonic evolution of eastern Arabia

10.5194/egusphere-egu21-9890 ◽

2021 ◽

Author(s):

Christian Weidle ◽

Lars Wiesenberg ◽

Andreas Scharf ◽

Philippe Agard ◽

Amr El-Sharkawy ◽

...

Keyword(s):

Late Cretaceous ◽

Ambient Noise ◽

Function Analysis ◽

Oceanic Lithosphere ◽

Receiver Functions ◽

Crustal Thickening ◽

Ambient Noise Tomography ◽

First Order ◽

Pan African ◽

Semail Ophiolite

The Semail Ophiolite is the world&#8216;s largest and best exposed oceanic lithosphere on land and a primary reference site for studies of creation of oceanic lithosphere, initiation of subduction, geodynamic models of obduction, subduction and exhumation of continental rocks during obduction. Five decades of geological mapping, structural, petrological and geochronological research provide a robust understanding of the geodynamic evolution of the shallow continental crust in northern Oman and how the late Cretaceous obduction process largely shaped the present-day landscape. Yet, prior to obduction, other first-order tectonic processes have left their imprint in the lithosphere, in particular the Neoproterozoic accretion of Arabia and Permian breakup of Pangea. Due to the scarcity of deep structure imaging below the ophiolite, the presence and significance of inherited structures for the obduction process remain unclear.We discuss a new 3-D anisotropic shear wave velocity model of the crust below northern Oman derived from ambient noise tomography and Receiver Function analysis which allows to resolve some key unknowns in geodynamics of eastern Arabia: (1) Several NE-trending structural boundaries in the middle and lower crust are attributed to the Pan-African orogeny and align with first-order lateral changes in surface geology and topography. (2) The well-known Semail Gap Fault Zone is an upper crustal feature whereas two other deep crustal faults are newly identified. (3) Permian rifting occurred on both eastern and northern margins but large-scale mafic intrusions and/or underplating occurred only in the east. (4) While obduction is inherently lithospheric by nature, its effects are mostly observed at shallow crustal depths, and lateral variations in its geometry and dynamics can be explained by effects on pre-existing Pan-African and Permian structures. (5) Continental subduction and exhumation during late Cretaceous obduction may be the cause for crustal thickening below today&#8216;s topography. (6) Thinning of the continental lithosphere below northern Oman in late Eocene times &#8211; possibly related to thermal effects of the incipient Afar mantle plume - provides a plausible mechanism for the broad emergence of the Oman Mountains and in particular the Jabal Akhdar Dome. Uplift might thus be unrelated to compressional tectonics during Arabia-Eurasia convergence as previously believed.

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Dynamics and evolution of continental margin clinoform systems

10.5194/egusphere-egu2020-21495 ◽

2020 ◽

Author(s):

Gerben de Jager ◽

Dicky Harishidayat ◽

Benjamin Emmel ◽

Ståle Emil Johansen

Keyword(s):

Sea Level ◽

Continental Margin ◽

Water Depth ◽

Large Scale ◽

Barents Sea ◽

Source Rocks ◽

Sea Level Changes ◽

Seismic Reflection Data ◽

Reflection Data ◽

Geological Processes

Clinoforms are aquatic sedimentary features commonly associated with strata prograding from a shallower water depth into a deeper water depth. They are very sensitive to changes in water depth, rapidly moving along the shelf in response to sea level changes. &#160;By reconstructing the initial clinoform geometry of buried clinoforms, an estimate of the paleo water depth (PWD) can be made. When this is done for several subsequent clinoform sets the amounts and rates of bathymetric changes can be calculated.Here we present a novel approach to estimate clinoform parameters and depositional depths for continental margin clinoforms using seismic reflections, wellbore and biostratigraphy data. Seismic interpretation of three relatively east-west regional full-stack seismic reflection data from the continental margin of the western Barents Sea revealed twelve Late Cenozoic horizons. The clinoform shapes have been restored by removing the effects of compaction and flexural isostasy (backstripping). This includes the effects of glacial/interglacial scenarios on horizons with strong glaciomarine seismic indications.Based on the reconstructed clinoform geometries we use empirical relationships from literature between clinoform geometry and depositional depth to estimate PWD values. In these analyses it is possible to estimate the PWD of the upper rollover point and the toe point by measuring the bottomset height, foreset height and topset height. A sensitivity analysis study has also been done on several different scenarios, varying elastic thickness, decompaction and net to gross ratio. Comparison with biostratigraphic water depth estimates indicate that PWD estimates revealed from clinoform parameters give reliable results.Any mismatch between the backstripped PWD values and the PWD values derived from the clinoform geometry can then be attributed to geological processes not included in the backstripping process. Among others, these could be explained by rifting, thermal effects in the lithosphere, faulting or eustatic sea level changes. This allows the quantification of the magnitude of these large-scale crustal processes through time.We will demonstrate that this method can further constrain the PWD on the continental margin clinoform system and thus can help to improve the understanding of the interplay between sedimentary processes and large-scale crustal processes. Furthermore, the PWD estimates will be a reliable input for further analysis of source-to-sink and stratigraphic forward modeling studies as well as reservoir and source rocks prediction on the petroleum development and exploration.&#160;

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Chapter 5 Tectonic evolution of the Oman Mountains

Geological Society London Memoirs ◽

10.1144/m54.5 ◽

2021 ◽

Vol 54 (1) ◽

pp. 67-103

Author(s):

Andreas Scharf ◽

Frank Mattern ◽

Mohammed Al-Wardi ◽

Gianluca Frijia ◽

Daniel Moraetis ◽

...

Keyword(s):

Subduction Zone ◽

Late Cretaceous ◽

Tectonic Evolution ◽

Oceanic Lithosphere ◽

Passive Margin ◽

Arabian Plate ◽

Continental Lithosphere ◽

Oman Mountains ◽

Semail Ophiolite ◽

Arabian Platform

AbstractThe tectonic evolution of the Oman Mountains as of the Neoproterozoic begins with a major extensional event, the Neoproterozoic Abu Mahara rifting. It was followed by the compressional Nabitah event, still during the Neoproterozoic, in Oman but possibly not in the study area. During the earliest Cambrian, the Jabal Akhdar area was affected by the Cadomian Orogeny, marked by NE--SW shortening. It is unclear, whether the Saih Hatat area was exposed to the Cadomian deformation, too. Still during the lower Cambrian, the Angudan Orogeny followed, characterized by NW--SE shortening. An episode of rifting affected the Saih Hatat area during the mid-Ordovician. During the mid-Carboniferous, both dome areas were deformed by tilting and large-scale open folding in the course of the ‘Hercynian’ event. As a consequence, a major unconformity formed. As another Late Paleozoic event, the Permian break-up of Pangaea and subsequent formation of the Hawasina ocean basin, are recorded in the Southeastern Oman Mountains. As a result, a passive margin formed which existed until the mid-Cretaceous, characterized by deposition of mostly shelfal carbonates. This interval of general tectonic quiescence was interrupted during the early Jurassic by uplift and tilting of the Arabian Platform. The platform collapsed during the late Cretaceous, related to the arrival of the obducted allochthonous nappes including the Semail Ophiolite, transforming the passive margin to an active margin.The Semail Ophiolite formed most likely above a subduction zone within the Neo-Tethys Ocean during the Cenomanian while parts of the Arabian Plate were subducted to the NE. Formation of oceanic lithosphere and SW-thrusting was broadly coeval, resulting in ophiolite obduction onto the Hawasina Basin. The Semail Ophiolite and the Hawasina rocks combined were thrust further onto the Arabian Plate. Their load created a foreland basin and forebulge within the Arabian Platform. Once the continental lithosphere of the Arabian Platform was forced into the subduction zone, a tear between the dense oceanic lithosphere and the buoyant continental lithosphere developed. This led to rapid uplift and exhumation of subducted continental lithosphere of the Saih Hatat area, while obduction was still going on, causing in multiple and intense folding/thrusting within the eastern Saih Hatat Dome. Exhumation of the Saih Hatat Dome was massive. The emplacement of the ophiolite was completed during the Campanian/Maastrichtian. For completeness, we also present alternative models for the developmental history of the Semail Ophiolite.Immediately after emplacement, the Arabian lithosphere underwent intense top-to-the-NE extensional shearing. Most of the Saih Hatat Dome was exhumed during the latest Cretaceous to Early Eocene, associated with major extensional shearing at its flanks. Further convergence during the late Eocene to Miocene resulted in exhumation of the Jabal Akhdar Dome and some gentle exhumation of the Saih Hatat Dome, shaping the present-day Southeastern Oman Mountains. In the coastal area, east and SE of the Saih Hatat Dome, some late Cretaceous to present-day uplift is evident by, e.g., uplifted marine terraces. The entire Oman Mountains are uplifting today, which is evident by the massive wadi incision into various rock units, including wadi deposits which may form overhangs.

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Alkaline peridotite, pyroxenite, and gabbroic intrusions in the Oman Mountains, Arabia

Canadian Journal of Earth Sciences ◽

10.1139/e84-043 ◽

1984 ◽

Vol 21 (4) ◽

pp. 396-406 ◽

Cited By ~ 18

Author(s):

Michael P. Searle

Keyword(s):

Continental Margin ◽

Late Cretaceous ◽

Volatile Components ◽

Titanium Oxides ◽

Structural Mapping ◽

Oman Mountains ◽

Intrusive Rocks ◽

Alkaline Magmas ◽

High Level ◽

Semail Ophiolite

High-level intrusions of highly undersaturated alkalic ultrabasic and gabbroic rocks occur in four areas of the Oman Mountains. They all intrude either the Haybi volcanic – Oman Exotic limestone (Permo-Triassic) thrust slice immediately beneath the Semail Ophiolite (Cenomanian) or the uppermost thrust slice of the underlying Hawasina (Permian to Cenomanian) Tethyan sediments. Detailed structural mapping indicates that the sills were all emplaced prior to the Late Cretaceous thrusting of the Oman allochthon onto the Mesozoic continental margin of Arabia, and therefore in an oceanic setting. These differentiated sills consist of biotite wehrlites at the base and kaersutite-bearing jacupirangites above, with kaersutite gabbros at the top. Olivine occurs only at the base. Titanaugite, kaersutite, titanium phlogopite, apatite, and opaque iron–titanium oxides are common mineral phases.Fractional crystallization and gravity differentiation processes and a rapid increase in volatile components at decreasing pressures all played a part in the petrogenesis of these uncommon intrusive rocks. K–Ar ages on biotites span the mid-Jurassic to Cenomanian, and in the northern Oman Mountains kaersutite jacupirangites are incorporated into the Cenomanian–Turonian amphibolite facies metamorphic sheet beneath the Semail Ophiolite. Alkaline magmas were present at depth along the passive continental margin, right up until Cenomanian times when northeast subduction was initiated and compressional tectonics began. Alkaline volcanism of Cenomanian age in the Dibba Zone indicates that tensional rifting processes were operative along the continental margin at the same time as compressional thrusting was occurring outboard. The alkaline rocks are unrelated to the ophiolite but are artifacts of Mesozoic rifting events in Tethys now preserved in footwall thrust slices beneath the ophiolite.

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Tectonically controlled initiation of contemporaneous deep-water channel systems along a Late Cretaceous continental margin, western British Columbia, Canada

Sedimentology ◽

10.1111/sed.12472 ◽

2018 ◽

Vol 65 (7) ◽

pp. 2404-2438 ◽

Cited By ~ 10

Author(s):

Rebecca G. Englert ◽

Stephen M. Hubbard ◽

Daniel S. Coutts ◽

William A. Matthews

Keyword(s):

British Columbia ◽

Continental Margin ◽

Late Cretaceous ◽

Deep Water ◽

Water Channel ◽

Channel Systems

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Alpine tectonic evolution of the Northern Serbo-Macedonian sub-unit: inferences from kinematic and petrological investigations

10.5194/egusphere-egu21-202 ◽

2021 ◽

Author(s):

Bojan Kostić ◽

Uroš Stojadinović ◽

Nemanja Krstekanić ◽

Marija Ružić ◽

Aleksa Luković

Keyword(s):

Continental Margin ◽

Late Cretaceous ◽

Pannonian Basin ◽

Oceanic Lithosphere ◽

Normal Faults ◽

Low Grade ◽

The South ◽

The North ◽

Neogene Sediments ◽

Subduction System

The Serbo-Macedonian Massif represents a belt of medium to lower amphibolite facies metamorphics situated along the European continental margin between the Pannonian Basin in the north and the Aegean Sea in the south. Structurally, it comprises the innermost segments of the Dacia mega-unit of the European affinity and is juxtaposed against the Adria-derived units of the Dinarides across the Adria-Europe zone of collision. The peak metamorphic event in the Serbo-Macedonian Massif is Variscan in age, while its magmatism had a complex pre-Alpine evolution, with the youngest stage being related to the crustal extension during the Triassic opening of the northern branch of Neotethys Ocean (or the Vardar Ocean). The subsequent Late Jurassic&#8211;Paleogene closure of the Vardar Ocean led to the E-ward subduction of the Neotethys oceanic lithosphere beneath the upper European plate (i.e., the Sava subduction system). The retreating and steepening of subducting lithosphere during the Late Cretaceous triggered syn-subductional extension in the upper plate of the Sava subduction system. The Late Cretaceous extension exhumed and structurally juxtaposed the high-grade Serbo-Macedonian metamorphics against the low-grade metamorphics of the Carpathians Supragetic Unit. The contact is marked by the E-dipping shear zone that can be traced along the eastern margin of Serbo-Macedonian Massif, from the Vr&#353;ac Mts in the north, across the Jastrebac Mts and further towards the south in the Central Serbo-Macedonian sub-unit of south-eastern Serbia. The Late Cretaceous extension exhumed the Serbo-Macedonian metamorphic core, concurrently creating subsidence in a forearc basin along the frontal part of the European continental margin.Due to its unique position in the interference zone of the two retreating Carpathian and Dinaridic slabs, the Northern Serbo-Macedonian sub-unit between the Vr&#353;ac Mts in the north and the Jastrebac Mts in the south was strongly influenced by processes associated with the Oligocene&#8211;Miocene Pannonian extension. Hence, large segments of the Northern Serbo-Macedonian sub-unit including its contact with the Supragetic Unit were buried beneath the Neogene sediments of the Morava Valley Corridor, as the southern prolongation of the Pannonian Basin. In order to segregate and quantify the effects of the Oligocene&#8211;Miocene extension we have conducted a coupled kinematic, petrological and thermochronological study in the segments of Northern Serbo-Macedonian sub-unit adjacent to the Dinarides and Carpathians. The recent tectonic uplift of the Vr&#353;ac Mts occurred in the Middle to Late Miocene along the WSW-dipping normal faults that control deposition in the adjacent Zagajica depression. The ENE-WSW oriented extension, which was triggered by the retreat of Carpathian slab, exhumed the core of the mountains and exposed the Late Cretaceous Serbo-Macedonian\Supragetic extensional contact. South from the Vr&#353;ac Mts such exhumation was hampered by the presence of rigid Moesian indenter. Tectonic exhumation of the Jastrebac Mts, together with a cluster of Serbo-Macedonian gneiss domes that emerge from the surrounding Neogene sediments in the western-central part of the Morava Valley Corridor, was induced by corrugated detachment faults during the Oligocene&#8211;Miocene E-W oriented Dinaridic extension.

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Chapter 3 Thrusts, extensional faults and fold patterns of the major units

Geological Society London Memoirs ◽

10.1144/m54.3 ◽

2021 ◽

Vol 54 (1) ◽

pp. 49-60 ◽

Cited By ~ 2

Author(s):

Andreas Scharf ◽

Frank Mattern ◽

Mohammed Al-Wardi ◽

Gianluca Frijia ◽

Daniel Moraetis ◽

...

Keyword(s):

Late Cretaceous ◽

Large Scale ◽

Oman Mountains ◽

Semail Ophiolite ◽

Cylindrical Folds ◽

Arabian Platform

AbstractThis chapter is concerned with the main faults and folds within the Southeastern Oman Mountains based on available literature. The main, best and most widely exposed thrusts are those related to the SW-directed late Cretaceous obduction of the allochthonous nappes onto the Arabian platform and margin. These thrusts are related to obduction of rocks, which had formed hundreds of kilometres offshore Oman. The thrusts were active from the Cenomanian to the Campanian. Obduction-related thrusts and folds are spectacularly exposed within the rocks of the Arabian platform in the eastern part of the Saih Hatat Dome, including large-scale recumbent cylindrical folds and sheath folds. At least six fold sets can be studied in the Southeastern Oman Mountains. At least two of them had formed prior to obduction and are exposed in the Pre-Permian formations of the Jabal Akhdar Dome. At least three fold sets formed in the course of obduction, while at least one fold set is postobductional in age. Besides the compressional structures, the Oman Mountains expose major post-obductional extensional faults, mostly at the margins of the Jabal Akhdar and Saih Hatat domes. The throw of these faults amounts to a few to several kilometres. Finally, this chapter provides an overview of the enigmatic Batinah Mélange which consists of slivers of Hawasina rocks, resting (unusually) structurally above the Semail Ophiolite.

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Late Cretaceous–Early Eocene tectonic development of the Tethyan suture zone in the Erzincan area, Eastern Pontides, Turkey

Geological Magazine ◽

10.1017/s0016756809006360 ◽

2009 ◽

Vol 146 (4) ◽

pp. 567-590 ◽

Cited By ~ 71

Author(s):

SAMUEL P. RICE ◽

ALASTAIR H. F. ROBERTSON ◽

TIMUR USTAÖMER ◽

NURDAN İNAN ◽

KEMAL TASLI

Keyword(s):

Subduction Zone ◽

Late Cretaceous ◽

Upper Cretaceous ◽

Accretionary Prism ◽

Oceanic Lithosphere ◽

Suture Zone ◽

Passive Margin ◽

Early Eocene ◽

Volcanic Arc ◽

Eastern Pontides

AbstractSix individual tectonostratigraphic units are identified within the İzmir–Ankara–Erzincan Suture Zone in the critical Erzincan area of the Eastern Pontides. The Ayıkayası Formation of Campanian–Maastrichtian age is composed of bedded pelagic limestones intercalated with polymict, massive conglomerates. The Ayıkayası Formation conformably overlies the Tauride passive margin sequence in the Munzur Mountains to the south and is interpreted as an underfilled foredeep basin. The Refahiye Complex, of possible Late Cretaceous age, is a partial ophiolite composed of ~75% (by volume) serpentinized peridotite (mainly harzburgite), ~20% diabase and minor amounts of gabbro and plagiogranite. The complex is interpreted as oceanic lithosphere that formed by spreading above a subduction zone. Unusual screens of metamorphic rocks (e.g. marble and schist) locally occur between sheeted diabase dykes. The Upper Cretaceous Karayaprak Mélange exhibits two lithological associations: (1) the basalt + radiolarite + serpentinite association, including depleted arc-type basalts; (2) the massive neritic limestone + lava + volcaniclastic association that includes fractionated, intermediate-composition lavas, and is interpreted as accreted Neotethyan seamount(s). The several-kilometre-thick Karadağ Formation, of Campanian–Maastrichtian age, is composed of greenschist-facies volcanogenic rocks of mainly basaltic to andesitic composition, and is interpreted as an emplaced Upper Cretaceous volcanic arc. The Campanian–Early Eocene Sütpınar Formation (~1500 m thick) is a coarsening-upward succession of turbiditic calcarenite, sandstone, laminated mudrock, volcaniclastic sedimentary rocks that includes rare andesitic lava, and is interpreted as a regressive forearc basin. The Late Paleocene–Eocene Sipikör Formation is a laterally varied succession of shallow-marine carbonate and siliciclastic lithofacies that overlies deformed Upper Cretaceous units with an angular unconformity. Structural study indicates that the assembled accretionary prism, supra-subduction zone-type oceanic lithosphere and volcanic arc units were emplaced northwards onto the Eurasian margin and also southwards onto the Tauride (Gondwana-related) margin during Campanian–Maastrichtian time. Further, mainly southward thrusting took place during the Eocene in this area, related to final closure of Tethys. Our preferred tectonic model involves northward subduction, supra-subduction zone ophiolite genesis and arc magmatism near the northerly, Eurasian margin of the Mesozoic Tethys.

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The syn- and post-obduction history of the offshore north Oman margin

10.5194/egusphere-egu2020-22476 ◽

2020 ◽

Author(s):

Dia Ninkabou ◽

Philippe Agard ◽

Charlotte Nielsen ◽

Jeroen Smit ◽

Bilal Haq ◽

...

Keyword(s):

Continental Margin ◽

Late Cretaceous ◽

Detachment Fault ◽

Passive Margin ◽

Gulf Of Oman ◽

Pan African ◽

History Of ◽

Ophiolite Emplacement ◽

Well Data ◽

Seismic Lines

The offshore north Oman margin, located north of the Hajar Mountains in the Gulf of Oman, remains a key area for understanding the evolution of the obduction Emails Ophiolite. With the help of a grid of 2D-multichannel seismic lines linked to well data, we present a new view of the obduction and post-obduction history of the Oman margin. Offshore deposits, overlying on what we interpret as being the offshore extension of the ophiolites, can be divided into two mega-sequences. The older one is comprised of late Cretaceous to Paleogene deposits mainly located in the Sohar basin and offshore of the Abat trough. In the Sohar basin, the latest stages of obduction are recorded by the deposition of the erosional products of the Autochthonous Arabian sediments and the ophiolite, in a flexural basin induced by a volcanic high. Offshore of the Abat trough, a Maastrichtian-Paleocene basin develops above a detachment fault system linked to the extension phase associated to the exhumation/expulsion of the subducted continental margin. Both sectors are divided by a structured high located offshore of the Semail Gap transfer fault. We propose that this transfer fault, likely a major Pan-African structure, impacted both the architecture of the passive margin following the rifting of the Neotethys and later ophiolite emplacement, during (continental) subduction and obduction.

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