Erratum: New constraints on the thickness of the Semail ophiolite in the Northern Emirates

Naville, Charles; Ancel, Martine; Andriessen, Paul; Ricarte, Patrice; Roure, François

doi:10.1007/s12517-010-0258-3

Cited by 4 publications

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“…We use our structural mapping constraints to restore the Bani Hamid thrust sheet in relation to the known geometry of the Semail ophiolite thrust sheet and present a tectonic evolution based on our new data combined with U-Pb timing constraints (Styles et al, 2006;Rioux et al, 2012aRioux et al, , 2013. We speculate on the composition and structure of the lower crust as imaged on recently acquired deep seismic profiles across the mountains in northern Oman and the UAE (Rouré et al, 2006;Tarapoanca et al, 2010;Naville et al, 2010). We integrate geological constraints from the northeastern Oman mountains where high-pressure eclogites have been exhumed east of Muscat (As Sifah eclogites; Searle et al, 1994Searle et al, , 2004Warren et al, 2003;Agard et al, 2010), and from the northern mountains where the Bani Hamid granulites crop out, to formulate a model for ophiolite obduction and emplacement.…”

Section: Introductionmentioning

confidence: 93%

“…Four deep seismic profiles were shot by WesternGeco (2005) on behalf of the Ministry of Energy of the UAE and preliminary results were presented by Batty et al (2004), Tarapoanca et al (2010), and Naville et al (2010). In addition, a new aeromagnetic survey in the UAE was carried out by Fugro (Batty et al, 2004;Styles et al, 2006).…”

Section: Deep Seismic Constraints From the Uaementioning

confidence: 99%

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Structure and metamorphism beneath the obducting Oman ophiolite: Evidence from the Bani Hamid granulites, northern Oman mountains

et al. 2015

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The Cretaceous Semail ophiolite (northern Oman and the United ArabEmirates) includes an intact thrust slice of Tethyan oceanic crust and upper mantle formed above a northeast-dipping subduction zone that was the site of initiation of obduction. The normal metamorphic sole of the Semail ophiolite comprises a highly condensed sequence of hornblende + plagioclase ± garnet amphibolites with small enclaves of garnet + clinopyroxene granulites immediately beneath the mantle sequence peridotites, tectonically underlain by a series of epidote amphibolite and greenschist facies lithologies in a highly deformed ductile shear zone. Peak metamorphic conditions of 770-900 °C and 11-15 kbar indicate metamorphism at depths far greater than can be accounted for by the preserved thickness of the ophiolite (~15 km). In the mountains of northern Oman, the 1.2-km-thick Bani Hamid thrust sheet is composed of intensely folded granulite and amphibolite facies rocks within mantle sequence peridotites, exhumed by late-stage out-of-sequence thrusting along the Bani Hamid thrust. The Bani Hamid thrust slice includes two-pyroxene quartzites (± hornblende, cordierite, sapphirine), diopside + andradite garnet + wollastonite + scapolite marbles and calc-silicates and amphibolites (hornblende + plagioclase ± clinopyroxene ± biotite) with localized partial melting, intruded by hornblende pegmatites. The Bani Hamid granulites represent metamorphosed cherts and calcareous turbidites probably derived from the distal Haybi Complex and Oman Exotic limestones, which have an alkali basaltic substrate. Metamorphic modeling using the program THERMOCALC in the system NCKFMASHTO (Na 2 O-CaO-K 2 O-FeO-MgO-Al 2 O 3 -SiO 2 -H 2 O-TiO 2 -O)gives peak pressure-temperature conditions of 850 ± 60 °C and 6.3 ± 0.5 kbar, a pressure that is much lower than that of the metamorphic sole, suggesting a different origin. The 206 Pb/ 238 U zircon dates indicate that the gabbroic crust of the ophiolite formed by ridge magmatism from before 96.1 to 95.5 Ma. The 206 Pb/ 238 U zircon dates from the metamorphic sole range from 95.7 to 94.5 Ma, and suggest that metamorphism and melting was either synchronous with or slightly postdated ridge magmatism. The Bani Hamid granulites are younger; zircon and titanite U-Pb dates span ca. 94.5-89.8 Ma. Peraluminous granitic dikes intruding the mantle sequence peridotites are as young as 91.4 Ma and likely reflect localized partial melting of crustal material during the late stage of the obduction process. A minimum of 130 km shortening is recorded by restoration of the major folds within the Bani Hamid thrust sheet, and more than 30 km offset has occurred along the west-directed breaching out-of-sequence Bani Hamid thrust. These rocks may be representative of deep-level duplexes imaged on recent seismic sections across the mountains of northern Oman-United Arab Emirates.

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Section: Introductionmentioning

confidence: 93%

Section: Deep Seismic Constraints From the Uaementioning

confidence: 99%

Structure and metamorphism beneath the obducting Oman ophiolite: Evidence from the Bani Hamid granulites, northern Oman mountains

et al. 2015

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“…Four deep seismic profiles, two along the strike of the mountains and two across the strike were acquired in the UAE by WesternGeco (2005) for the Ministry of Energy, UAE (Figure 6). Two of these lines cross the mountains, one (D4 line) from Umm al Quwain across the southern tip of the shelf carbonates, Dibba Zone and northern ophiolite to Ras Dadnah, the other (D1 line) from Ajman to Dhaid across the ophiolite and the Bani Hamid thrust sheet to south of Khawr Fakkan (Roure et al, 2006;Tarapoanca et al, 2010;Naville et al, 2010). The other two lines are aligned NNE-SSW, one along the foreland west of the mountain front (D3 line), the other runs along the Masafi corridor south into the ophiolite.…”

Section: Seismic Constraints On the Deep Structurementioning

confidence: 99%

Tectonics of the Musandam Peninsula and northern Oman Mountains: From ophiolite obduction to continental collision

Searle¹,

Cherry²,

Ali³

et al. 2014

GeoArabia

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The tectonics of the Musandam Peninsula in northern Oman shows a transition between the Late Cretaceous ophiolite emplacement related tectonics recorded along the Oman Mountains and Dibba Zone to the SE and the Late Cenozoic continent-continent collision tectonics along the Zagros Mountains in Iran to the northwest. Three stages in the continental collision process have been recognized. Stage one involves the emplacement of the Semail Ophiolite from NE to SW onto the Mid-Permian–Mesozoic passive continental margin of Arabia. The Semail Ophiolite shows a lower ocean ridge axis suite of gabbros, tonalites, trondhjemites and lavas (Geotimes V1 unit) dated by U-Pb zircon between 96.4–95.4 Ma overlain by a post-ridge suite including island-arc related volcanics including boninites formed between 95.4–94.7 Ma (Lasail, V2 unit). The ophiolite obduction process began at 96 Ma with subduction of Triassic–Jurassic oceanic crust to depths of > 40 km to form the amphibolite/granulite facies metamorphic sole along an ENE-dipping subduction zone. U-Pb ages of partial melts in the sole amphibolites (95.6– 94.5 Ma) overlap precisely in age with the ophiolite crustal sequence, implying that subduction was occurring at the same time as the ophiolite was forming. The ophiolite, together with the underlying Haybi and Hawasina thrust sheets, were thrust southwest on top of the Permian–Mesozoic shelf carbonate sequence during the Late Cenomanian–Campanian. Subduction ended as unsubductable cherts and limestones (Oman Exotics) jammed at depths of 25–30 km. The Bani Hamid quartzites and calc-silicates associated with amphibolites derived from alkali basalt show high-temperature granulite facies mineral assemblages and represent lower crust material exhumed by late-stage out-of-sequence thrusting. Ophiolite obduction ended at ca. 70 Ma (Maastrichtian) with deposition of shallow-marine limestones transgressing all underlying thrust sheets. Stable shallow-marine conditions followed for at least 30 million years (from 65–35 Ma) along the WSW and ENE flanks of the mountain belt. Stage two occurred during the Late Oligocene–Early Miocene when a second phase of compression occurred in Musandam as the Arabian Plate began to collide with the Iran-western Makran continental margin. The Middle Permian to Cenomanian shelf carbonates, up to 4 km thick, together with pre-Permian basement rocks were thrust westwards along the Hagab Thrust for a minimum of 15 km. Early Miocene out-of-sequence thrusts cut through the shelf carbonates and overlying Pabdeh foreland basin in the subsurface offshore Ras al Khaimah and Musandam. This phase of crustal compression followed deposition of the Eocene Dammam and Oligocene Asmari formations in the United Arab Emirates (UAE), but ended by the mid-Miocene as thrust tip lines are all truncated along a regional unconformity at the base of the Upper Miocene Mishan Formation. The Oligocene–Early Miocene culmination of Musandam and late Cenozoic folding along the UAE foreland marks the initiation of the collision of Arabia with Central Iran in the Strait of Hormuz region. Stage three involved collision of Arabia and the Central Iran Plate during the Pliocene, with ca. 50 km of NE-SW shortening across the Zagros Fold Belt. Related deformation in the Musandam Peninsula is largely limited to north and eastward tilting of the peninsula to create a deeply indented coastline of drowned valleys (rias).

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“…In addition to specific values derived from the refraction test and gravity modelling for defining the ophiolite thickness (see Naville et al 2010), we used more generalized velocity assumptions to generate the depth sections farther to the east, i.e., in the vicinity of D2, where still thick sedimentary units are imaged by seismic reflection.…”

Section: Depth Migration and Construction Of The Structural Sectionmentioning

confidence: 99%

Forward kinematic modelling of a regional transect in the Northern Emirates using geological and apatite fission track age constraints on paleo-burial history

Tărăpoancă

Andriessen²,

Broto

et al. 2010

Arab J Geosci

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This paper aims to simulate the kinematic evolution of a regional transect crossing the Northern Emirates in the northernmost part of the Semail Ophiolite and the Dibba zone, just south of the Musandam Platform exposures. The studied section comprises, from top to bottom and from inner to outer zones, (1) the erosional remnants of the Semail Ophiolite, mainly made up of serpentinized ultramafics in the west and gabbros in the east, (2) high-grade metamorphic rocks which are currently exposed in the core of a nappe anticline near Masafi, (3) far-travelled Hawasina basinal units and Sumeini paleoslope units of the Dibba Zone, (4) parautochthonous platform carbonates, which are currently well exposed in the Musandam area, and (5) a flexural basin filled with uppermost Cretaceous to Neogene sediments. Two main compressional episodes are generally identified, resulting first in the obduction of the Semail Ophiolite and then in the stacking of underlying platform carbonate units of the former Arabian passive margin, thus accounting for the present architecture of this transect: (1) first, deformation at the plate boundary initiated in the Late Cretaceous, resulting in the obduction of the Semail Ophiolite and the progressive accretion of the Hawasina and Sumeini tectonic wedge on top of the Arabian foreland, leading to a progressive bending of its lithosphere and development of a wide flexural basin; (2) compression resumed during the Neogene, leading to the tectonic stacking of the parautochthonous platform duplexes of Musandam and Margham trends, the development of out-of-sequence thrusts and triangle zones, refolding of the sole thrust of the former Late Cretaceous accretionary wedge and coeval normal (?) high-angle faulting along the contact between the Musandam and Dibba zones. However, seismic profiles and paleo-thermometers also help in identifying another erosional event at the boundary between the Paleogene Pabdeh and the Neogene Fars series. Evidenced by the local erosional truncation of the Pabdeh series in the vicinity of the frontal triangle zone (i.e. the inner part of the former Late Cretaceous foredeep), this Paleogene uplift/unroofing episode is tentatively interpreted here as an evidence for a continuum of compressional deformation lasting from the Late Cretaceous to the Middle Miocene although one may alternatively speculate that it was related to the detachment of the subducted slab. Although carbonate facies are usually not suitable for apatite fission track (AFT) studies, we were able to extract detrital apatites from quartz-bearing Triassic dolomites in the Musandam area. However, the yield and the quality were both poor and too few fission track lengths could be measured, making it difficult to interpret the meaning of the FT ages. The FT dates obtained in this study are therefore compared with those existing in Arab J Geosci (2010) 3:395-411 DOI 10.1007 the literature. Fortunately enough, for each sample, at least ten apatite crystals could be used for fission track dating, except f...

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Erratum: New constraints on the thickness of the Semail ophiolite in the Northern Emirates

Abstract: aThe online version of the original article can be found at http://dx.doi.

Cited by 4 publications

References 0 publications

Structure and metamorphism beneath the obducting Oman ophiolite: Evidence from the Bani Hamid granulites, northern Oman mountains

Structure and metamorphism beneath the obducting Oman ophiolite: Evidence from the Bani Hamid granulites, northern Oman mountains

Tectonics of the Musandam Peninsula and northern Oman Mountains: From ophiolite obduction to continental collision

Forward kinematic modelling of a regional transect in the Northern Emirates using geological and apatite fission track age constraints on paleo-burial history

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