The transition from a passive margin to an Upper Cretaceous foreland basin related to ophiolite emplacement in the Oman Mountains

Robertson, Alastair H.F.

doi:10.1130/0016-7606(1987)99<633:ttfapm>2.0.co;2

Cited by 147 publications

(98 citation statements)

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“…In northern Oman, the unconformity at the base of the Aruma Group was interpreted by Robertson (1987) as recording the erosion of a flexural bulge during late Cenomanian to Turonian times, and is responsible for the removal of the deeper water Turonian sediments of the top of the Natih Formation in Wadi Mi'aidin (Philip et al 1995). Clasts within the limestones from the uppermost part of the Muti Formation were derived from all levels of the platform sequence, down to strata of Permian age, highlighting the depth of erosion associated with this regional low-angle unconformity.…”

Section: Base Aruma Group (Turonian) Unconformitymentioning

confidence: 99%

“…Clasts within the limestones from the uppermost part of the Muti Formation were derived from all levels of the platform sequence, down to strata of Permian age, highlighting the depth of erosion associated with this regional low-angle unconformity. The unconformity results in the Muti Formation resting on progressively older strata to the north of the Jebal Akhdar Massif, down to the Triassic Mahil Formation (Glennie et al 1974;Robertson 1987).…”

Section: Base Aruma Group (Turonian) Unconformitymentioning

confidence: 99%

“… A lower unit dominated by a sequence of packstones, wackestones and mudstones with ferruginous and phosphatic deposits, interpreted by Robertson (1987) as representing a shallow shoal and bioclastic bank setting. The ferruginous horizons denote hardgrounds within this sequence, with current-winnowed lag deposits forming during these breaks in sedimentation.…”

Section: Muti Formationmentioning

confidence: 99%

“…12c), probably sourced from the Thamama and Wasia groups, and quartz grains in the lower part, are considered to reflect erosion of the adjacent carbonate platform. Robertson (1987) considered the upper unit of the Muti Formation to document the collapse of this platform. The Muti Formation at Wadi Mi'aidin is now interpreted as inner ramp deposits.…”

Section: Muti Formationmentioning

confidence: 99%

“…This re-evaluation is largely based on mapping at the 1:25,000 and 1:50,000 scales of the UAE undertaken by the British Geological Survey between 2002 and 2006 . During the course of this work the definitions of the main stratigraphical units and tectonic evolutionary history established by Glennie et al (1974) and followed by Searle et al (1983), Robertson et al (1987), and Robertson and Searle (1990) were evaluated. The principle concept that the autochthonous, parautochthonous and allochthonous sequences in the UAE record the transition from platform, slope to basin sedimentation has been fundamental to the interpretation of the geological history of the region.…”

Section: Introductionmentioning

confidence: 99%

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The Jurassic–Cretaceous depositional and tectonic evolution of the southernwestern margin of the Neotethys Ocean, Northern Oman and United Arab Emirates

Phillips

Waters

Ellison

2012

Lithosphere Dynamics and Sedimentary Basins: The Arabian Plate and Analogues

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The concept that the autochthonous, parautochthonous and allochthonous Permian-Cretaceous sequences in the United Arab Emirates (UAE) and Oman record the transition from platform, slope to basin sedimentation within the southern part of Neotethys has been fundamental to the interpretation of the geological history of the region. The results of a major geological mapping programme of the UAE, carried out by the British Geological Survey for the Federal Government of the UAE, coupled with the detailed examination of key sections within northern Oman has led to a re-evaluation of the geological evolution of this region. This detailed study has led to a greater appreciation of the sedimentology and depositional setting of the sediments laid down along the northeastern Arabian continental margin during the Jurassic to Cretaceous, allowing a more refined model of Neotethys Ocean basin evolution to be established. The model charts the progressive breakup of the Arabian continental margin and closure of Neotethys during the mid to late Cretaceous and is divided into three main stages: Stage 1 -Initial rifting and formation of the Neotethys Ocean, followed by a prolonged period of stable, passive margin sedimentation which extended from the Permian to Late Jurassic times; Stage 2 -Uplift and erosion of the shelf margin during the Late Jurassic to Early Cretaceous, coincident with increased carbonate-clastic sedimentation in the outer ramp, distal slope and basinal areas; Stage 3 -Increased instability during the Late Cretaceous leading to the breakup of the platform margin and foreland basin sedimentation accompanying the obduction of the Oman-UAE ophiolite. Data obtained for the upper part of the platform and platform margin to slope successions has revealed that the topography of the "shelf"-slope-basinal margin was more subdued than previously thought, with this more gentle ramp margin morphology persisting until early to midCretaceous times when the platform margin started to become unstable during ophiolite obduction. The thrust-repeated allochthonous sedimentary rocks of the Hamrat Duru Group were deposited on the outer platform margin/lower slope rise to basinal plain of this basin margin and includes the dismembered remains of two turbidite fan systems which fed carbonate-rich detritus into deeper parts of the ocean. A re-evaluation of the chert-rich sequences, previously equated with deposition on the abyssal plain of Neotethys, has led to the conclusion that they may record sedimentation at a much shallower level within a starved ocean basin, possibly in a mid-ramp (above storm wave base) to outer ramp setting. A marked change in basin dynamics occurred during the mid-Cretaceous leading to the development of a shallow ramp basin margin in Oman with terrestrial to shallow marine sedimentary rocks interdigitating with red siliceous mudstones. By contrast, the contemporaneous succession in the Dibba Zone of the UAE indicates considerable instability on a steep shelf break. This instability is recorded by t...

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Section: Base Aruma Group (Turonian) Unconformitymentioning

confidence: 99%

Section: Base Aruma Group (Turonian) Unconformitymentioning

confidence: 99%

Section: Muti Formationmentioning

confidence: 99%

Section: Muti Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Jurassic–Cretaceous depositional and tectonic evolution of the southernwestern margin of the Neotethys Ocean, Northern Oman and United Arab Emirates

Phillips

Waters

Ellison

2012

Lithosphere Dynamics and Sedimentary Basins: The Arabian Plate and Analogues

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Complex fault-fold interactions during the growth of the Jabal Qusaybah anticline at the western tip of the Salakh Arch, Oman

et al. 2015

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The Jabal Qusaybah anticline is located at the western end of the Salakh Arch, a major salient in the foothills of the Oman Mountains. We performed a structural and petrographical-geochemical study of vein sets and fault zones associated with the development of this anticline. Our data illustrate a complex deformation pattern both in space and time, characterized by the unusual presence of widespread NE-SW left-lateral strike-slip fault zones trending oblique to the E-W fold axial strike, and of abundant and well-developed N-S fold-perpendicular extensional fault zones associated with axial bulging and dilation, well developed in the central region of the anticlinal crest. We propose a three-stage evolution for the Jabal Qusaybah anticline, starting with prefolding jointing in the foreland of the late Cretaceous Oman Mountains, and followed by development of extensional faulting in Campanian times. Positive inversion of the Qusaybah Fault, possibly in Miocene times, caused development of a layer-parallel shortening fabric and amplification the Jabal Qusaybah Anticline, in concomitance with the activity of NE-SW left-lateral strike-slip fault zones that triggered N-S, fold-perpendicular extensional faulting, particularly in the axial bump of the anticline. The final evolutionary stage was characterized by further amplification of the axial bump and related N-S extensional fracturing and by uplift and exhumation. To explain the complex noncylindrical fault-fold interactions in the study anticline, we tentatively propose that they were triggered by near foredeep-parallel tapering of the sedimentary/tectonic overburden of the Ara evaporites.

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Multiphase Structural Evolution of a Continental Margin During Obduction Orogeny: Insights From the Jebel Akhdar Dome, Oman Mountains

et al. 2018

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The structural evolution of the carbonate platform in the footwall of the Semail ophiolite emplaced onto the passive continental margin of Arabia helps to better understand the early stages of obduction‐related orogens. These early stages are rarely observable in other orogens as they are mostly overprinted by later mountain building phases. We present an extensive structural analysis of the Jebel Akhdar anticline, the largest tectonic window of the Oman Mountains, and integrate it on different scales. Outcrop observations can be linked to plate motion data, providing an absolute timeframe for structural generations consistent with radiometric dating of veins. Top‐to‐S overthrusting of the Semail ophiolite and Hawasina nappes onto the carbonate platform during high plate convergence rates between Arabia and Eurasia caused rapid burial and overpressure, generation and migration of hydrocarbons, and bedding‐confined veins, but no major deformation in the carbonate platform. At reduced convergence rates, subsequent tectonic thinning of the ophiolite took place above a top‐to‐NNE, crustal‐scale ductile shear zone, deforming existing veins and forming a cleavage in clay‐rich layers in early Campanian times. Ongoing extension occurred along normal‐ to oblique‐slip faults, forming horst‐graben structures and a precursor of the Jebel Akhdar dome (Campanian to Maastrichtian). This was followed by NE‐SW oriented ductile shortening and the formation of the Jebel Akhdar dome, deforming the earlier structures. Thereafter, exhumation was associated with low‐angle normal faults on the northern flank of the anticline. We correlate the top‐to‐NNE crustal‐scale shear zone with a similar structure in the Saih Hatat window to develop a unified model of the tectonic evolution of the Oman Mountains.

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The transition from a passive margin to an Upper Cretaceous foreland basin related to ophiolite emplacement in the Oman Mountains

Cited by 147 publications

References 0 publications

The Jurassic–Cretaceous depositional and tectonic evolution of the southernwestern margin of the Neotethys Ocean, Northern Oman and United Arab Emirates

The Jurassic–Cretaceous depositional and tectonic evolution of the southernwestern margin of the Neotethys Ocean, Northern Oman and United Arab Emirates

Complex fault-fold interactions during the growth of the Jabal Qusaybah anticline at the western tip of the Salakh Arch, Oman

Multiphase Structural Evolution of a Continental Margin During Obduction Orogeny: Insights From the Jebel Akhdar Dome, Oman Mountains

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