Duality of magmatism in the plutonic sequence of the Sumail Nappe, Oman

Juteau, Thierry; Ernewein, Michelle; Reuber, I.; Whitechurch, Hubert; Dahl, Richard

doi:10.1016/0040-1951(88)90243-0

Cited by 125 publications

(120 citation statements)

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“…The layered gabbros are often ductiley deformed (foliated or boudinaged), possibly in response to syn-magmatic extension of the nascent crust. This has been documented in Troodos [Malpas, 1990], Oman [Juteau et al, 1988a;Juteau et al, 1988b;Nicolas, 1992], and California [Shervais and Beaman, 1991]. This deformation is rarely seen in later magmatic series so it must relate to the extremely rapid early extension of the SSZ crust.…”

Section: Life Cycle Of Ssz Ophiolitesmentioning

confidence: 95%

“…(Table 2). These rocks intrude the older plutonic section of layered and foliated gabbro, in places forming thin sills intruded parallel to the older layering and elsewhere forming stocks and dikes that clearly crosscut the older layering and foliation (e.g., Oman [Ernewein et al, 1988;Juteau et al, 1988a;Juteau et al, 1988b]; Troodos [Laurent, 1992;Malpas, 1990]; Coast Range ophiolite [Evarts et al, 1999;Hopson and Frano, 1977;Shervais and Beaman, 1991]; Bay of Islands [Bedard and Hebert, 1996;). Age relations relative to the older layered gabbros are shown by xenoliths of the older rocks in the younger intrusions, by intrusive contacts that crosscut layering and foliation in the older rocks, and by the lack of fabric in the younger rocks.…”

Section: Stage 2: Youthmentioning

confidence: 99%

“…gabbros of the lower crust [Benn et al, 1988;Browning, 1984;Ernewein et al, 1988;Juteau et al, 1988a;Juteau et al, 1988b;Pallister and Hopson, 1981]. Basalts of the Geotimes unit (along with most of the sheeted dike complex) have been attributed to formation at a mid-ocean spreading axis because they resemble MORB in many aspects of their geochemistry.…”

Section: Gc000080mentioning

confidence: 99%

“…[51] Gabbros associated with the stage 1 magma series are layered on a centimetric to decimetric scale, with layers defined by variations in modal proportions, by the appearance or loss of a cumulus phase, and by variations in the size of the cumulus crystals [Benn et al, 1988;Browning, 1984;Ernewein et al, 1988;Juteau et al, 1988aJuteau et al, , 1988bPallister and Hopson, 1981]. The layers display both synmagmatic deformation textures (e.g., ductile normal faults with amphibolite facies minerals [Ernewein et al, 1988;Lippard et al, 1986]) and subsolidus ductile deformation (Figure 8a).…”

Section: Gc000080mentioning

confidence: 99%

“…3. The common occurrence of refractory, second stage melts with high MgO (more olivine in source), high silica (more enstatite in source), and high LILE (slab component added with aqueous fluids or melts expelled from the subducting slab) [Crawford et al, 1989;Ernewein et al, 1988;Juteau et al, 1988aJuteau et al, , 1988bMalpas, 1990;Robinson and Malpas, 1990]. 4.…”

Section: Introductionmentioning

confidence: 99%

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Birth, death, and resurrection: The life cycle of suprasubduction zone ophiolites

Shervais

2001

Geochem Geophys Geosyst

460

275

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[1] Abstract: Suprasubduction zone (SSZ) ophiolites display a consistent sequence of events during their formation and evolution that suggests that they form in response to processes that are common to all such ophiolites. This sequence includes the following: (1) birth, which entails the formation of the ophiolite above a nascent or reconfigured subduction zone; this stage is typically characterized by the eruption of arc tholeiite lavas and the formation of layered gabbros and sheeted dike complex; (2) youth, during which is continued melting of refractory asthenosphere (depleted during birth) occurs in response to fluid flux from the subducting slab, with extensional deformation of the older plutonic suite, eruption of refractory lavas, and the intrusion of wehrlite-pyroxenite; (3) maturity, with the onset of semistable arc volcanism, typically calc-alkaline, as the subduction zone matures and stabilizes, and the intrusion of quartz diorite and eruption of silicic lavas; and (4) death, which is the sudden demise of active spreading and ophiolite-related volcanism, which in many cases is linked to collision with an active spreading center and the onset of shallow underthrusting of the buoyant spreading axis; expressed as dikes and lavas with oceanic basalt compositions that crosscut or overlie rocks of the older suites; (5) resurrection, with emplacement by obduction onto a passive margin or accretionary uplift with continued subduction. The early stages (1± 3) may be diachronous, and each stage may overlap in both time and space. The existence of this consistent progression implies that ophiolite formation is not a stochastic event but is a natural consequence of the SSZ tectonic setting.

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Section: Life Cycle Of Ssz Ophiolitesmentioning

confidence: 95%

Section: Stage 2: Youthmentioning

confidence: 99%

Section: Gc000080mentioning

confidence: 99%

Section: Gc000080mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Birth, death, and resurrection: The life cycle of suprasubduction zone ophiolites

Shervais

2001

Geochem Geophys Geosyst

460

275

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Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Chavagnac

Ceuleneer

Monnin

et al. 2013

Geochem Geophys Geosyst

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[1] We report on the mineralogical assemblages found in the hyperalkaline springs hosted on Liguria and Oman ophiolites based on exhaustive X-ray diffraction and scanning electron microprobe analyses. In Liguria, hyperalkaline springs produce a thin brownish calcite precipitate that covers the bedrock due to the concomitant atmospheric CO 2 uptake and neutralization of the hyperalkaline waters. No brucite and portlandite minerals are observed. The discharge of alkaline waters in Oman ophiolite forms white-orange precipitates. Calcium carbonate minerals (calcite and/or aragonite) are the most abundant and ubiquitous precipitates and are produced by the same mechanism as in Liguria. This process is observed as a thin surface crust made of rhombohedral calcite. Morphological features of aragonite vary from needle-, bouquet-, dumbbell-, spheroidal-like habitus according to the origin of carbon, temperature, and ionic composition of the hyperalkaline springs, and the biochemical and organic compounds. Brucite is observed both at hyperalkaline springs located at the thrust plane and at the paleo-Moho. The varying mixing proportions between the surface runoff waters and the hyperalkaline ones control brucite precipitation. The layered double hydroxide minerals occur solely in the vicinity of hyperalkaline springs emerging within the bedded gabbros. Finally, the dominant mineralogical associations we found in Oman (Ca-bearing carbonates and brucite) in a serpentinizing environment driven by the meteoric waters are surprisingly the same as those observed at the Lost City hydrothermal site in a totally marine environment.

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Intrusive lherzolites within the basalts of Küre ophiolite (Turkey): an occurrence in the Tethyan suprasubduction marginal basin

Çakir

Genç

Paktunç³

2006

Geological Journal

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The Küre ophiolite is interpreted as the remnants of the suprasubduction marginal basin formed on the northwardly subducted Tethyan oceanic lithosphere. The Küre Basin was opened during late Late Triassic and closed during late Middle Jurassic.Intrusive lherzolites cut the lower part of the basalts forming the volcanic upper unit of the Küre ophiolite. Lherzolites occur in tabular form with hectometric dimensions and have a massive character. High temperature metamorphic effects were developed in the wallrock along a zone a few metres thick. The lherzolite is relatively fresh and displays poikilitic texture where subhedral and anhedral olivines are included in large pyroxenes. The primary mineral paragenesis of the lherzolite is represented by olivine and chromite as early cumulus phases. Diopside, bronzite and plagioclase are the late igneous minerals. Hornblende and titanite formed during the late stage of crystallization at the expense of clinopyroxene. Serpentine minerals, phlogopite and hydrogrossular are the secondary minerals formed at the expense of olivine, bronzite and diopside. Tremolite, actinolite, chlorite and sericite are the late alteration products of the lherzolite.High temperature and low pressure conditions are indicated based on the mineral compositions. The crystallization temperature of the olivine and chromite is estimated to be 1015-1070 C, and that of the pyroxenes, the last crystallized primary minerals, around 900-950 C. The solidification of the magma was completed in the lower part of the basalts, at a depth of c. 2.7 km. The Küre lherzolite has a very high oxygen fugacity indicating an oxidized arc magma origin. The magma rose as a crystal mush and intruded the basalts. The generation of the parental magma may be explained by extensive melting of the upper mantle, facilitated by the presence of hydrous fluids released from the subducted Tethyan oceanic lithosphere.

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Duality of magmatism in the plutonic sequence of the Sumail Nappe, Oman

Cited by 125 publications

References 19 publications

Birth, death, and resurrection: The life cycle of suprasubduction zone ophiolites

Birth, death, and resurrection: The life cycle of suprasubduction zone ophiolites

Mineralogical assemblages forming at hyperalkaline warm springs hosted on ultramafic rocks: A case study of Oman and Ligurian ophiolites

Intrusive lherzolites within the basalts of Küre ophiolite (Turkey): an occurrence in the Tethyan suprasubduction marginal basin

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