On the tectonic regimes of ophiolite genesis

Upadhyay, H. D.; Neale, E R W

doi:10.1016/0012-821x(79)90158-4

Cited by 40 publications

(10 citation statements)

References 34 publications

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“…Such calcalkaline components, occurring as volcaniclastic andesites stratigraphically above ophiolites, are recorded elsewhere (Upadhyay & Neale 1979;Alabaster et al 1980). In the Matakaoa Volcanics at East Cape, Strong (1976a, b; has described fossiliferous sediments with ages of late Early Cretaceous and EarlyMiddle Eocene.…”

Section: K-ar Ages Of the Opidolitesmentioning

confidence: 93%

Obducted ophiolites of North Island, New Zealand: Origin, age, emplacement and tectonic implications for Tertiary and Quaternary volcanicity

Delaloye¹

1982

New Zealand Journal of Geology and Geophysics

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Igrieous massifs in Northland and EastCape contain disrupted ophiolite sequences (pillow lavas, sheeted dikes, noncumulate and cumulate gabbros) with low-grade metamorphic assemblages. Sediments associated with pillow lavas, or as cappings on individual massifs, have fossils ranging in age from Early Cretaceous to Early Miocene. KAr ages extend from 102 to 20 Ma; an isochron age at 33.6 ± 2.1 Ma reflects argon homogenisation by plate boundary deformation at the ophiolite sites prior to obduction of the disrupted massifs during the Late Oligocene-Early Miocene. The compatibility of the fossil and radiometric ages, and the diversity of rock types (tholeiitic to alkali basalt and alkaline syenite), indicate long-continued igneous activity at localised seamounts along a nonconvergent plate boundary (transform zone) which was situated off the northeast coast of North Island and extended at least from near North Cape to East Cape. Obduction was from northeast to southwest by gravity sliding of the dismembered seamounts upon an autochthonous substrate of Permo-Jurassic greywackes and Cretaceous-Oligocene sediments. The obductive event also marked the start of midTertiary calcalkaline volcanicity in North Island. Obductive overriding of the transform zone during the latest Oligocene-earliest Miocene produced andesites along the Northland east coast, but Early Miocene-Quaternary calcalkaline belts were oriented northeast-southwest with a decreasing age for volcanism towards the Taupo Volcanic Zone. Regional tensional rifts in the latest Pliocene or Quaternary followed northwest-southeast trends.

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Section: K-ar Ages Of the Opidolitesmentioning

confidence: 93%

Obducted ophiolites of North Island, New Zealand: Origin, age, emplacement and tectonic implications for Tertiary and Quaternary volcanicity

Delaloye¹

1982

New Zealand Journal of Geology and Geophysics

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“…However, the oldest preserved Appalachian ophiolites barely exceed 500 m.y. (Mattinson, 1975(Mattinson, , 1976, and most seem to have formed in the vicinity of island arcs (Upadhyay and Neale, 1979). Since there is no contemporary volcanism or plutonism to suggest subduction beneath the North American miogeocline, then the island arcs and coeval ophiolites must have evolved elsewhere.…”

Section: Suspect Terranes Above the North American Miogeoclinementioning

confidence: 99%

Appalachian suspect terranes

Williams

Hatcher²

1983

Geological Society of America Memoirs

281

135

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Since the advent of plate tectonics, the widely accepted model for the development of the Appalachian orogen has involved the opening and closing of a late Precambrian-Paleozoic Iapetus Ocean. Only a few of a growing number of geologically distinctive terranes are easily explained by this model. Vestiges of Iapetus are nowhere coupled to the ancient North American margin. Furthermore, it cannot be demonstrated that any of the extensive Appalachian terranes, now east of the Iapetus tract or its suture, were once connected to the North American miogeocline. All are therefore suspect.The major suspect terranes of the Appalachian orogen are in most respects analogous to previously recognized zones or tectonic lithofacies belts. In the north, these are the Dunnage, Gander, Avalon, and Meguma terranes. In the south, they include easterly parts of the Blue Ridge, the Piedmont, Slate Beit, and the geophysically distinctive Brunswick and Tallahassee-Suwannee terranes beneath the Atlantic Coastal Plain. Most of these are composite and include smaller terranes of uncertain paleogeography. Taconic allochthons are included because they fit the definition of suspect terranes.Stratigraphic and sedimentologic analyses indicate that the Appalachian orogen built up during three major Paleozoic accretionary events. Their timing coincides with the times of structural, metamorphic, and plutonic effects assigned to the Taconian, Acadian, and Alleghanian orogenies.Accretion of the Appalachian orogen progressed from the North American miogeocline outward. The boundaries of the earliest accreted western terranes are marked by melange zones and ophiolite complexes, implying head-on collisions. Later boundaries between eastern terranes are steep mylonite zones and brittle faults, implying oblique movements.The suspect terrane concept, first developed for the North American Cordilleran, provides new insights into the evolution of the Appalachian orogen and solves several enigmas. It is a surgically clean analytical approach and a superior framework in which to view the anatomy of any complex orogen. 33 on May 15, 2015 memoirs.gsapubs.org Downloaded from

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“…Miyashiro 1973;Pearce et al 1984) and/or they have thick volcanogenic sediments of arc origin (e.g. Upadhyay & Neale 1979). Combined with the presence of well-developed sheeted dyke complexes indicative of a spreading ridge, a spreading centre above a subduction zone (i.e.…”

mentioning

confidence: 99%

“…Combined with the presence of well-developed sheeted dyke complexes indicative of a spreading ridge, a spreading centre above a subduction zone (i.e. a back-arc basin) is favoured as a locus for the genesis of such SSZ ophiolites (Upadhyay & Neale 1979;Moores et al 1984;Pearce et al 1984). The Oman ophiolite ( Fig.…”

mentioning

confidence: 99%

Widespread arc-related melting in the mantle section of the northern Oman ophiolite as inferred from detrital chromian spinels

Arai

Kadoshima

Morishita

2006

JGS

166

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We examined detrital chromian spinels, in recent river beds, derived from the mantle section to deterrmine whether the mantle peridotite of the northern Oman ophiolite is of oceanic or arc origin. The Crnumber (¼ Cr/(Cr þ Al) atomic ratio) of the detrital chromian spinels mostly ranges from 0.4 to 0.8, and more than 60% of them have Cr-numbers higher than 0.6. This indicates a significant extent of island-arc nature because chromian spinels seldom have Cr-numbers higher than 0.6 in ocean-floor rocks. The high-Crnumber (.0.6) spinels, which are also low in TiO 2 (,0.3 wt%), are probably derived from an arc setting. Lherzolite with spinel Cr-numbers ,0.2 is absent except near the base of the section. The high-Cr-number detrital chromian spinels are more abundant from the mantle section with more frequent discordant dunite pods. Post-deformational discordant dunite and adjacent harzburgite include the high-Cr-number spinels in outcrops. The upper mantle of the northern Oman ophiolite was formed at a fast-spreading ridge and was later modified by island-arc magmatism in a subduction-zone environment. This switch of tectonic setting from a mid-oceanic ridge to an island arc is essential in the explanation of obduction of a slice of oceanic lithosphere onto a continental margin as an ophiolite.

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On the tectonic regimes of ophiolite genesis

Cited by 40 publications

References 34 publications

Obducted ophiolites of North Island, New Zealand: Origin, age, emplacement and tectonic implications for Tertiary and Quaternary volcanicity

Obducted ophiolites of North Island, New Zealand: Origin, age, emplacement and tectonic implications for Tertiary and Quaternary volcanicity

Appalachian suspect terranes

Widespread arc-related melting in the mantle section of the northern Oman ophiolite as inferred from detrital chromian spinels

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