Ultramafic rocks from the Markov Deep in the rift valley of the Mid-Atlantic Ridge

Savel'eva, G. N.; Бортников, Н. С.; Peyve, A. A.; Skolotnev, S. G.

doi:10.1134/s0016702906110024

Cited by 6 publications

(6 citation statements)

References 19 publications

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“…Спектр драгированных во впадине Маркова пород описан во многих публикациях [Pushcharovsky et al, 2004;Sharkov et al, 2005Sharkov et al, , 2007Sharkov et al, , 2008Savel'eva et al, 2006;и др. ] и весьма обычен для ВОК медленноспрединговых хребтов.…”

Section: строение нижней коры срединно-атлантического хребта (на примunclassified

“…1. Катаклазированные серпентинизированные ультрабазиты (преимущественно гарцбургиты, реже дуниты и лерцолиты), в основном мантийные реститы, а также кумулаты (некоторые дуниты) [Savel'eva et al, 2006]. Было драгировано несколько образцов, в которых ультрабазиты не подверглись серпентинизации, сохранились их структуры и минеральный состав (рис.…”

Section: строение нижней коры срединно-атлантического хребта (на примunclassified

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The Origin and Structure of the Lower Crust of Oceans and Back-Arc Seas: Evidence From the Markov Deep (Mid-Atlantic Ridge) and the Voikar Ophiolite Association (Polar Urals)

Шарков

2019

Geodin. tektonofiz.

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The Markov Deep (the axial part of the slow-spreading Mid-Atlantic Ridge, 6°N, Sierra Leone oceanic core complex) and the Paleozoic Voikar ophiolite association (Polar Urals) formed in the back-arc sea conditions. In both cases, the lower crust of a close structure was formed on the basements composed ofdepleted peridotites of the ancient lithospheric mantle. The available data show that the composition of the lower crust of the oceans and back-arc seas is dominated by layeredmafic-ultramafic intrusions originating from the MORB melts, and suggest a similar asthenospheric source of magmas. Sills and dykes formed from other magma sources represent the second structural element of the lower oceanic crust: in case of the ocean, mainly ferrogabbroids originating from specific melts with the OIB involvement, and, in case of the back-sea sea, gabbro-norites of the supra-subduction calc-alkaline series. In both cases, the upper crust originates frombasaltic flows that occurred later and are associated with new episodes in the tectonic development. According to [Sharkov,2012], the development of slow-spreading ridges takes place in discrete impulses and non-simultaneously along their entire length. Furthermore, oceanic core complexes (OCC) in their axial parts are the ridge segments, where spreading is resumed. At the OCC stage, newly formed basalt melts move upwards from the magma generation zone into fractures (dykes) through the lithospheric mantle, and the thickness of the lower crust is built up by sills. As spreading develops in this area, the crust becomes thicker from below due to underplating in form of large layered intrusions. The newly formed restites, in their turn, cause an increase in the lithospheric mantle thickness from below. Apparently, the lower crust formed in the back-arc seas according to a similar scenario, although complicated by the processes taking place in the subduction zone.

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Section: строение нижней коры срединно-атлантического хребта (на примunclassified

The Origin and Structure of the Lower Crust of Oceans and Back-Arc Seas: Evidence From the Markov Deep (Mid-Atlantic Ridge) and the Voikar Ophiolite Association (Polar Urals)

Шарков

2019

Geodin. tektonofiz.

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“…Strongly serpentinized mantle peridotites, like in the most ophiolites including Voikar's, represented here by typical mantle restites -harzburgites and subordinate depleted lherzolite and dunites (Savelieva et al, 2006). Some of these peridotites, judging on rare good preserved samples, have cataclastic structure (Fig.…”

Section: Origin Of Lower Oceanic Crust: Evidence From Sierra Leone Areamentioning

confidence: 99%

“…The spectrum of dredged rocks at the area is typical for slow-spreading ridges (Sharkov et al, 2005. Savelieva et al, 2006):…”

Section: Dredged Rocks From the Sierra Leone Areamentioning

confidence: 99%

“…Such work was done on example of Sierra Leone area, located in axis of the MAR (5-7°N). It was based on materials dredged during the cruises of R/V "Akademik Ioffe" (10th cruise, [2001][2002] and "Professor Logachev" (22th cruise, 2003) (Sharkov et al, 2005(Sharkov et al, , 2007Savelieva et al, 2006;Simonov et al, 2009;Aranovich et al, 2010). Judging on presence here of serpentinites upon mantle peridotites and altered tectonized lower-crustal gabbros, as well as widespread development of extensional structures, including normal faults, the Sierra Leone area can be determined as OCC.…”

Section: Tectonics -Recent Advancesmentioning

confidence: 99%

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Cyclic Development of Axial Parts of Slow-Spreading Ridges: Evidence from Sierra Leone Area, the Mid-Atlantic Ridge, 5-7°N

Шарков¹

2012

Tectonics - Recent Advances

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Composition and inner structure of the third layer in the oceanic crust in the subequatorial segment of the Mid-Atlantic Ridge (5°–7° N)

Skolotnev

Eskin

2013

Geochem. Int.

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Ultramafic rocks from the Markov Deep in the rift valley of the Mid-Atlantic Ridge

Cited by 6 publications

References 19 publications

The Origin and Structure of the Lower Crust of Oceans and Back-Arc Seas: Evidence From the Markov Deep (Mid-Atlantic Ridge) and the Voikar Ophiolite Association (Polar Urals)

The Origin and Structure of the Lower Crust of Oceans and Back-Arc Seas: Evidence From the Markov Deep (Mid-Atlantic Ridge) and the Voikar Ophiolite Association (Polar Urals)

Cyclic Development of Axial Parts of Slow-Spreading Ridges: Evidence from Sierra Leone Area, the Mid-Atlantic Ridge, 5-7°N

Composition and inner structure of the third layer in the oceanic crust in the subequatorial segment of the Mid-Atlantic Ridge (5°–7° N)

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