Finds of young and ancient zircons in gabbroids of the Markov Deep, Mid-Atlantic Ridge, 5°54′–5°02.2′ N (Results of SHRIMP-II U-Pb Dating): Implication for deep geodynamics of modern oceans

2008 ◽  
Vol 421 (1) ◽  
pp. 859-866 ◽  
Author(s):  
N. S. Bortnikov ◽  
E. V. Sharkov ◽  
O. A. Bogatikov ◽  
T. F. Zinger ◽  
E. N. Lepekhina ◽  
...  
Keyword(s):  
Mid Atlantic Ridge ◽  
Markov Deep

scholarly journals 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)

2019 ◽  
Vol 10 (1) ◽  
pp. 101-121
Author(s):  
E. V. Sharkov
Keyword(s):  
Lithospheric Mantle ◽  
Lower Crust ◽  
Structural Element ◽  
Polar Urals ◽  
Magma Sources ◽  
Mid Atlantic Ridge ◽  
Tectonic Development ◽  
Slow Spreading ◽  
Back Arc ◽  
Markov Deep

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.

Hydrothermal alteration and sulfide mineralization in gabbroids of the Markov Deep (Mid-Atlantic Ridge, 6° N)

2007 ◽  
Vol 49 (6) ◽  
pp. 467-486 ◽  
Author(s):  
E. V. Sharkov ◽  
S. S. Abramov ◽  
V. A. Simonov ◽  
D. I. Krinov ◽  
S. G. Skolotnev ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Sulfide Mineralization ◽  
Mid Atlantic Ridge ◽  
Markov Deep

Zircon in gabbroids from the axial zone of the Mid-Atlantic ridge, Markov Deep, 6° N: Correlation of geochemical features with petrogenetic processes

Petrology ◽  
2013 ◽  
Vol 21 (1) ◽  
pp. 1-15 ◽  
Author(s):  
L. Ya. Aranovich ◽  
T. F. Zinger ◽  
N. S. Bortnikov ◽  
E. V. Sharkov ◽  
A. V. Antonov
Keyword(s):  
Axial Zone ◽  
Mid Atlantic Ridge ◽  
Markov Deep

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

2006 ◽  
Vol 44 (11) ◽  
pp. 1105-1120 ◽  
Author(s):  
G. N. Savel’eva ◽  
N. S. Bortnikov ◽  
A. A. Peyve ◽  
S. G. Skolotnev
Keyword(s):  
Rift Valley ◽  
Ultramafic Rocks ◽  
Mid Atlantic Ridge ◽  
Markov Deep

Acoustic Reverberation at Selected Sites in the Mid-Atlantic Ridge Region,

1993 ◽  
Author(s):  
Jerald W. Caruthers ◽  
J. R. Fricke ◽  
Ralph A. Stephen
Keyword(s):  
Mid Atlantic Ridge ◽  
Acoustic Reverberation

The age of magmatic and metamorphic events in the Mid-Atlantic Ridge: interpretation of K-Ar isotope dating data

2001 ◽  
Vol 2 (3) ◽  
pp. 269-278
Author(s):  
S. A. Silantiev ◽  
L. K. Levskiy ◽  
M. M. Arakelyants ◽  
V. A. Lebedev ◽  
A. Bugo ◽  
...  
Keyword(s):  
Mid Atlantic Ridge ◽  
Isotope Dating

PRELIMINARY FORESHOCK ANALYSIS OF SUBMARINE TRANSFORM FAULT EARTHQUAKES ALONG THE EQUATORIAL MID-ATLANTIC RIDGE

2016 ◽  
Author(s):  
Ross P. Meyer ◽  
◽  
Joe H. Haxel ◽  
Robert P. Dziak ◽  
Deborah K. Smith
Keyword(s):  
Transform Fault ◽  
Mid Atlantic Ridge

scholarly journals Geochemical Fractions of Heavy Metals in Bottom Sediments of the Pobeda Hydrothermal Field, Mid-Atlantic Ridge (17°07′–17°08′ N)

2021 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
Liudmila Demina ◽  
Irina Gablina ◽  
Olga Dara ◽  
Dmitry Budko ◽  
Nina Gorkova ◽  
...  
Keyword(s):  
Total Content ◽  
Element Distribution ◽  
Hydrothermal Field ◽  
Residual Fraction ◽  
Carbonate Sediments ◽  
Metalliferous Sediments ◽  
Geochemical Fractions ◽  
Metalliferous Sediment ◽  
Fe And Mn ◽  
Mid Atlantic Ridge

We examined the distribution of Fe, Mn, Cu, Zn, and Pb in one core of metalliferous, and one core of non-mineralized (background) carbonate sediments (located 69 km northwards), from the Pobeda hydrothermal field. Mechanisms of metal accumulation in sediments (12 samples) were evaluated based on sequential extraction of geochemical fractions, including mobile (exchangeable complex, authigenic Fe-Mn hydroxides, and sulfides), and lithogenic (fixed in crystalline lattices) forms. Maps of element distribution in sediment components were obtained using a scanning electron microscope equipped with an energy-dispersive spectrometry detector. In metalliferous sediments, according to X-ray diffraction data, the main Fe mineral phase was goethite FeOOH (37–44% on a carbonate-free basis). The contents of Fe and Mn reached 31.6 and 0.18%, respectively, whereas concentrations of Cu, Zn and Pb were 0.98, 0.36, and 0.059%. The coefficient of metal enrichment relative to background values varied from 16 to 125 times. The exception was Mn, for which no increased accumulation was recorded. Essential mass of Fe (up to 70% of total content) was represented by the residual fraction composed of crystallized goethite, aluminosilicates, the minerals derived from bedrock destruction processes. Among geochemically mobile fractions, 90–97% of total Fe was found in the form of authigenic oxyhydroxides. The same fraction was the predominant host for Mn in both metalliferous and background sediments (55–85%). A total of 40–96 % of Cd, Cu, Zn, and Pb were associated with these Fe and Mn fractions. The sulfide fraction amounted to roughly 10% of each metal. In metalliferous sediment core, the maximum concentrations of metals and their geochemically mobile fractions were recorded in deeper core intercepts, an observation that might be attributed to influence of hydrothermal diffused fluids. Our data suggested that metals are mostly accumulated in carbonate sediments in their contact zone with the underlying serpentinized basalts.

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