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.

scholarly journals A thin mantle transition zone beneath the equatorial Mid-Atlantic Ridge

Nature ◽  
2021 ◽  
Vol 589 (7843) ◽  
pp. 562-566
Author(s):  
Matthew R. Agius ◽  
Catherine A. Rychert ◽  
Nicholas Harmon ◽  
Saikiran Tharimena ◽  
J.-Michael Kendall
Keyword(s):  
Transition Zone ◽  
Mantle Transition Zone ◽  
Mid Atlantic Ridge

scholarly journals Microbial ecology of the newly discovered serpentinite-hosted Old City hydrothermal field (southwest Indian ridge)

2020 ◽  
Author(s):  
Aurélien Lecoeuvre ◽  
Bénédicte Ménez ◽  
Mathilde Cannat ◽  
Valérie Chavagnac ◽  
Emmanuelle Gérard
Keyword(s):  
Microbial Ecology ◽  
New Caledonia ◽  
Southwest Indian Ridge ◽  
Hydrothermal Field ◽  
Metagenomic Sequencing ◽  
Lost City ◽  
Old City ◽  
Mid Atlantic Ridge ◽  
Indian Ridge ◽  
Geochemical Analyses

Abstract Lost City (mid-Atlantic ridge) is a unique oceanic hydrothermal field where carbonate-brucite chimneys are colonized by a single phylotype of archaeal Methanosarcinales, as well as sulfur- and methane-metabolizing bacteria. So far, only one submarine analog of Lost City has been characterized, the Prony Bay hydrothermal field (New Caledonia), which nonetheless shows more microbiological similarities with ecosystems associated with continental ophiolites. This study presents the microbial ecology of the ‘Lost City’-type Old City hydrothermal field, recently discovered along the southwest Indian ridge. Five carbonate-brucite chimneys were sampled and subjected to mineralogical and geochemical analyses, microimaging, as well as 16S rRNA-encoding gene and metagenomic sequencing. Dominant taxa and metabolisms vary between chimneys, in conjunction with the predicted redox state, while potential formate- and CO-metabolizing microorganisms as well as sulfur-metabolizing bacteria are always abundant. We hypothesize that the variable environmental conditions resulting from the slow and diffuse hydrothermal fluid discharge that currently characterizes Old City could lead to different microbial populations between chimneys that utilize CO and formate differently as carbon or electron sources. Old City discovery and this first description of its microbial ecology opens up attractive perspectives for understanding environmental factors shaping communities and metabolisms in oceanic serpentinite-hosted ecosystems.

scholarly journals The Condor seamount at Mid-Atlantic Ridge as a supplementary source of trace and rare earth elements to the sediments

2013 ◽  
Vol 98 ◽  
pp. 24-37 ◽  
Author(s):  
Miguel Caetano ◽  
Carlos Vale ◽  
Bárbara Anes ◽  
Joana Raimundo ◽  
Teresa Drago ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Mid Atlantic Ridge ◽  
Condor Seamount
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